Dougie Mann, one of&nbsp;<a href="https://www.3dhubs.com/education/student-grant/" target="_blank">3D Hubs Student Grant 2019</a> finalists, wanted to make it easier for people with disabilities to use smartphones. His end product is a 3D printed keyboard with just 5 buttons instead of 50. As the keyboard is built into a phone case, users can type without having to look, with only one hand, and without having to remove their phone from their pocket.<h2>Making the the smartphone smart - for everyone</h2>People who are visually impaired struggle to see the buttons on a flat touchscreen. Dougie's keyboard facilitates the use of an ordinary smart phone, without having to rely on the more stigmatizing solutions like voice-to-text devices.Amputees are another use case where typing on a full keyboard and mouse can be time consuming, whereas a single handed gestural keyboard can streamline the human-computer interaction.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1594221148905-ezgif-5-1b5d38df9980.gif" style="width: 788px;" class="fr-fic fr-dib">Designed with one-handed individuals in mind, such as amputees, stroke victims or hemiplegics, TypeCase simplifies a traditional keyboard down to a beautifully intuitive and effortless interaction. By integrating the board into a phone case, it reintroduces tactility back into touchscreen smartphones, offering the visually impaired a discrete alternative to the more stigmatizing voice-to-text methods.The keyboard works in &nbsp;a similar way to Braille, by showing the user how to press the right buttons when holding the phone. For the visually impaired, TypeCase uses haptic feedback that allows users not only to send messages, but to receive them as well. Reversing the interaction, you can ‘feel’ text using the same code with small vibrations in each of your fingers.This system could revolutionize communication for the blind. Simultaneously, it facilitates a whole new way for everyone to use a smartphone, and all without the need for audio.<img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk0MDQ4MDcxMjIyLWFydGljbGUtYS0zZC1wcmludGVkLWtleWJvYXJkLWZvci10aGUtYmxpbmQtaW1hZ2UtMy5qcGciLCAiZWRpdHMiOiB7InJlc2l6ZSI6IHsid2lkdGgiOiA5NTAsICJmaXQiOiAiY292ZXIifX19" style="width: 788px;">Dougie worked with a free and experimental process, starting with broader thematic questions about disability design. He studied the balance of form and function, the role of fashion and aesthetics in accessibility products, and tried a lot of different technologies before he arrived at the solution that became TypeCase.&nbsp;<img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk0MDQ4MDkyNDM1LWFydGljbGUtYS0zZC1wcmludGVkLWtleWJvYXJkLWZvci10aGUtYmxpbmQtaW1hZ2UtNC5qcGciLCAiZWRpdHMiOiB7InJlc2l6ZSI6IHsid2lkdGgiOiA5NTAsICJmaXQiOiAiY292ZXIifX19" style="width: 788px;">Starting with rapid prototyping of the electronics and designs, the first user tests were conducted on more functional prototypes in <a href="https://www.3dhubs.com/3d-printing/plastic/resin/" target="_blank">3D printed resin</a>. &nbsp;&nbsp;<img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk0MDQ4MTQ4ODI0LWFydGljbGUtYS0zZC1wcmludGVkLWtleWJvYXJkLWZvci10aGUtYmxpbmQtaW1hZ2UtNi5qcGciLCAiZWRpdHMiOiB7InJlc2l6ZSI6IHsid2lkdGgiOiA5NTAsICJmaXQiOiAiY292ZXIifX19" style="width: 788px;">Dougie spent a lot of time really pinning down the problems the intended users face to find a practical and real-world solution that would provide a genuine benefit. By re-framing the product as an inclusive design, he’ll be able to pitch the idea to a broader audience and also get the more traditional users excited in the concept and thereby be able to make it available to more users whose life TypeCase can have a real impact on.&nbsp;<img class="fr-fic fr-dib" src="https://images.wevolver.com/eyJidWNrZXQiOiAid2V2b2x2ZXItcHJvamVjdC1pbWFnZXMiLCAia2V5IjogImZyb2FsYS8xNTk0MDQ4MTY5NjQ5LWFydGljbGUtYS0zZC1wcmludGVkLWtleWJvYXJkLWZvci10aGUtYmxpbmQtaW1hZ2UtNy5qcGciLCAiZWRpdHMiOiB7InJlc2l6ZSI6IHsid2lkdGgiOiA5NTAsICJmaXQiOiAiY292ZXIifX19" style="width: 788px;"><h2>Dougie Mann</h2>The creator and designer behind TypeCase,&nbsp;<a href="https://www.dougiemann.co.uk/" target="_blank">Dougie Mann</a>, is a recent university graduate with master's degrees in both Mechanical Engineering and Product Design from Imperial College London and The Royal College of Art. After graduating, Dougie worked at NASA in their Human Factors Division, and then with startups and research labs around the world working on a broad spectrum of Design and Engineering projects. At the moment, Dougie is working as a Biomedical Design. Dougie comments:"The product still needs a lot of work and development on the hardware and design. Not to mention, there is a whole untouched software side to the project which could really make a huge difference to the usability and functionality. Ultimately, I would love to get it to the point where it makes someone's life easier - then I'll be happy."

Dougie Mann wanted to make it easier for people with disabilities to use smartphones. His end product is a 3D printed keyboard with just 5 buttons instead of 50.

A 3D printed keyboard for the blind

The current revolution brought by 3D printing extends to the most surprising applications, even the ones as far removed as possible from the traditional “geek” sphere. One example: fashion!The seemingly ‘niche’ market of <a href="http://www.goscan3d.com/en/applications/3d-printing-goscan-3d-scanner" target="_blank">3D printing</a> in fashion is growing rapidly and presents a very refreshing and interesting counterpoint to the most traditional, industrial uses. Here is a recent 3D printing and <a href="http://www.goscan3d.com/en/features" target="_blank">3D scanning</a> example, which prove that pairing technology and creativity is always in style!WOW – The World of Wearable ArtEarlier this year, the Auckland Museum, in New Zealand, presented a fascinating exhibition based on a theatrical fashion show presented in Wellington every year since 1987 – <a href="http://worldofwearableart.com/" rel="noopener" target="_blank">The World of Wearable Art</a>. The event aims at taking art off the walls of galleries and used it to adorn the human body in eccentric, imaginative ways.Among many creative designers, this year’s show and following museum exhibition featured the work of Dylan Mulder, a 27-year-old New Zealander who presented a fantastically elaborate costume named ‘Samurai Silent Dragon’.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1592839677900-N6P8313-e1473222424963.jpg" style="width: 788px;" class="fr-fic fr-dib">The Asian-inspired adornment did not come from a sewing machine, but rather from… (you’ve guessed it!) a computer, a 3D scanner and a 3D printer.The costume took 4 months to complete. For this industrial designer, the technological advances are a big source of inspiration… and challenge. For this year’s WOW, he chose to create &nbsp;something that “slipped out of the 3D printer in sheets of blank plastic, to be pieced together into wearable art; a virtual reality outfit that became a reality!”<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1592839704698-98836_06157-1024x683.jpg" style="width: 788px;" class="fr-fic fr-dib">Samurai Silent Dragon was not Mulder’s first attempt at 3D printing fashion. He won the WOW Design Award last year for another creation, and the prize money helped him push his passion a little further. He purchased a 3D scanner and a 3D printer, which enabled him to see most of his creation come to life right by his side, in his own living room. Doing it himself saved a lot of time and effort as parts of his costume, for instance spikes and rivets, simply were not available in New Zealand. In the end, only a small part of the hat was sent to be 3D printed in the Netherlands, because Mulder wanted “a higher level of detail and accuracy”.Mulder loves that his creations help demystify the process of 3D printing to the majority of the population, who is unfamiliar with the technology. His explanation for the average laymen to the WOW: “A spool of plastic cord feeds into a heated nozzle, a little bit like a glue gun. I have 3D files, and a software slices the file into layers when a code is plugged into the 3D printer… The plastic is melting, and a very fine layer of plastic spits out. The bed drops down and puts in another layer, and eventually, the layers build up until it’s a 3D piece!”

The current revolution brought by 3D printing extends to the most surprising applications, even the ones as far removed as possible from the traditional “geek” sphere. One example: fashion!

The World Of Wearable Art... In 3D

Most traditional&nbsp;<a href="https://www.engineeringclicks.com/markforged-metal-x-price/" target="_blank">3D printers</a> create a shape by excreting a synthetic resin layer by layer, which is then hardened using UV light. Thanks to the abundance of scientific activity in this field, we have a number of resins and&nbsp;<a href="https://www.engineeringclicks.com/category/3d-printing-prototyping/" target="_blank">3D printing</a> methods to choose from. However, These resins are very expensive – A typical high-resolution photo-curable resin used in SLA/DLP can cost upwards of $500 per litre.Scientists from the&nbsp;<a href="https://www.chemistry.utoronto.ca/" rel="noopener" target="_blank">University of Toronto</a> have an innovative solution to this problem: Waste cooking oil from McDonald’s. The oils that we use today fall into two categories: saturated and unsaturated. The carbon chains in saturated oils are all connected using single bonds. All the other hands of carbons are tied to other functional groups particularly hydrogen.The unsaturated cooking oil used in McDonald’s has a lot of double bonds which allows it to undergo a chemical process called ‘acrylization’. Essentially, this causes the cooking oil to change into a resin that is sensitive to light in the same way that commercial 3D printing resins are. Acrylization has previously been demonstrated for soybean oil. The researchers wondered if this could be extended to waste cooking oil (WCO) – a commodity produced in abundance thanks to our growing fast food habits.McDonald’s alone produces 600 tons of WCO every day. Disposing of all of this using conventional techniques will lead to severely clogged drains. They are therefore sold off to biodiesel plants and soap manufacturers. While efficiently getting rid of the WCO, it is not very cost-effective as the end products are rather cheap.The 3D printing resin technique, however, may prove to be highly viable economically.The cooking oil is retrieved at the end of the day and subjected to filtration to remove the residual solids (think french fry particles). They are then chemically treated using acrylic acid and boron trifluoride etherate, among others. The resin is formed in a single step – which is an improvement over other acrylizaton techniques that require complex chemical setups.The team has successfully demonstrated 3D printing of complex shapes using their novel resin.Resolutions of up to 100 um have been attained making this on par with synthetic resins in terms of capability. The butterfly shown on the left was printed using the new resin while the one on the right was printed using a commercial resin. The results speak for themselves.The difference is that the WCO resin only costs 50 cents per litre. Significantly, the new resin is environmentally compatible and degrades in the soil. None of the additives added are harmful in any way. The scientists who have developed this technique hope that it can be extended to all waste cooking oils from all brands.The significant reduction in the price combined with the enormous benefit to the environment is likely to make this method mainstream in the near future.

Image source: https://pubs.acs.org/doi/pdf/10.1021/acssuschemeng.9b06281

Most traditional 3D printers create a shape by excreting a synthetic resin layer by layer, which is then hardened using UV light. Thanks to the abundance of scientific activity in this field, we have a number of resins and 3D printing methods to choose from.

Used cooking oil from McDonalds: a sustainable material for 3D printing

While it seems like we have only skimmed the surface of all the ways <a href="http://www.goscan3d.com/blog/3d-printing-dummies_176" target="_blank">3D printing</a> could eventually transform our lives, it increasingly emerges as a truly out-of-this-world component. And bad pun intended, we are actually being literal here: the technology is unveiling itself as one of the most essential building blocks of space exploration.Of course, 3D printing for space manufacturing makes perfect sense, since it circumvents several issues relative to traditional manufacturing: custom tools and machinery for each part, raw material availability, not to mention the weight and bulk of both&hellip; Manufacturing in space instead of bringing materials and components from Earth thus saves time and simplifies the process, while also expanding possibilities and opportunities. The need for a specific tool or replacement part suddenly arises? A 3D printer can (theoretically at least) produce it quickly and efficiently, without having to wait for the next shuttle from Earth!<h2>How it started</h2>In 2011, European aerospace giant Airbus sent the first 3D printed part outside of our atmosphere; it was a titanium alloy bracket used on the Atlantic Bird 7 telecom satellite.The company repeated the feat in 2015, when it produced the first space-qualified 3D printed to replace a satellite component, a structural bracket. The new part weighed 35 % less than the previous one, while being 40 % stiffer. Moreover, it was made into a single piece, instead of 4 riveted together in 44 places as for the old one. That&rsquo;s a very significant improvement!<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1588041075490-3d-printed-architecture-1.jpg" style="width: 788px;" class="fr-fic fr-dib">Still, as Airbus Telecommunications Satellites R&amp;D Manager Alan Cox puts it, large-scale 3D printing in space is not quite a reality yet. &ldquo;We must first be able to prove the repeatability of 3D processes and our ability to consistently produce high-quality, affordable components,&rdquo; he explained.<h2>The Gravity Problem</h2>One of the challenges this new field faces is the absence of gravity in space. When 3D printing an object, a nozzle extrudes layer upon layer of material according to a 3D plan (which you can obtain using our&nbsp;<a href="https://www.goscan3d.com/en" target="_blank">3D scanners for 3D printing</a> for example) in order to slowly &ldquo;build&rdquo; it into the real world.Engineers and scientists have already figured out that some processes are much more suited for a &ldquo;microgravity&rdquo; environment than others: a filament deposition modelling with plastic heated to a relatively low temperature works fairly well, for instance. But other additive manufacturing techniques, such as those using molten metal, resin or powder, prove to be much more difficult to use in space, since the materials are less stable. The powder would just float around into a cloud, among other things.For these reasons, a 3D printer using the filament deposition modelling process is currently being tested by the NASA (using this prototype <a href="http://www.madeinspace.us/projects/3dp/" target="_blank">Zero-G 3D printer</a>) on the International Space Station and it already produced 21 parts, including the wrench shown below. Only a few minor issues have come up so far: for instance, objects sticking a little too well to the build plate and becoming slightly damaged after being &ldquo;forced&rdquo; out. NASA experts are trying to figure out if that is in fact due to the microgravity effect; if so, they are planning to find workarounds.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1588041111836-3d-printed-architecture-2.jpg" style="width: 788px;" class="fr-fic fr-dib">Quincy Bean, a materials engineer and the principal investigator for this project, expects that once the technique is fully operational, astronauts will use 3D printing to replace crew tools, to replace life support systems or to build any specific tooling they need.<h2>Lunar Habitations Coming Up?</h2>Airbus is even taking part in an exciting project led by the European Space Agency, called AMAZE. Combining 28 partners from the industry as well as from the academic world, AMAZE aims at refining 3D printing techniques in order to make it possible to mass produce space-grade parts, even in metal.London-based architecture firm Foster + Partners is also part of the project, and their own participation is a very intriguing one&hellip; They imagined a lunar base for four people, using 3D printing techniques and regolith, or lunar soil, as a material.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1588041246210-3d-printed-architecture-3v2.jpg" style="width: 788px;" class="fr-fic fr-dib"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1588041259343-3d-printed-architecture-5.jpg" style="width: 788px;" class="fr-fic fr-dib">The complex would shield astronauts from meteorites, gamma radiation and temperature variations. A tubular module would first be shipped from Earth by space rocket. Once landed, it would then be extended by an inflatable dome to support building structure. Finally, a robot-operated 3D printer would form a protective shell from regolith. The shell itself would be created using a hollow cellular structure a little bit like a honeycomb, for both solidity as well as raw material economy.&nbsp;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1588041282848-3d-printed-architecture-6.jpg" style="width: 788px;" class="fr-fic fr-dib">The firm built a 1.5-ton mockup using simulated lunar soil, and tested the 3D printing techniques in a vacuum chamber mimicking moon conditions. We recently talked to you about the first 3D printed building, and we happen to think that&nbsp;<a href="http://www.goscan3d.com/blog/is-the-building-of-the-future-3d-printed_600" target="_blank">3D printed architecture</a> is one of the most promising applications for the technology. But this project truly is something else!It will be incredibly interesting to watch this all unfold. And not only just to be able to reply to the question &ldquo;Where will technology takes us next?&rdquo; by a resounding &ldquo;Well, to space!&rdquo; one day.

While it seems like we have only skimmed the surface of all the ways 3D printing could eventually transform our lives, it increasingly emerges as a truly out-of-this-world component.

3D Printed Architecture in Space: 3D Printing on the Moon

Four trends are setting the scene for 3D printing to become ever more versatile and deliver products that are closer to end-use, production level

Trends in 3D Printing

Engineers looking to create high-performance metallic alloys that are resistant to corrosion, fatigue and wear while remaining strong often use a trial-and-error method to find the right combination of elements. Now, engineers at Washington University in St. Louis plan to use computational methods and additive manufacturing to find the best combinations, saving significant time and money.Katharine Flores, professor of mechanical engineering &amp; materials science in the School of Engineering &amp; Applied Science, will build on some foundational work in high-entropy alloys &mdash; single-phase substances of five or more metallic elements in relatively equal parts &mdash; to find new alloys for structural, load-bearing applications, such as in aircraft, power generators and energy storage devices. Instead of the time-consuming trial-and-error method, Flores will work with Rohan Mishra, assistant professor of mechanical engineering &amp; materials science, who will use quantum-mechanical computation to identify combinations of elements that have the most promise. Once identified, Flores will synthesize the alloys using a laser-aided metal-on-metal&nbsp;deposition technique to create a library of potential alloys for further testing.With a three-year, $496,077 grant from the National Science Foundation, Flores and Mishra will use these methods to look for high-entropy alloys that can withstand high temperatures. Mishra will perform the computational calculations on some of the most powerful supercomputers to identify promising candidates from a large composition space. Then Flores will use her lab&#39;s technique to create a 2-D library, a one-inch square piece of metal on which about 100 tiny dots of individual candidate alloys can be fabricated. Flores&#39; laser-deposition technique creates the library in about 30 minutes with just a few grams of material.The additive manufacturing technique is similar to polymer 3-D printing where the machine draws the material onto a surface layer by layer. However, Flores uses a laser to melt a small region of a base material, then adds up to four different powders to the melt.<blockquote>&quot;What we&#39;re doing with this research is changing the composition of the powders as we raster the laser across the surface, and there are a few ways we can do that,&quot; Flores said.</blockquote>&quot;We can change the composition of the powder continuously to produce a gradient, or we can make individual dots with different compositions.&quot;While Flores has been doing similar work in bulk metallic glasses for several years, the high-entropy alloys are a new class of materials generating significant interest, she said. One particular attribute that is appealing is that the materials don&#39;t undergo phase separation, or become less homogenous at different temperatures as other metals do.&quot;On the calculation side, Rohan is going to identify combinations of elements that produce a single phase or produce an interesting combination of other phases,&quot; said Flores, who also is director of the university&#39;s Institute of Materials Science &amp; Engineering. &quot;He will tell us what combinations to try, then we will deposit those elements and do the microstructural characterization and mechanical property measurements to test the strength and stiffness and map out those properties.&quot;Once Flores&#39; lab has the measurements, she will provide them to Mishra, who can feed them back into his computational model to improve his predictions. In addition, Mishra&#39;s team will use one of the world&#39;s most powerful microscopes at Oak Ridge National Laboratory to look at the structure of the materials at the atomic scale.In addition to accelerating the development of new alloys, the work will contribute to the growing field of additive manufacturing, which could be used to make complicated parts in a single manufacturing process.&quot;When making a part for an airplane that has 20 different pieces that need to go together, if you can make it in one piece, you eliminate all of the fasteners, which means less weight, improved fuel efficiency and reduced manufacturing and maintenance time,&quot; she said.Previously, Flores&#39; lab created 21 alloys with aluminum, cobalt, chromium, iron&nbsp;and&nbsp;nickel and tested them using X-ray diffraction, microscopy and nanoindentation, a method used to test the hardness and stiffness of materials. In research recently published in&nbsp;Intermetallics, the team found that the laser-deposition technique created alloys consistent with those created with traditional methods, showing that the technique is a highly efficient method that can speed up the process of identifying and refining the most promising compositions prior to creating larger quantities.

Research using quantum-mechanical computation will be used to identify combinations of elements that have the most promise for load-bearing applications

Materials scientists combine supercomputers, 3-D printers to create strong metallic alloys

Researchers at Georgia Tech 3-D printed an object made with tensegrity, a structural system of floating rods in compression and cables in continuous tension. (Credit: Rob Felt)

A team of researchers from the Georgia Institute of Technology has developed a way to use 3-D printers to create objects capable of expanding dramatically that could someday be used in applications ranging from space missions to biomedical devices.

Researchers Create 3-D Printed Tensegrity Objects Capable of Dramatic Shape Change

<h2 data-element-id="headingsMap-4-0">Introduction</h2>3D printing technologies based on <a href="https://www.wevolver.com/article/digital.light.processing.3d.printing.explained" rel="noopener noreferrer" target="_blank">DLP printing (Digital Light Processing)</a> are frequently used for fabricating complex objects without tooling and machining. DLP printing involves the light-mediated conversion of a liquid resin containing monomer or oligomer photopolymers to a solid object. This process leverages the versatility of polymer chemistry to make complex objects with programmable optical, chemical or mechanical properties. Versatility underpins the popularity of polymer materials within the 3D printing community, encouraging research in photopolymer chemistry and printing applications. <iframe src="https://www.youtube.com/embed/97ARLiTHjX0?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 500px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>This video explains the process and working of DLP printers in detail - by Professor Bill Hammack, Department of Chemical Engineering, University of Illinois Despite the growing enthusiasm for 3D printing in rapid prototyping applications, implementation in manufacturing environments to produce end-use parts has lagged. Common problems include setting and maintaining minimum specifications, specifically those related to material durability and weathering. Additive manufacturing methods rely on tight synchronicity between hardware, software and chemistry to achieve reproducibility at scale. This article highlights the role of polymerization in the co-development and simultaneous tuning of each component in the DLP process. By understanding the fundamentals of polymerization, developers can simultaneously tune process components, avoiding common pitfalls contributing to part defects, detachment, post-processing and weathering problems.This article is sponsored by polySpectra, which makes functional materials for advanced additive manufacturing. PolySpectra CEO Raymond Weitekamp explained to Wevolver that they've spent thousands of hours and hundreds of thousands of dollars characterizing the thermomechanical properties of dozens of additive manufacturing polymers. For Wevolver readers they are providing a free specification sheet of their newest materials at&nbsp;<a href="http://www.polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">www.polyspectra.com/wevolver</a> <h2 data-element-id="headingsMap-6-0">Photopolymerization: A multi-stage, dynamic process</h2>A photopolymer is a polymer whose properties alter upon exposure to light. Photopolymers are a liquid mixture containing monomers and oligomers, which can be manipulated to achieve specified physical properties. The process of photopolymerization (also known as photocuring or photo crosslinking) describes the crosslinking of monomers / oligomers within the liquid resin to form a network polymer. This process typically occurs via cationic or radical mechanisms and is mediated by the addition of photoinitiators. Photoinitiators are molecules that convert photolytic energy into reactive species to activate polymerization through specific functional groups.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4Mjk2NjE4NDExLVBob3RvLXBvbHltZXJfc2NoZW1lMSAwMi5wbmciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 550px;" class="fr-fic fr-dib">Photopolymerization is an attractive method of curing polymers for 3D printing applications because it can be performed selectively. However, the process of photopolymerization is complex and sensitive to a range of parameters including wavelength, temperature and moisture. The extent and homogeneity of the polymerized cross-linked network is an important determinant in the properties of the final hardened material. Photopolymerization is a multi-stage and dynamic process. <a href="http://rawwerks.com/sla-utility/" rel="noopener noreferrer" target="_blank">Photopolymerization kinetics</a> is described as a “working curve”, mapping cure depth (depth to which light induces polymer crosslinking) as a function of light exposure at different wavelengths. Critical exposure (Y-intercept on the working curve) is defined as the minimum light exposure required for the onset of curing. The behaviour of the photopolymer under specified light exposure conditions (wavelength, power, exposure time and velocity) affect the printing process. There are a wide range of photopolymers available, responding to wavelengths in the UV (190-400 nm), visible (400-700 nm) and IR ranges (700-1000 nm). Light of different wavelengths penetrate materials to different cure depths. <img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4Mjk4MzAwNTYzLVBSLTQ4LVdDLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=">An example of a Working Curved that shows the relation between UV light dose and curing depth of the resin. Image courtesy Polyspectra. <iframe src="https://www.youtube.com/embed/Lw3BY2_yGVU?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 470px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>This video explains how the working curve impacts the 3D print and how to find the correct settings - by Autodesk Ember <h2 data-element-id="headingsMap-8-0">Photopolymerization: A fundamental process in DLP printing</h2>The dynamic nature of photopolymerization suggests that it is a non-binary process. In DLP printing, light is projected into the polymer resin forming a 2D image. This simultaneously exposes all the designated regions within a polymer layer. The overall printing time is reduced through compared to rastered stereolithography, due to the parallelization of the photocuring process. The projected 2D image is composed of pixels, which become voxels when translated into three dimensions. This has led to the misconception that DLP is an essentially digital binary processtechnology and that print resolution is purely a function of printer hardwarethe DLP optics. In reality, voxels contain photopolymers that are fluxing between stages of the photopolymerization process: going from liquid to their gel point and then on towards their full cross-linking density.<iframe src="https://www.youtube.com/embed/5qTAmPrHLow?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 470px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true" data-headingsmap-frameid="1370"></iframe>This video shows the impact of voxels on the 3D print and how printers can actually achieve resolutions smaller than the nominal resolution of the DLP projector - by Autodesk Ember. This can influence the 3D printing process in several ways. Firstly, printing speed should be calibrated to account for photopolymerization kinetics. If not, voxels may expand beyond their digitally defined physical space, reducing feature resolution of the finished part. Further, photopolymerization may cause shrinkage in the hardened polymer. Shrinkage coupled with cycles of thermal expansion and contraction experienced during the printing process may induce stressinduces stresses on the part, . These stresseswhich can manifest in warping or layer splitting or separation in the finished object. Strategies to mitigate these effects include tuning both software and hardware to select appropriate exposure protocols (velocity and speed) and control environmental influences (temperature and humidity). Finally, the cure depth is an important parameter to consider when implementing a DLP printing protocol. Cure depth directly impacts the z- axis settings of the printer. It may also influence the selection of printing parameters such as print velocity.Recommended reading:&nbsp;<a href="https://www.wevolver.com/article/digital.light.processing.3d.printing.explained" rel="noopener noreferrer" target="_blank">Digital Light Processing 3D printing explained</a><h2 data-element-id="headingsMap-10-0">Detachment: Building and breaking interactions between materials and hardware</h2>3D objects are rendered through the sequential hardening of photopolymer layers onto a substrate (known as a build plate). An essential step in any 3D printing process is the detachment of the finished part from the substrate. This step can prove problematic, as the printing process can induce suction forces, securing the part to the substrate. Numerous separation mechanics have been described to overcome these suction forces. Examples include tilting the resin tray and peeling the part off or using a sliding mechanism. Building the part on a flexible window, to which pressure may be applied to break suction forces is also a common method.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4MzU3NDgwMzU4LUNhcmJvbiBCZWQuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==">A print (with support structure) attached to a print bed after printing. Source: Carbon 3DBuilding an oxygen permeable window within the substrate allows oxygen to access the photopolymer directly in contact with the substrate. This creates a depletion zone of inactive resin which does not adhere to the substrate, facilitating part removal. However, this method is only suitable for photopolymers which are quenched by oxygen, such as acrylates and methacrylates. An alternative strategy is to modify the viscosity of the liquid photopolymer resin. Low viscosity solutions enable higher printing speeds and concomitant reduction in the suction forces adhering the part to the substrate. This highlights an important aspect of 3D printing; the relationship between the photopolymer materials and the design of the printer hardware. It is widely recognised that surface adhesion is important to provide a foundation for the object to build upon. Consequently, the materials within the hardware and the finished printed object should be compatible.<h2 data-element-id="headingsMap-11-0">Post-processing: The significance of photopolymerization in scaling production</h2>DLP printing found initial application as an instrument for rapid prototyping in research settings. Introducing DLP printing into manufacturing settings has been slower due to problems with scaling production, reproducibility and part quality. The co-development of printing processes and materials is not only critical during the initial build process. Photopolymerization kinetics also affect post-processing of end-use parts. The acceptance of 3D printing into manufacturing settings has been restricted by extensive post-processing requirements including:<ul><li>Removal of the support structure (onto which the part is fabricated).</li><li>Part cleaning to remove debris and residual materials.</li><li>Post-curing (usually thermal or optical) to completely harden certain materials.</li><li>Part finishing (such as sanding, painting or varnishing) to remove the “boxy” surface finish characteristic of DLP printing.</li></ul><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4MzU3NTQ3NzY2LXBvc3QgcHJvY2Vzc2luZy5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 766px;" class="fr-fic fr-dib">Rinsing off resing, removing support, and curing with UV light. Source: FormlabsPost-processing steps are often performed in small batches under carefully controlled conditions. These processes can be difficult to automate, adding substantial time and cost to the production process. Advances in automation are ongoing, with some companies utilising robotics to automate assembly lines integrating 3D printers with post-processing equipment. Advances in printing hardware and software enabling automated monitoring could enable DLP printing at scale. However, the widespread implementation of automated processing lines has yet to be realised. Post-processing requirements are heavily dependent on photopolymer characteristics, with some materials requiring more extensive modification than others. Strategies to streamline operations should include selecting materials with limited post-processing requirements yet withstand weathering processes to maintain durability.<h2 data-element-id="headingsMap-12-0">Conclusion</h2>The combination of pivotal developments in 3D printing hardware, software and materials has paved the way towards the implementation in prototyping and manufacturing. With an increased awareness of the importance of co-developing each component simultaneously, the development of new applications for 3D printing of end-use parts is slowly becoming a reality. The relevance of DLP printing in the manufacturing sector will depend heavily on the ability to cost-effectively produce end-parts that are durable. The dynamic nature of photopolymerization continues throughout the lifetime of a part. The weatherability of hardened polymers is an important determinant of part durability, specifically the ability to maintain toughness and impact strength over time. By understanding the kinetics of photopolymerization and thermodynamic properties of the resulting polymer networks, developers can select materials to mitigate common problems, yet maintain desired properties throughout the lifetime of a part. <hr>This article was sponsored by&nbsp;<a href="http://polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">polySpectra</a>. polySpectra makes functional materials for advanced additive manufacturing in Berkeley, California, USA. They use light-activated catalysts to 3D print advanced functional materials. Polyspectra's platform enables them to deliver materials with a broad spectrum of tailored properties from a single chemical system.For Wevolver readers polySpectra is providing a free specification sheet of their newest materials at&nbsp;<a href="http://www.polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">www.polyspectra.com/wevolver</a>

DLP (Digital Light Processing) 3D printing uses photopolymerization to create 3D objects. Understanding the photopolymerization process can help you mitigate common problems that make your prints fail or that reduce print quality.

DLP 3D Printing: Understanding process and materials enables you to prevent production problems

What is DLP is a 3D printing? This article aims to provide an in-depth understanding of DLP 3D printing, its working principles, advantages, limitations, and diverse applications in various sectors.

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