<section id="isPasted"><p>Soft lithography creates three-dimensional patterns and structures at the microscale and nanoscale levels. Unlike photolithography, a fabrication technique used by the semiconductor industry, soft lithography produces microfluidic devices, microarrays, and microelectromechanical systems (MEMS). The “soft” in <a href="https://www.sciencedirect.com/topics/materials-science/soft-lithography" target="_blank">soft lithography</a> refers to its use of mechanically soft materials such as polydimethylsiloxane (PDMS) to produce a stamp or mold. Lithography is a printing process that renders an image on a flat surface.</p></section><section><h2><strong>How Soft Lithography Works</strong></h2><p>During soft lithography, a master mold with the desired microscale or nanoscale pattern is fabricated. Computer-aided design (CAD) software is used to produce this pattern, and traditional microfabrication techniques are used to produce the master mold. These fabrication techniques include photolithography, which uses light to etch features, and electron beam lithography, which patterns features with an accelerated beam of electrons. To achieve nanoscale features, nanoimprint lithography can be used.</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1726560423573-21-BMF-0056-Molding-Graphic-V1.png" style="width: 100%px;" class="fr-fic fr-dib"><span class="fr-inner">CAD Drawing of a PDMS Mold</span></span></span></p><section id="isPasted"><p>It’s important to note that soft lithography’s master mold is not made of PDMS. Rather, it’s made of a material such as chrome-coated glass, which is light-sensitive. When this photosensitive material is exposed to light during photolithography, it loses its resistance to etching. To produce the desired pattern, a photomask with transparent areas allows light to shine through. In other words, the photomask determines where the light shines onto the chrome-coated glass and, in turn, where patterns are etched.</p><p>Next, a liquid polymer such as PDMS is poured into the etched areas or channels of the master mold and allowed to cure, typically at an elevated temperature of ∼70°C overnight. After the PDMS hardens, it is peeled away from the mold. This PDMS stamp, as it’s known, carries the reverse pattern of the master mold and is pressed onto the target substrate. Through physical contact, capillary action, bonding, or other surface actions, the pattern is applied. Various substrate materials, including glass slides, can be used.</p></section><section><h2><strong>How Soft Lithography Compares to 3D Printing</strong></h2><p>Like soft lithography, 3D printing can create structures at the microscale and nanoscale levels; however, many 3D printers are limited to the macroscale. In addition, most (but not all) 3D printers can’t match soft lithography in terms of resolution. 3D printing also has some things in common with photolithography, which is commonly used with soft lithography. Both photolithography and resin 3D printing, a group of 3DP technologies, use a light source and a polymer. Yet that’s where the similarities end.</p><p>During soft lithography, material is removed to create features such as microchannels. In a subsequent step, a liquid polymer such as PDMS is poured into these channels and allowed to cure, typically with the application of heat. By contrast, resin 3D printing adds rather than subtracts material. The material that is added is a polymer, but this polymer cures or hardens with the application of light rather than heat. In addition, this photosensitive polymer is added one layer at a time rather than poured all at once.</p><p>There isn’t just one type of resin 3D printing, however. Members of this technology family include stereolithography (SLA), digital light processing (DLP), and projection micro stereolithography (PµSL). SLA and DLP are generally used for macroscale rather than microscale and nanoscale applications. By contrast, PµSL technology from Boston Microfabrication (BMF) is designed for microscale 3D printing. For applications such as microfluidics, BMF’s microArch® series of 3D printers can replace soft lithography.</p></section><section><h2><strong>Soft Lithography vs. P</strong><strong>µ</strong><strong>SL 3D Printing</strong></h2><p>Unlike soft lithography, PµSL 3D Printing uses a machine rather than a master mold and a press for a PDMS stamp. Even more importantly, this form of resin 3D printing can create complex 3D channels that are difficult if not impossible to achieve with soft lithography. In addition to achieving high accuracy, precision, and resolution, PµSL 3D printing eliminates the challenge of using soft lithography to cut microscale features into layers and then bond these layers together to create one functioning device.</p><hr><p>To learn more about PµSL 3D Printing for microfluidics,&nbsp;<a href="https://bmf3d.com/resource/the-importance-of-machine-tolerance/" target="_blank" rel="noopener" id="isPasted">download this white paper</a>. BMF also invites you to examine our&nbsp;<a href="https://bmf3d.com/ultra-high-resolution-3d-printers/" target="_blank" rel="noopener">microArch® series of 3d printers</a> and to&nbsp;<a href="https://bmf3d.com/contact/" target="_blank" rel="noopener">contact us</a> with your questions.</p></section></section>

Soft lithography creates three-dimensional patterns and structures at the microscale and nanoscale levels. Unlike photolithography, a fabrication technique used by the semiconductor industry, soft lithography produces microfluidic devices, microarrays, and microelectromechanical systems (MEMS).

What is Soft Lithography and How Does It Compare to 3D Printing?

<p id="isPasted">To advance soft robotics, skin-integrated electronics and biomedical devices, researchers at Penn State have developed a 3D-printed material that is soft and stretchable — traits needed for matching the properties of tissues and organs — and that self-assembles. Their approach employs a process that eliminates many drawbacks of previous fabrication methods, such as less conductivity or device failure, the team said. &nbsp;</p><p>They published their results in <a href="https://onlinelibrary.wiley.com/doi/10.1002/adma.202400082" target="_blank">Advanced Materials</a>. &nbsp;&nbsp;</p><p>“People have been developing soft and stretchable conductors for almost a decade, but the conductivity is not usually very high,” said corresponding author Tao Zhou, Penn State assistant professor of engineering science and mechanics and of biomedical engineering in the College of Engineering and of materials science and engineering in the College of Earth and Mineral Sciences. “Researchers realized they could reach high conductivity with liquid metal-based conductors, but the significant limitation of that is that it requires a secondary method to activate the material before it can reach a high conductivity.”&nbsp;</p><p>Liquid metal-based stretchable conductors suffer from inherent complexity and challenges posed by the post-fabrication activation process, the researchers said. The secondary activation methods include stretching, compressing, shear friction, mechanical sintering and laser activation, all of which can lead to challenges in fabrication and can cause the liquid metal to leak, resulting in device failure. &nbsp;&nbsp;</p><p>“Our method does not require any secondary activation to make the material conductive,” said Zhou, who also has affiliations with the Huck Institutes of the Life Sciences and the Materials Research Institute. “The material can self-assemble to make its bottom surface be very conductive and its top surface self-insulated.”&nbsp;</p><p>In the new method, the researchers combine liquid metal, a conductive polymer mixture called PEDOT:PSS and hydrophilic polyurethane that enables the liquid metal to transform into particles. When the composite soft material is printed and heated, the liquid metal particles on its bottom surface self-assemble into a conductive pathway. The particles in the top layer are exposed to an oxygen-rich environment and oxidize, forming an insulated top layer. The conductive layer is critical for conveying information to the sensor — such as muscle activity recordings and strain sensing on the body — while the insulated layer helps prevent signal leakage that could lead to less accurate data collection.&nbsp;</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 790px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1719495196118-240205-psnbody1-tao.jpg" style="width: 100%px;" class="fr-fic fr-dib"><span class="fr-inner">The new material, shown here, can self-assemble to make its bottom surface conductive and its top surface self-insulated. <span data-testid="credit" id="isPasted">Credit: Marzia Momin. All Rights Reserved.</span></span></span></span></p><p id="isPasted">“Our innovation here is a materials one,” Zhou said. “Normally, when liquid metal mixes with polymers, they are not conductive and require secondary activation to achieve conductivity. But these three components allow for the self-assembly that produces the high conductivity of soft and stretchable material without a secondary activation method.” &nbsp;</p><p>The material can also be 3D-printed, Zhou said, making it easier to fabricate wearable devices. The researchers are continuing to explore potential applications, with a focus on assistive technology for people with disabilities.&nbsp;</p><p>The papers other authors are Salahuddin Ahmed, Marzia Momin and Jiashu Ren, all doctoral students in the Penn State engineering science and mechanics department, and Hyunjin Lee, a doctoral student in the biomedical engineering department at Penn State. This work was supported by the National Taipei University of Technology-Penn State Collaborative Seed Grant Program and by the Department of Engineering Science and Mechanics, the Materials Research Institute and the Huck Institutes of the Life Sciences at Penn State.&nbsp;</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 790px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1719495222063-240205-psnbody2-tao.jpg" style="width: 100%px;" class="fr-fic fr-dib"><span class="fr-inner">The researchers 3D print the novel material.&nbsp;<span data-testid="credit" id="isPasted">Credit: Marzia Momin. All Rights Reserved.</span></span></span></span></p><p><br></p>

Penn State researchers developed a new soft and stretchable material that can be 3D-printed. The material can be used to fabricate wearable devices, such a sensor that can be worn on a finger, as shown here. Credit: Marzia Momin. All Rights Reserved.

To advance soft robotics, skin-integrated electronics and biomedical devices, researchers at Penn State have developed a 3D-printed material that is soft and stretchable — traits needed for matching the properties of tissues and organs — and that self-assembles.

Self-assembling, highly conductive sensors could improve wearable devices

<p id="isPasted">In this article, we have a look at one of the most common inkjet problems seen by our customers: satellite drops. Satellites, the small droplets unintentionally formed during jetting, can cause major print quality and system maintenance headaches. We will discover that there are multiple potential causes of satellites and explore some of the ways to minimize their formation and effect. This post was produced with knowledge and data contributed by <a target="_blank" rel="noopener noreferrer" href="https://www.systemceramics.com/en">System Ceramics</a>, a leader in the inkjet ceramics market.</p><h3>Tell-tale Signs</h3><p>One easy way that you might be able to identify the presence of satellite drops and mist (exceptionally small satellites) is by looking at your printer itself. If you open up the printer and the inside is a nice shade of CMYK, then you have determined that you have satellites. By studying the color, you might even be able to identify if a particular ink has worse satellite problems than the others.</p><p>If you happen to have a JetXpert dropwatcher already, you might be able to see satellites in the jetting itself. We have labelled some of the parts of the image to introduce some terminology that we’ll use throughout this article.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Minimize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDE5OTgwLTE3MTc3MDEwMTk5ODAucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p>Satellites also show up in the printed substrate. In multiple-pass printers, such as those used in graphics, satellite drops are most often seen as an “overspray” effect at the ends of the carriage where the airflow is dominated by the entrained flow under the carriage. In the middle of the carriage, satellite drops can often be seen surrounding print detail like text.</p><p data-placeholder="Write here. You can also include @mentions."><br></p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Minimize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDE5OTg5LTE3MTc3MDEwMTk5ODkuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p>If the carriage speed is higher or the print gap is larger, then the effects tend to be worse. This is for two reasons: (1) the turbulence from airflow interactions can increase significantly and (2) the stray satellite drops have more distance over which to decelerate and thus become misdirected.</p><div contenteditable="false"><hr></div><h3>What Causes Satellites?</h3><p>The process of forming inkjet drops essentially involves squeezing a low-viscosity fluid through a tiny hole, which can subject the fluid to quite a lot of forces. The harder the ink is pushed, the more stress on the fluid, and the more formulation details, like viscosity, surface tension and particle content, impact the drop formation behaviour.</p><p>An interesting finding is that the number of satellites formed is often proportional to the ligament length, which in turn is also proportional to several measurable characteristics of your system. System Ceramics presents the formula for ligament length as follows:</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDA4LTE3MTc3MDEwMjAwMDguanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p>As you can see, some of these aspects of the system are for the most part fixed (e.g. nozzle diameter, density) whereas some of them you have control over. Keep this in mind as we look at potential solutions for the satellite problem.</p><hr><p><strong>We are giving a masterclass at the </strong><a href="https://www.techblick.com/electronicsreshaped" target="_blank" rel="noopener noreferrer"><strong>Future of Electronics RESHAPED conference and exhibition</strong></a><strong> in Berlin on 23 &amp; 24 OCT 2024. Please join us and learn the latest</strong></p><p><a href="https://www.techblick.com/electronicsreshaped" target="_blank" rel="noopener noreferrer"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1724682147416-ImageXpert+-+MC+Speaker+Cards+%28BERLIN-Oct-2024%29.jpg" style="width: 100%px;" class="fr-fic fr-dib"></a></p><h3>Impact Of Waveform</h3><p>Because satellites are formed by forces on the fluid, and the waveform provides the driving force behind jetting, investigating the design of your waveform seems like a logical place to begin. Let’s make a real comparison of what happens as a print head is driven to higher and higher drop velocity by increasing the amplitude of the waveform. The first image (created using <a target="_blank" rel="noopener noreferrer" href="https://imagexpert.com/drop-analysis/dropwatcher-add-ons/">JetXpert Stitch</a>) is the drop formation at 16V waveform amplitude, the second is that same drop formation at 20V. Remember from our formula above that ligament length (and number of satellites) is directly proportional to drop velocity. The practical results show the same thing: at higher voltages the ligament is longer, the drop is traveling faster, and there are more satellites.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDE2LTE3MTc3MDEwMjAwMTYuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p>As you can see, some of these aspects of the system are for the most part fixed (e.g. nozzle diameter, density) whereas some of them you have control over. Keep this in mind as we look at potential solutions for the satellite problem.</p><h3>Impact Of Waveform</h3><p>Because satellites are formed by forces on the fluid, and the waveform provides the driving force behind jetting, investigating the design of your waveform seems like a logical place to begin. Let’s make a real comparison of what happens as a print head is driven to higher and higher drop velocity by increasing the amplitude of the waveform. The first image (created using <a target="_blank" rel="noopener noreferrer" href="https://imagexpert.com/drop-analysis/dropwatcher-add-ons/">JetXpert Stitch</a>) is the drop formation at 16V waveform amplitude, the second is that same drop formation at 20V. Remember from our formula above that ligament length (and number of satellites) is directly proportional to drop velocity. The practical results show the same thing: at higher voltages the ligament is longer, the drop is traveling faster, and there are more satellites.</p><div contenteditable="false"><hr></div><h3>We are Exhibiting in Boston.</h3><p><strong>Let's RESHAPE the Future of Electronics together, making it Additive, Sustainable, Flexible, Hybrid, &nbsp;Wearable, Structural, and 3D.</strong></p><p>Visit our booth at this long-awaited <a rel="noopener noreferrer" href="https://www.techblick.com/electronicsreshapedusa" target="_blank">TechBlick US event on 12-13 June 2024 in Boston</a>. This is the most important industry and research meeting in our field in the US.</p><div contenteditable="false"><hr></div><h3>Impact Of Ink Formulation</h3><p>If waveform optimization is not enough to eliminate satellites, modifying the ink itself is another option. The study of fluids under stress and shear is called rheology, and the inkjet process is so extreme that it has driven a lot of studies into inventing techniques that can try and predict things like satellite drops. A lot of research groups have studied model systems and real fluids and come up with some helpful rules, based on so-called dimensionless variables (like Weber number, or Ohnesorge number). The issue is that a lot of different fluid measurements are required to be able to calculate these quantities, which might not be for everyone. Here we try to simplify things down to two important variables: viscosity and surface tension.</p><p>Viscosity is always going to be an important variable in inkjet because it defines how easily the inks will flow through the head channels and squeeze out of the nozzle. In this case, it also influences how the ligament might extend before pinching off or breaking up. Based on our formula above, a lower viscosity should produce shorter ligaments and fewer satellites. Practical experimentation also suggests the same. System Ceramics performed a test where the viscosity was lowered for otherwise identical fluids, producing drops that had shorter ligaments without loss in velocity.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDM1LTE3MTc3MDEwMjAwMzUuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p data-placeholder="Write here. You can also include @mentions."><br></p><p>With this in mind, if you can lower the viscosity of your fluid, then you may see a reduction in satellites. It is important to remember though that in most cases, the viscosity of the ink is confined to a range that the head manufacturer stipulates. You may be limited in your fine-tuning for this reason.</p><p>Surface tension also has a lot to say about how a longer ligament will break up since it determines how much the ink would like to form a nice round drop again. Theory suggests that higher surface tension will decrease the ligament length and number of satellites. However, this is not so easy in practice because you have to have precise control over the surface tension of the drop at the moment that it is being formed. It is more challenging to adjust the surface tension at 50-100 us after being jetted than at 10 seconds.</p><p>Finally, for many types of inks, we have to consider the particle content, which for a pigment-based ink can be a big factor. We can see this by comparing the two images below showing white (left) and black (right) prints from the same printer, deposited in the same resolution (although different substrates). The white clearly shows more satellite drops, which is not untypical because of the typically much higher solid content of larger primary particle size.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDQ0LTE3MTc3MDEwMjAwNDQuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><h3>Printer Design</h3><p>Apart from the waveform, which is related to the drop velocity as mentioned above, other aspects of the machine design can influence the impact of satellites significantly. While the machine design might not be able to prevent the satellites from being formed, it certainly can play a role in containing them.</p><p>One way to control satellites is by controlling the effect of electrical charge. Since many inks are insulating, the printhead can induce a small charge onto the droplets and that can have surprisingly strong effects on the printing, especially if the substrate is also non-conducting. This is not a new issue as the patent image below, showing an electrostatic mist removal concept from HP confirms.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDU1LTE3MTc3MDEwMjAwNTUuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><p>The usual way of mitigating these effects is to ensure printer components are well grounded and that ionization bars are used to control the build-up of static electricity when the substrate is insulating. There are no hard-and-fast rules, but it is important to consider that static charge is often one of the reasons it is harder to connect a drop-watcher result to a printer failure.</p><p>As a simpler measure, many different printer manufacturers have patented air inlet, air extraction, and filtration devices to collect the ink before it reaches the substrate. When UV curing ink, this also prevents the ink from collecting on the UV cure lamps where it can eventually block the curing process. The picture below comes from such a patent.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Maximize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDY0LTE3MTc3MDEwMjAwNjQuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></div><figcaption data-placeholder="Add caption for image (optional)"><br></figcaption></figure><h3>Measuring Your Progress</h3><p>It’s easy to see satellites visually using the JetXpert dropwatcher, but it is also important to determine if those satellites actually have an effect by studying the print. Some applications are more forgiving for satellites than others, depending on the absorbency of the substrate, throw distance, and viewing distance. For this reason, it is difficult to determine if the amount of satellites is acceptable based on the dropwatching alone.</p><p>Analyzing the printed image will give you more insight into how the jetting quality relates to the end product quality. This can be done automatically using the same machine vision technology the JetXpert is built on. For example, you can easily view satellites with the drop-watcher, print a sample image, and automatically count the number of satellites present in the print all on one machine. For more information about these systems, such as the one shown below, check out our <a target="_blank" rel="noopener noreferrer" href="https://imagexpert.com/industrial-printing/">Print Station</a> page or contact ImageXpert.</p><div contenteditable="false"><hr></div><h3>We are also Exhibiting in Berlin.</h3><p>Visit our booth at the <a rel="noopener noreferrer" href="https://www.techblick.com/electronicsreshaped" target="_blank">TechBlick event on 23-24 October 2024 in Berlin</a>.</p><figure><div contenteditable="false"><button data-test-resize-image-button="true">Minimize image</button><button data-test-edit-image-button="true">Edit image</button><button data-test-delete-image-button="true">Delete image</button><a href="https://www.techblick.com/electronicsreshaped" target="_blank" rel="noopener nofollow"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE3NzAxMDIwMDc2LTE3MTc3MDEwMjAwNzYuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="" class="fr-fic fr-dii"></a></div><figcaption data-placeholder=""><br></figcaption></figure>

How to optimize the art of inkjet printing for functional and electronics printing? We will discover that there are multiple potential causes of satellites and explore some of the ways to minimize their formation and effect. 

How to Reduce Satellites Produced by Inkjet Printing

<p id="isPasted">Surface energy is a fundamental topic with implications in nearly every field of engineering, and frankly, it can be a bit mind-boggling. In the world of printed electronics, surface energy often comes up around the interactions of materials, specifically when we’re printing conductive inks onto various surfaces (substrates). While there are several factors that determine if an ink and a substrate will work together, surface energy plays its own very specific role. Let’s dig a bit deeper into how surface energy works, and more importantly, how it can impact&nbsp;<em>your&nbsp;</em>work.&nbsp;</p><p>If you use&nbsp;<a href="https://www.voltera.io/blog/introduction-inkjet-technology" target="_blank">inkjet</a> technology, then the surface energy rating of your materials is a key determinant in whether or not an ink will be compatible with a substrate. Due to their low viscosity, inkjet inks are significantly impacted by surface energy. But, when you read the surface tension rating on your ink, how does it translate into the compatibility of your materials?&nbsp;</p><p><strong>If you’re using low-viscosity inkjet inks</strong>, then read on, because surface energy has a big impact on your materials' compatibility.&nbsp;</p><p><strong>If you’re using high-viscosity screen-printable inks</strong>, surface energy isn’t really a concern for you, but there are several other factors to consider when you’re trying to figure out whether an ink and substrate are compatible. Stay tuned for a future blog post covering this!</p><h3><strong><em>Sci-Snack</em></strong></h3><p><a href="https://www.voltera.io/blog/what-is-viscosity" target="_blank"><strong><em>Viscosity</em></strong></a><em>&nbsp;is the measure of a fluid’s resistance to flow, due to the internal friction of the fluid. Low-viscosity inks, like inkjet inks, have very little friction between the molecules of the ink, so the match or mismatch of surface energy has a significant impact on how your ink and substrate interact.&nbsp;</em></p><p><em>High-viscosity screen-printable inks have a lot of friction between the molecules in the ink. Molecular friction helps these inks hold their shape and stay where you put them, regardless of the surface energy of the substrate to which they are applied.&nbsp;</em></p><h2><strong>What is surface energy and how does it work?</strong></h2><p><strong>Surface area&nbsp;</strong>is the measure of the total area that the surface of the object or liquid occupies<strong>.</strong></p><p><strong>Surface energy&nbsp;</strong>is the amount of energy required to increase the surface area of a material. It applies to liquids and solids.</p><p>In other words, it’s the energy required to increase the space between the molecules. The surface energy of your ink and the surface energy of your substrate — and how those two energies interact — will dictate if your ink spreads out on the substrate, forms nice contained traces, or beads up like water on a non-stick pan.&nbsp;</p><p>Surface energy manifests itself in&nbsp;<strong>surface tension&nbsp;</strong>— when a liquid minimizes its surface area due to the cohesive forces between the molecules. Surface tension occurs in liquids only, never gasses or solids. Surface tension is calculated by measuring the surface energy over a surface area.&nbsp;</p><p>This concept might seem complex, but if you look around, you’ll see examples of it everywhere in your day-to-day life. Right now, there’s a viral trend all over TikTok that demonstrates the cohesive forces between water molecules. You’d recognize it as “<a href="https://twitter.com/overtime/status/1509659771993042949?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1509659771993042949%7Ctwgr%5E9eaf2411d9aaf80dbe5a8f8d579d14cedd5f5df6%7Ctwcon%5Es1_c10&ref_url=https%3A%2F%2Fkotaku.com%2Fembed%2Finset%2Fiframe%3Fid%3Dtwitter-1509659771993042949autosize%3D1" target="_blank">The Water Cup Challenge</a>”.&nbsp;</p><p>In the water cup challenge, players take turns adding drops of water to a full cup. The objective is to gradually add water to the cup, and reach the threshold of surface tension without the water overflowing. The literal tension of the players builds as the surface tension of the water reaches its threshold, mushrooming above the rim of the cup, yet miraculously holding itself together. Eventually the water overflows, and the loser who poured that critical last drop gets thrown into a swimming pool. Fun times.</p><h3><strong><em>Sci-Snack</em></strong></h3><ul><li><strong><em>Surface area&nbsp;</em></strong><em>is the measurement of the total area that the surface of the object or liquid occupies</em><strong><em>.</em></strong></li><li><strong><em>Surface energy&nbsp;</em></strong><em>is the amount of energy required to increase the surface area of a material. It applies to liquids and solids.</em><strong><em>‍</em></strong></li><li><strong><em>Surface tension&nbsp;</em></strong><em>is when a liquid minimizes its surface area due to the cohesive forces between the molecules. Surface tension occurs in liquids only, never gasses or solids.</em></li></ul><p>To demonstrate the concept of surface tension at the molecular level, we’re going to take a look at penguins. When it’s really cold out, penguins form a huddle to share body heat. Think of any material as a penguin huddle and the penguins are molecules. The penguins on the outer edge of the huddle — the ones at the surface — are very tightly packed together, trying to preserve heat. You can imagine that these surface penguins would be pretty difficult to remove or push around. The desire of the penguins to stay close together is like the surface tension or surface energy between molecules or atoms.&nbsp;</p><p>If it’s a warm day, the penguins spread out, increasing the surface area they occupy.</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjEwMzUzODU5LTYzNzNiZDI2YWYwZjkxZjQ2MjUwMDMzY19zN3d6T3ktcDltZHJTTlptTEcxa0l2OFFhRU9FOWVPVnc4ZWprOVpUejZYR21Ia0VEQk5DQnN1LUduNGFPMm81WEZIUUFWellHb2sxTS00QjV2M0IybzZSSmxKSDZCMVZGSWtPWS1ZRVNTaDRQRnpLNERMc2s2c01UcHYtTGpNQ3FzY1Q4NXJ0ejBGeE5TV1RlRjVDX1hpX0xCeVFfRmZMdUxENzMyTE5YTENGSlZDekVQbVRpbXA2Y05TZi5qcGVnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p>If it’s cold outside, the penguins huddle together tightly to share body heat, reducing the surface area they occupy.</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjEwMzcxNjQ2LTYzNzNiZDNmNjM5YTUyMjI3ZTc5MjYxOV9mUFVDZTdWLUdObE9MeHY1X3gzV1FkVi1aQlBuaGhzeDJFSDFiRHhyNjFtdXlvUHlfNVRqUXNYUDd6VkNyZldkWTg0d0R2R1lqWFVsblRqYVgydHFLa0hueWZZSlNsTXJ2WFdtLU9EcFlmNllUZGV3Q0JxMjlKdjh0VDNlTl9QLTIzME14NHdyNXZ5RE9qNGYtbTB6REJFTDVmQS14bmY1cmtRNlhZQWlqdmc3aFJaanNodm9McmlDbDhnQS5qcGVnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><h3 id="isPasted"><strong><em>Sci-Snack</em></strong></h3><p><em>If a material has&nbsp;</em><strong><em>high surface energy</em></strong><em>, that means it’s going to take a lot of energy to change the surface area of the material, so it’s going to be resistant to change. Materials with high surface energy include glass, ceramic, and most metals (and cold penguins).</em></p><p><em>If a material has&nbsp;</em><strong><em>low surface energy</em></strong><em>, that means it will change its surface area relatively easily. Materials with low surface energy include soft low-density plastics like vinyl, polystyrene, and polyethylene.&nbsp;</em></p><p>Liquid mercury, as another example, has incredibly high surface tension. When poured onto a surface, the liquid mercury pulls itself together into a perfect sphere. A sphere is the easiest way for a substance to minimize its surface area.</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjEwMzg2ODY2LTYzNzNiZDU3YTQyMTdmMmEwMTNjZTNiMV8tUTFkNUw3NFhCdlBCdWlYWmZmZlZMYTNLNzJWUXFLTmJGS1RLTDNhdW1aaXFCY29QaUxoRXowd2x5amxySDE4U0RSWjY5UTdNbEdsYXNuS1pHSXhZMEVjcC1PYXEzWWs1eGJRMGU1SkpWb2hlWDZCX0t4RDQyQ0pRYTRRdUpuMTgzc3B1RUNaSEkyRDdBME9iZ1VZRU9HZDdVc0QyQm9HNFZ0cVV4UHpobGZXT2lCa2kxQnhkR3RmNzV3aHYucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p>In the iconic film Terminator 2, the terminator is smashed to pieces, and then liquifies into molten metal and pulls back together into the shape of a man. This is a great science-fiction demonstration of surface tension.</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210457655-ezgif-3-db889fabbf.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p id="isPasted">Each material has its own surface energy rating based on the chemical makeup of the material. This applies to liquids (inks) as well as solids (substrates).</p><p>When you deposit ink onto a substrate, the interaction between the ink and the substrate’s respective surface energies can result in changes to the shape of your traces. This is where you’ll see your ink do one of three things — become very runny and flat, contain itself properly, or bead up.</p><p>You can determine the difference in surface energies between an ink and a substrate by measuring the contact angle — the angle of the ink droplet relative to the substrate. This angle determines if a liquid is spreading, wetting well, or not wetting at all.</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjEwNTAxMDAwLTYzNzNiZDdhNDM1MzkxNWUwY2JkNjI2Nl81a1h4TFExRkZsUEhkQjU2UndUVUNkUWh1cXFIWUFKZ0JjTGZiQ2pnZTIyaGV1UFJoblNlYzZsZ0hlSkNOVUUyMmEweW5UdW1talFYbzcwM0ZVUTBjSzVLcHpacGNlQ0lpZGs2NEF1T29UTVhRQW9UVzJ1LVdPcDNaeDF3TFZEa1QwLUs2Um1leXdvbEJ1ZzRSR3hMSUN4WEh4SldTbkMwQVVOTFJBVDRFRXBDcWVDNVF3aFdQOWRXc1RVMi5qcGVnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><h2 id="isPasted"><strong>Matching the surface energies of your ink and substrate</strong></h2><p>The shape-quality of your traces depends on how well you’ve matched the surface energy of your ink and substrate. If the surface energies of these materials are relatively similar, then the ink and substrate will interact compatibly. You’ll get nice traces that contain themselves and stay where you put them.&nbsp;</p><p>If the surface energies of your ink and substrate are quite different, they are incompatibly matched. Surface energy forces are going to change the shape of the ink and you’ll end up with traces that either bead up, or spread out too much.</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjEwNTM2NTIxLTYzNzNiZGE2YzZlOGEzZDBjMjBhNDY5N19FNi0wRVJXd09Eb01yUzh6UXhRNGRhZmVTendxSnl3bWNyNXBBcG9leGJxdXczTVFpRzVqZzhTSXVyMl9oSzJETy1RVHlZbUZ5bEs4WVYzaU1sRG10ZWFlM1I4Vl81ZlVYM294elhNNGVhSHlxZzd4OHExZzVPQlhJclBvNFRjVHpPRU8wc2hpM1ZVYzRHWWVKdXBabTFoc01mWjlFd2NLZDlxLXhCYlotcnoySk55WjhDQjExbXhQRmZ3Y0oucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p id="isPasted">Inks have different surface tension ratings, and substrates have different surface energy ratings, which influence how these materials interact. The objective is to find a match between the surface energy of the substrate and the surface tension of the ink, resulting in traces that make a nice domed shape and hold together properly: &nbsp;</p><p>Take a look at how inks with surface tension ratings of 30 and 60 interact with different substrates.&nbsp;</p><p>First, let’s take a look at different inks on polyimide. The ink on the left has a low surface tension rating of 30, and it wets and spreads out a bit too much. The ink on the right has a high surface tension rating of 60, and it beads. Based on how the inks perform, we can deduce that the surface energy of the polyimide substrate is somewhere in between 30 and 60.</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210551204-6373c500a4217f28973d6f3a_Polyimide+Viscosity_optimized.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p>In this example, the same inks are applied to a sheet of PET with silica flakes to promote adhesion. The ink with a surface tension of 30 wets out significantly, flooding the substrate. The ink with a surface tension of 60 still beads a bit, but it’s closer to the kind of match you’d want for traces.</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210574950-6373c54100a60421a99cdfa6_PET+Viscosity_optimized.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p>Now look at how these inks perform on the same PET, but without the adhesion promoter. The ink with a surface tension of 30 wets out a bit. The ink with a surface tension of 60 beads significantly.</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210597173-6373c58100a60485769ce6c4_PET+Adhesion+Promoter+Viscosity_optimized.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p>Next, we tried an ink with a surface tension rating of 44, in between our bookends of 30 and 60. Check out how this one interacts with the three different substrates:</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210784581-ezgif-3-e49a46355c.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210832807-ezgif-3-68b99b268c.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707210877485-ezgif-3-c854dd3a7b.gif" style="width: 300px;" class="fr-fic fr-dib"></p><p id="isPasted">Based on the way the 44 dyne pen behaves, what does this tell you about the surface energy of each of the substrates? &nbsp;</p><h2><strong>So what does this mean for choosing an inkjet ink?</strong></h2><p>If your surface energies don’t match, it can be very challenging to get a good quality print. Unfortunately, every substrate is different, so prepare yourself for a lot of trial and error. There are some options to modify the surface energy of your substrate, if you’re willing to roll up your sleeves and do some lab work. We consulted with a friend, <a href="https://uwaterloo.ca/sensors-integrated-microsystems-lab/people-profiles/krishna-iyer" target="_blank">Krishna Iyer</a>, Optical Systems Engineer at University of Waterloo's <a href="https://uwaterloo.ca/sensors-integrated-microsystems-lab/" target="_blank">Sensors and Integrated Microsystems Laboratory</a>, to learn more about surface energy modification:</p><ul><li><strong>Surface treatments&nbsp;</strong><strong>—</strong> substrates can be treated to help match the surface energy of the ink. Surface treatments include surfactants (anionic, cationic, zwitterionic, or amphoteric), as well as plasma, corona, or acid/alkaline surface treatments.&nbsp;</li><li><strong>Temperature —&nbsp;</strong>temperature doesn’t directly affect surface energy, but it <em>does</em> affect viscosity. By controlling the processing temperature, you can have a significant impact on the coverage of your ink or coating material.&nbsp;</li><li><strong>Surface coatings —&nbsp;</strong>you can add coatings to affect the surface energy of your substrate while still preserving the mechanical properties. For example, coating PET with an adhesion promoter, or coating a surface with Teflon.&nbsp;</li><li><strong>Surface preparation —&nbsp;</strong>there are inexpensive, accessible, non-chemical approaches to making a surface more favorable for wetting. For example, a surface with higher roughness increases the surface area and improves wetting without affecting the surface energy, but this can have the opposite effect if roughness is too high (see <a href="https://www.youtube.com/watch?v=54lDqR6LU8E" target="_blank">Wenzel effects</a>).&nbsp;</li></ul><p>With higher viscosity screen printing inks, like those used with <a href="http://voltera.io/nova" target="_blank">NOVA</a>, the internal friction of the ink makes it less impacted by surface energy effects. This enables you to print on a much wider variety of materials without changing your formulation, so you may want to consider switching technologies to avoid the headache.&nbsp;</p>

In the world of printed electronics, surface energy often comes up around the interactions of materials, specifically when we’re printing conductive inks onto various surfaces (substrates).

What is Surface Energy?

<p id="isPasted">The adoption of healthcare monitoring devices that are both flexible and conform to the wearer have gained traction<sup>1</sup>. Spurred on by the need for remote care during the COVID-19 pandemic and technological advances in sensor accuracy, wearable health monitoring devices have become more ubiquitous in many areas of healthcare. In particular, there has been a rise in the development of wearable sensing and monitoring devices for telemedicine operations. Telemedicine has grown significantly in the last few years—and even more so during the COVID-19 pandemic when doctor-patient contact was limited—to remotely monitor patients in their own homes so hospitals could free up much-needed beds. While wearable technologies can be used in clinical environments to provide an analysis, much of their potential is in remote health monitoring.</p><p>These wearable sensing devices typically make use of flexible materials, such as polymers, thin films, 2D materials and other nanomaterials. Health monitoring devices often consist of a flexible material that conforms to the wearer and is integrated with electronic components, including sensors, a power source—be it a battery, solar cell, or some other type of energy harvester like a nanogenerator—communication technologies if it transmits data to a central processing system, and any relevant circuitry.</p><p>Building electronic components that are small and flexible enough to be used in wearable technologies is not that straightforward, and is why different nanomaterials—especially 2D materials—are often used to create the components because they fit the bill and can be easily integrated. But another approach is gathering interest: printing sensors—the most crucial aspects of a monitoring system—directly onto the wearable device.</p><p>These printed sensors are sometimes made of 2D materials and other nanomaterials, but other materials can also be used as well. The ability to print sensors onto wearable health monitoring devices could pave a way to a much simpler and easier route to commercializing more wearable monitoring devices—especially if conventional, inexpensive, or easy-to-use printing technologies are used to print the sensor.</p><h2>Why Printed Sensors?</h2><p>While a range of advanced deposition and nanodeposition methods exist that can fabricate thin-film sensors on the substrate for wearable devices—often a soft polymer due to their flexibility and conformability—a number of biomedical sensors can be printed using screen printing techniques. Other techniques, such as inkjet and transfer printing, can be used as well, but screen printing is seen as the best option for printing sensors.</p><p>Screen printing equipment is widely available, has a relatively low cost, and is easier to use than more advanced deposition methods, so it offers a much more scalable and commercially feasible route for using printed sensors in healthcare monitoring devices. Screen printing can also be used with many materials—from polymer solutions to conductive nanomaterial inks—so it is a versatile platform for printing a number of sensors.</p><p>So, why print sensors instead of creating them through other manufacturing routes? Screen printing is a simple, fast, and efficient printing technique that can produce a large number of identical patterns in a single print. For large-scale operations and commercialization potential, screen printing can easily be adapted for mass production at a lower cost than other methods.</p><p>From a performance perspective, screen printing provides high-resolution patterning and can print over large areas. The ability of screen printing to deposit material on demand in a given location also helps to reduce waste—especially on large scales—compared to traditional manufacturing methods because it is all done in a single step.</p><p>There are, therefore, a number of manufacturing benefits with using printing methods. Beyond that, a greater design capability exists for health wearables because printing methods enable the production of sensors that are not only very thin but also provide the ability to print on the surface of the device. This approach is much simpler than trying to integrate devices into the material matrix of the wearable. You can also create a more customized sensor because you can print on demand, and the printing process can be changed to make a different sensor much easier than a typical manufacturing line.</p><p>In terms of the materials compatible with screen printing, the scope is vast. Depending on the type of sensor being created, a whole host of materials can be used. On the one hand, a range of metals can be made into printable conductive inks to build the sensor. Common metals for wearable health sensors include gold, copper, platinum, nickel, aluminum, and silver. Beyond metals, a range of nanomaterial composites (graphene, carbon nanotubes composites), functional nanomaterial inks, and silver composites have all been used as the active sensing surface in printed health wearable sensors.</p><p>The sensors also need a platform to be printed on. This often takes the form of a conductive polymer so that the sensor can better interact with the skin and the other components to provide higher sensitivity and reliability. PEDOT:PSS is the polymer platform that is most widely used for printed sensors, but other polymer materials include polyacetylene, polypyrrol, polyphenylene, poly (p-phenylene vinylene), and polythiophene polyaniline.</p><h2>The Printed Sensors of Interest in Healthcare Monitoring Applications</h2><p>Just as many materials can be used to create printed health sensors, many different types of printable sensors are used in health monitoring devices. Take, for example, strain-based sensors. Strain-based sensors measure a form of movement, and these wearable sensors are used in human-physiological signal monitoring and human-joint motion monitoring approaches.</p><p>Another healthcare specialty measures different biomolecules and human signals. Non-strain-based sensors detect the biomolecule of interest directly or by directly measuring a physiological parameter that the patient exhibits. From a molecule-sensing perspective, a number of biomolecules in the blood can be detected, with glucose levels being a common one as well as the presence of sweat on a person’s skin. From a signal detection perspective, printed sensors can now detect respiration and heartbeat levels in a patient and provide remote electrocardiogram (ECG) monitoring.</p><p>Another class of printed sensors for wearables is sensor arrays. In sensor arrays, multiple sensors work together to detect more complex issues or issues that require analysis from several stimuli angles. Sensor arrays are helpful in monitoring gait during walking, monitoring the sitting posture of wheelchair users, and monitoring the skin.</p><p>Finally, there’s been advances in the development of printed temperature sensors for wearable health devices. Thermal sensing is a key area in disease detection because the body suffers thermal stresses when there is a disease present, and the rise in both skin and deep body temperature can be a primary indicator of a serious disease. Using printed temperature sensors, health wearables can detect a range of chronic diseases, such as cardiovascular, diabetic, and pulmonological diseases, as well as cancer.</p><h2>Conclusion</h2><p>Health monitoring wearables are gaining acceptance as an effective way to remotely measure many health factors of a patient. The most important aspect of these wearables is the sensing system that provides the analysis on the patient. For patients to be willing to wear the health monitoring device over an extended amount of time, the sensors and other components need to flex with the wearable component. While integrating flexible sensors is possible—for example, by using thin nanomaterials—printing sensors on the device’s surface is much easier, requires less material, and is much more scalable.</p><p>A variety of printed health wearables are already in existence (commercially and academically. The printing methods discussed offer a route to achieve widespread distribution of health wearables. While many options are available, screen printing is the leading printing technology because it is highly versatile and can be used with many materials to create sensors that monitor different aspects of a person’s health—from heart rate to detecting a chance of a disease, to the different biomolecules in their blood, and many more in between.</p>

The COVID-19 pandemic and advancements in sensor technology have led to the widespread adoption of wearable health monitoring devices, particularly for telemedicine, to facilitate remote patient monitoring.

Printable Sensors: A Key Technology for Health Wearables?

<p id="isPasted"><a href="https://www.alpineadvancedmaterials.com/" rel="noopener" target="_blank">Alpine Advanced Materials</a>, a leading expert in the design and manufacturing of custom-engineered parts for the world’s most demanding aerospace, defense, energy, space, and transportation applications, sought to overcome the challenges associated with traditional metal parts. By introducing high-performance injection molded composites that are significantly lighter than metal yet equally as strong, Alpine is able to provide scalable and flexible manufacturing services that are more economical and environmentally conscious as well.</p><p>Partnering with Nexa3D and utilizing the <a href="https://nexa3d.com/3d-printers/xip/" target="_blank">XiP desktop 3D Printer</a> and <a href="https://nexa3d.com/digital-tooling/" target="_blank">Freeform Injection Molding (FIM)</a> process to produce 3D printed tools, Alpine is able to drastically reduce both their prototype tooling production times and costs in order to put parts in the hands of their customers for swift validation, testing, and customer acceptance before making large investments in permanent tools.</p><h2>The Challenge</h2><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2NjgyNjQyMTc0LWFscGluZS0zZC1wcmludGVkLXRvb2xpbmctMTgwMHgxMDEzLmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 766px;" class="fr-fic fr-dib"></p><h3>Conventional tooling is too costly and has long lead times</h3><p>For Alpine Advanced Materials, the conventional injection molding approach required significant upfront investment in permanent steel tooling, hindering the ability to rapidly produce prototype parts for testing and validation in key high-performance materials like HX5®, a multi-scale reinforced polymer with exceptional performance over a wide range of temperatures and extreme environmental conditions.</p><p>Additionally, standard 3D printing had proven too costly and it couldn’t withstand the high molding temperatures of their composite polymers.</p><blockquote id="isPasted"><p>“Our customers are using the FIM process to de-risk the path to new thermoplastic materials. Rapidly molded prototypes are being used for validation testing, product demonstration and even low-rate initial production.”<strong>Jeremy Smith, Alpine Advanced Materials</strong></p></blockquote><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2NjgyNzE0NzYxLXhpcC1kZXNrdG9wLXJlc2luLTNkLXByaW50ZXItbmV4YTNkLmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 766px;" class="fr-fic fr-dib"></p><h3 id="isPasted">Customer</h3><p>Alpine Advanced Materials</p><h3>Industry</h3><p>Contract Manufacturing</p><h3>Products</h3><ul><li>XiP Desktop 3D Printer</li><li>xMOLD 3D printed tooling resin</li></ul><h3>Application</h3><p>3D Printed Tooling</p><h3>Advantages</h3><ul><li>Ability to offer injection molding services in as fast as 10 days</li><li>Significantly reduced production costs</li><li>Enhanced strength and surface finish</li><li>De-risked material innovation</li></ul><h2 id="isPasted">The Solution</h2><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2NjgyNzYzOTg1LWJlbmVmaXRzLW9mLWluamVjdGlvbi1tb2xkaW5nLWFscGluZS5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib"></p><h3>3D printed tooling using xMOLD and Freeform Injection Molding</h3><p>Recognizing the potential of additive manufacturing, Alpine Advanced Materials decided to integrate Nexa3D’s XiP 3D Printer into their operation. The XiP printer, along with Nexa3D’s xMOLD resin, offered Alpine the ideal solution for their injection molding needs. Freeform Injection Molding (FIM) with xMOLD allowed them to overcome the challenges associated with traditional metal tooling, providing a faster and more cost-effective way to produce prototype parts for customer validation. The resin’s compatibility with hundreds of plastics provided the versatile solution Alpine needed to ensure they could mold for a myriad of commercial applications.</p><h2 id="isPasted">The Benefits</h2><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2NjgyNzk0NDM1LUZJTS1wcm9jZXNzLXVzaW5nLU5leGEzRC1YaVAtM0QtcHJpbnRlci5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib"></p><h3><em>Reduced production costs by as much as 86% and lead time by as much as 91%</em></h3><p>By adopting the FIM process using Nexa3D’s XiP 3D printer and xMOLD material, Alpine Advanced Materials reaped numerous benefits:</p><p><strong>Rapid Prototyping:</strong> FIM enabled Alpine to quickly produce high-quality prototype parts for customer demonstration and validation testing. The mechanical properties of FIM parts closely matched those produced with permanent steel tools, ensuring accurate performance evaluation.</p><p><strong>Enhanced Strength and Surface Finish:</strong> Compared to parts directly 3D printed, parts molded with FIM exhibited superior strength and surface finish. This made them suitable for a wide range of applications, including product demonstrations and low-rate initial production.</p><p><strong>Time and Cost Savings:</strong> FIM drastically reduced the time and cost required for tooling production. The XiP printer’s exceptional speed allowed for the creation of multiple molds per hour, surpassing the capabilities of traditional CNC machining. Alpine could produce 5-10 prototype molds for a fraction of the cost of a production tool, delivering significant savings to their customers.</p><p><strong>De-risking Material Innovation:</strong> FIM enabled Alpine’s customers to de-risk the path to new thermoplastic materials. Rapidly molded prototypes provided the opportunity for comprehensive validation testing, ensuring the successful adoption of innovative materials.</p><h2 id="isPasted">Customer Impact</h2><h3>Custom tool and parts delivered in 10 days saving thousands in tooling costs</h3><p>A defense firm in Huntsville, AL approached Alpine Advanced Materials for rapid parts to perform a UAV system demonstration. The firm required parts with higher strength than those achievable through traditional 3D printing methods, but their metal machining capacity was overwhelmed. Leveraging FIM, Alpine designed, printed, molded, and delivered all 60 required parts within just 10 business days, meeting the tight three-week timeframe and ensuring the successful completion of the demonstration.</p><p>The collaboration between Alpine Advanced Materials and Nexa3D has created unlimited possibilities for the manufacturing industry through the integration of 3D printing and Freeform Injection Molding. By leveraging Nexa3D’s XiP 3D Printer and xMOLD material, Alpine has successfully addressed the challenges associated with traditional metal tools. The FIM process has enabled Alpine to deliver rapid prototypes, comparatively enhance part strength and surface finish, and achieve significant time and cost savings.</p>

Turnkey design and part manufacturer uses 3D printed tooling to provide injection molding service in as fast as 10 days

Advanced Materials Injects Speed into Molding

<p id="isPasted">Researchers at the Georgia Institute of Technology have developed a light-based means of printing nano-sized metal structures that is significantly faster and cheaper than any technology currently available. It is a scalable solution that could transform a scientific field long reliant on technologies that are prohibitively expensive and slow. The breakthrough has the potential to bring new technologies out of labs and into the world.</p><p>Technological advances in many fields rely on the ability to print metallic structures that are nano-sized — a scale hundreds of times smaller than the width of a human hair. <a href="https://www.me.gatech.edu/faculty/saha" target="_blank">Sourabh Saha</a>, assistant professor in the <a href="https://www.me.gatech.edu/" target="_blank">George W. Woodruff School of Mechanical Engineering</a>, and Jungho Choi, a Ph.D. student in Saha’s lab, developed a technique for printing metal nanostructures that is 480 times faster and 35 times cheaper than the current conventional method.</p><p>Their research was <a href="https://onlinelibrary.wiley.com/doi/10.1002/adma.202308112" target="_blank">published</a> in the journal <em>Advanced Materials</em>.</p><p>Printing metal on the nanoscale — a technique known as nanopatterning — allows for the creation of unique structures with interesting functions. It is crucial for the development of many technologies, including electronic devices, solar energy conversion, sensors, and other systems.</p><p>It is generally believed that high-intensity light sources are required for nanoscale printing. But this type of tool, known as a femtosecond laser, can cost up to half a million dollars and is too expensive for most research labs and small businesses.</p><p>“As a scientific community, we don’t have the ability to make enough of these nanomaterials quickly and affordably, and that is why promising technologies often stay limited to the lab and don’t get translated into real-world applications,” Saha said.</p><p>“The question we wanted to answer is, ‘Do we really need a high-intensity femtosecond laser to print on the nanoscale?’ Our hypothesis was that we don’t need that light source to get the type of printing we want.”</p><p>They searched for a low-cost, low-intensity light that could be focused in a way similar to femtosecond lasers, and chose superluminescent light emitting diodes (SLEDs) for their commercial availability. SLEDs emit light that is a billion times less intense than that of femtosecond lasers.</p><p>Saha and Choi set out to create an original projection-style printing technology, designing a system that converts digital images into optical images and displays them on a glass surface. The system operates like digital projectors but produces images that are more sharply focused. They leveraged the unique properties of the superluminescent light to generate sharply focused images with minimal defects.</p><p>They then developed a clear ink solution made up of metal salt and added other chemicals to make sure the liquid could absorb light. When light from their projection system hit the solution, it caused a chemical reaction that converted the salt solution into metal. The metal nanoparticles stuck to the surface of the glass, and the agglomeration of the metal particles creates the nanostructures. Because it is a projection type of printing, it can print an entire structure in one go, rather than point by point — making it much faster.</p><p>After testing the technique, they found that projection-style nanoscale printing is possible even with low-intensity light, but only if the images are sharply focused. Saha and Choi believe that researchers can readily replicate their work using commercially available hardware. Unlike a pricey femtosecond laser, the type of SLED that Saha and Choi used in their printer costs about $3,000.</p><p>“At present, only top universities have access to these expensive technologies, and even then, they are located in shared facilities and are not always available,” Choi said. “We want to democratize the capability of nanoscale 3D printing, and we hope our research opens the door for greater access to this type of process at a low cost.”</p><p>The researchers say their technique will be particularly useful for people working in the fields of electronics, optics, and plasmonics, which all require a variety of complex metallic nanostructures.</p><p>“I think the metrics of cost and speed have been greatly undervalued in the scientific community that works on fabrication and manufacturing of tiny structures,” Saha said.</p><p>“In the real world, these metrics are important when it comes to translating discoveries from the lab to industry. Only when we have manufacturing techniques that take these metrics into account will we be able to fully leverage nanotechnology for societal benefit.”</p><hr><p id="isPasted"><strong>Citation</strong>: J. Choi, S. K. Saha, Scalable Printing of Metal Nanostructures through Superluminescent Light Projection. <em>Adv. Mater.</em> 2024, 36, 2308112.</p><p><strong>DOI</strong>: https://doi.org/10.1002/adma.202308112</p>

The researchers developed a light-based means of printing nano-sized metal structures that is 480 times faster and 35 times cheaper than the current conventional method.

Researchers Create Faster and Cheaper Way to Print Tiny Metal Structures With Light

<p id="isPasted">What if items in a room could "talk" to each other wirelessly — without any configuration, batteries, or contact? What if instead of having to wait in line at the supermarket, you could just checkout by walking out the front door? Or the next time you misplace your keys, they could tell you where they were located? RFID is a technology that can do all this and more.</p><p>Radio Frequency Identification (commonly known as RFID) is a technology that leverages wireless communication over radio waves to both transfer data and locate objects. Many of us use RFID as part of our everyday life without noticing it, whether it be entry keycards, contactless payments, or toll road transponders on vehicles. While RFID has been streamlining processes for decades, there has been an explosion in the applications of RFID in recent years.</p><p>Retail businesses have started using RFID to speed up the checkout process and improve customer experience. Some countries have begun using RFID to augment their passports with additional information to verify an individual’s identity. RFID is even used in healthcare, with the FDA certifying the use of RFID to track donated blood, including using RFID tags to track the origin, type, and date of donation for blood [1].</p><p>So what’s the catch? &nbsp;Well, with nearly 28 billion RFID tags sold in 2021 and a yearly growth of 36% [2], the sheer volume of these tags will result in significant environmental challenges, due to the wasteful and resource intensive nature of current production methods. In addition, current RFID tags leverage aging material technology that is quickly being supplanted in performance and cost by novel approaches, namely nano copper inks, like&nbsp;<a href="https://www.copprint.com/wp-content/uploads/2021/12/TDS-LF-301-Beta-22-08-21.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">Copprint LF-301</a>.</p><p>Nano copper inks offer several advantages over existing materials used in RFID production. &nbsp;The most common way tags are made today is by etching aluminum, a subtractive process similar to how PCBs are made. A laminate of aluminum foil and PET is put through a chemical process where excess aluminum is subtracted to form the final tag pattern. In contrast, nano copper inks use additive processes where conductor material is deposited onto a substrate in the desired pattern. This results in no copper waste, or toxic chemical byproducts from the production process. What’s more, with an ink like Copprint LF-301 the tag can be made right on a paper substrate such that the RFID tag is compostable, a big change compared to non-recyclable and non-compostable etched aluminum tags.</p><p>We set out to create an RFID tag using this innovative ink by&nbsp;<a href="https://www.copprint.com/" target="_blank">Copprint</a>. Specifically, we designed, printed, assembled and tested an UHF (ultra-high frequency) RFID tag. This sort of tag is commonly used in asset-tracking applications, like logistics and consumer retail. Using industry-standard design and simulation software, a high-performance UHF RFID tag was designed, but as with everything, you don’t know how something really works until you make your first prototype.</p><p>Fortunately, getting up to speed with a new ink and substrate is a breeze with&nbsp;<a href="https://www.voltera.io/nova" target="_blank">NOVA</a>. Using the Smart Dispenser, combined with the built-in ink calibration workflow, we were able to tune an ink profile to use with Copprint LF-301. What’s more, NOVA’s Vacuum Table module made it a breeze working with paper substrates. After placing the paper on the Vacuum Table, it is held in place until the print is complete. Once the ink was dialed in, and paper substrate was in place, we were ready to print — no upfront costs or time waiting for custom screens to print our prototype pattern: just NOVA, Copprint LF-301, and cardstock paper.</p><p>With NOVA set up, we printed the RFID antenna pattern which was based on the Modified Half-Dipole antenna topology which is commonly used in this sort of application. From beginning to end, including surface-mapping with the Smart Probe, it took less than 15 minutes to produce one RFID tag antenna print. &nbsp;</p><p>Once printed, we followed the sintering instructions provided by Copprint; sintering is a critical step for nano copper inks as it transforms the structure of the material, from many disconnected microscopic particles of copper to one continuous bulk. This is the magic of Copprint’s ink, as the sintering process transforms the easy-to-print ink into a high performance copper antenna. &nbsp;This is achieved by using a simple oven and heat press, all within our lab.</p><p>With the antenna printed and processed, all that was left was to bond the RFID transceiver integrated circuit to the antenna itself. This IC controls the antenna and responds to an incoming RFID signal. While these are often bonded using specialized adhesives known as Anisotropic Conductive Adhesives (ACA), we chose to simply solder the IC to the antenna as the sintered ink behaves just like bulk copper on a PCB. And with that, our tag was complete!</p><p>After testing the RFID tag we produced, we were surprised at the performance: this custom tag which was designed and prototyped in-house in a week performed slightly better than the off-the-shelf tag we purchased from a market-volume leader in RFID. This was accomplished with minimal upfront cost, using NOVA to rapidly prototype our design, moreover with the quick production time for each tag, iterations of the design can be rapidly created and tested.</p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="640" height="360" src="https://www.youtube.com/embed/2COFihlYVos?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span><br></p>

Radio Frequency Identification (commonly known as RFID) is a technology that leverages wireless communication over radio waves to both transfer data and locate objects. 

Making an RFID Tag using Revolutionary Copper Ink on Paper

<p id="isPasted">From 17-18 October 2023, the "Future of Electronics Reshaped" global conference and exhibition took place at the Estrel Congress Center in Berlin, Germany. The event aimed to reshape the future of electronics, emphasizing additive, sustainable, flexible, hybrid, wearable, structural, and 3D electronics.&nbsp;</p><p>The TechBlick event gathered the global industry in Berlin, where the latest updates were unveiled, key conversations occurred, and new ideas and projects were initiated. Attendees benefited from a curated world-class agenda and masterclass program. They also had the opportunity to experience the latest technologies and products at 78 booths and connected with over 650 peers, partners, and customers from around the world. Notably, the exhibition had grown by 50% compared to its 2022 iteration.</p><p>The event also featured a unique hybrid package, allowing attendees to participate in the 2-day in-person event in Berlin and gain year-round access to all TechBlick live-online virtual conferences, masterclasses, and an on-demand library of previous presentations.</p><p>Wevolver attended the event and spoke to some of the exhibitions about their technology and its impact. We include just some of the exciting companies below.</p><h2>Voltera</h2><p><a href="https://www.wevolver.com/profile/voltera" target="_blank" rel="noopener noreferrer">Voltera</a> is at the forefront of the future of electronics, emphasizing additive methods. They specialize in rapid prototyping platforms for printed electronics, catering to both traditional circuit boards and the evolving world of flexible, stretchable, conformable, and biocompatible electronics. Their product range includes the V-One, suitable for PCB prototyping and the Nova, which is ideal for printed electronics R&amp;D, flexible electronics, microdispensing, and functional materials research.</p><h3>Key Insights:</h3><p><strong>Unlocking New Possibilities:&nbsp;</strong>Voltera believes that the future of electronics will be cost-effective, lightweight, bendable, and seamlessly integrated into structures. Their platforms are designed to give users a competitive edge in this direction.</p><p><strong>Materials Freedom:&nbsp;</strong>The additive technology they employ offers freedom in choosing inks and substrates. This opens doors to new applications in wearable electronics, biomedical devices, printed sensors, and more.</p><p><strong>Efficiency in Design Iteration:&nbsp;</strong>Digital additive prototyping, as championed by Voltera, is faster than many alternative methods. It allows for quicker design iterations without the need for heavy investments or long waits for tooling.</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 302px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk4MDQ3ODUxMjM0LWxhcmdlVm9uZS5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib"><span class="fr-inner">V-One, Voltera's desktop PCB printer. Image credit: Voltera.&nbsp;</span></span></span></p><h2>Fraunhofer IAP</h2><p><a href="https://www.iap.fraunhofer.de/en.html" target="_blank" rel="noopener noreferrer">The Fraunhofer Institute for Applied Polymer Research&nbsp;</a>(IAP) is dedicated to creating materials that are fit for the future. They focus on innovative solutions to address contemporary and upcoming challenges such as climate change, pandemics, energy transitions, structural changes, and evolving mobility concepts.&nbsp;</p><p>The institute emphasizes bioeconomy and sustainability by exploring sustainable raw materials and promoting a circular economy to decrease reliance on fossil energy sources. They believe that integrating innovative materials into products is crucial for energy transition and the development of new mobility solutions. Additionally, the institute works on new active ingredients, products, and processes for the medical and health sectors. Fraunhofer IAP supports the entire value chain, from the inception of innovative materials to the development of market-relevant prototypes.</p><h3>Key Insights:</h3><p><strong>Addressing Global Challenges:&nbsp;</strong>Fraunhofer IAP is actively involved in finding creative solutions to global challenges, ensuring that materials and processes are sustainable and future-ready.</p><p><strong>Promotion of Circular Bioeconomy: T</strong>he institute has a roadmap for a circular bioeconomy in Germany, emphasizing the strategic research field of bioeconomy.</p><p><strong>Engagement in Various Research Fields:&nbsp;</strong>From biopolymers and functional polymer systems to life sciences and bioprocesses, the institute covers a wide range of research areas.</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 302px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk4MDQ3OTMxNzU0LUFiYmlsZHVuZzItRm90by1UaWxsLUJ1ZGRlLmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 300px;" class="fr-fic fr-dib"><span class="fr-inner">Fraunhofer IAP are developing polymers with a focuis on bioeconomy and sustainability.&nbsp;</span></span></span></p><h2>Molex</h2><p><a href="https://www.techblick.com/post/smart-skin-patches-and-noninvasive-medical-sensing-molex" target="_blank" rel="noopener noreferrer">Molex</a>, a global leader in connectivity solutions, is pioneering the development of smart skin patches that leverage hybrid printed electronics to enhance medical sensing capabilities. These patches are designed to improve patient outcomes by offering a range of functions:</p><p>Evolution of Smart Skin Patches: Modern smart skin patches have evolved from containing a single wired sensor to incorporating a myriad of functions. They utilize hybrid printed electronics, allowing for the integration of various electronic devices and noninvasive sensors onto a thin, flexible substrate. This advancement enables the creation of connected devices that can monitor vital signs or activity without invasive methods.</p><h3>Key Insights</h3><p><strong>Demand for Connected Medical Sensing:&nbsp;</strong>The COVID-19 pandemic underscored the importance of remote patient monitoring. Smart skin patches offer a lightweight, comfortable, and portable solution for monitoring patients both within and outside healthcare facilities. They are also gaining traction for home health monitoring, sleep and brainwave activity tracking, and femtech applications like pregnancy monitoring.</p><p><strong>Design and Architecture:&nbsp;</strong>Smart skin patches utilize flexible printed circuit technology and skin-safe adhesives. Their design can be customized based on the application, with options for disposable or reusable patches. Reusable patches have a design where only the skin-contacting electrodes are disposable, reducing waste.</p><p><strong>Opportunities and Challenges:&nbsp;</strong>Designing smart skin patches involves integrating various electronic devices, including sensors, batteries, microcontrollers, and RF antennas. Achieving system reliability requires expertise in multiple engineering disciplines, from material science to electronic component reliability. Ensuring product performance and meeting regulatory compliance standards are also paramount.</p><p><span class="fr-img-caption fr-fic fr-dib" style="width: 302px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk4MDQ4Mzk2MDQ4LW1vbGV4LmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 300px;" class="fr-fic fr-dib"><span class="fr-inner">Molex smart skin patch. Image credit: Molex.&nbsp;</span></span></span></p><p><br></p><p>Themes explored during the event included printed flexible hybrid electronics, structural and in-mold electronics, sustainable electronics, wearable electronics, electronic textiles, smart skin patches, continuous vital signs monitoring, 3D printed electronics, and many more.&nbsp;</p><p>Stay up to date on <a href="https://www.wevolver.com/profile/techblick" target="_blank" rel="noopener noreferrer">TechBlick</a> events by following their <a href="https://www.wevolver.com/profile/techblick" target="_blank" rel="noopener noreferrer">Wevolver profile.</a></p>

From stretching skin patches, to printed circuit boards, the Electronics ReShaped Event gave an insight into the exciting future of printed and flexible electronics. 



TechBlick's Electronics Reshaped Event - Berlin 2023

<p>When it comes to global sustainability, the manufacturing industry is under intense scrutiny to improve its practices. &nbsp;Amidst continuous search for alternatives to greener practices, additive technologies such as <a href="https://www.wevolver.com/article/sls-printing-unlocking-the-potential-of-selective-laser-sintering" target="_blank">Selective Laser Sintering (SLS)</a> has turned out to be a promising technology for the manufacturing industry. It has the potential to transform traditional production lines into eco-friendly models of efficiency. In this article, we will explore how SLS enables manufacturers to meet greener environmental guidelines while maintaining economical efficiency.&nbsp;</p><h2 dir="ltr">Four Eco-Friendly Benefits of SLS Boosting ROI</h2><h3 dir="ltr">Increased Material Efficiency</h3><p dir="ltr">SLS enhances material efficiency, unlike the subtractive manufacturing process. It builds objects using only necessary material. Any excess powder not sintered in SLS can be recycled and reused for subsequent prints, reducing waste. If the parts are densely stacked and the software has nesting features to optimize the material usage, the efficiency is further increased. In contrast, subtractive manufacturing starts with a large block, carving away material to form an object. This often results in non-reusable scraps and increased waste.&nbsp;</p><h3 dir="ltr">Liberty from Tooling Management&nbsp;</h3><p dir="ltr">Traditional manufacturing methods, whether forging, casting, or injection molding, consistently lean on intricate tooling. These tools – molds, dies, and jigs – come with a heavy overhead. Their production demands substantial financial investment, not to mention the time and energy spent on their design, testing, and refinement. Additionally, the environmental footprint of their fabrication and eventual disposal can't be ignored.</p><p dir="ltr">With SLS technology, manufacturers <a href="https://utw10945.utweb.utexas.edu/Manuscripts/1991/1991-17-Nutt.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">bypass the entire tooling phase</a>. The complex 3D object springs directly from digital blueprints, without any molds or support structure, streamlining the production pipeline immensely. There's no longer a need for large storage areas for tools or the continual upkeep and repair costs associated with wear and tear. Furthermore, the freedom to transition seamlessly from a digital model to a physical product paves the way for intricate designs previously thought unachievable.</p><h3 dir="ltr">Prevent Overproduction and Decrease Scrap</h3><p dir="ltr">Mass production, with its inevitable inventory build-ups, often results in overproduction. Such excess not only ties up resources but also contributes to a significant amount of waste when unsold products become obsolete. However, with the on-demand customized production capability of SLS, manufacturers can prevent overproduction, optimize inventory storage, and decrease scrap with ease.&nbsp;</p><p dir="ltr">By preventing overproduction, we can reduce the waste and ecological harm stemming from both production and disposal of surplus goods. Additionally, the ability to produce parts locally with SLS further drastically reduces carbon emissions associated with long-distance shipping that eventually increases carbon footprint in the atmosphere.&nbsp;</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 302px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1697727294303-sintratec-kit-part-4.jpg" style="width: 300px;" class="fr-fic fr-dib"><span class="fr-inner">SLS printing enables complex geometries with loewr waste. Image credit: Sinatrec.</span></span></span></p><h3 dir="ltr">Multi-Use Plastics</h3><p dir="ltr">Selective Laser Sintering has the potential to pivot the industry from single-use plastics to durable, multi-use options.</p><p dir="ltr">Traditional manufacturing frequently employs injection molding to create single-use plastic items. This method efficiently produces large quantities of identical products. However, these short-lived items quickly become waste, significantly amplifying the global plastic pollution problem.</p><p dir="ltr">In contrast to traditional methods, SLS harnesses the power of lasers to sinter polymer powders layer by layer, crafting parts with superior strength and precision. These high-quality polymer parts are inherently more durable, reducing their wear and tear over time, leading to a reduction in the overall generation of plastic waste. Also, <a href="https://www.wevolver.com/article/the-guide-to-selective-laser-sintering-sls-post-processing" target="_blank">SLS post-processing options</a> are eco-friendly and ensure appearance and functionality of the component are top-notch.</p><p dir="ltr">Moreover, one of the significant hurdles is in sourcing spare parts for outdated machinery, making replacements a daunting task. However, <a href="https://www.wevolver.com/article/3d-printing-obsolete-parts" target="_blank">3D printing</a> can replicate these parts with precision with a wide range of industrial-grade materials, ensuring a seamless fit and high shelf life of the machinery.</p><h2 dir="ltr">Conclusion</h2><p dir="ltr">3D printing and SLS are greener manufacturing practices with numerous benefits. Manufacturers can leverage SLS to reduce material waste, eliminate unnecessary tools, meet on-demand production, and promote recycling, without hurting their production line. In the long run, it helps industries position themselves at the forefront of innovation and sustainability, crafting a future for the next generation where efficiency and ecology go hand in hand.</p>

Object printed in laser sintering machine

SLS 3D Printing: An Eco-Friendly 3D manufacturing solution that reduces waste and energy use while enabling on-demand production and quick customization

Selective Laser Sintering: Bridging the Gap to Sustainable Innovations

<p id="isPasted">When 3D printed parts are used in any application, their failure can result in dangerous situations. If a part isn't durable, it might break under pressure, resulting in equipment malfunction or even injuries. Testing is crucial for manufacturers to determine the suitability of different materials for their specific applications. By subjecting the components printed by the Sintratec S2 to rigorous testing, Sintratec can identify their strengths and weaknesses, ensuring that only durable and high-quality 3D-printed parts are released to the market.&nbsp;</p><p>This article explores the robust testing processes and the impressive resilience displayed by the Sintratec S2 components, which highlights the company's unwavering commitment to delivering superior quality products.</p><h2>Testing 3D prints</h2><p id="isPasted">Sintratec, a Swiss startup specializing in Selective Laser Sintering (SLS) 3D printers, has shared the process of testing their new machine, the Sintratec S2. The test demonstrates the strength of Sintratec's PA12 powder and the efficiency of the Sintratec S2 machine in producing durable prints. This article explores the rigorous testing processes and the resilience of components printed by the Sintratec S2.</p><p dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 302px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk2MjcxNTg2Mzc3LVNpbnRyYXRlYy1TMi1Gcm9udC5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib" alt=" Sintratec S2"><span class="fr-inner" spellcheck="false">&nbsp;The Sintratec S2 3D printer.&nbsp;</span></span></span></p><p>In the comprehensive video produced by Sinatrec, we see Andi, a lead engineer at Sintratec, demonstrating the strength and durability of the parts produced by this new machine. The project involves designing a functional electric ducted fan (EDF) driven by an 800-watt RC brushless in-runner motor to see how much power the part could handle without being damaged.</p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="640" height="360" src="https://www.youtube.com/embed/BYieQ-PVlQs?&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true" data-gtm-yt-inspected-10="true" id="743390312" title="3D printed Electric Ducted Fan TESTED – How strong is SLS?! (EDF Turbine Test)"><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p><p dir="ltr">Once the design was completed, the part was printed using <a href="https://sintratec.com/3d-printing-materials/sintratec-pa12-powder/" target="_blank">Sintratec's strong PA12 material</a>. The next step involved balancing the fan with lead balls around the rotation axis to prepare it for <a href="https://www.wevolver.com/article/all-you-need-to-know-about-test-3d-prints" target="_blank">testing 3D prints</a>. The EDF was then tied to a metal cord, mounted on a rail, and clamped to a table for the testing phase. With proper safety measures in place, the engine was started, and the speed was increased gradually.</p><p dir="ltr">However, the test was aborted at around a quarter to full speed due to concerns about powder emission from the front. Upon investigation, it was found that this resulted from a <a href="https://www.wevolver.com/article/7-design-tips-for-structural-optimization-lightweighting" target="_blank">design flaw</a> where a small inner area was not closed. The initial prototype had a hollow shell, which made the EDF too soft and pliable. The interior walls were reinforced with additional structures to address this, and the part was printed again.</p><h2 dir="ltr">Testing round two</h2><p dir="ltr">In the subsequent test, the EDF was fixed onto a more stable workbench, and the power was increased once again. Although an imbalance in the spinner was noticed, it was removed, and the test continued. Smoke was added to visualize the airflow, and the peak power reached about 1,400 watts, a result considered impressive, especially given the motor's nominal power of 800 watts. The EDF sustained the test without any damage, showcasing the strength of Sintratec's PA12 powder and the efficiency of the Sintratec S2 machine in producing durable prints.</p><h2 dir="ltr"><strong>End Thoughts</strong></h2><p dir="ltr">Testing the durability of 3D printed parts is crucial for multiple reasons such as safety, material understanding, quality control, design optimization, regulatory compliance etc. Moreover, the durability of 3D-printed parts enhances the reputation of the products or services they're associated with.&nbsp;</p><p dir="ltr">The commendable performance of the Sintratec S2 system in the tests highlights Sintratec's commitment to giving customers the best and most reliable products, reaffirming its reputation in the world of 3D printing technology.&nbsp;</p><p dir="ltr"><a href="https://sintratec.com/sls-3d-printer/amp/sintratec-s2/" target="_blank" rel="noopener noreferrer">Learn more about Sintratec here.</a></p>

Aircraft turbine wheel printed on metal 3D printer.

Sintratec, a Swiss startup specializing in Selective Laser Sintering (SLS) 3D printers, is in the process of testing their new machine, the Sintratec S2.  

Testing the Durability of 3D Printed Parts

<p id="isPasted">The Norwegian start-up Renasys has made it its mission to transform water filtration and wastewater treatment. A newly developed, innovative filtration system removes 99% of dirt particles and suspended matter over 5 microns in size from the water.</p><p>80% of the world&rsquo;s wastewater is released into the environment untreated, polluting our rivers, seas and oceans (source: <a href="https://www.unesco.org/en/wwap/wwdr#2017" target="_blank">UN WWDR 2017</a>). One consequence of this is that some 4.5 billion people around the world use contaminated, unclean water (source: <a href="https://www.iea.org/commentaries/the-energy-sector-should-care-about-wastewater" target="_blank">IEA</a>). This significantly increases the risk of serious health problems. For example, diseases such as dysentery, typhus, cholera and polio are far more common in countries with poor drinking water quality than in those with clean drinking water. It would cost 8.2 trillion US dollars to modernise and sustainably restructure the global water infrastructure (source: <a href="https://www.oecd.org/env/cc/g20-climate/Technical-note-estimates-of-infrastructure-investment-needs.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">OECD&nbsp;</a>).</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1695018966303-1695018966303.png" style="width: 707px;" class="fr-fic fr-dib"></p><p id="isPasted">With the global population continually growing, industrial expansion progressing and laws becoming ever tighter, wastewater treatment plants and their operators are compelled to improve their water treatment systems. The start-up&nbsp;<a href="https://www.renasys.com/" target="_blank">Renasys</a> is based in Norway, where it also focuses its work: after all, Norway&rsquo;s plan alone of further developing and modernising the existing water infrastructure between 2021 and 2040 will require some 17.6 million US dollars of investment. The country currently has around 2,000 wastewater treatment plants (source:&nbsp;<a href="https://295965-www.web.tornado-node.net/wp-content/uploads/Rapport259.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">Norsk Vann</a>), 93% of which are purely municipal treatment systems, i.e. systems that are only used locally in one place and are not connected to the central water supply systems. In addition, 55% of Norwegian wastewater treatment plants no longer meet the more stringent legal regulations and requirements (source:&nbsp;<a href="https://295965-www.web.tornado-node.net/wp-content/uploads/Rapport259.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">Norsk Vann</a>).</p><p>Renasys&rsquo;s mission is to preserve, protect and defend the world&rsquo;s most valuable resource. As part of their joint &lsquo;Mission Zero&rsquo;, Renasys and Haver &amp; Boecker have come together as strategic partners and developed a filtration system that removes 99% of wastewater particles over 5 microns in size. This system enables the start-up to achieve a far higher filtration and separation level than legally required in Norway. As a result, the solution is more than promising and can also be transferred to other sectors and areas of use. For example, even today, the innovative Renasys system is not only successfully used in wastewater treatment plants but also in aqua farms. It could also potentially help transform wastewater treatment in the agricultural and shipping sectors as well as in the textile industry and industrial consumer goods production.</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1695018981341-1695018981341.png" style="width: 747px;" class="fr-fic fr-dib"></p><p id="isPasted">Renasys&rsquo;s work is helping achieve a sustainable circular economy in the water industry and preparing current infrastructures for the future. Furthermore, existing wastewater treatment plants could act as energy suppliers as the filtered particles could be converted into energy and heat through the use of biogas systems, for example. As the primary energy required to do this is already found in the wastewater, no additional energy input would be needed. The amount of energy potentially generated would more than cover the wastewater treatment plants&rsquo; needs and the excess energy could be used elsewhere. The CO<sub>2</sub> equivalent emissions would therefore be zero, making the wastewater treatment plants climate neutral or even climate positive. At present, Europe&rsquo;s wastewater treatment plants alone use the same amount of energy as 55 million people, equating to around 12.3% of the continent&rsquo;s population (source:&nbsp;<a href="https://www.destatis.de/Europa/DE/Thema/Basistabelle/Bevoelkerung.html" target="_blank">German Statistical Office</a>). The CO<sub>2</sub>e savings therefore play an important role in decarbonising the water and wastewater sector. Energy-producing wastewater treatment plants also reduce the dependency on fossil fuels.</p><p><em>But how exactly does the Renasys system work and how can it filter so many more particles from the water?&nbsp;</em></p><p>At the heart of the filtration system is a very special metal filter mesh. Here at Haver &amp; Boecker, we have been working with Renasys on new technologies for water and liquid filtration since 2018 within the scope of our strategic partnership. The technical solution centres on our patented <a href="https://www.haverboecker.com/en/product-solutions/filter-mesh/rpd-hiflo-s/" target="_blank">MINIMESH<sup>&reg;</sup> RPD HIFLO-S</a> filter weave. This special filter weave has an innovative three-dimensional mesh structure and pore geometry, which significantly increases the porosity within the same area and enables double the flow rate of standard weaves with the same pore size. In cooperation with Renasys, an innovative, closed-loop wastewater filtration solution was therefore developed that is both efficient and scalable.</p><p>&nbsp;<img border="0" width="517" src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1695018990309-1695018990309.jpeg" alt="[Translate to English:] MINIMESH® RPD HIFLO-S-Tressen " class="fr-fic fr-dii"></p><p>In addition to the aforementioned properties, the three-dimensional, high-performance metal filter mesh is also characterised by higher stability and durability. This is where the MINIMESH<sup>&reg;</sup> RPD HIFLO-S weave&rsquo;s outstanding separation performance and dirt absorption capacity come in as these promote longer filter service lives and usage intervals. As the filter mesh&rsquo;s underlying structure prevents it from becoming blocked as quickly, longer and more efficient filtration phases are possible between the cleaning and backwashing intervals.</p><p>In addition, the RPD HIFLO-S filter weaves can be made from comparatively thick wires despite being fine pored. This not only has a positive impact on the costs with regard to the standard stainless steel alloys but also makes it possible to use highly corrosion and temperature-resistant special materials, such as duplex/super duplex, Alloy 310 S, Inconel 600, Hasteloy C22 or titanium, which would otherwise not be suitable for use for creating such fine pores.</p><p>As a further benefit, the pore sizes of the MINIMESH<sup>&reg;</sup> RPD-HIFLO-S filter weaves can be precisely varied between 5 and 40 microns depending on the application. This enables the desired filtration processes to occur reliably, efficiently and precisely every time. The filter elements used also impress with excellent long-term stability and a long service life.</p><p><em>In cooperation with Renasys...&nbsp;</em></p><p>we&rsquo;ve taken the first step towards sustainable, closed-loop water treatment. Our advanced Renasys water treatment systems not only enable us to make an important contribution to global climate and water protection, but also show that, as a global community, we can use knowledge, technical innovation and passion to face the greatest challenges of the upcoming climate transformation.</p><p>At Haver &amp; Boecker, we are proud to work with partners like Renasys to actively shape the road to a more sustainable future with our innovative wire mesh and filter solutions.</p><p id="isPasted"><em>We invite you</em></p><p>On our website, in addition to an overview of clever solutions in water management, you will find comprehensive technical articles on selected areas of application:&nbsp;</p><ul><li>Microplastics filtration</li><li>Wastewater filtration and treatment</li><li>Ballast water treatment</li></ul><p>Click <a href="https://www.haverboecker.com/en/industries/energy-and-the-environment/#c5717?lso=wevolver-wasserfiltration-beitrag&utm_campaign=wasserfiltration&utm_source=wevolver&utm_medium=beitrag&utm_content=_092023" target="_blank" rel="noopener noreferrer">here</a> to visit our website and read our professional articles. We look forward to your visit and invite you to contact us directly if you have any questions about our product solutions or your specific requirements - even beyond the areas mentioned.</p>

The Norwegian start-up Renasys has made it its mission to transform water filtration and wastewater treatment. A newly developed, innovative filtration system removes 99% of dirt particles and suspended matter over 5 microns in size from the water.

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