Join us on Wednesday, October 13 at noon Pacific for the Resin Printing Hack Chat with Andrew Sink!
At its heart, 3D printing is such a simple idea that it’s a wonder nobody thought of it sooner. Granted, fused deposition modeling does go back to the 80s, and the relatively recent explosion in cheap, mass-market FDM printers has more to do with cheap components than anything else. But really, at the end of the day, commodity 3D printers are really not much more than glorified hot-glue guns, and while they’re still a foundational technology of the maker movement, they’ve gotten a bit dull.
So it’s natural that we in this community would look for other ways to push the 3D printing envelope, and stereolithography has become the new hotness. And with good reason — messy though it may be, the ability to gradually pull a model from a tank of goo by selective photopolymerization looks magical, and the fine level of detail resin printers are capable of is just as enchanting. So too are the prices of resin printers, which are quickly becoming competitive with commodity FDM printers.
If there’s a resin printer in your future, then you’ll want to swing by the Hack Chat when Andrew Sink visits us. Andrew has been doing a lot of 3D printing stuff in general, and resin printing in particular, over on his YouTube channel lately. We’ve featured a couple of his tricks and hacks for getting the most from a resin printer, and he’ll be sharing some of what he has learned lately. Join us as we discuss the ins and outs of resin printing, what’s involved in taking the dive, and the pros and cons of SLA versus FDM.
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.
This one comes to us by way of [Andrew Sink], who recently showed us a neat trick for adding a dash of color to resin printed parts. As with that tip, this one centers around his Elegoo resin printer, which is capable of intricately detailed prints but like any additive process, takes quite a bit of time to finish a print. Luckily, though, the printer uses the MSLA, or masked stereolithography, process, which exposes the entire resin tank to ultraviolet light in one exposure. That means that, unlike FDM printers, it takes no more time to print a dozen models than it does to print one. The upshot of this is that however many models can fit on the MSLA print platform can be printed in the same amount of time it takes to print the part with the most layers. In [Andrew]’s case, 22 identical figurine models were printed in the same three hours it took to print just one copy.
It seems obvious, but sometimes the simplest tips are the best. And the next step is obvious, especially as MSLA printer prices fall: a resin printer farm, with each printer working on dozens of small parts at a time. Such a setup might rival injection molding in terms of throughput, and would likely be far cheaper as far as tooling goes. Continue reading “Making The Most Of Your Resin Printer Investment”→
The fascination of watching a 3D printer go through its paces does tend to wear off after you spent a few hours doing it, in which case those cool time-lapse videos come in handy. Trouble is they tend to look choppy and unpleasant unless the exposures are synchronized to the motion of the gantry. That’s easy enough to do on FDM printers, but resin printers are another thing altogether.
Or are they? [Alex] found a way to make gorgeous time-lapse videos of resin printers that have to be seen to be believed. The advantage of his method is that it’ll work with any camera and requires no hardware other than a little LED throwie attached to the build platform of the printer. The LED acts as a fiducial that OpenCV can easily find in each frame, one that indicates the Z-axis position of the stage when the photo was taken. A Python program then sorts the frames, so it looks like the resin print is being pulled out of the vat in one smooth pull.
To smooth things out further, [Alex] also used frame interpolation to fill in the gaps where the build platform appears to jump between frames using real-time intermediate flow estimation, or RIFE. The details of that technique alone were worth the price of admission, and the results are spectacular. Alex kindly provides his code if you want to give this a whack; it’s almost worth buying a resin printer just to try.
As cool as resin-based 3D printers are, they’re not without their shortcomings. One sore point, especially for those looking to document their prints, is that the translucent resins often favored for stereolithography can make the finest details difficult to see. Injecting paint into the model is how [Andrew Sink] decided to attack this problem, and the results are pretty striking.
For sure, this isn’t a problem that everyone making resin prints is going to face. Some resins are nicely opaque, and the fine details of a print show up just fine. But transparent resins lend a nice look to some projects, and might benefit from [Andrew]’s technique. It’s pretty much as simple as it sounds: choose a hollow model — or modify an existing one — print it up in the usual way, and clean thoroughly inside and out with isopropanol before curing under UV. Using a curing station that can get UV light up into the voids is probably a smart idea.
To finish off, the cured model is injected with acrylic paint. Nothing special here, just craft store acrylic in a syringe. [Andrew] seemed to prefer a thicker paint; we don’t want to second guess, but intuitively a thinner paint would seem to have some advantages. In any case, be sure to provide adequate vent holes for the displaced air. The video below has a few before and after shots, and the technique really works well to show off surface detail. Plus it just plain looks cool.
This seems like a good technique to keep in mind, and might even work well for hollow FDM prints done with transparent filaments. Still on the fence about FDM vs. SLA? We can help with that.
Wind energy isn’t quite as common of an alternative energy source as solar, at least for small installations. It’s usually much easier just to throw a few panels and a battery together than it is to have a working turbine with many moving parts that need to be maintained when only a small amount of power is needed. However, if you find yourself where the wind blows but the sun don’t shine, there are a few new tools available to help create the most efficient wind turbine possible, provided you have a 3D printer.
[Jan] created this turbine with the help of QBlade, a piece of software that helps design turbine blades. It doesn’t have any support for 3D printing though, such as separating the blades into segments, infill, and attachment points, so [Jan] built YBlade to help take care of all of this and made the software available on the project’s GitHub page. The blades are only part of this story, though. [Jan] goes on to build a complete full-scale wind turbine that can generate nearly a kilowatt of power at peak production, although it does not currently have a generator attached and all of the energy gets converted to heat.
While we hope that future versions include a generator and perhaps even pitched blades to control rotor speed, [Jan] plans to focus his efforts into improving the blade design via the 3D printer. He is using an SLA printer for these builds, but presumably any type of printer would be up to the task of building a turbine like this. If you need inspiration for building a generator, take a look at this build which attempted to adapt a ceiling fan motor into a wind turbine generator.
The epicenter of the Chinese electronics scene drew a lot of attention this week as a 70-story skyscraper started wobbling in exactly the way skyscrapers shouldn’t. The 1,000-ft (305-m) SEG Plaza tower in Shenzhen began its unexpected movements on Tuesday morning, causing a bit of a panic as people ran for their lives. With no earthquakes or severe weather events in the area, there’s no clear cause for the shaking, which was clearly visible from the outside of the building in some of the videos shot by brave souls on the sidewalks below. The preliminary investigation declared the building safe and blamed the shaking on a combination of wind, vibration from a subway line under the building, and a rapid change in outside temperature, all of which we’d suspect would have occurred at some point in the 21-year history of the building. Others are speculating that a Kármán vortex Street, an aerodynamic phenomenon that has been known to catastrophically impact structures before, could be to blame; this seems a bit more likely to us. Regardless, since the first ten floors of SEG Plaza are home to one of the larger electronics markets in Shenzhen, we hope this is resolved quickly and that all our friends there remain safe.
In other architectural news, perched atop Building 54 at the Massachusetts Institute of Technology campus in Cambridge for the last 55 years has been a large, fiberglass geodesic sphere, known simply as The Radome. It’s visible from all over campus, and beyond; we used to work in Kendall Square, and the golf-ball-like structure was an important landmark for navigating the complex streets of Cambridge. The Radome was originally used for experiments with weather radar, but fell out of use as the technology it helped invent moved on. That led to plans to remove the iconic structure, which consequently kicked off a “Save the Radome” campaign. The effort is being led by the students and faculty members of the MIT Radio Society, who have put the radome to good use over the years — it currently houses an amateur radio repeater, and the Radio Society uses the dish within it to conduct Earth-Moon-Earth (EME) microwave communications experiments. The students are serious — they applied for and received a $1.6-million grant from Amateur Radio Digital Communications (ARDC) to finance their efforts. The funds will be used to renovate the deteriorating structure.
Well, this looks like fun: Python on a graphing calculator. Texas Instruments has announced that their TI-84 Plus CE Python graphing calculator uses a modified version of CircuitPython. They’ve included seven modules, mostly related to math and time, but also a suite of TI-specific modules that interact with the calculator hardware. The Python version of the calculator doesn’t seem to be for sale in the US yet, although the UK site does have a few “where to buy” entries listed. It’ll be interesting to see the hacks that come from this when these are readily available.
Did you know that PCBWay, the prolific producer of cheap PCBs, also offers 3D-printing services too? We admit that we did not know that, and were therefore doubly surprised to learn that they also offer SLA resin printing. But what’s really surprising is the quality of their clear resin prints, at least the ones shown on this Twitter thread. As one commenter noted, these look more like machined acrylic than resin prints. Digging deeper into PCBWay’s offerings, which not only includes all kinds of 3D printing but CNC machining, sheet metal fabrication, and even injection molding services, it’s becoming harder and harder to justify keeping those capabilities in-house, even for the home gamer. Although with what we’ve learned about supply chain fragility over the last year, we don’t want to give up the ability to make parts locally just yet.
And finally, how well-calibrated are your fingers? If they’re just right, perhaps you can put them to use for quick and dirty RF power measurements. And this is really quick and really dirty, as well as potentially really painful. It comes by way of amateur radio operator VK3YE, who simply uses a resistive dummy load connected to a transmitter and his fingers to monitor the heat generated while keying up the radio. He times how long it takes to not be able to tolerate the pain anymore, plots that against the power used, and comes up with a rough calibration curve that lets him measure the output of an unknown signal. It’s brilliantly janky, but given some of the burns we’ve suffered accidentally while pursuing this hobby, we’d just as soon find another way to measure RF power.
Over the past years, additive manufacturing (AM) has become a common tool for hackers and makers, with first FDM and now SLA 3D printers becoming affordable for the masses. While these machines are incredibly useful, they utilize a slow layer-by-layer approach to produce objects. A relatively new technology called Volumetric Additive Manufacturing (VAM) promises to change all that by printing the entire object in one go, and according to a recent article in Nature, it just got a big resolution boost.
The concept is similar to SLA printing, but instead of curing the resin by projecting a 2D image of the current layer into the container, VAM uses multiple lasers to create intersecting points within the liquid. After exposing the resin to this projection for several seconds, the 3D model is built all at once. Not only is this far faster, but it removes the need for support materials and even a traditional build plate is unnecessary.
Visualization of the dual-color printing process as used by Regehly et al. (Credit: Nature)
Up till now the resolution and maximum object size of VAM has left a lot to be desired, but in this new research by Regehly et al. claim to have accomplished a feature resolution of ‘up to 25 micrometers’ and a solidification rate of ‘up to 55 cm3/s’. They used two crossing laser beams of different wavelengths, one to form the ‘light sheet’ (blue in the graphic) and a second beam (in red) to project the slide onto this light sheet. They refer to this technique as ‘xolography’, as a mesh-up of ‘holo’ (Greek for ‘whole’) and the ‘X’ shape formed by the crossing laser beams.
Key to making this work is the chemistry of the resin: the first wavelength excites the molecules called DCPI (Dual-Color Photo Initiators) that are dissolved in the resin. The second wavelength when hitting the same molecules initiates the resin polymerization process. The object pictured at the top of the page was a test print; producing such a design on a traditional 3D printer would have required a considerable amount of difficult to remove support material.
While this is obviously not a technology hobbyists will be using to replace their FDM and SLA printers with any time soon, there are still many companies and institutes working on various VAM technologies and approaches. As more and more of the complexities and challenges are dealt with, who knows when VAM may become a viable replacement for at least some SLA applications?
Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 13 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.
