Additive PCB Prototyping

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Electroluminescent Displays

Flexible Membrane Switches

Functional Ink Development

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Prototype custom flexible PCBs entirely in-house

Solder Paste Printing

Wearable Flexible Electronics

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<figure class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/UhzsusIzwY0"><div><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/UhzsusIzwY0" title="Developing a Custom Carbon Ink for Printing a Variable Resistor on PET | Functional Ink Development"></iframe></div></figure><h2 id="">Project overview</h2><h3 id="">Purpose</h3><p id="">In this project, we demonstrate the development of a carbon resistive ink through testing different ink formulations and validating the performance through a potentiometer and an LED circuit.&nbsp;</p><h3 id="">Design</h3><p id="">We divided the design into four parts:</p><ol id=""><li id="">Developing the carbon resistive ink</li><li id="">Printing the potentiometer circuit&nbsp;</li><li id="">Printing the LED circuit</li><li id="">3D printing the enclosure with a sliding wiper</li></ol><h3 id="">Desired outcome</h3><p id="">The goal was to develop an ink with great printability, which, for this project, we measured by viscosity (between 1,000–10,000 cPs, compatible with <a href="https://www.voltera.io/blog/introduction-direct-ink-writing-printing-technology" id="">direct ink writing</a> and <a href="https://www.voltera.io/blog/introduction-screen-printing" id="">screen printing</a>). We also aimed to achieve excellent adhesion to the substrate, with no flaking or cracking after curing at 90°C for 5 minutes. In addition, the ink should support a potentiometer to function properly, which means the resistance range should fall between 600 Ω to 6000 Ω.</p><h3 id="">Functionality</h3><p id="">When connected to the LED dimmer board (powered by a 9V battery), sliding the wiper altered the potentiometer’s resistance, dimming or brightening three LEDs. Resistivity was tunable by adjusting carbon concentration, curing time and temperature, or printing thicker or shorter traces.&nbsp;</p><p id="">While this formulation served as a functional prototype, higher carbon loadings (up to 20%) could be explored for enhanced conductivity, though viscosity adjustments would be necessary to maintain printability. Users can also change resistance by modifying the size of the conductive pad.</p><h2 id="">Developing the carbon resistive ink*</h2><p id="">The development of custom functional inks, whether conductive, dielectric, resistive, or semiconducting, requires balancing particle loading, solvent compatibility, and binder selection to achieve target electrical and mechanical properties. While conductive inks rely on metallic particles like silver for low resistivity, resistive inks prioritize tunable compositions.</p><p id="">Guided by these principles, we formulated a carbon-based resistive ink using carbon black for its cost-effectiveness and moderate conductivity, paired with PVP as a binder to enhance particle dispersion and substrate adhesion. The solvent blend, 2-(2-butoxyethoxy)ethyl acetate and ethanol, balanced evaporation rates and ink stability, critical for nozzle performance and film uniformity. Our iterative testing refined these ratios for compatibility with NOVA and the intended application.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db234e8478c9ccd60dab3b_developing-custom-carbon-ink-voltera-applications.webp" loading="lazy" alt="An image showing a cartridge of carbon resistive ink from two angles" width="auto" height="auto" id=""></div><figcaption id="">Carbon resistive ink developed by Voltera’s Applications team</figcaption></figure><p id="">We started by dissolving 1.04 g of PVP into 4.88 g of ethanol using a magnetic stirrer at 1,500 rpm for 15 minutes. We then added 0.48 g of carbon black to the PVP-ethanol solution to minimize airborne particles, followed by the dropwise incorporation of 1.6 g of 2-(2-butoxyethoxy)ethyl acetate. We stirred the mixture for an additional 15 minutes under parafilm to prevent solvent evaporation, which resulted in a stable, homogenous ink.&nbsp;</p><p id="">The final composition included 13% PVP as a binder, 6% carbon black for conductivity, 20% 2-(2-butoxyethoxy)ethyl acetate as a solvent, and 61% ethanol to stabilize the dispersion. This combination achieved a viscosity of about 1,500 cps, enabling smooth dispensing through the Nordson EFD 7018333 dispensing tip with an inner diameter of 250 µm.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67db28aab0e1d42fef0ef690_Applications_custom%20carbon%20ink%20white%20paper%20table%201.txt[/script]</p><p id="">Final ink formulation**</p><p id="">* Follow the guidelines in the safety data sheet when handling the carbon black powder.</p><p id="">** The formulation in the table is for an 8 g resistive ink and is scalable using the provided weight percentages.&nbsp;</p><h2 id="">Printing the potentiometer circuit</h2><p id="">This circuit consists of two layers:</p><ol id=""><li id="">Bottom conductive layer (in blue): Includes silver traces for solderable contacts, as well as a</li></ol><p id="">conductive pad to be glued onto the wiper of the potentiometer. Sliding the wiper up and down alters the carbon resistor’s effective length and changes the resistance of the circuit.</p><ol start="2" id=""><li id="">Top resistive layer (in red): Carbon traces for the resistive element</li></ol><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db239dba6cb209f70f7f02_developing-custom-carbon-ink-potentiometer-circuit.webp" loading="lazy" alt="An image showing electrical circuit design of the potentiometer" width="auto" height="auto" id=""></div><figcaption id="">Potentiometer circuit design</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67db28ab26e599160ebabfb0_Applications_custom%20carbon%20ink%20white%20paper%20table%202.txt[/script]</p><h3 id="">Bottom conductive layer</h3><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db23f7819e463cd5e89953_developing-custom-carbon-ink-bottom-settings.webp" loading="lazy" alt="An image showing NOVA print settings for the bottom conductive layeru" width="auto" height="auto" id=""></div><figcaption id="">NOVA settings, bottom conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db242b2af9eece9de27ad7_developing-custom-carbon-ink-bottom-result.webp" loading="lazy" alt="An image showing the printed bottom conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Bottom conductive layer, print result</figcaption></figure><h3 id="">Top resistive layer</h3><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67db28aa1064d50441616ae1_Applications_custom%20carbon%20ink%20white%20paper%20table%203.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db2456e5d7bbc0f36c716a_developing-custom-carbon-ink-top-settings.webp" loading="lazy" alt="An image showing NOVA print settings for the top resistive layer" width="auto" height="auto" id=""></div><figcaption id="">NOVA settings, top resistive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db248452fb141c61207543_developing-custom-carbon-ink-final-print.webp" loading="lazy" alt="An image showing the final print with two layers" width="auto" height="auto" id=""></div><figcaption id="">Final print</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db249e1a3d8dfe60437c1f_developing-custom-carbon-ink-wiper-potentiometer.webp" loading="lazy" alt="An image showing a hand holding the wiper of the potentiometer, with conductive traces taped onto it" width="auto" height="auto" id=""></div><figcaption id="">The wiper of the potentiometer</figcaption></figure><h2 id="">Printing the LED dimmer circuit</h2><p id="">This circuit was designed to visually demonstrate resistance changes by linking three LEDs to the potentiometer. Silver traces printed on an FR1 substrate formed conductive pathways, connecting the 9V power input to the potentiometer and LEDs.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db24d234e8c037ad011b37_developing-custom-carbon-ink-led-circuit.webp" loading="lazy" alt="An image showing the electrical circuit design for the LED circuit " width="auto" height="auto" id=""></div><figcaption id="">LED circuit design</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67db28aa124ff9bb6aaaac52_Applications_custom%20carbon%20ink%20white%20paper%20table%204.txt[/script]</p><p id="">Once the circuit was cured, we manually placed and soldered the LEDs and reflowed the solder paste on V-One’s heated bed.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db25512cd2c49c282d4086_developing-custom-carbon-ink-led-circuit.webp" loading="lazy" alt="An image showing the LED circuit, with components mounted and wires connected" width="auto" height="auto" id=""></div><figcaption id="">The LED circuit board, soldered</figcaption></figure><h2 id="">Printing the enclosure</h2><p id="">To house the potentiometer, we designed and 3D-printed a custom enclosure using PLA filament. The enclosure features a built-in sliding wiper mechanism for adjusting resistance and a compartment to securely hold the circuit components. After fabricating the enclosure, we cut the potentiometer circuit from the PET sheet and carefully taped it into the enclosure. Next, we soldered wires to the silver pads on the circuit to establish robust electrical connections.</p><p id="">We then taped the conductive pad onto the wiper to ensure reliable contact with the resistive layer. After placing the wiper inside the enclosure, we twisted it 90 degrees to lock it into place. Finally, we connected the potentiometer to the LED dimmer circuit, which enabled real-time resistance adjustments for LED brightness control.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67db2589712076af076d34d1_developing-custom-carbon-ink-potentiometer-enclosure.webp" loading="lazy" alt="An image showing the potentiometer circuit sitting in an 3D-printed enclosure" width="auto" height="auto" id=""></div><figcaption id="">The potentiometer circuit in the enclosure</figcaption></figure><h2 id="">Challenges and advice</h2><h3 id="">Clogging the nozzle</h3><p id="">During initial ink formulation trials, the carbon black particles aggregated in the solvent, which caused nozzle clogs and led to incomplete traces. After some investigation, we realized that the issue stemmed from insufficient dispersion stability — carbon particles settled unevenly in the solvent, forming dense clusters that blocked the nozzle.&nbsp;</p><p id="">To address this, we introduced PVP as a dispersant and binder. We also adjusted the solvent ratio, reducing the volatile 2-(2-butoxyethoxy)ethyl acetate and increasing ethanol to improve particle suspension. Additionally, we recommend using a dual asymmetric centrifugal mixer to ensure homogeneous ink mixing. Lastly, we recommend using larger nozzles for particle-laden formulations to reduce shear stress during dispensing, as evidenced by better print results produced by the 330 µm nozzle, compared to the 200 µm nozzle.</p><h2 id="">Conclusion</h2><p id="">As our first custom ink project, the bulk of work involved was iterating on ink formulation, trying to find the balance between printability and functionality. Using <a href="https://www.voltera.io/nova" id="">NOVA</a>, we validated a new material in less than a month and created a repeatable process for developing carbon resistive ink. NOVA enabled our materials R&amp;D process by allowing us to get immediate feedback on printability, iterate formulations right on our benchtop, and create novel electronics.</p><p id="">If you’re interested in our other projects involving novel inks, take a look at:</p><ul id=""><li id=""><a href="https://www.voltera.io/use-cases/white-papers/printing-ecg-electrodes-biocompatible-gold-ink-tpu" id="">Printing ECG Electrodes with Biocompatible Gold Ink on TPU&nbsp;</a></li><li id=""><a href="https://www.voltera.io/use-cases/white-papers/printing-rfid-tag-copper-ink-paper" id="">Printing an RFID Tag with Copper Ink on Paper</a></li><li id=""><a href="https://www.voltera.io/use-cases/white-papers/printing-electroluminescent-ink-paper-pet" id="">Printing Electroluminescent Ink on Paper and PET</a></li></ul><p id="">Want to be notified when we post new white papers? <a href="https://share.hsforms.com/1DG3jeG6BRDOZ6o0OGyVv-g34u2a?" id="">Sign up for our newsletter</a>.</p>

Developing a Custom Carbon Ink for Printing a Variable Resistor on PET

Developing your own inks? Check out how we developed a carbon resistive ink for potentiometer applications, using common materials such as carbon black.

custom-ink

<h2 id="">Video</h2><figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/V3AAvR96LYI?si=-aiMy5nN-CMjZ1gD"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/V3AAvR96LYI" title="Dispensing Solder Paste on Factory Fabricated PCBs with V-One"></iframe></div></figure><h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to demonstrate the feasibility of dispensing solder paste on factory fabricated PCBs precisely and reflowing the solder paste automatically.</p><h3 id="">Design&nbsp;</h3><p id="">The board we selected for this project was a PCB used in the module hub of our <a href="https://www.voltera.io/nova" id="">NOVA material dispensing system</a>. Since we designed the board in-house, we had the Gerber file for this project, which we uploaded into V-One’s software.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb5d_671258c82d1ca1651ec702af_Dispensing-solder-paste-design-vone-software.webp" loading="lazy" alt="Gerber file loaded into the V-One software" width="auto" height="auto" id=""></div><figcaption id="">Figure 1:&nbsp;Gerber file loaded into the V-One software</figcaption></figure><h3 id="">Desired outcome</h3><p id="">The solder paste should be evenly dispensed on the designated spots of the FR4 board, with no overflow or voids. Once reflowed, the PCB should fit into the bottom of NOVA’s module hub. When connected to power, this board will allow NOVA to capture images of its work area.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb71_671258e5061699e15bac2a49_Dispensing-solder-paste-desired-outcome.webp" loading="lazy" alt="NOVA sits on a table" width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;Front view of NOVA&nbsp;showing its module hub and work area</figcaption></figure><h3 id="">Functionality</h3><p id="">The PCB contains a camera, LEDs, and other components that enable NOVA to capture images of the printed traces and pads, facilitating examination and ensuring optimal alignment.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb74_67125907059c059c678b235e_Dispensing-solder-paste-functionality.webp" loading="lazy" alt="PCB mounted into NOVA's module hub" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;PCB&nbsp;mounted into NOVA's module hub</figcaption></figure><h2 id="">Preparing V-One</h2><p id="">The V-One software is intuitive and guides you through every step of the PCB prototyping process, including printing, soldering, heating, and drilling. Since the PCB was prefabricated, we didn’t need to print conductive traces or drill through holes. Instead, we followed the <strong id="">SOLDER</strong> workflow.</p><p id="">The software prompted us to add the appropriate solder paste. We selected the T4 solder paste, and were then prompted to load a Gerber file. After loading the file, the software guided us through a quality check.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb60_671259241cd20cf8f41b36eb_Dispensing-solder-paste-preparing-vone.webp" loading="lazy" alt="The print profile for T4 solder paste in the V-One software" width="auto" height="auto" id=""></div><figcaption id="">Figure 4:&nbsp;Profile for T4 solder paste</figcaption></figure><p id="">We cleaned the calibration switches using a few cotton swabs to remove any residual materials from previous use. Next, we clamped the PCB to the heated bed using four thumb screws and two clamps. After ensuring the PCB was securely fastened to the heated bed, we proceeded to probe the PCB.</p><h2 id="">Probing the PCB</h2><p id="">To accurately dispense solder across the PCB surface, V-One first needed to generate a height map. We mounted the probe onto the carriage, and the software prompted us to align the features on the board with the features displayed in the software.</p><p id="">This process was semi-automatic. Our task was to select reference points and adjust the probe's position using the software’s arrow controls. Once we were satisfied with the alignment, V-One began mapping the board's height.</p><p id="">‍</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb5a_6712593cbe4558dee376946f_Dispensing-solder-paste-probing-pcb.webp" loading="lazy" alt="V-One software showing probe points filled in and complete" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;Probed points</figcaption></figure><h2 id="">Dispensing solder paste on the PCB</h2><p id="">We inserted the solder paste into the dispenser slot, attached a disposable nozzle to the tip, and twisted the gear to prime the paste. Once there was a steady flow from the nozzle, we turned the gear back half a turn to slow down the flow and gently mounted the dispenser onto the carriage.</p><p id="">Next, we selected the features we wanted to print in the software, and the dispenser moved to the designated positions to begin dispensing solder paste. Throughout the process, it was easy to adjust the paste flow by clicking the <strong id="">+</strong> and <strong id="">-</strong> buttons in the software.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb81_6712595902d372e84a577814_Dispensing-solder-paste-pcb-vone.webp" loading="lazy" alt="V-One dispensing solder paste" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;V-One dispensing solder paste on PCB</figcaption></figure><h2 id="">Populating the PCB and reflow</h2><p id="">At this stage, the solder workflow was complete. We placed the components onto the board and selected <strong id="">HEAT</strong> &gt; <strong id="">REFLOW</strong> &gt; the T4 solder paste we used in the software. The heated bed started to heat the board automatically. The reflow process will last a few minutes where the solder paste is melted and cured, just like in a reflow oven. Once the board cooled down, we removed the board from V-one and our PCBA was completed.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6712598f7b5b9d33b521fb63_6712597ad3b2768729d082c3_Dispensing-solder-paste-populating-pcb-reflow.webp" loading="lazy" alt="V-One software showing a selection request for which solder paste is being reflowed" width="auto" height="auto" id=""></div><figcaption id="">Figure 7:&nbsp;Choosing solder paste in software</figcaption></figure><h2 id="">Advice for dispensing solder paste</h2><p id="">To ensure optimal performance, it is recommended to take the solder paste out of the refrigerator about 15 minutes before dispensing it onto the PCB. This acclimation period allows the paste to reach room temperature, improving its flow and consistency during application. Proper temperature adjustment helps prevent issues such as uneven dispensing or poor adhesion, which can result from changes in the paste's viscosity due to its thermal properties and temperature differences.</p><h2 id="">Conclusion</h2><p id="">The board measures 100 mm × 83 mm. It took &lt;7 minutes to complete the solder paste dispensing and about 24 minutes to complete the reflow step, which included heating up and cooldown time of V-One. After the reflow process, all the components were securely bonded to the PCB.&nbsp;</p><p id="">When we attached the camera to the board and mounted it to the bottom of NOVA’s module hub, we were able to view the work area clearly in NOVA’s software.</p><p id="">With precise control of the flow and flexible selection of features, V-One is an easy tool with intuitive processes for dispensing solder paste on factory fabricated PCBs.&nbsp;</p><p id="">As we continue to explore the possibilities of solder paste dispensing, we invite you to view the <a href="https://www.voltera.io/applications" id="">other projects</a> we’ve completed.</p>

Dispensing Solder Paste on Factory Fabricated PCBs

Say goodbye to hand soldering and solder wire — Discover how quickly and accurately V-One can dispense and reflow solder paste on prefabricated PCBs. 

Dispensing Solder Paste on Factory Fabricated PCBs | Voltera

solder-paste

Dispensing Solder Paste

Say goodbye to hand soldering and solder wire — discover how quickly and accurately V-One can dispense and reflow solder paste on prefabricated PCBs.

<figure class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://www.youtube.com/watch?v=H9EFmO5rXmc"><div><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/H9EFmO5rXmc" title="Printing a Line Following Robot Control Board with Silver Ink on FR1 | Additive PCB Prototyping"></iframe></div></figure><h2 id="">Project overview</h2><h3 id="">Purpose</h3><p id="">The goal of this project was to prototype a circuit board that controls a line-following robot, using a simple design that could be used to teach electronics in a hands-on way.&nbsp;</p><h3 id="">Design</h3><p id="">For the control board, we separated the ground traces and other signal traces on opposite sides of the FR1 board, with through-holes to mount key components like the 16-pin L293DNE motor driver.&nbsp;</p><p id="">These through-holes also serve to accommodate other components such as LEDs, infrared proximity sensors, and motors, which could not be surface-mounted due to their size and functional requirements.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e34f4_67867f1f4fe491a4ba8bd9fc_line-following-robot-control-board-schematic.webp" loading="lazy" alt="line following robot, circuit design" width="auto" height="auto" id=""></div><figcaption id="">Figure 1: Circuit design</figcaption></figure><p id="">We divided the robot’s main body into small parts and printed them with a 3D printer.</p><h3 id="">Desired outcome</h3><p id="">Once connected to power, a 9V battery, the assembled robot should be able to distinguish its designated paths from the background and navigate along the paths, making turns as needed.</p><h3 id="">Functionality</h3><p id="">By using infrared proximity sensors, motors, and a motor driver, our design enabled the robot to move along the yellow tape on the black floor and navigate corners, all without relying on a microcontroller or onboard code, which would have introduced unnecessary complexity.</p><p id="">For the purpose of this project, we did not require a specific travel speed. However, the design can be customized for other activities, such as robot racing or obstacle avoidance challenges by reducing the overall weight of the robot, adjusting the configuration of sensors, or choosing high speed rated motors.</p><h2 id="">Printing the control board</h2><h3 id="">Printing the front side</h3><p id="">Before dispensing the silver ink, we drilled 39 through-holes with a diameter of 1.6 mm on the FR1 board using V-One.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e3530_67867f62a9f693d5f2d7da4e_line-following-robot-drilled-through-holes.webp" loading="lazy" alt="Board with through holes drilled with a V-One PCB printer" width="auto" height="auto" id=""></div><figcaption id="">Figure 2: Through-holes drilled with a V-One PCB printer</figcaption></figure><p id="">On the front side of the board, two infrared proximity sensors detect the paths and send signals to the motor driver, which controls the robot's movement by turning the motors on or off.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e34df_67867f917f95f638bd6cc49a_line-following-robot-front-view-schematic.webp" loading="lazy" alt="schematic for control board, front view" width="auto" height="auto" id=""></div><figcaption id="">Figure 3: Schematic for the control board, front side</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/678683097f95f638bd706979_Applications_line%20following%20robot%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e34e5_67867fbb7f95f638bd6cf8b3_line-following-robot-vone-dispensing-settings.webp" loading="lazy" alt="dispensing settings in the v-one software" width="auto" height="auto" id=""></div><figcaption id="">Figure 4: V-One dispensing settings</figcaption></figure><h3 id="">Printing the back side</h3><p id="">The back side of the board consists of traces that connect to the ground pins of the components and complete the circuit.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e34d1_67867fe2c4b3eb20f1d635d0_line-following-robot-back-view-schematic.webp" loading="lazy" alt="schematic for control board, back view" width="auto" height="auto" id=""></div><figcaption id="">Figure 5: Schematic for the control board, back side</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67868313690e9bd108c5eaef_Applications_line%20following%20robot%20white%20paper%20table%202.txt[/script]</p><h3 id="">Post processing the control board</h3><p id="">When both sides were complete, we inserted rivets into the through-holes and dispensed solder paste for resistors and the NE555 timer using V-One’s built-in solder paste dispensing workflow. We then populated the components and manually soldered the motor driver, capacitor, motors, infrared proximity sensors, and LEDs.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e3524_67867ffb82a2108e6206293b_line-following-robot-control-board-components.webp" loading="lazy" alt="populated control board" width="auto" height="auto" id=""></div><figcaption id="">Figure 6: Control board with components</figcaption></figure><h2 id="">3D printing the main body</h2><p id="">To house the control board and serve as the robot’s movement platform, we designed a main body divided into four parts. These parts were 3D printed using PLA filament:</p><ul id=""><li id="">Two wheels&nbsp;</li><li id="">Two motor brackets&nbsp;</li><li id="">A case</li><li id="">A lid&nbsp;</li></ul><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67868064daeba8787c8e34e2_67868043da47e689aea50f73_line-following-robot-design-main-body.webp" loading="lazy" alt="3D render of the main body" width="auto" height="auto" id=""></div><figcaption id="">Figure 7: Design of the main body</figcaption></figure><p id="">We then put the control board into the case and assembled the parts.</p><h2 id="">Challenges and advice</h2><h3 id="">Soldering issues</h3><p id="">Conductive ink, when applied to FR1, can sometimes adhere less robustly compared to traditional copper traces on a PCB. This makes it prone to being lifted off the board during soldering if excessive heat, pressure, or mechanical stress is applied.</p><p id="">To improve solderability, we lowered the curing temperature of the ink. This adjustment enhanced wettability, allowing solder to adhere more effectively to conductive pads, especially for sensitive connections and larger components.</p><h2 id="">Conclusion</h2><p id="">Through this project, we developed a line-following robot controlled by a double-sided PCB, using a relatively simple design and readily accessible components. This highlights the feasibility of incorporating advanced robotics and electronics concepts into educational programs. Depending on the students' skill levels and the intended applications the design can be adjusted to make it more or less challenging.</p><p id="">If you’re interested in exploring other PCB prototyping projects we have completed, take a look at:</p><ul id=""><li id=""><a href="https://www.voltera.io/application-whitepapers/printing-flexible-pcb-silver-ink-pet" id="">Printing a Flexible PCB with Silver Ink on PET</a></li><li id=""><a href="https://www.voltera.io/application-whitepapers/dispensing-solder-paste-factory-fabricated-pcbs" id="">Dispensing Solder Paste on Factory Fabricated PCBs</a></li><li id=""><a href="https://www.voltera.io/application-whitepapers/printing-strain-gauges-tpu-laminated-glove-remote-hand-control" id="">Printing Strain Gauges on TPU laminated on a Glove for Remote Hand Control</a></li></ul>

Printing a Control Board for a Line Following Robot with Silver Ink on FR1

Are you interested in building robots? Learn how we created a line-following robot controlled by a double-sided PCB printed with silver ink on a FR1 board.

Printing a Control Board for a Line Following Robot with Silver Ink on FR1 | Voltera

line-following

Line Following Robot

Are you interested in building robots? Learn how we used our PCB prototyping machine, V-One, to build a fully assembled line-following robot controlled by a double-sided PCB printed with silver ink on an FR1 board.

<figure class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/xaPmLgafT38"><div><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/xaPmLgafT38" title="Printing a Decimal Counter Circuit with Silver Conductive Ink on FR1 | Additive PCB Prototyping"></iframe></div></figure><h2 id="">Project overview</h2><h3 id="">Purpose</h3><p id="">The goal of this project was to demonstrate PCB development through key concepts:&nbsp;</p><ul id=""><li id="">Linear and switching regulators</li><li id="">Variable resistors</li><li id="">Seven-segment displays</li><li id="">Prototyping techniques <br><ul id=""><li id="">Conductive trace printing</li><li id="">Component placement</li><li id="">Solder reflow</li></ul></li></ul><h3 id="">Design</h3><p id="">The original PCB layouts were provided by <a href="http://itiz.co.kr/vone/" target="_blank" id="">ITIZ</a>, Voltera’s authorized reseller in Korea. We modified the design to create an integrated circuit system, which was comprised of three interconnected PCBs:</p><ol id=""><li id="">Voltage regulator board</li><li id="">Pulse generator board</li><li id="">Decimal counter board</li></ol><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b6101ea243ef8c4ab6136d_printing-decimal-counter-circuit-itiz-design.webp" loading="lazy" alt="ITIZ design of the boards" width="auto" height="auto" id=""></div><figcaption id="">ITIZ design of the boards</figcaption></figure><h3 id="">Desired outcome</h3><p id="">When connected to a 7V–12V DC source, the system should function as follows:&nbsp;</p><ul id=""><li id="">The voltage regulator board converts the input to a steady 5V output.</li><li id="">The pulse generator board uses this 5V supply to create adjustable pulse signals.</li><li id="">The decimal counter board drives two seven-segment displays to count from 00 to 99 at a speed controlled by the pulse generator.</li></ul><h3 id="">Functionality</h3><p id="">When powered by a 9V battery, the circuit successfully counted from 0 to 99 at an adjustable speed. A reset button allowed restarting the sequence, and the integration of both a linear regulator (78M05) and switching regulator (LM2575) on the same board provided a practical way to compare their efficiency, thermal behavior, and noise generation.</p><h2 id="">Printing the boards on V-One</h2><h3 id="">Voltage regulator board</h3><p id="">This board converts a 9V input into a steady 5V output. It includes the following components:</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0d1960ace12a70ac19_Applications_decimal%20counter%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b610584f957b9b534ee9cc_printing-decimal-counter-voltage-regulator-design.webp" loading="lazy" alt="Voltage regulator board design" width="auto" height="auto" id=""></div><figcaption id="">Voltage regulator board design</figcaption></figure><p id=""><a href="https://en.wikipedia.org/wiki/Voltage_regulator" target="_blank" id="">Voltage regulators</a> maintain a stable output voltage regardless of fluctuations in input voltage or load conditions. They play a critical role in circuit stability by preventing voltage spikes or drops that could damage components. In this circuit, we included two different types of regulators for ease of comparison.&nbsp;</p><p id="">The 78M05 linear regulator (U1) dissipates excess energy as heat, providing a stable 5V output at lower efficiency. In contrast, the LM2575 switching regulator (U2) achieves higher efficiency by rapidly switching an internal transistor to store energy in an inductor (L1) and capacitor (C6), though this can introduce noise into the circuit due to rapid switching.&nbsp;</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0d63b856844e8e2732_Applications_decimal%20counter%20white%20paper%20table%202.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67867fbb7f95f638bd6cf8b3_line-following-robot-vone-dispensing-settings.webp" loading="lazy" alt="__wf_reserved_inherit" width="auto" height="auto" id=""></div><figcaption id="">V-One print settings for all three boards</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b610e6abedd8d32b146ba0_printing-decimal-counter-voltage-regulator-board.webp" loading="lazy" alt="__wf_reserved_inherit" width="auto" height="auto" id=""></div><figcaption id="">V-One probing the voltage regulator board</figcaption></figure><h3 id="">Pulse generator board</h3><p id="">This board uses a 555 timer IC (NE555) to generate adjustable pulse signals that drive the decimal counter board. It includes the following components:</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0de764a209419e0d1e_Applications_decimal%20counter%20white%20paper%20table%203.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b6110d15406924eb522d31_printing-decimal-counter-pulse-generator-design.webp" loading="lazy" alt="Pulse generator board design" width="auto" height="auto" id=""></div><figcaption id="">Pulse generator board design</figcaption></figure><p id="">The <a href="https://en.wikipedia.org/wiki/555_timer_IC" target="_blank" id="">NE555 timer</a> (U1) is a versatile and widely-used integrated circuit (IC) that can generate stable time delays or oscillations, depending on the external components configured around it. On this board, it operates in <a href="https://ae-iitr.vlabs.ac.in/exp/astable-monostable-multivibrator/theory.html" target="_blank" id="">astable mode</a> to generate continuous pulse signals.</p><p id="">The variable resistor (R3) functions as a <a href="https://fr.farnell.com/exploring-the-potential-of-variable-resistors-trc-ar#:~:text=Variable%20resistors%20are%20electronic%20components,resistance%20offered%20to%20the%20current." target="_blank" id="">potentiometer</a> in this circuit, altering the charging and discharging time of capacitor C1. This adjusts the pulse frequency, which controls the counting speed of the seven-segment displays on the decimal counter board.</p><p id="">The green LED (D1) blinks in sync with the output pulses.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0d337b9cd9e419effe_Applications_decimal%20counter%20white%20paper%20table%204.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b6115c1511cdff281b3827_printing-decimal-counter-pulse-generator-board.webp" loading="lazy" alt="" width="auto" height="auto" id=""></div><figcaption id="">V-One dispensing silver ink on pulse generator board</figcaption></figure><h3 id="">Decimal counter board</h3><p id="">This board drives two seven-segment displays to count from 00 to 99, with adjustable speed (by the pulse generator board) and a reset function. It includes the following components:</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0d291643b0b4d8b7e6_Applications_decimal%20counter%20white%20paper%20table%205.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b61183a14f57e5a291c028_printing-decimal-counter-circuit-board-design.webp" loading="lazy" alt="Decimal counter board design" width="auto" height="auto" id=""></div><figcaption id="">Decimal counter board design</figcaption></figure><p id="">A <a href="https://en.wikipedia.org/wiki/Seven-segment_display" target="_blank" id="">seven-segment display</a> consists of seven individual LEDs arranged to form the shape of the number 8. By turning specific segments on or off, the display can represent any numeral between 0 and 9.&nbsp;</p><p id="">In this circuit, the 74LS93 counters (U1, U2) process incoming pulses into <a href="https://en.wikipedia.org/wiki/Binary-coded_decimal" target="_blank" id="">binary-coded decimal</a> (BCD) outputs. The 74LS47 decoders (U3, U4) convert BCD signals into segment activation patterns for the seven-segment displays (FND1, FND2). A manual reset button (SW1) allows restarting the count.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0d58e266b5f6275cc0_Applications_decimal%20counter%20white%20paper%20table%206.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b611b9350f70772bf8b9bb_printing-decimal-counter-v-one-conductive.webp" loading="lazy" alt="V-One dispensing silver ink on decimal counter board" width="auto" height="auto" id=""></div><figcaption id="">V-One dispensing silver ink on decimal counter board</figcaption></figure><h2 id="">Post-processing</h2><h3 id="">Populating and reflow</h3><p id="">After all three circuits were cured, we dispensed solder paste using V-One and carefully populated the components using a pair of tweezers. The solder paste was then reflowed on V-One’s heated bed.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/67b60f0e239b4a593806c515_19f2dda00d79269990ba211a8ab02841_Applications_decimal%20counter%20white%20paper%20table%207.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b611e261b0bec88d8c19f8_printing-decimal-counter-solder-paste-settings.webp" loading="lazy" alt="V-One dispensing solder paste on decimal counter board" width="auto" height="auto" id=""></div><figcaption id="">V-One dispense settings for solder paste</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b611fbfe442789178d1bf0_printing-decimal-counter-dispensing-solder-paste.webp" loading="lazy" alt="" width="auto" height="auto" id=""></div><figcaption id="">V-One dispensing solder paste on decimal counter board</figcaption></figure><h3 id="">Connecting the boards</h3><p id="">The three boards were linked using JST-SM connectors and wires. We connected the voltage regulator board to a battery and the pulse generator. We then connected the pulse generator outputs to the decimal counter’s clock input pins.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b6121db8bc92cddce00d9b_printing-decimal-counter-three-boards-connected.webp" loading="lazy" alt="The connected boards" width="auto" height="auto" id=""></div><figcaption id="">The connected boards</figcaption></figure><h3 id="">Printing enclosures</h3><p id="">To protect the circuits from any impact during handling, we designed and 3D printed three enclosures using PLA filament.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67b6123517e8883f762c20bf_printing-decimal-counter-3d-printed-enclosures.webp" loading="lazy" alt="3D printed enclosures for the boards" width="auto" height="auto" id=""></div><figcaption id="">3D printed enclosures for the boards</figcaption></figure><h2 id="">Challenges and advice&nbsp;</h2><h3 id="">Troubleshooting interconnected circuits</h3><p id="">Errors in interconnected systems could originate from any board, which made troubleshooting a bit more complex than a single board. To streamline the process, we recommend checking component polarity and orientation before populating the components, and reference their datasheets when necessary. Additionally, it’s helpful to check for continuity with a multimeter, or with an oscilloscope to calculate and view the frequency of the pulses.</p><h2 id="">Conclusion</h2><p id="">This project highlights the potential of additive PCB prototyping in electronics education. By combining theory and practice, students can explore how digital counting systems function, understand the role of BCD-to-seven-segment conversion, and observe how timing signals interact with display components. Direct ink writing platforms like V-One empower the next generation of engineers to innovate beyond breadboards and rapidly iterate on electronics designs.&nbsp;</p><p id="">If you are interested in exploring other PCB prototyping projects we have completed, take a look at:</p><ul id=""><li id=""><a href="https://www.voltera.io/use-cases/white-papers/printing-control-board-line-following-robot-silver-ink-fr1" id="">Printing a Control Board for a Line Following Robot with Silver Ink on FR1</a></li><li id=""><a href="https://www.voltera.io/use-cases/white-papers/printing-flexible-pcb-silver-ink-pet" id="">Printing a Flexible PCB with Silver Ink on PET</a></li><li id=""><a href="https://www.voltera.io/use-cases/white-papers/dispensing-solder-paste-factory-fabricated-pcbs" id="">Dispensing Solder Paste on Factory Fabricated PCBs</a></li></ul><p id="">Want to be notified when we post new white papers? <a href="https://share.hsforms.com/1DG3jeG6BRDOZ6o0OGyVv-g34u2a?__hstc=13863464.a6e861abd69863d5e355c083710f6ae2.1708615212577.1739388705374.1739394929902.659&__hssc=13863464.8.1739394929902&__hsfp=3867785717" id="">Sign up for our newsletter</a>.</p>

Printing a Decimal Counter Circuit with Silver Conductive Ink on FR1

Looking to go beyond breadboards? Read how we created a decimal counter with three interconnected circuits to teach the fundamentals of PCB development.

Printing a Decimal Counter Circuit with Silver Conductive Ink on FR1 | Voltera

decimal-counter

Decimal Counter Circuit

<h2 id="">Video</h2><figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/n3ZVfqWDtJU?si=z4j9WOXPW6Pz-pzW"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/n3ZVfqWDtJU" title="Printing a Flexible Multilayer Membrane Keyboard with Voltera NOVA"></iframe></div></figure><h2 id="">Project overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project is to demonstrate how NOVA prints multilayer electrical circuits on a highly flexible substrate (PET), and dispenses ink with high precision on sections that are as small as 250 µm W × 40 µm H.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a3fe8_670922e2efba3a9da3b8f456_Printing-flexible-membrane-keyboard-purpose.webp" loading="lazy" alt="A three layered print on PET with crossovers" width="auto" height="auto" id=""></div><figcaption id="">Figure 1:&nbsp;Three layered print with crossovers</figcaption></figure><h3 id="">Design layout</h3><p id="">We divided the layout into three layers:</p><ol id=""><li id="">Base conductive layer (ACI SS1109 Stretchable Silver Ink)</li><li id="">Dielectric layer (ACI SI3104 Stretchable Printed Insulator)</li><li id="">Top conductive layer (ACI SS1109 Stretchable Silver Ink)</li></ol><h3 id="">Desired outcome</h3><p id="">Based on a matrix style keyboard design, we limited the number of pins used to only seven on the controller (Arduino Micro, A000053). Once connected to a power source, pressing any key on the keyboard will trigger the controller to register the key.&nbsp;</p><h3 id="">Functionality</h3><p id="">We determined a 10-numbered keypad design would be suitable for this project. However, other flexible membrane keyboard designs have the potential for further customization, such as specific graphics, colors, or lighting, which could be beneficial for specialized equipment, including customized control panels, wearable devices, and foldable electronics.</p><h2 id="">Printing and curing the flexible substrate</h2><h3 id="">Base conductive layer</h3><p id="">This layer consists of a 4’’ × 3’’ matrix grid for 10 numbered keys, excluding the 10 dielectric pads (see dielectric layer).</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244d9b0c2b80f33a3fb9_670923005ab20b4c6a573338_Printing-flexible-membrane-keyboard-base-conductive-layer-schematic.webp" loading="lazy" alt="Base conductive layer schematic" width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;Base conductive layer schematic</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a4047_6709231c5bb93f90a2cdcfcf_Printing-flexible-membrane-keyboard-base-conductive-layer-printing.webp" loading="lazy" alt="NOVA Dispenser printing layer 1 on PET" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;Base conductive layer being printed with NOVA</figcaption></figure><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/661988c7b384dd7ea5d77f7a_Flexible%20membrane%20keyboard%20whitepaper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244c9b0c2b80f33a3fac_67092339362ae204a8569f3b_Printing-flexible-membrane-keyboard-base-conductive-layer-print-settings.webp" loading="lazy" alt="NOVA settings for base conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 4:&nbsp;NOVA&nbsp;print settings, base conductive layer</figcaption></figure><h3 id="">Dielectric layer&nbsp;</h3><p id="">This layer consists of 10 dielectric pads. To ensure full coverage of the dielectric ink, we did two passes for this layer, each cured after dispensing.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244c9b0c2b80f33a3fa9_67092356708e26b2cc8d222e_Printing-flexible-membrane-keyboard-dielectric-layer-schematic.webp" loading="lazy" alt="Dielectric layer schematic" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;Dielectric layer schematic</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a3ffd_6709236e994543d8a36f6105_Printing-flexible-membrane-keyboard-dielectric-layer-print-result.webp" loading="lazy" alt="Dielectric layer print result" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;Dielectric layer print result</figcaption></figure><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/66198a8a04b1f825dac46907_Flexible%20membrane%20keyboard%20whitepaper%20table%202.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244d9b0c2b80f33a3fbe_67092388bd5f734676f835a5_Printing-flexible-membrane-keyboard-dielectric-layer-print-settings.webp" loading="lazy" alt="NOVA print settings for the dielectric layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 7:&nbsp;NOVA&nbsp;print settings, dielectric layer</figcaption></figure><h3 id="">Top conductive layer</h3><p id="">This layer consists of 10 fine crossover lines that connect the red signal paths and complete the circuitry. </p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244d9b0c2b80f33a3fb6_670923ababdea1f85b1530df_Printing-flexible-membrane-keyboard-top-conductive-layer-schematic.webp" loading="lazy" alt="Top conductive layer schematic" width="auto" height="auto" id=""></div><figcaption id="">Figure 8:&nbsp;Top conductive layer schematic</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a3fd8_670923cfabdea1f85b154f1d_Printing-flexible-membrane-keyboard-top-conductive-layer-print-result.webp" loading="lazy" alt="Top conductive layer with crossovers" width="auto" height="auto" id=""></div><figcaption id="">Figure 9:&nbsp;Top conductive layer print result with crossovers</figcaption></figure><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/66198b6c59c79a384d6119df_Flexible%20membrane%20keyboard%20whitepaper%20table%203.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a3fe4_670923ef79f68cb3137c9c83_Printing-flexible-membrane-keyboard-top-conductive-layer-print-settings.webp" loading="lazy" alt="NOVA settings for the top conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 10:&nbsp;NOVA print settings, top conductive layer</figcaption></figure><h2 id="">Challenges and advice for printing multilayer</h2><h3 id="">Broken layers</h3><p id="">Because inks from different manufacturers have different properties – they may contain solvents that dissolve existing traces for example – printing and curing each new layer risks breaking the layer previously completed. It is, therefore, crucial that you choose compatible materials based on the degree of flexibility required.</p><p id="">For this project, we selected compatible inks from ACI Materials, but for projects that involve using multiple inks from different manufacturers, it is recommended that you <strong id="">check the materials’ technical data sheets</strong>.</p><h3 id="">Electrical shorts</h3><p id="">Due to the matrix design of the keyboard, the signal lines have a number of crossovers, which could cause electrical shorts if not insulated properly.</p><p id="">Printing a second pass of the dielectric layer achieves an appropriately thick insulating layer and supports further printing on top.&nbsp;</p><h3 id="">Connection issues</h3><p id="">Because the crossover sections are intricate (250 µm W × 40 µm H), if the nozzle scratches the ink while printing, the electrical paths may not function as planned.</p><p id="">Separating the crossover sections into their own layer (the top conductive layer) allows each crossover pad to be probed accurately and have specialized settings, yielding a higher success rate.</p><p id="">In addition, because changes in height can happen drastically when printing over existing traces, setting a low probe pitch will make the height map more accurate. An accurate height map means the height transition at the edges of features is accurate and the risk of traces being printed off-course is low.</p><h2 id="">Post-printing: A fully flexible electronic device</h2><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244e9b0c2b80f33a400f_6709241ab070d58e6f035de8_Printing-flexible-membrane-keyboard-post-printing-fully-flexible-electronic-device.webp" loading="lazy" alt="Flexible keyboard assembled and plugged in" width="auto" height="auto" id=""></div><figcaption id="">Figure 11:&nbsp;Flexible keyboard assembly</figcaption></figure><p id="">To ensure the Arduino Micro was securely in place, we used a FR1 board, cut it to 30 mm × 60 mm, and placed it beneath the flexible substrate (PET sheet). Next we drilled through holes on the board and the flexible substrate with the <a href="https://www.voltera.io/v-one" id="">Voltera V-One PCB printer</a>.</p><p id="">We then dispensed solder paste, placed the diodes on the flexible substrate, and riveted it together with the FR1 board, before placing the metal switches on the rectangle-shaped contacts. To secure the metal switches, we covered them with Kapton tape.</p><p id="">Next, we secured the controller to the flexible substrate and connected it to a power source. We also gave the keyboard a finishing touch by placing it inside a 3D-printed enclosure with graphical silicone keys.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6709244d9b0c2b80f33a3fd3_67092437df6f44a8a78c9bfb_Printing-flexible-membrane-keyboard-post-printing-final-hard-case.webp" loading="lazy" alt="final assembly in 3D-printed case" width="auto" height="auto" id=""></div><figcaption id="">Figure 12:&nbsp;Final assembly in 3D-printed case</figcaption></figure><h2 id="">Conclusion&nbsp;</h2><p id="">This project highlights the innovative potential of printing on flexible substrates. It also points to the critical role of fine-tuning print settings to achieve success in multilayer projects.&nbsp;</p><p id="">As achieved by this project, using compatible materials helps ensure optimal performance, and is key to unlocking the full potential of flexible electronics. As we continue to explore the boundaries of what’s possible with flexible substrates, we invite you to view the <a href="https://www.voltera.io/applications" id="">other projects</a> we’ve completed.</p>

Printing a Flexible Membrane Keyboard with Conductive Silver Ink and Dielectric Ink on PET

Discover the design, printing, and assembly of a multilayer flexible membrane keyboard printed with conductive silver ink and dielectric ink on PET.

Printing a Flexible Membrane Keyboard with Conductive Silver Ink and Dielectric Ink on PET | Voltera

keyboard

Flexible Membrane Keyboard

For this project, we used NOVA to print multilayer electrical circuits to make a compact, adaptable, flexible membrane keyboard.

<h2 id="">Watch the Video</h2><figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/FCSASyN0K3I?si=A3aL5DJVimgH4cq5"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/FCSASyN0K3I" title="Printing a Flexible PCB LED Roulette with Silver Ink on PET | LED Applications, Flex Circuits"></iframe></div></figure><h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The goal of this project was to prototype a flexible multilayer LED wheel roulette circuit that was traditionally considered rigid and validate the redesign of the circuit.&nbsp;</p><h3 id="">Design&nbsp;</h3><p id="">This project involves a multilayer <a href="https://www.voltera.io/blog/flexible-hybrid-electronics" id="">flexible PCB</a> for the LED roulette circuit and a traditional control board that powers it. We adapted the design of an LED roulette circuit, originally developed for a 3” × 4” FR4 board by <a href="http://itiz.co.kr/" id="">ITIZ</a>, Voltera’s authorized reseller in Korea. This new version is printed on a coated biaxially oriented PET substrate, allowing the circuit to remain flexible — even when populated with components.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a64_673b81e19467b3fc401543a5_flexible-pcb-itiz-led-roulette-circuit.webp" loading="lazy" alt="Original LED roulette circuit design by ITIZ" width="auto" height="auto" id=""></div><figcaption id="">Figure 1: Original LED roulette circuit design by ITIZ</figcaption></figure><p id="">We divided the LED roulette circuit design into three layers:</p><ul id=""><li id="">Base conductive layer</li><li id="">Dielectric layer</li><li id="">Top conductive layer</li></ul><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a58_673b820e2668f8a32be1be4c_flexible-pcb-led-roulette-circuit-schematic.webp" loading="lazy" alt="Voltera's modified design of the LED roulette circuit" width="auto" height="auto" id=""></div><figcaption id="">Figure 2: Voltera modified design of the LED roulette circuit</figcaption></figure><h3 id="">Desired outcome</h3><p id="">We anticipated the circuit would function like a roulette wheel: each time the pulse generator is triggered, the LEDs on the flexible PCB light up in a rapid circular sequence before slowing down and stopping on a single LED.</p><h3 id="">Functionality</h3><p id="">By printing a dielectric and crossover layer on top of the base conductive layer, we created a compact and lightweight LED roulette circuit without using jumpers. Each layer remained flexible after curing, and the circuit maintained its integrity even after encapsulation and repeated flexing.&nbsp;</p><p id="">When connected to power, pressing the switch on the control board caused the LEDs on the flexible PCB to light up, replicating the behavior of a roulette wheel as intended.</p><h2 id="">Printing the control board</h2><p id="">This board controls the pulse signals and powers the LED roulette wheel circuit. We used V-One to print the circuit and reflow the components, which included:</p><ul id=""><li id="">NE555DR timer</li><li id="">LED</li><li id="">Switch</li><li id="">47 µF capacitor</li><li id="">0.1 µF capacitor</li><li id="">10 nF capacitor</li><li id="">100 kΩ resistor</li><li id="">330 Ω resistor</li></ul><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a5b_673b825108fc1d87420a0c06_flexible-pcb-led-control-board-schematic.webp" loading="lazy" alt="Schematic for the control board" width="auto" height="auto" id=""></div><figcaption id="">Figure 3: Schematic for the control board</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862c67fe0d06201b4545_Applications_LED%20roulette%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673cbad5909c9ae473ff0408_673cba9cd0a8c205bdb84721_flexible-pcb-led-circuit-control-board.webp" loading="lazy" alt="The control board" width="auto" height="auto" id=""></div><figcaption id="">Figure 4: The control board</figcaption></figure><h2 id="">Printing the flexible PCB</h2><p id="">This flexible PCB receives signals from the control board and lights up the LEDs as directed.&nbsp;</p><h3 id="">Base conductive layer</h3><p id="">This layer consists of a roulette-shaped circuit (90 mm L × 70 mm W) that connects to the control board, as well as power and ground terminals, with designated gaps for dielectric pads.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a6a_673b83d197286b4449739ba7_flexible-pcb-base-conductive-layer-schematic.webp" loading="lazy" alt="The schematic for the base conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 5: Schematic for the base conductive layer</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862cb4da9c3601bba3fe_Applications_LED%20roulette%20white%20paper%20table%202.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a5e_673b840520cda3b3ae547ba5_flexible-pcb-nova-settings-base-layer.webp" loading="lazy" alt="NOVA print settings, base conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 6: NOVA print settings, base conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86092c4ed105d1f99acb_673b84262760f4b16bd4c131_flexible-pcb-layer-one-result.webp" loading="lazy" alt="The print result, base conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 7: Print result, base conductive layer</figcaption></figure><h3 id="">Dielectric layer</h3><p id="">This layer consists of 29 dielectric pads that provide insulation for the top conductive layer. For better coverage, we printed two passes of dielectric ink.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a49_673b844b15838b3c71a77804_flexible-pcb-led-dielectric-layer-schematic.webp" loading="lazy" alt="The schematic for the dielectric layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 8: Schematic for the dielectric layer</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862c472ed1158ba2460d_Applications_LED%20roulette%20white%20paper%20table%203.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a67_673b84768e7d474c7d82fe5a_flexible-pcb-dielectric-layer-nova-settings.webp" loading="lazy" alt="An image showing NOVA print settings for dielectric layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 9: NOVA print settings, dielectric layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86082c4ed105d1f99aa8_673b84969b09b4b9a3bb6490_Flexible-pcb-layer-two-result.webp" loading="lazy" alt="The print result for dielectric layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 10: Print result, dielectric layer</figcaption></figure><h3 id="">Top conductive layer</h3><p id="">This layer consists of 29 fine crossover traces that connect the paths to the power terminal and control board. To address potential gaps over height changes, we decreased the trace width to 100 mm to enhance trace continuity.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a61_673b84cf72b7b1eeee04f153_flexible-pcb-top-conductive-layer-schematic.webp" loading="lazy" alt="An image showing  the schematic for the top conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 11: Schematic for the top conductive layer</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862cfbc296b62bb711a6_Applications_LED%20roulette%20white%20paper%20table%204.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a5e_673b840520cda3b3ae547ba5_flexible-pcb-nova-settings-base-layer.webp" loading="lazy" alt="An image showing NOVA print settings, top conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 12: NOVA print settings, top conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86082c4ed105d1f99aa2_673b8513e8c7693a1d09a24f_flexible-pcb-layer-three-crossovers.webp" loading="lazy" alt="The print result, bottom conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 13: Print result, bottom conductive layer</figcaption></figure><h2 id="">Post-processing the flexible PCB</h2><h3 id="">Dispensing solder paste and reflowing the components</h3><p id="">Once the circuit was cured, we dispensed solder paste using NOVA and populated the components before reflowing them in an oven.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862cf8f6f130ea02dee0_Applications_LED%20roulette%20white%20paper%20table%205.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a4c_673b853808fc1d87420c376a_flexible-pcb-nova-settings-solder-paste.webp" loading="lazy" alt="NOVA print settings, solder paste" width="auto" height="auto" id=""></div><figcaption id="">Figure 14: NOVA print settings, solder paste</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86082c4ed105d1f99a86_673b855a8af066bbb936caec_flexible-pcb-solder-dispensing.webp" loading="lazy" alt="An image showing NOVA dispensing solder paste" width="auto" height="auto" id=""></div><figcaption id="">Figure 15: NOVA dispensing solder paste</figcaption></figure><p id="">Because the wires are not heat-resistant, we manually soldered them onto both the companion board and the flexible roulette circuit.</p><h3 id="">Encapsulating the components</h3><p id="">To reinforce their connection to the substrate, we dispensed encapsulation resin using a syringe onto the components and cured the resin in a UV light box.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/673b862c6a87e820ffa1d286_Applications_LED%20roulette%20white%20paper%20table%206.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86082c4ed105d1f99aa5_673b857fcd2ccc2a63c43e16_flexible-pcb-uv-curing-resin.webp" loading="lazy" alt="Encapsulated circuit being cured in a UV light box" width="auto" height="auto" id=""></div><figcaption id="">Figure 16: Encapsulated circuit being cured in a UV light box</figcaption></figure><p id="">Once cured, we manually soldered the wires of the control board and the wires of the flexible roulette circuit together.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/673b86072c4ed105d1f99a6e_673b85ac08fc1d87420c84c7_flexible-pcb-led-manual-solder-wire.webp" loading="lazy" alt="An image showing soldering the wires together" width="auto" height="auto" id=""></div><figcaption id="">Figure 17: Soldering the wires together</figcaption></figure><h2 id="">Challenges and advice</h2><h3 id="">Electrical shorts</h3><p id="">We encountered issues with shorts due to multiple crossover lines on the dielectric layer. To address this, we recommend printing a second pass of the dielectric layer to achieve a thicker insulating layer that better supports additional layers printed on top.</p><h3 id="">Drastic height changes</h3><p id="">A second pass of the dielectric layer can result in significant height differences. To handle this, it is advisable to set a low probe pitch to ensure a more accurate height map and print a thicker crossover layer for improved contact on the top layer.</p><h3 id="">Maintaining flexibility with components attached&nbsp;</h3><p id="">To ensure the circuit remained flexible after populating components, we opted for smaller, more flexible components. This, combined with the use of a flexible substrate, encapsulant, and inks, allowed the circuit to bend without damaging the connections.</p><h2 id="">Conclusion</h2><p id="">This project highlights the educational value of converting rigid circuit designs into flexible ones, allowing students to explore diverse materials and optimize print settings through experimentation. It also demonstrates the potential of prototyping flexible PCBs to replace electronics that were considered rigid, achieving lightweight, compact, and resilient designs.</p><p id="">As flexible PCBs gain more popularity, hands-on experience with these technologies becomes essential for staying ahead in the rapidly evolving electronics industry. We invite you to explore our <a href="http://www.voltera.io/applications" id="">other projects</a> as we continue to explore the possibilities of flexible PCBs and printed electronics.</p><p id="">‍</p>

Printing a Flexible PCB with Silver Ink on PET

Discover how we redesigned an LED roulette wheel circuit from FR4 to PET so it could withstand flexing with components populated.

Printing a Flexible PCB with Silver Ink on PET | Voltera

flex-pcb

Flexible PCB

This project demonstrates how we redesigned an LED roulette circuit from FR4 to PET to withstand flexing with components populated.

Printing a Magnesium Zinc Battery with Saral Inks on PET

Discover the design and printing process of a functional multilayer magnesium zinc printed battery onto a flexible PET substrate, using a variety of conductive and insulating inks.

Printing a Seven-Layer Magnesium Zinc Battery with Saral Inks on PET | Voltera

battery

Magnesium Zinc Battery

This project demonstrates printing a functional multilayer magnesium zinc battery onto a flexible PET substrate, using a variety of conductive and insulating inks.

<h2 id="">Video</h2><figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/2COFihlYVos?si=4MCQiz9wPVlpbzXR"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/2COFihlYVos" title="Voltera NOVA: Printing Copper RFID Tags"></iframe></div></figure><h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to demonstrate how we used the <a href="https://www.voltera.io/nova" id="">Voltera NOVA</a> materials dispensing system to create an ultra-high frequency (UHF) RFID tag using nano copper ink on a paper substrate.</p><h3 id="">Design</h3><p id="">We designed a meander half-dipole antenna with an opening at the center to place and solder a transceiver, which controls the antenna and responds to incoming RFID signals. The length of the meander trace was adjusted to ensure we could easily fine-tune the antenna and achieve the best performance.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/671260b1059c059c6792b369_67126082acad8d5154a427ce_Printing-rfid-tag-copper-paper-design.webp" loading="lazy" alt="RFID tag layout" width="auto" height="auto" id=""></div><figcaption id="">Figure 1:&nbsp;RFID tag layout</figcaption></figure><h3 id="">Desired outcome</h3><p id="">Our hypothesis was that we could develop an omnidirectional RFID tag that would be readable from a long range (6 meters) and from all orientations relative to the reader.</p><h3 id="">Functionality</h3><p id="">The meander half-dipole antenna design was selected due to its ability to increase the trace length of the antenna without significantly increasing its physical size (95 mm L × 15 mm W).</p><p id="">This design allows for effective tuning of the antenna within a compact package. Additionally, the half-dipole design was intentionally made symmetrical to ensure balanced radiation, thereby minimizing the risk of interference and signal distortion.</p><h2 id="">Printing and post-processing of the RFID antenna</h2><h3 id="">Printing the antenna</h3><p id="">We chose the Copprint LF-301 copper ink because it’s more cost-effective than silver (3–5 times cost savings), and the ink provides excellent conductivity (&lt; 0.003 Ω/square for a 25 μm thickness). It contains a special sintering agent that prevents the nano copper mixture from oxidizing, thereby ensuring long-term conductivity after production. It took NOVA 15 minutes to print the antenna, including the time to create the height map for the paper substrate.</p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/667dbd635c785013a4f72733_Applications_RFID%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/671260b1059c059c6792b364_67126099227da58806261108_Printing-rfid-tag-copper-paper-print-settings.webp" loading="lazy" alt="NOVA print settings for copper ink LF301" width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;Print settings</figcaption></figure><h3 id="">Sintering the copper ink</h3><p id="">Once printed, we followed the <a href="https://www.copprint.com/wp-content/uploads/2021/12/TDS-LF-301-Beta-22-08-21.pdf" id="">sintering instructions provided by Copprint</a>. Sintering is a critical process for nano copper inks, as it transitions the particles from a separated state to a cohesive particle matrix. We placed the final print into an oven and left it to dry for 5 minutes at 80°C before using a heat press to sinter it for 15 seconds at 270°C.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67126158f1a288b7b41d023d_671260c37673266a3f1d5da4_Printing-rfid-tag-copper-paper-sintering.webp" loading="lazy" alt="Copper print sintered" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;Sintered print</figcaption></figure><h3 id="">Soldering the transceiver&nbsp;</h3><p id="">Due to the high copper content of Copprint LF-301, the resulting sintered antenna exhibited excellent solderability. Consequently, the transceiver was successfully soldered onto the antenna after the sintering process was completed. To ensure a solid solder connection to the transceiver, we used a burnishing pad to burnish the surface of the print before placing the transceiver onto it. We then manually soldered the transceiver to the opening in the center and cured it with an air reflow station.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67126158f1a288b7b41d022a_671260d97b5b9d33b528d700_Printing-rfid-tag-copper-paper-soldering-transceiver.webp" loading="lazy" alt="Placing the transceiver onto the copper print" width="auto" height="auto" id=""></div><figcaption id="">Figure 4:&nbsp;Placing the transceiver</figcaption></figure><h2 id="">Challenges and advice</h2><p id="">Using NOVA to print the RFID tag turned out to be straightforward. We were able to modify&nbsp; designs promptly to achieve optimal performance for the desired frequency range. One minor challenge was characterizing the performance of the RFID tag. Given its compact size, even slight alterations in geometry had a significant impact on the results.</p><p id="">To minimize rework, we used the <a href="https://www.mathworks.com/products/antenna.html" id="">MATLAB® Antenna Toolbox™</a> to simulate the design performance, including sensitivity and directionality. We then refined the antenna's dimensions and geometry based on simulation outcomes. This allowed us to achieve the optimum design within only three iterations.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67126158f1a288b7b41d0215_671260f9cbc0d0bc71df12dc_Printing-rfid-tag-copper-paper-first-design.webp" loading="lazy" alt="Schematic for the first version of the RFID tag" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;The first version of the RFID tag</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/671260b1059c059c6792b369_67126082acad8d5154a427ce_Printing-rfid-tag-copper-paper-design.webp" loading="lazy" alt="The second version of the RFID tag" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;The second version of the RFID&nbsp;tag</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67126158f1a288b7b41d0222_6712612979b6b0c14f3a80fb_Printing-rfid-tag-copper-paper-third-design.webp" loading="lazy" alt="The third version of the RFID tag" width="auto" height="auto" id=""></div><figcaption id="">Figure 7:&nbsp;The third version of the RFID tag</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67126158f1a288b7b41d021f_6712613fffb0121327872229_Printing-rfid-tag-copper-paper-fourth-design.webp" loading="lazy" alt="The fourth version of the RFID tag" width="auto" height="auto" id=""></div><figcaption id="">Figure 8:&nbsp;The fourth version of the RFID tag</figcaption></figure><h2 id="">Conclusion</h2><p id="">The final RFID tag exhibited a minimum self-reflection coefficient (S11) of -29.42 dB at 922.50 MHz, surpassing the required maximum of -10 dB. This value represents the resonant frequency where the tag will function best — well within the 902 MHz to 928 MHz frequency bandwidth for North American RFID tags. Its performance exceeded that of off-the-shelf RFID tags from market leaders.</p><p id="">The tag is well-suited for applications requiring reliable, long-range, and orientation-independent reading capabilities, such as tracking the inventory of electronics, furniture, luggage, and vehicles. In addition, while the commercial tags we acquired were made of non-recyclable laminate, our design was composed of paper and copper ink, making the RFID tag compostable. This highlights an emerging use case for copper inks in RFID or NFC applications.&nbsp;</p><p id="">As we continue to explore the possibilities of printing antennas, we invite you to view the <a href="https://www.voltera.io/applications" id="">other projects</a> we’ve completed.</p>

Printing an RFID Tag with Copper Ink on Paper

Discover the design and printing process of a fully compostable, ultra-high frequency RFID tag on cardstock paper with the Copprint nano copper ink.

Printing an RFID Tag with Copper Ink on Paper | Voltera

rfid

Copper RFID Tag

This project demonstrates how NOVA printed a fully compostable, ultra-high frequency RFID tag on cardstock paper with Copprint nano copper ink.

<figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/zsniZR1if1s?feature=shared"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/zsniZR1if1s" title=""></iframe></div></figure><h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to demonstrate how we validated the effectiveness of printing ECG electrodes on TPU using biocompatible gold ink and stretchable silver ink. We used the <a href="https://www.voltera.io/nova" id="">Voltera NOVA</a> materials dispensing system and the <a href="https://www.voltera.io/v-one" id="">Voltera V-One</a> PCB printer for this purpose.</p><h3 id="">Design&nbsp;</h3><p id="">We divided the project into three main parts:</p><ol id=""><li id="">The ECG electrodes to be attached to the skin&nbsp;</li><li id="">The control unit with the heart rate monitor and the controller</li><li id="">An enclosure that protects the control unit from impact</li></ol><p id="">The SparkFun Heart Rate Monitor AD8232 (SENS-12650) acts as a pre-amplifier, transforming the heart’s biopotentials picked up by the ECG electrodes into a usable voltage while also rejecting electrical noise inherent in the measurement. The Arduino Micro captures the voltage and interprets it as a graph of the heart waveform through a program that we custom-made for this project.<br></p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/6734f07a02c798f6d398a29a_6734f018c7119d868b77b789_gold-ecg-electrodes-biosensors-wave-reading.webp" loading="lazy" alt="A graph showing beats per minute and ECG wave reading" width="auto" height="auto" id=""></div><figcaption id="">Figure 1: A graph showing beats per minute and ECG wave reading</figcaption></figure><h3 id="">Desired outcome</h3><p id="">The printed electrodes should be <a href="https://www.voltera.io/blog/flexible-hybrid-electronics" id="">flexible</a> enough to conform to body movement and different physiques. Once the gold ECG electrodes are attached to the skin and connected to the circuit, we connect the circuit to power. The Arduino Micro controller should accurately interpret heart rates and rhythm readings.</p><h3 id="">Functionality</h3><p id="">Inspired by <a href="https://pubs.aip.org/aip/apr/article/10/4/041408/2919081/Dry-electrode-geometry-optimization-for-wearable" id="">this study</a> where researchers developed a hexagonal labyrinth pattern as an optimized dry electrode geometry, this design allowed for maximum sensitivity while eliminating the need for wet gel, which can cause skin irritation in some patients.&nbsp;</p><p id="">For this project we printed a set of three electrodes, to be placed on the chest, as a proof of concept. Although this design was able to output data into meaningful graphs, commercial ECGs typically have 12 points of readings. As such, this project is <strong id="">not intended for diagnosis or treatment</strong> of any medical conditions.</p><h2 id="">Printing and post-processing the ECG electrodes</h2><p id="">To ensure the electrodes could conform to body movement and accommodate different physiques, we designed the corners to be stretchable. We divided the layout into two layers:</p><ol id=""><li id="">Base silver layer for stretchability&nbsp;</li><li id="">Top gold layer for biocompatibility&nbsp;</li></ol><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604bfb_67125b4e73b289c270fc0de9_Printing-ecg-electrodes-gold-ink-post-processing.webp" loading="lazy" alt="Layer overview of the ECG electrodes " width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;Layer overview of the ECG electrodes</figcaption></figure><p id="">This approach allowed us to use a relatively small amount of gold ink to minimize costs while achieving the desired outcome.</p><h3 id="">Printing the base silver layer</h3><p id="">This layer consists of three circle patterns designed to connect to metal snaps, as well as traces that connect to the gold layer. For ease of alignment, we also included four sets of fiducials at each corner of the individual patterns.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604bf8_67125b6fa3704b80c7a5716a_Printing-ecg-electrodes-gold-ink-base-silver-layer.webp" loading="lazy" alt="Silver layer schematic" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;Silver layer schematic</figcaption></figure><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/66c63350ade6770f2f50b0c0_Applications_ECG%20sensors%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604bef_67125b9146610e7337041882_Printing-ecg-electrodes-gold-ink-base-silver-layer-settings.webp" loading="lazy" alt="NOVA print settings for the base silver layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 4:&nbsp;NOVA&nbsp;print settings for the silver layer</figcaption></figure><h3 id="">Printing the top gold layer</h3><p id="">This layer consists of three hexagonal labyrinth patterns with traces that connect to the silver layer.&nbsp;</p><p id="">Similar to the silver layer, we included four sets of fiducials for better alignment and precise cutting of the substrate.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604bf2_67125bb553e4784db0cbb5ad_Printing-ecg-electrodes-gold-ink-top-gold-layer.webp" loading="lazy" alt="Gold layer schematic" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;Gold layer schematic</figcaption></figure><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/670821f9e2888ed6b34c060d_Applications_ECG%20sensors%20white%20paper%20table%202.txt[/script]</p><p id="">‍</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604be9_67125bd0d3b2768729d2b653_Printing-ecg-electrodes-gold-ink-top-gold-layer-settings.webp" loading="lazy" alt="NOVA settings for the top gold layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;NOVA&nbsp;print settings for the gold layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d02b760271028604bdb_67125bf37673266a3f18cd62_Printing-ecg-electrodes-gold-ink-top-gold-layer-results.webp" loading="lazy" alt="Finished print of the electrodes" width="auto" height="auto" id=""></div><figcaption id="">Figure 7:&nbsp;Finished print of the electrodes</figcaption></figure><h3 id="">Post-processing of the electrodes</h3><p id="">After the electrodes were printed, we punched a hole in the middle of the silver circle on each electrode for the metal snaps. Next, we folded the electrodes in the middle and inserted the metal snaps into the punched holes.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604c25_67125c0e059c059c678dd211_Printing-ecg-electrodes-gold-ink-post-processing-assembly.webp" loading="lazy" alt="One of the printed electrodes with a hole for a metal snap " width="auto" height="auto" id=""></div><figcaption id="">Figure 8:&nbsp;One of the printed electrodes with a hole for a metal snap</figcaption></figure><p id="">We cut three PET sheets proportional to the labyrinth pattern with the intention of inserting them between the layers of TPU. This added strength to the electrodes, preventing excessive stretching that could cause the gold ink to lose conductivity. We laminated them together using a T-shirt press machine. The electrodes were now ready to be connected to the heart rate monitor via the sensor cable.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604c19_67125c2cbe4558dee3791a5a_Printing-ecg-electrodes-gold-ink-post-processing-laminating.webp" loading="lazy" alt="Laminating the two sides of the TPU together" width="auto" height="auto" id=""></div><figcaption id="">Figure 9:&nbsp;Laminating the two sides of the TPU&nbsp;together</figcaption></figure><h2 id="">Printing the control unit</h2><p id="">To mount the Arduino Micro controller and the SparkFun Heart Rate Monitor, we needed to drill a few holes on an FR1 board using V-One. After drilling, we used V-One to print silver traces that electrically connected the two components together.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d02b760271028604bd8_67125c4e4bb4a042fffc5135_Printing-ecg-electrodes-gold-ink-control-unit.webp" loading="lazy" alt="Schematic for the FR1 mounting board" width="auto" height="auto" id=""></div><figcaption id="">Figure 10:&nbsp; FR1 mounting board schematic</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604be3_67125c6f47a508f72a443f92_Printing-ecg-electrodes-gold-ink-control-unit-mounting.webp" loading="lazy" alt="FR1 mounting board with conductive traces printed" width="auto" height="auto" id=""></div><figcaption id="">Figure 11:&nbsp;FR1 mounting board</figcaption></figure><p id="">We then inserted rivets, mounted the components in place, and connected the wires from the heart rate monitor to the electrodes.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d02b760271028604bd5_67125c8be17acaac99a8c23b_Printing-ecg-electrodes-gold-ink-control-unit-components.webp" loading="lazy" alt="FR1 board with components and case" width="auto" height="auto" id=""></div><figcaption id="">Figure 12:&nbsp;FR1 board with components</figcaption></figure><h2 id="">Printing the enclosure</h2><p id="">To protect the control unit from impact, we designed and 3D printed an enclosure that consists of a top and a bottom cover.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604be6_67125ca85f72b4574cb8e952_Printing-ecg-electrodes-gold-ink-control-unit-enclosure.webp" loading="lazy" alt="Top cover of the enclosure" width="auto" height="auto" id=""></div><figcaption id="">Figure 13:&nbsp;Top cover of the enclosure</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d02b760271028604bde_67125cc759814ff97bfe9e84_Printing-ecg-electrodes-gold-ink-control-unit-enclosure-side.webp" loading="lazy" alt="Bottom cover of the enclosure" width="auto" height="auto" id=""></div><figcaption id="">Figure 14:&nbsp;Bottom cover of the enclosure</figcaption></figure><p id="">After placing the control unit inside, we bolted the top and bottom covers together.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125d03b760271028604c16_67125cec55fc1153db6cdb2c_Printing-ecg-electrodes-gold-ink-enclosure-components.webp" loading="lazy" alt="Components and the enclosure" width="auto" height="auto" id=""></div><figcaption id="">Figure 15:&nbsp;Components and the enclosure</figcaption></figure><h2 id="">Challenges and advice</h2><h3 id="">Minimizing material waste</h3><p id="">One of the primary challenges we encountered was managing the gold ink. Given its high cost, we aimed to avoid waste. To mitigate this risk, we initially experimented with alternative inks to validate the electrode design. We tested silver ink first to ensure successful prints before proceeding with the gold ink. We also included overlapping fiducial marks for the two layers in our design to ensure precise alignment.</p><h3 id="">Optimizing ink flow</h3><p id="">The gold particles settled at the bottom due to being left unused for extended periods, which initially resulted in the nozzle clogging. We resolved this issue by mixing the gold ink using a dual asymmetric centrifugal mixer before printing.</p><h2 id="">Conclusion</h2><p id="">While working with gold ink presented new challenges, using NOVA allowed us to precisely control the amount of ink dispensed, a benefit particularly relevant for applications using expensive materials. </p><p id="">If you are interested to learn more, Voltera’s co-founder and Director of Revenue, Katarina Ilić, gave a keynote on this project at TechBlick’s Printed Electronics Innovation Day, December 11, 2024. Watch the video:</p><figure class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/hKK7YWAN46U"><div><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/hKK7YWAN46U" title="ECG Sensors Printed with Gold | Voltera Keynote at TechBlick Printed Electronics Innovation Day 2024"></iframe></div></figure>

Printing ECG Electrodes with Biocompatible Gold Ink on TPU

Discover how we validated the effectiveness of printing ECG electrodes on TPU using biocompatible gold ink and stretchable silver ink.

Printing ECG Electrodes with Gold Ink on TPU | Voltera

electrodes

Gold ECG Electrodes

This project demonstrates how we validated the effectiveness of printing ECG electrodes on TPU using biocompatible gold ink and stretchable silver ink.

<h2 id="">Video</h2><figure id="" class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://youtu.be/Yc8nEoVnpDY?si=CALdcAhurK0yBHQs"><div id=""><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/Yc8nEoVnpDY" title="Printing Electroluminescent Ink with Voltera NOVA"></iframe></div></figure><h2 id="">Project overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to demonstrate the multilayer capability of <a href="https://www.voltera.io/nova" id="">Voltera NOVA</a>. We printed a blue light-emitting pattern — the Voltera logo — on two substrates: paper and PET separately, using electroluminescent ink.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349cc_67091ac24ff580aed0ee4302_Printing-electroluminescent-ink-paper-pet-purpose.webp" loading="lazy" alt="NOVA printing a layer of the logo" width="auto" height="auto" id=""></div><figcaption id="">Figure 1:&nbsp;NOVA&nbsp;printing a layer of the electroluminescent logo</figcaption></figure><h3 id="">Design layout</h3><p id="">Electroluminescence operates by exciting a phosphor material with an electric field. An inverter is needed to convert the direct current from the power source into alternating current.</p><p id="">Based on this mechanism, our design positions a phosphor layer between two conductive layers, incorporating a dielectric ink layer to insulate the phosphor. The printing sequence is as follows:</p><ul id=""><li id="">Layer 1: Base conductive layer&nbsp;</li><li id="">Layer 2: Dielectric layer&nbsp;</li><li id="">Layer 3: Phosphor layer</li><li id="">Layer 4: Top conductive layer</li></ul><h3 id="">Layer overview</h3><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349bd_67091ae09acab270adbdf20e_Printing-electroluminescent-ink-paper-pet-layer-overview.webp" loading="lazy" alt="Layer overview. Layer 1: Saral Silver 700, Layer 2: Saral Dielectric 600, Layer 3: Saral Blue PhosphorL 800, Layer 4: Saral Conducting Polymer 700" width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;Layer overview</figcaption></figure><h3 id="">Desired outcome</h3><p id="">Once connected to an alternating current (140 V, 1.862 kHz), the phosphor layer emits blue light, illuminating the Voltera logo with an even glow across both prints.</p><h3 id="">Functionality</h3><p id="">We determined the Voltera logo would be suitable for this project. It is feasible to incorporate designs into larger electronic applications, including billboards, branded merchandise, and control panels.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a1b_67091b02bdc7f308274e583c_Printing-electroluminescent-ink-paper-pet-functionality.webp" loading="lazy" alt="Two alligator clips connect to a circuit printed on paper, the ink that makes up the printed Voltera logo glows in the dark" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;Final print on paper</figcaption></figure><h2 id="">Printing the electroluminescent Voltera logo</h2><h3 id="">Base conductive layer</h3><p id="">This layer consists of a Voltera logo pattern (55.5 mm L × 19.75 mm W) and positive and negative traces that connect to power and ground terminals. </p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/6633ceca359ea3df5b90bf76_Applications_Electroluminescent%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349c3_67091b1d9aa70f5ad577fd0b_Printing-electroluminescent-ink-base-conductive-layer-settings.webp" loading="lazy" alt="NOVA settings for base conductive layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 4:&nbsp;NOVA&nbsp;settings, base conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349d2_67091b3ba4c7564aec9fc4c0_Printing-electroluminescent-ink-base-conductive-layer-paper-result.webp" loading="lazy" alt="Base conductive layer printed onto paper" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;Result on paper, base conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a00_67091b566f34a25480b46ae4_Printing-electroluminescent-ink-base-conductive-layer-pet-result.webp" loading="lazy" alt="Base conductive layer printed on PET" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;Result on PET, base conductive layer</figcaption></figure><h3 id="">Dielectric layer</h3><p id="">This layer features a dielectric Voltera logo pattern which measures 23 mm L × 15 mm W and two dielectric pads. These extra pads help ensure the top conductive layer is appropriately insulated.</p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/6633ceca3745e8a644821d08_Applications_Electroluminescent%20table%202.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349c0_67091b7716905ac65aa4e290_Printing-electroluminescent-ink-dielectric-layer-settings.webp" loading="lazy" alt="NOVA settings for the dielectric layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 7:&nbsp;NOVA settings, dielectric layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349cf_67091b9107b512cf5a4ae562_Printing-electroluminescent-ink-dielectric-layer-paper-result.webp" loading="lazy" alt="Dielectric layer printed on paper" width="auto" height="auto" id=""></div><figcaption id="">Figure 8:&nbsp;Result on paper, dielectric layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a15_67091bafbdc7f308274eea1a_Printing-electroluminescent-ink-dielectric-layer-pet-result.webp" loading="lazy" alt="Dielectric layer printed on PET" width="auto" height="auto" id=""></div><figcaption id="">Figure 9:&nbsp;Result on PET, dielectric layer</figcaption></figure><h3 id="">Phosphor layer</h3><p id="">This layer contains a Voltera logo pattern, slightly smaller than the dielectric layer (by 0.5 mm each way), printed with blue light-emitting ink.</p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/6633ceca0e5019bd03401730_Applications_Electroluminescent%20table%203.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349c9_67091bcf07c69e92aba81f70_Printing-electroluminescent-ink-phosphor-layer-settings.webp" loading="lazy" alt="An image showing NOVA settings for the phosphor layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 10:&nbsp;NOVA&nbsp;settings, phosphor layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349d5_67091be50886a22f6b31099d_Printing-electroluminescent-ink-phosphor-layer-paper-result.webp" loading="lazy" alt="Phosphor layer printed on paper" width="auto" height="auto" id=""></div><figcaption id="">Figure 11:&nbsp;Result on paper, phosphor layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a1e_67091c028b83f4ea5977853c_Printing-electroluminescent-ink-phosphor-layer-pet-result.webp" loading="lazy" alt="NOVA settings for the phosphor layer" width="auto" height="auto" id=""></div><figcaption id="">Figure 12:&nbsp;Result on PET, phosphor layer</figcaption></figure><h3 id="">Top conductive layer</h3><p id="">Lastly, this layer includes a conductive overlay with an opening at the bottom left to prevent short circuiting. It measures 29.5 mm L × 21.5 mm W and connects to the ground terminal.</p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/6633cecaeaa1520a2637badc_Applications_Electroluminescent%20table%204.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ba38b9d9305e349db_67091c23c63ef691b7477c26_Printing-electroluminescent-ink-top-conductive-layer-settings.webp" loading="lazy" alt="Top conductive layer print settings on NOVA" width="auto" height="auto" id=""></div><figcaption id="">Figure 13:&nbsp;NOVA settings, top conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a12_67091c394819899b375fb8eb_Printing-electroluminescent-ink-top-conductive-layer-paper-result.webp" loading="lazy" alt="Top conductive layer printed on paper" width="auto" height="auto" id=""></div><figcaption id="">Figure 14:&nbsp;Result on paper, top conductive layer</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a18_67091c534ec56a943f81fc4f_Printing-electroluminescent-ink-top-conductive-layer-pet-result.webp" loading="lazy" alt="Top conductive layer printed on PET" width="auto" height="auto" id=""></div><figcaption id="">Figure 15:&nbsp;Result on PET, top conductive layer</figcaption></figure><h2 id="">Challenges and advice for printing multilayer electroluminescent displays</h2><h3 id="">Trapped air</h3><p id="">Air bubbles can form in inks that have been left unused for an extended period. These bubbles caused the dielectric layer to break when we cured it in the oven.&nbsp;</p><p id="">Mixing the ink with a dual asymmetric centrifugal mixer before printing will eliminate air bubbles. Additionally, it is recommended to allow the dielectric layer to dry naturally at room temperature instead of curing it in an oven.&nbsp;</p><h3 id="">Uneven glow&nbsp;</h3><p id="">During our experiments, some prints exhibited dark areas, leading to an uneven glow. This issue can arise from several factors:&nbsp;</p><ul id=""><li id="">The top conductive layer being too thick</li><li id="">The phosphor layer being too thin or getting scratched off during dispensing of the ink for the top conductive layer</li><li id="">Irregularities in print height</li></ul><p id="">Adding fiducials to each layer helps improve alignment and print quality. In terms of print settings, if the layer is too thick, increasing the print speed, reducing the height (we reduced it to approximately 40 µm), and using a smaller nozzle can be helpful. If the layer is too thin, try to reduce the print speed.&nbsp;</p><p id="">Furthermore, in multilayer projects, changes in height can happen drastically when printing over existing traces. Setting a low probe pitch will make the height map more accurate, ensuring the height transition at the edges of features is accurate and reducing the risk of traces being printed off-course.</p><h2 id="">Conclusion</h2><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67091c8ca38b9d9305e34a03_67091c71bdc7f308274f8ff7_Printing-electroluminescent-ink-paper-pet-conclusion.webp" loading="lazy" alt="Alligator clips connect to a circuit printed on paper, the ink on the paper glows" width="auto" height="auto" id=""></div><figcaption id="">Figure 16:&nbsp;Electroluminescent logo final print</figcaption></figure><p id="">The paper substrate provided consistent results throughout our experimentation, due to its absorbent nature. Each layer was smoother on paper than on PET, highlighting the potential of using paper as a substrate in EL display applications.&nbsp;&nbsp;</p><p id="">On the other hand, PET, being flexible and chemically resistant, offers the advantage of suitability for more demanding use cases. As demonstrated by this project, with careful attention and fine-tuning of the print settings, the results of EL display on PET are equally impressive.</p><p id="">EL displays are also intriguing when printed on glass and other non-conductive substrates. As we continue to explore the possibilities of electroluminescent inks, we invite you to view the <a href="https://www.voltera.io/applications" id="">other projects</a> we’ve completed.</p>

Printing Electroluminescent Ink on Paper and PET

Discover the design and printing process for a uniformly illuminated electroluminescent display printed on PET and paper using Saral’s conductive inks, phosphor ink, and dielectric ink.

Printing Electroluminescent Ink on Paper and PET | Voltera

electroluminescent

Electroluminescent Ink

See how we printed an electroluminescent display on PET and paper using Saral’s conductive inks, phosphor ink, and dielectric ink — all on our NOVA dispensing platform.

<figure class="w-richtext-figure-type-video w-richtext-align-center" style="padding-bottom:33.723653395784545%" data-rt-type="video" data-rt-align="center" data-rt-max-width="" data-rt-max-height="33.723653395784545%" data-rt-dimensions="854:480" data-page-url="https://www.youtube.com/watch?v=EZNg21U0loE"><div><iframe allowfullscreen="true" frameborder="0" scrolling="no" src="https://www.youtube.com/embed/EZNg21U0loE" title="Printing a Heated Glove on Cotton with Voltera NOVA"></iframe></div></figure><h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to create&nbsp; a heated mitten utilizing silver conductive ink printed directly onto cotton fabric, as well as validate optimal print settings for working with cotton fabric as a substrate.</p><h3 id="">Design&nbsp;</h3><p id="">We designed a heating element pattern made up of meander lines that resemble a hand with a trace width of 5 mm. We left an opening near the wrist for inserting metal snaps that connect the printed circuit to the power source. We planned to print on both sides of the fabric to allow the ink to penetrate the fibers evenly.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092a8e2bf9d5ed6bb54246_67082a82a2bd04a9555ca35d_heated-glove-cotton-fabric-design-layout.webp" loading="lazy" alt="Heat element design" width="auto" height="auto" id=""></div><figcaption id="">Figure 1: The heat element circuit</figcaption></figure><h3 id="">Desired outcome</h3><p id="">The goal was to create a functional heated mitten capable of reaching 40°C when powered by a 12V power source, with the duration depending on the battery used and ambient temperature. The cured ink should remain both conductive and stretchable, maintaining its integrity as the hand flexes and relaxes.</p><h3 id="">Functionality</h3><p id="">The printed conductive traces heated up to 40°C when powered at 12V, with the mitten’s temperature adjusting based on different voltage inputs. An internal liner protects the user from direct contact with the heat element, ensuring both comfort and safety.&nbsp;</p><p id="">While this proof of concept was not designed to be wireless, integrating an embedded power supply could make the mitten portable. It could be further customized with a thermistor and LEDs for temperature control and status indication, along with water- and scratch-resistant materials to withstand extreme weather conditions.</p><h2 id="">Printing the heat-generating conductive traces</h2><h3 id="">Preparing the fabric substrate</h3><p id="">Before printing, we ironed the cotton fabric substrate using a heat press machine at 200°C for about 10 seconds to eliminate any wrinkles or surface irregularities, as a smooth surface is essential for optimal ink adhesion. We then used Kapton tape on the bottom side of the fabric to secure the porous fabric to the vacuum bed for the printing process.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092a8e2bf9d5ed6bb54240_670928dc2a5c3a95b1f391f6_heated-glove-cotton-fabric-attach-kapton.webp" loading="lazy" alt="Kapton being applied" width="auto" height="auto" id=""></div><figcaption id="">Figure 2: Attaching Kapton tape to the cotton fabric</figcaption></figure><h3 id="">Printing the circuits</h3><p id="">We chose the ACI SH5025 Printed Fixed Resistance Heater Ink to print the heating pattern on both sides of the cotton fabric, because this ink is optimized for heating applications integrated onto elastomeric substrates. It not only exhibits a prescribed resistance value when cured, it also has excellent stretchability.</p><p id="">[script]https://cdn.prod.website-files.com/6334888a34bfac591c6aa6e9/670821ff6324d226fa90b380_Applications_heated%20glove%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092bbec257ad43bc5e482d_67092b643f746425b5f7b1f3_heated-glove-cotton-fabric-print-settings.webp" loading="lazy" alt="An image showing NOVA print settings" width="auto" height="auto" id=""></div><figcaption id="">Figure 3: NOVA print settings</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092a8e2bf9d5ed6bb54276_6709298c46eca33cec276e7e_heated-glove-cotton-fabric-heat-element.webp" loading="lazy" alt="Heat element being printed" width="auto" height="auto" id=""></div><figcaption id="">Figure 4: Printing the heat element</figcaption></figure><p id="">Once the first side was printed, the circuit was cured in an oven for 5 minutes at 135°C. We then took out the fabric, removed the Kapton tape, and applied it to the opposite side. With the aid of a marker, we aligned the features in the software with the printed features on the mitten, and started printing on the opposite side to ensure full connectivity and coverage of the heating elements.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092a8e2bf9d5ed6bb5427a_670929df83f184b18ebc4965_heated-glove-cotton-fabric-curing-topside.webp" loading="lazy" alt="The print being cured" width="auto" height="auto" id=""></div><figcaption id="">Figure 5: Curing the top side</figcaption></figure><h2 id="">Post-processing the mitten</h2><p id="">Because the heated element could reach up to 60°C with a high voltage, we sewed the printed pattern to a liner to protect the user from direct contact with the heated element. We then put the liner into a Voltera branded mitten, inserted a pair of metal snaps, and connected them to power. The mitten heated quickly, as shown by our thermal camera.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67092a8e2bf9d5ed6bb54252_67092a315bb93f90a2d53301_heated-glove-cotton-fabric-thermal-camera.webp" loading="lazy" alt="Camera reading" width="auto" height="auto" id=""></div><figcaption id="">Figure 6: Thermal camera reading 44.2°C</figcaption></figure><h2 id="">Challenges and advice</h2><h3 id="">Choosing the right fabric&nbsp;</h3><p id="">Printing on fabric presented several challenges. First, loose weaves can cause the tip of the nozzle to snag or lead to poor ink permeability. As such, choosing tightly woven fabric was critical to the success of this project. We also found that ironing the fabric ensured a uniform surface, and significantly improved print quality.</p><h3 id="">Retaining conductivity for stretchability&nbsp;&nbsp;</h3><p id="">During our first few attempts, we discovered that while the ink is labeled stretchable, it relies heavily on the fabric's properties for flexibility. Setting the nozzle to a low height with a slow print speed and high pressure greatly improved the durability of the printed circuits, as it allowed the ink to saturate the fabric, rather than sitting on the surface.&nbsp;</p><h2 id="">Conclusion</h2><p id="">The printed traces of the mitten reached temperatures of 40°C when powered by a 12V source, and the mitten's temperature could be adjusted by varying the voltage. By optimizing print settings, such as lowering the nozzle height, using high pressure, and printing on both sides of the fabric, we achieved strong ink penetration and conductivity.</p><p id="">While this proof of concept was not wireless, it opens the door for future upgrades. The ability to print directly onto fabric opens up numerous possibilities for consumer and research applications, such as heated clothing for outdoor activities, medical wearables for circulation improvement, and smart textile electronics for advanced monitoring and control.&nbsp;</p><p id="">As we continue to explore the possibilities of wearables, we invite you to view the<a href="https://www.voltera.io/applications/" id=""> other projects</a> we’ve completed.</p>

Printing Silver Conductive Ink on Cotton Fabric

Discover the design and printing process of a functional heated mitten using stretchable silver conductive ink directly onto a cotton fabric. 

Printing Silver Conductive Ink on Cotton Fabric | Voltera

cotton

Printing on Cotton Fabric

This project demonstrated how we used NOVA to print stretchable silver conductive ink directly onto cotton fabric to create a functional heated mitten. 

<h2 id="">Project Overview</h2><h3 id="">Purpose</h3><p id="">The purpose of this project was to demonstrate how we used <a href="https://www.voltera.io/nova" id="">NOVA</a> and <a href="https://www.voltera.io/v-one" id="">V-One</a> to create a wearable device — a glove equipped with printed strain gauges — to transmit signals to a robotic hand, enabling the robotic hand to mimic human hand movements.</p><h3 id="">Design</h3><p id="">We divided the design into three main parts:</p><ol id=""><li id="">The glove with strain gauges</li><li id="">The 3D printed robotic hand</li><li id="">The breakout PCB boards</li></ol><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/66aa40d4821adfb61c989244_668d86e25b181507a92e5aa0_Printing-strain-gauges-design-overview.webp" loading="lazy" alt="Design overview" width="auto" height="auto" id=""></div><figcaption id="">Figure 1: Design overview</figcaption></figure><p id="">The Arduino Uno takes data from each strain gauge printed on the glove, and the nRF24L01+ transmitter module sends data to the receiver module. Upon receiving the data, the other Arduino Uno sends signals to the servos, which manipulate the robotic fingers.&nbsp;</p><h3 id="">Desired outcome</h3><p id="">Once the two controllers are connected to power, the robotic hand is able to mimic the movement of the human hand wearing the glove. As the hand moves and stretches the strain gauges on the glove, the strain gauges remain conductive and exhibit a measurable change in resistance.</p><h3 id="">Functionality</h3><p id="">The fingers on the robotic hand could bend up to 60°, allowing the hand to grab and grip a medium sized object, such as a mug. Depending on its intended use, more components could be added to increase the glove’s complexity. For example, adding gyro sensors could allow for features like orientation detection while performing tasks in variable terrains.</p><h2 id="">Printing PCBs and wearable strain gauges</h2><h3 id="">The glove with strain gauges</h3><p id="">We needed a wearable device to encase a hand, receive pressure feedback, and send signals to the controller. To meet this requirement, we printed conductive traces on a sheet of TPU, covered the traces with another layer of TPU for protection, and laminated the layers onto an off-the-shelf gardening glove.</p><p id="">[script]https://uploads-ssl.webflow.com/6334888a34bfac591c6aa6e9/668d764615860628c29a20d4_Robotic%20hand%20white%20paper%20table%201.txt[/script]</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab2b_67125e68cfe525e44f1c92ce_Printing-strain-gauges-glove-settings.webp" loading="lazy" alt="NOVA print settings for PE874 material" width="auto" height="auto" id=""></div><figcaption id="">Figure 2:&nbsp;NOVA print settings</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/66aa40d4821adfb61c98922f_668d7c95e40c3d1e83dd7e93_Printing-strain-gauges-circuit-design.webp" loading="lazy" alt="Circuit design of the strain gauges" width="auto" height="auto" id=""></div><figcaption id="">Figure 3:&nbsp;Strain gauge circuit design</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/66aa40d4821adfb61c989256_668d870127c0b064dee5b346_Printing-strain-gauges-glove-traces-laminated.webp" loading="lazy" alt="Glove with conductive traces laminated" width="auto" height="auto" id=""></div><figcaption id="">Figure 4: glove with conductive traces laminated</figcaption></figure><p id="">Depending on finger and hand size, the dimensions of the traces can vary. In our case, we designed the traces to be proportional to the purchased glove, making the circuits for the thumb and pinky finger shorter than those for the other fingers. From left to right, the traces correspond to the pinky, ring, middle, index, and thumb, respectively.&nbsp;</p><p id="">The traces form a meander that runs up and down the length of the fingers, creating a longer trace length to make the strain gauge more sensitive to bending. We bonded the wires to the conductive pads at the bottom of each circuit using a conductive adhesive. These wires connect the pads to the transmitter board.&nbsp;</p><p id="">To mount the transmitter board, we 3D printed a wrist wrap base using PLA filament. After mounting it to the base, we threaded a band through the narrow openings on either side of the base, securing the board on the forearm.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab13_67125e91d6a28d0aaf7aab74_Printing-strain-gauges-glove-render-wrist-strap.webp" loading="lazy" alt="A 3D render of the base for the wrist strap" width="auto" height="auto" id=""></div><figcaption id="">Figure 5:&nbsp;Render for the wrist strap base</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/66aa40d4821adfb61c98925a_668d7d33b767fdbe51525e52_Printing-strain-gauges-wrist-strap.webp" loading="lazy" alt="Printed wrist strap secured to wrist and attached to circuit board" width="auto" height="auto" id=""></div><figcaption id="">Figure 6:&nbsp;Wrist strap secured to wrist</figcaption></figure><h3 id="">The 3D printed robotic hand</h3><p id="">Apart from the glove with strain gauges, we also needed a robotic hand to mimic and execute the movements of the human hand. We 3D printed the hand with flexible fingers using a readily available<a href="https://www.thingiverse.com/thing:242639" id=""> .stl file</a>, with PLA and TPU filaments for different parts:</p><ul id=""><li id="">TPU Filament: Used for the joints and tendons of the hand</li><li id="">PLA Filament: Used for the hand and the base</li></ul><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/66aa40d4821adfb61c989228_668d88dd5a6388bcc0341229_printing-strain-gauges-robotic-hand-render.webp" loading="lazy" alt="Render for the robotic hand" width="auto" height="auto" id=""></div><figcaption id="">Figure 7: <a href="https://www.thingiverse.com/thing:242639" id="">Render for the robotic hand</a></figcaption></figure><p id="">We also designed and 3D printed a base for the hand that houses five servo motors. The servo motors were connected to wires that were run internally as “tendons” through the fingers.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f78870b94723035ab0e_67125eccb807dbb72ae6888f_Printing-strain-gauges-glove-render-hand-base.webp" loading="lazy" alt="A 3D render of the base for the robot hand" width="auto" height="auto" id=""></div><figcaption id="">Figure 8:&nbsp;Render for the robotic hand base</figcaption></figure><h3 id="">The breakout PCB boards</h3><p id="">A crucial component of this project was its controllers: two breakout boards mounted on Arduino Unos. The breakout boards were customized to act as transmitter and receiver, respectively.</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab16_67125ef947a508f72a466efa_Printing-strain-gauges-glove-transmitter-board-schematic.webp" loading="lazy" alt="Circuit design for the transmitter board" width="auto" height="auto" id=""></div><figcaption id="">Figure 9:&nbsp;Schematic for the transmitter board</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab1a_67125f1aee86ae4f6ad1662a_Printing-strain-gauges-glove-receiver-board-schematic.webp" loading="lazy" alt="Circuit design for the receiver board" width="auto" height="auto" id=""></div><figcaption id="">Figure 10:&nbsp;Schematic for the receiver board</figcaption></figure><p id="">We used the <a href="https://www.voltera.io/v-one" id="">Voltera V-One PCB printer</a> to drill vias on the boards, and printed the traces using Voltera Conductor 2 silver ink (discontinued, replaced by <a href="https://store.voltera.io/products/conductor-3-ink-cartridge-2ml" id="">Conductor 3</a>). We then dispensed solder paste and mounted a series of components including resistors, integrated circuits, batteries, and nRF24L01+ 2.4 GHz transceiver modules.&nbsp;</p><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab6d_67125f3b0054dba92e43a868_Printing-strain-gauges-glove-transmitter-board.webp" loading="lazy" alt="The printed transmitter board mounted on the wrist strap" width="auto" height="auto" id=""></div><figcaption id="">Figure 11:&nbsp;The printed transmitter board</figcaption></figure><figure id="" class="w-richtext-figure-type-image w-richtext-align-center" data-rt-type="image" data-rt-align="center"><div id=""><img src="https://cdn.prod.website-files.com/6334888a34bfac03b46aa715/67125f79870b94723035ab4b_67125f5ccb0e01e6d1df0e5a_Printing-strain-gauges-glove-receiver-board.webp" loading="lazy" alt="The printed receiver board sitting on a table" width="auto" height="auto" id=""></div><figcaption id="">Figure 12:&nbsp;The printed receiver board</figcaption></figure><p id="">As a final step, we connected the wires, starting with the pinky finger connecting to the leftmost port, followed by the other fingers in sequence. The robotic hand is now able to function as intended.</p><h2 id="">Challenges and advice for printing stretchable circuits</h2><p id="">Although the DuPont™ Intexar™ PE874 Stretchable Silver Conductor Ink is stretchable, it required some trial and error to allow the gauges to fully stretch without losing conductivity, while still providing a measurable change in resistance.</p><p id="">We found that printing thicker traces (about 1 mm in line width) worked better and offered more consistent continuity while stretching. We recommend decreasing the print speed, increasing print height, or using a larger nozzle for better results.</p><h2 id="">Conclusion</h2><p id="">Through this project, we developed a wearable device that controls a robotic hand through printed strain gauges on a glove. This hand, capable of mimicking human movements, highlights its potential application in fields such as prosthetics, where robotic hands enable amputees or those with limb differences to control artificial limbs intuitively.</p><p id="">In addition, robotic hands can be used in hazardous environment operations, such as handling hazardous materials, performing tasks in extreme temperatures, or in conditions with toxic exposure. Operators can use this technology to minimize the risk for humans, while still maintaining control.</p><p id="">In virtual reality (VR) and augmented reality (AR) applications, such as training simulations, gaming, and special educational tools, using robotic hands allows for immersive experience. As we continue to explore the possibilities of wearable electronics, we invite you to view the <a href="https://www.voltera.io/applications" id="">other projects</a> we’ve completed.</p>

Printing Strain Gauges on TPU laminated on a Glove for Remote Hand Control

Discover the design and printing process of a wearable circuit that controls a robotic hand on TPU with stretchable conductive silver ink.

Printing Strain Gauges on a Glove for Remote Hand Control | Voltera

robotic-hand

Strain Gauges on a Glove

This project demonstrates how NOVA and V-One printed a wearable circuit that controls a robotic hand on TPU with stretchable conductive silver ink.

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