3D Printing Flies High now. Articles on three-dimensional printers are popping up everywhere these days. And nowadays there are many 3D printer products. Some are small enough to fit in a briefcase and others are large enough to print houses.
Everything you ever wanted to know about 3D printing article tells that 3D printing is having its “Macintosh moment,” declares Wired editor -in-chief Chris Anderson in cover story on the subject. 3D printers are now where the PC was 30 years ago. They are just becoming affordable and accessible to non-geeks, will be maybe able to democratize manufacturing the same way that PCs democratized publishing.
Gartner’s 2012 Hype Cycle for Emerging Technologies Identifies “Tipping Point” Technologies That Will Unlock Long-Awaited Technology Scenarios lists 3D Print It at Home as important topic. In this scenario, 3D printing allows consumers to print physical objects, such as toys or housewares, at home, just as they print digital photos today. Combined with 3D scanning, it may be possible to scan certain objects with a smartphone and print a near-duplicate. Analysts predict that 3D printing will take more than five years to mature beyond the niche market. Eventually, 3D printing will enable individuals to print just about anything from the comfort of their own homes.Slideshow: 3D Printers Make Prototypes Pop article tells that advances in performance, and the durability and range of materials used in additive manufacturing and stereolithography offerings, are enabling companies to produce highly durable prototypes and parts, while also cost-effectively churning out manufactured products in limited production runs.
3D printing can have implications to manufacturers of some expensive products. The Pirate Bay declares 3D printed “physibles” as the next frontier of piracy. Pirate Bay Launches 3D-Printed ‘Physibles’ Downloads. The idea is to have freely available designs for different products that you can print at home with your 3D printer. Here a video demonstrating 3D home printing in operation.
Shapeways is a marketplace and community that encourages the making and sharing of 3D-printed designs. 3D Printing Shapes Factory of the Future article tells that recently New York Mayor Michael Bloomberg cut the Shapeways‘ Factory (filled with industrial-sized 3D printers) ribbon using a pair of 3D-printed scissors.
The Next Battle for Internet Freedom Could Be Over 3D Printing article tells up to date, 3D printing has primarily been used for rapid commercial prototyping largely because of its associated high costs. Now, companies such as MakerBot are selling 3D printers for under $2,000. Slideshow: 3D Printers Make Prototypes Pop article gives view a wide range of 3D printers, from half-million-dollar rapid prototyping systems to $1,000 home units. Cheapest 3D printers (with quite limited performance) now start from 500-1000 US dollars. It is rather expensive or inexpensive is how you view that.
RepRap Project is a cheap 3D printer that started huge 3D printing buzz. RepRap Project is an initiative to develop an open design 3D printer that can print most of its own components. RepRap (short for replicating rapid prototyper) uses a variant of fused deposition modeling, an additive manufacturing technique (The project calls it Fused Filament Fabrication (FFF) to avoid trademark issues around the “fused deposition modeling” term). It is almost like a small hot glue gun that melts special plastic is moved around to make the printout. I saw RepRap (Mendel) and Cupcake CNC 3D printers in operation at at Assembly Summer 2010.
There has been some time been trials to make 3D-Printed Circuit Boards. 3D Printers Will Build Circuit Boards ‘In Two Years’ article tells that printing actual electronics circuit boards is very close. Most of the assembly tools are already completely automated anyway.
3D printing can be used to prototype things like entire cars or planes. The makers of James Bond’s latest outing, Skyfall, cut a couple corners in production and used modern 3D printing techniques to fake the decimation of a classic 1960s Aston Martin DB5 (made1:3 scale replicas of the car for use in explosive scenes). The world’s first 3D printed racing car can pace at 140 km/h article tells that a group of 16 engineers named “Group T” has unveiled a racing car “Areion” that is competing in Formula Student 2012 challenge. It is described as the world’s first 3D printed race car. The Areion is not fully 3D printed but most of it is.
Student Engineers Design, Build, Fly ‘Printed’ Airplane article tells that when University of Virginia engineering students posted a YouTube video last spring of a plastic turbofan engine they had designed and built using 3-D printing technology, they didn’t expect it to lead to anything except some page views. But it lead to something bigger. 3-D Printing Enables UVA Student-Built Unmanned Plane article tells that in an effort that took four months and $2000, instead of the quarter million dollars and two years they estimate it would have using conventional design methods, a group of University of Virginia engineering students has built and flown an airplane of parts created on a 3-D printer. The plane is 6.5 feet in wingspan, and cruises at 45 mph.
3D printers can also print guns and synthetic chemical compounds (aka drugs). The potential policy implications are obvious. US Army Deploys 3D Printing Labs to Battlefield to print different things army needs. ‘Wiki Weapon Project’ Aims To Create A Gun Anyone Can 3D-Print At Home. If high-quality weapons can be printed by anyone with a 3D printer, and 3D printers are widely available, then law enforcement agencies will be forced to monitor what you’re printing in order to maintain current gun control laws.
Software Advances Do Their Part to Spur 3D Print Revolution article tells that much of the recent hype around 3D printing has been focused on the bevy of new, lower-cost printer models. Yet, significant improvements to content creation software on both the low and high end of the spectrum are also helping to advance the cause, making the technology more accessible and appealing to a broader audience. Slideshow: Content Creation Tools Push 3D Printing Mainstream article tells that there is still a sizeable bottleneck standing in the way of mainstream adoption of 3D printing: the easy to use software used to create the 3D content. Enter a new genre of low-cost (many even free like Tikercad) and easy-to-use 3D content creation tools. By putting the tools in reach, anyone with a compelling idea will be able to easily translate that concept into a physical working prototype without the baggage of full-blown CAD and without having to make the huge capital investments required for traditional manufacturing.
Finally when you have reached the end of the article there is time for some fun. Check out this 3D printing on Dilbert strip so see a creative use of 3D printing.
2,052 Comments
Tomi Engdahl says:
https://hackaday.com/2021/06/25/casting-a-simple-3d-print-in-aluminium/
Tomi Engdahl says:
To make metal 3D printing accessible, YouTuber Integza is experimenting with metal 3D printing with a welder.
Experiments with Metal 3D Printing Using a Welder
https://www.hackster.io/news/experiments-with-metal-3d-printing-using-a-welder-3b37470ec7e3
To make metal 3D printing accessible, YouTuber Integza is experimenting with metal 3D printing with a welder.
Tomi Engdahl says:
Custom 3D Printer Cart Hides Clever Features
https://hackaday.com/2021/06/26/custom-3d-printer-cart-hides-clever-features/
Tomi Engdahl says:
https://hackaday.com/2021/06/27/turning-a-mig-welder-into-a-metal-3d-printer/
Tomi Engdahl says:
https://hackaday.com/2021/06/29/petbot-turn-pet-bottles-into-filament/
Tomi Engdahl says:
https://hackaday.com/2021/07/04/machine-extrudes-filament/
Tomi Engdahl says:
Soft Robotic Hand Is Fast Enough to Play Video Games
https://www.hackster.io/news/soft-robotic-hand-is-fast-enough-to-play-video-games-2e78bf1ed7aa
University of Maryland engineers have created a 3D-printed robot hand capable of playing Nintendo
Tomi Engdahl says:
https://hackaday.com/2021/02/25/3d-printering-makerbot-prints-stainless-you-do-half-the-work/
Tomi Engdahl says:
Six years in the making, this bridge was 3D-printed out of almost 10,000 pounds of stainless steel in a process that had four robots spitting out 685 miles of melted wire.
3D-Printed Stainless Steel Bridge Opens in Amsterdam
https://www.treehugger.com/3d-printed-stainless-steel-bridge-amsterdam-5193958
Six years in the making, Joris Laarman’s dream is finally complete.
Tomi Engdahl says:
3D printing with kids – building and having fun together!
https://blog.prusaprinters.org/3d-printing-with-kids-building-and-having-fun-together_52597/
Tomi Engdahl says:
How bad is a $95 3D Printer??
https://www.youtube.com/watch?v=M3SMUpNH_6I
Just how bad can a $95 3D printer be? Well, its actually… not as bad as we thought?
Tomi Engdahl says:
https://hackaday.com/2021/08/27/resin-3d-prints-get-a-new-look-with-paint-injection/
Tomi Engdahl says:
First Permitted 3D Printed House in Florida | Printed Farms Strikes Again
https://www.youtube.com/watch?v=mEK9PnE8qcU
Over 100,000 people have watched the video of printed farms making their first 3-D printed building in Florida, that was just a two car garage and now they have advanced to building fully permitted home out of 3-D printed concrete in Tallahassee with general contractor Precision Builders & Renovating. They used a cobod bod 2 printer and in this home they printed all of the exterior and interior walls. The roof and appliances will be installed and I’ll do a future video on what the finishings of this home look like. There are many unique details in this project not found in another 3-D printed buildings so we’re going to take a walk around, look at some of the details and then finally share a recorded zoom call with the co-founder of printed farms, Fredrik Wannius.
Tomi Engdahl says:
https://hackaday.com/2021/08/30/3d-printering-is-hassle-free-bed-leveling-finally-here/
Tomi Engdahl says:
https://hackaday.com/2021/08/30/printing-ceramics-made-easier/
Tomi Engdahl says:
https://hackaday.com/2021/08/30/printing-ceramics-made-easier/
Creating things with ceramics is nothing new — people have done it for centuries. There are ways to 3D print ceramics, too. Well, you typically 3D print the wet ceramic and then fire it in a kiln. However, recent research is proposing a new way to produce 3D printed ceramics. The idea is to print using TPU which is infused with polysilazane, a preceramic polymer. Then the resulting print is fired to create the final ceramic product.
SiOC(N) Cellular Structures with Dense Struts by Integrating Fused Filament Fabrication 3D Printing with Polymer-Derived Ceramics
https://onlinelibrary.wiley.com/doi/10.1002/adem.202100535
Tomi Engdahl says:
https://hackaday.com/2021/09/17/add-on-lets-fdm-3d-printer-wash-and-cure-resin-parts/
Tomi Engdahl says:
3D-Printing Complex Sensors And Controls With Metamaterials
https://hackaday.com/2021/09/17/3d-printing-complex-sensors-and-controls-with-metamaterials/
If you’ve got a mechatronic project in mind, a 3D printer can be a big help. Gears, levers, adapters, enclosures — if you can dream it up, a 3D printer can probably churn out a useful part for you. But what about more complicated parts, like sensors and user-input devices? Surely you’ll always be stuck buying stuff like that from a commercial supplier. Right?
Maybe not, if a new 3D-printed metamaterial method out of MIT gets any traction. The project is called “MetaSense” and seeks to make 3D-printed compliant structures that have built-in elements to sense their deformation.
MetaSense
Using conductive and flex filament to 3d print interactive interfaces.
https://hackaday.io/project/181697-metasense
Tomi Engdahl says:
Up Close And Personal With An Unusual 3D Printer Kit
https://hackaday.com/2021/09/21/up-close-and-personal-with-an-unusual-3d-printer-kit/
While there are still plenty of folks out there tinkering with custom 3D printers, it’s safe to say that most people these days are using a commercially-available machine. The prices are just so low now, even on the resin printers, that unless you have some application that requires exacting specifications, it just doesn’t make a whole lot of sense to fiddle around with a homebrew machine.
As it so happens, [Nicolas Tranchant] actually does have such an application. He needs ultra-high resolution 3D prints for his jewelry company, but even expensive printers designed for doing dental work weren’t giving him the results he was looking for. Rather than spend five-figures on a machine that may or may not get the job done, he decided to check out what was available in kit form. That’s when he found the work of [Frédéric Lautré].
https://vivalatina-shop.com/blogs/custom-made-jewelry/3d-printer-test-and-review
Tomi Engdahl says:
https://www.academia.edu/5327317/A_Low_Cost_Open_Source_Metal_3_D_Printer?auto=download&email_work_card=download-paper
Tomi Engdahl says:
Making The Most Of Your Resin Printer Investment
https://hackaday.com/2021/10/06/making-the-most-of-your-resin-printer-investment/
To the extent that we think of 3D printers as production machines, we tend to imagine huge banks of FDM machines slowly but surely cranking out parts. These printer farms are a sensible way to turn a slow process into a high-volume operation, but it turns out there’s a way to do the same thing with only one printer — as long as you think small.
https://www.youtube.com/watch?v=KDacLm2snLE
Tomi Engdahl says:
G10 Is The 3D Print Surface You Crave
https://hackaday.com/2021/10/13/g10-is-the-3d-print-surface-you-crave/
Print surfaces have been a major part of 3D printer development and experimentation since the beginning. [Makers Muse] has been experimenting with G10, a cheap high-pressure fiberglass laminate, and found that it’s an excellent candidate for most of your FDM printing needs. (Video embedded after the break.)
You’re probably more familiar with the fire-resistant version of G10, FR-4, the fiberglass substrate used for most PCBs. It’s also known by the brand name Garolite. [Makers Muse] tested with PLA, PETG (on his headphone build), ABS, ASA, PET, PCTG, and nylon. All the materials displayed excellent bed adhesion when heated to the appropriate temperature, and would often self-release the part as it cooled down. For TPU, the bed was left unheated to prevent it from sticking too well. 0.5 mm, 1.5 mm, and 3 mm G10 sheet thicknesses were tested, and [Makers Muse] found 1.5 mm to be the perfect balance between rigidity, and flexibility for removing particularly sticky prints.
G10 has been used in some commercial 3D printers, but there is very little information regarding its use beyond high-temperature materials like nylon. It leaves an excellent surface finish on the bottom of parts, as long as you take care not to scratch the bed.
Tomi Engdahl says:
https://hackaday.com/2021/10/14/3d-printing-toothpaste-in-the-name-of-science/
Tomi Engdahl says:
https://hackaday.com/2021/10/20/spinning-threads-put-the-bite-on-filament-in-this-novel-extruder-design/
Tomi Engdahl says:
Turning Old Masks Into 3D Printer Filament
https://hackaday.com/2021/10/19/turning-old-masks-into-3d-printer-filament/
Disposable masks have been a necessity during the COVID-19 pandemic, but for all the good they’ve done, their disposal represents a monumental ecological challenge that has largely been ignored in favor of more immediate concerns. What exactly are we supposed to do with the hundreds of billions of masks that are used once or twice and then thrown away?
If the research being conducted at the University of Bristol’s Design and Manufacturing Futures Lab is any indication, at least some of those masks might get a second chance at life as a 3D printed object. Noting that the ubiquitous blue disposable mask is made up largely of polypropylene and not paper as most of us would assume, the team set out to determine if they could process the masks in such a way that they would end up with a filament that could be run through a standard 3D printer. While there’s still some fine tuning to be done, the results so far are exceptionally impressive; especially as it seems the technique is well within the means of the hobbyist.
Facemask to Filament: 3D Printing with Recycled Facemasks
https://dmf-lab.co.uk/blog/facemask-to-filament-3d-printing-with-recycled-disposable-facemasks/
As a first line of defence against the spread of COVID-19 the facemask, a simple covering worn to reduce the spread of infectious agents, has affected the lives of billions across the globe. An estimated 129 billion facemasks are used every month, of which, most are designed for single use. Naturally, this presents a challenge of immense scale to mitigate the impact of disused Personal Protective Equipment (PPE) on our environment.
Our lab here at the University of Bristol predominantly focuses on issues concerning Rapid Prototyping. We’ve been involved in numerous ‘hack the pandemic’ type projects since the outbreak of COVID-19, sharing our knowledge of Rapid Prototyping with the maker community at large. As such, our works under the title of Project Clean Access (PCA), a DMF lab initiative funded by the Royal Academy of Engineering, have previously contributed designs for low-cost, physical interventions to reduce the transmission of COVID-19.
However, as restrictions are slowly lifted and a sense of normality returns to many campuses across the UK, it’s evident that we’re now facing an altogether different problem; the pervasiveness of PPE litter in our local environment.
We realised through early experimentation that the fibrous composition of masks posed a challenge to any conventional methods of plastic recycling. Other researchers also identify this as the cause of many a ‘clogged machine’. To overcome this issue we introduce a step prior to grinding where the masks are heated and pressed to form a hard sheet; the idea being that by taking the material to its glass transition point we can fuse the Polypropylene fibers to create something with more rigidity. To do this we simply used an iron and non-stick paper.
The rigid sheets were then broken up into smaller bits to process through a blender (300W Breville Blend Active) achieving the fine granules of facemask blue PP pictured on the right.
Extrusion Settings
Nozzle temp: 170 C
Voltage: 11V (turned down to reduce speed)
Amps: 1.6 (current limited)
Cooling: On
Nozzle hole diameter: 1.75mm
Filawinder: Automatic speed
This set up produced good results however there are still issues with achieving a consistent filament diameter.
Nevertheless, 7 meters of ‘useable‘ filament was spooled with an average diameter of 1.5 mm (-0.25 mm below the standard of 1.75 mm). Initial results indicate that with further refinement it will be possible to achieve the desired diameter within a reasonable tolerance.
5: Printing with Facemasks
Polypropylene (PP) is notoriously difficult to 3D print as it doesn’t bond well to common printer build platforms. However, it does bond well to itself, PP. A trick is therefore to print on normal clear tape as this is often also PP. Using this method it was surprisingly straightforward to 3D print with our rudimentary stock of filament on a low-cost, run-of-the-mill machine. It’s very evident that issues currently reside in producing the filament and not in 3D printing with it.
Print Settings
Printer: Creality Ender 3 Max
Nozzle temp: 235 C
Bed temp: 100 C
Print speed: 40 mm/s (slow)
Fan speed: 100%
Retraction: 4mm (Bowden)
Retraction speed: 30 mm/s
Flowrate: 350% (account for thinner filament)
We find these settings to have worked well considering the inconsistency in diameter of filament.
Whilst not very widely used as a material in 3D printing, some properties of PP make it an alternative worth exploring. These include the materials durability, and resistance to chemicals and fatigue. Polypropylene is also both food and microwave safe.
In addition to the points above, PP is one of the most common polymers in use. From an environmental standpoint the use of recycled Polypropylene, and polymers in general, poses an opportunity to reduce the consumption of virgin material in rapid prototyping processes such as 3D printing and Injection Moulding.
Tomi Engdahl says:
Use Your 3D Printer to Create Custom T-Shirt Designs
https://www.hackster.io/news/use-your-3d-printer-to-create-custom-t-shirt-designs-4a9a98dbe8dc
Two methods can accomplish the same feat: one using iron-on 3D-printed designs and the other is printed directly on the shirt.
While 3D printers have been used to create functioning tools, gadgets and art pieces, the platform is now being used to create custom graphic t-shirt designs. Prusa Research has detailed two methods of adding 3D-printed designs on tees, with one using a thin iron-on and the other printed directly onto the fabric. The iron-on employs a thin layer of PLA that can survive several washes before peeling, so it’s not ideal for those looking for a more permanent solution. The direct alternative, although more complicated, provides a more permanent result.
How to Create your Own T-shirt Motif with a 3D printer?
https://blog.prusaprinters.org/how-to-print-on-t-shirts_55588/
Tomi Engdahl says:
3D Printer Cuts Metal
https://hackaday.com/2021/10/22/3d-printer-cuts-metal/
Every now and then we’ll see a 3D printer that can print an entire house out of concrete or print an entire rocket out of metal. But usually, for our budget-friendly hobbyist needs, most of our 3D printers will be printing small plastic parts. If you have patience and a little bit of salt water, though, take a look at this 3D printer which has been modified to cut parts out of any type of metal, built by [Morlock] who has turned a printer into a 5-axis CNC machine.
I 3D printed a 5-axis CNC machine
https://www.youtube.com/watch?v=KieJN-J4s38
Tomi Engdahl says:
https://hackaday.com/2021/10/26/3d-printer-bed-probing-using-a-tact-switch-and-coin-cell/
Tomi Engdahl says:
https://hackaday.com/2021/10/26/superslicer-reviewed-another-3dp-slicer/
https://github.com/supermerill/SuperSlicer
Tomi Engdahl says:
https://www.uusiteknologia.fi/2021/11/04/parempaa-elektroniikkaa-uudella-monimateriaalitulostimella/
Tomi Engdahl says:
Space Startup Agnikul Can 3D Print You a Customized Rocket Engine — in Just Three Days
Designed for use with a customizable launch vehicle, these 3D-printed rocket engines can be turned around in a few days.
https://www.hackster.io/news/space-startup-agnikul-can-3d-print-you-a-customized-rocket-engine-in-just-three-days-0540717dfc8d
Tomi Engdahl says:
https://etn.fi/index.php/13-news/12783-oulussa-3d-tulostetaan-aelykkaeitae-rakenteita
Tomi Engdahl says:
ULIO 3D Brix Allows You to Piece Together Your Own 3D Printer Out of Plastic Bricks
https://www.hackster.io/news/ulio-3d-brix-allows-you-to-piece-together-your-own-3d-printer-out-of-plastic-bricks-40cff3ae71ec
The ULIO 3D Brix can produce high-quality prints at a resolution ranging from 50 to 300 microns.
You can now build a fully functional 3D printer made entirely out of plastic bricks! ULIO 3D recently unveiled ULTIO 3D Brix, a brick set that anyone can snap together, brick by brick. The user just needs to follow the instructions packaged with the project. Anyone interested in purchasing this innovative do-it-yourself kit can back the project through the Kickstarter page.
The set includes more than 850 pieces of varying sizes and shapes, compatible with any major brand. Even more, the user doesn’t need to worry about dealing with heavy work like assembling the 3D printer’s mechanical parts. Instead, they need to snap everything together. Not only that, but it doesn’t require any soldering whatsoever since everything is pre-wired. Measuring 10” x 10” x 16” and weighing approximately 9 lbs, it only requires you to plug in seven terminals once the assembly process is complete.
The team behind this project also integrated Trinamic stepper drivers into the printer, ensuring a noise-free printing experience. Plus, the prints are high-quality, with the layer resolution reaching as low as 50 microns and as high as 300 microns. It even runs on Marlin firmware, uses fused filament fabrication (FFF) printing technology, and supports STL and OBJ file types.
https://www.ulio3d.com/
Tomi Engdahl says:
Ender 3 Meets MIG Welder To Make A Metal Benchy — Kind Of
https://hackaday.com/2021/11/23/ender-3-meets-mig-welder-to-make-a-metal-benchy-kind-of/
Tomi Engdahl says:
https://hackaday.com/2021/11/27/want-octoprint-but-lack-a-raspberry-pi-use-an-old-android-phone/
Tomi Engdahl says:
Co Print Makes Multi-Material 3D Printing a Snap
The new Co Print is a device that can switch between seven different filament spools and that is affordable.
https://www.hackster.io/news/co-print-makes-multi-material-3d-printing-a-snap-5bf78fc74d8b
Tomi Engdahl says:
https://hackaday.com/2021/11/29/do-you-really-need-to-dry-filament/
Tomi Engdahl says:
https://hackaday.com/2021/12/04/full-color-3d-printing-with-the-help-of-an-inkjet-head/
Tomi Engdahl says:
Semisolid Metal Printing
Print metal just like plastic.
https://hackaday.io/project/179846-semisolid-metal-printing
Ever since the start of RepRap, we have collectively dreamed of printing metal the same way we print plastic. I was inspired by Lulzbot’s experiments to start a student project at WPI, which eventually became a full-scale collaboration with Lawrence Livermore National Lab – and then the team gave up because it was hard. But I didn’t give up. Now almost 8 years of tinkering later, the time for SMP has arrived.
SMP uses the properties of semisolid alloys and mixtures as well as wettability and temperature boundary conditions to precisely and passively control the fluid flow properties of metal alloys to enable stable extrusion. This project makes the technology compatible with common RepRap hardware and software, aiming for a total retrofit cost under $500.
-no more arduous post processing
-no more struggling with misshapen or brittle sintered parts
-no more $500K+ metal printing machines
-no more dealing with expensive, messy and hazardous metal powders
Tomi Engdahl says:
Plastics: Photopolymers For 3D Printing And Beyond
https://hackaday.com/2021/12/21/plastics-photopolymers-for-3d-printing-and-beyond/
A good basis for understanding the chemical processes behind stereolithography resins is the polymerization of methylmethacrylate (MMA) into polymethylmethacrylate, also known as PMMA or simply acrylic. While formulations for SLA resins vary, many of them are based on acrylates, so the chemistry here is directly applicable to a lot of resins, as are the general principles.
The polymerization of methylmethacrylate is what’s known as a free-radical reaction. It works because MMA has a double bond between two of its carbon atoms, as well as a nearby ester group — the group with two oxygens, one of them in a double bond. The electronic structure of these two groups makes the double-bonded carbon susceptible to reduction, which is the gain of an electron.
Under normal circumstances, MMA monomers don’t react with each other because there are no free electrons floating around to reduce the carbon-carbon double bond. To get MMA to polymerize, an initiator — in this case, benzoyl peroxide — needs to be added to the mix. An initiator is a chemical compound that provides unpaired electrons, or free radicals. Once radicals are present, they bind to the carbon by reducing the double bond. The product of this first reaction will have its own unpaired electron, which can then go on and reduce the double bond in another MMA monomer, and so on. The production of a free radical product after initiation is the key to free-radical polymerization.
This is where photoinitiators come into play. Where an initiator like benzoyl peroxide will readily decompose into free radicals with the application of a little heat, photoinitiators need a little more coaxing. Hundreds of different photoinitiators have been developed by chemical companies over the years, each tailored to the specific set of monomers to be polymerized as well as to industrial needs, such as the efficiency of free radical formation, toxicity, and even odors imparted on the finished product. But they all share the common trait of being inactive until they are exposed to light of the correct wavelength.
A good example of a photoinitiator is 2,2-dimethoxy-2-phenylacetophenone, mercifully abbreviated to DMPA and sold under the trade name IRGACURE 651 by Ciba.
DMPA has absorption peaks are 250 nm and 340 nm
Tapping the Brakes
The mechanism of photopolymerization begs a question: how does the UV light in an SLA printer not just polymerize the whole tank of resin at once? It seems like that would be a problem, since polymerization is basically a chain reaction once initiated. But there are practical limits to the reaction, for both chemical and physical reasons.
Chemically, the amount of initiator in the resin is typically pretty low — just a few percent of the mix. So there aren’t many places to start the polymerization reaction. Polymerization reactions also tend to undergo chain termination spontaneously, either by having two growing radical chains bind together, or by reduction of a radical chain by contaminants such as oxygen. Some resins even have specific inhibitor compounds added to limit the speed of polymerization. Either way, spontaneous termination keeps the tanks from becoming a solid brick of plastic.
There are also physical reasons for photopolymerization not running wild through the build tank. The UV light coming from the LCD display at the bottom of the tank isn’t particularly strong, and tends to get absorbed by the resin before traveling very far. This is why SLA resins tend not to be heavily pigmented, and why any pigments that are added to the resin have to be carefully selected to not absorb UV light. It’s also why SLA prints need an additional cleaning and curing step after printing; the polymerization that occurs in the tank is incomplete, with unreacted resin remaining inside the print. Bathing the print in high-intensity UV light completes the process and hardens the print.
Not Just for Printing
While we’ve concentrated mainly on SLA printing resins here, that’s far from the only application for photopolymers. If you’ve had a tooth filled any time in the last three decades or so, chances are good that your dentist used a photopolymer containing methacrylate monomers and cured with a fiber optic wand that emits UV light. Printed circuit board manufacturers make wide use of photopolymers, both in the photoresist coatings that are used to etch the boards, and in the solder mask that’s applied to the board. Photopolymers are also used for masking during the photolithographic processes involved in manufacturing integrated circuits.
Tomi Engdahl says:
3D Printering: Adding A Web Interface Where There Was None Before
https://hackaday.com/2021/12/31/3d-printering-adding-a-web-interface-where-there-was-none-before/
Tomi Engdahl says:
https://hackaday.com/2022/01/05/3d-printering-one-bed-level-to-rule-them-all/
Tomi Engdahl says:
https://hackaday.com/2022/01/04/uv-resin-perfects-3d-print-but-not-how-you-think/
you can actually use UV resin to improve the finish quality of your FDM prints. The idea is to put a layer of resin over the layer lines and other imperfections of the 3D print, cure it with a handheld UV flashlight, and then sand it smooth. Essentially it’s like using resin in place of a body filler like Bondo, with the advantage here being that the resin cures in seconds.
Tomi Engdahl says:
https://lowpoly3d.xyz/
Tomi Engdahl says:
https://hackaday.com/2022/01/14/3d-printering-getting-started-with-universal-bed-leveling/
Tomi Engdahl says:
https://hackaday.com/2022/01/15/recycling-soda-bottles-into-filament-to-print-smaller-soda-bottles/
Tomi Engdahl says:
Extreme Thermal Mods For 3D Printing Exotic Materials
https://hackaday.com/2022/01/19/extreme-thermal-mods-for-3d-printing-exotic-materials/
For general everyday use, there’s nothing wrong with the standard selection of plastics that most 3D printer filaments are available in. PLA, ABS, PETG — they’ve all got their place, and they’re all pretty easy to work with. But if you need to work with more exotic materials, you might need to go to extremes and modify an off-the-shelf printer for high-temperature work.
For the team led by [Andreas Hagerup Birkelid] at the Norwegian University of Science and Technology, the standard menu of printer chow wasn’t up to the jobs they had in mind. They wanted to print using polyether ether ketone, or PEEK, a high-performance thermoplastic with useful mechanical and thermal properties, in addition to chemical resistance. Trouble is, the melting point of PEEK is a whopping 343°C (649°F), making it necessary to turn up the heat — a lot.
High-performance polymer 3D printing – Open-source liquid cooled scalable printer design
https://www.sciencedirect.com/science/article/pii/S2468067222000104
Tomi Engdahl says:
https://hackaday.com/2022/01/20/3d-printing-copper/
Tomi Engdahl says:
Review: Phrozen Sonic Mini 8K
We got our hands on the new Phrozen Sonic Mini 8K and put it to the test.
https://www.hackster.io/news/review-phrozen-sonic-mini-8k-17a0d39b0cd2
Tomi Engdahl says:
How to print with metal – on a big scale
https://www.etteplan.com/stories/how-print-metal-big-scale?utm_campaign=newsletter-1-2022&utm_content=newsletter&utm_medium=email&utm_source=apsis-anp-3&pe_data=D43445A477046455B45724541514B71%7C30320219
3D printing is not just for plastic. WAAM is a relatively new technology which makes it possible to print large metal objects. Applications range from rockets to engine brackets. In this article, we look at the latest trends and practical solutions in printing with metal.