Continuous Printing On LCD Resin Printer: No More Wasted Time On Peeling? Is It Possible?

Anyone who has done any amount of 3D printing with SLA printers is probably well aware of the peeling step with each layer. This involves the newly printed layer being pulled away from the FEP film that is attached to the bottom of the resin vat. Due to the forces involved, the retraction speed of the build plate on the Z-axis has to be carefully tuned to not have something terrible happen, like the object being pulled off the build plate. Ultimately this is what limits SLA print speed, yet [Jan Mrázek] postulates that replacing the FEP with an oxygen-rich layer can help here.

The principle is relatively simple: the presence of oxygen inhibits the curing of resin, which is why for fast curing of resin parts you want to do so in a low oxygen environment, such as when submerged in water. Commercial printers by Carbon use a patented method called “continuous liquid interface production” (CLIP), with resin printers by other companies using a variety of other (also patented) methods that reduce or remove the need for peeling. Theoretically by using an oxygen-permeating layer instead of the FEP film, even a consumer grade SLA printer can skip the peeling step.

The initial attempt by [Jan] to create an oxygen-permeating silicone film to replace the FEP film worked great for about 10 layers, until it seems the oxygen available to the resin ran out and the peeling force became too much. Next attempts involved trying to create an oxygen replenishment mechanism, but unfortunately without much success so far.

Regardless of these setbacks, it’s an interesting research direction that could make cheap consumer-level SLA printers that much more efficient.

(Thumbnail image: the silicone sheet prior to attaching. Heading image: the silicone sheet attached to a resin vat. Both images by [Jan Mrázek])

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Hackaday Links: October 6, 2019

“If you or someone you love has been exposed to questionable quality electrolytic capacitors, you could be entitled to financial compensation.” Perhaps that’s not exactly the pitch behind this class action lawsuit against capacitor manufacturers, but it might as well be. The suit claims that the defendants, a group of capacitor manufacturers that includes Nichicon, Matsuo, ELNA, and Panasonic, “engaged in an unlawful conspiracy to fix, raise, maintain, or stabilize the prices of Capacitors.” Translation: if you bought capacitors between 2002 and 2014 from a distributor, you paid too much for them. The suit aims to recover a bunch of money from the defendants and divide it up between all the class members, so make sure you go back through all your receipts from Mouser and DigiKey over the last 17 years so you can file a claim that could be worth several dozen cents.

When are people going to learn that posting pictures of their illegal activities online is an Official Bad Idea? One SpaceX fan earned a night in jail after posting selfies he took with Starhopper, the SpaceX test article currently residing at Elon Musk’s would-be spaceport at Boca Chica, Texas. JB Wagoner, a SpaceX super-fan, made the pilgrimage from California to Texas — in his Tesla of course — to see the recent Starship Mark 1 unveiling, and decided to take a side trip to see the Starhopper. He parked at a beach, climbed a dune, and was able to walk right up to Starhopper and go selfie-crazy. After posting the pictures on Facebook, he was arrested, interviewed by Homeland Security, charged with criminal trespass, and thrown in a cell overnight. Wagoner has since been bonded out, but the charges might not stick, since Texas trespassing law requires clear signage or verbal notification of trespass, neither of which Wagoner encountered. SpaceX had even let the fence between the beach and the Starhopper collapse, so Wagoner seems to have had no way of knowing he was trespassing. Still, posting the pictures online was probably asking for trouble.

As satire and dark comedy, the 1987 cyberpunk classic RoboCop can’t be beat. But it also managed to accurately foreshadow a lot of what was to come in the world in terms of technology. No, we don’t have cyborg law enforcement — yet — but we do have something predicted by one throwaway scene: robotic realtors. In the movie, kiosks were set up around Murphy’s old house to extol the various virtues of living there, which ended up triggering the cyborg and starting the film’s climactic rampage. The real-life robotic realtor is a little more flexible, more like a telepresence robot — described aptly as “a Segway with an iPad on top.” The robotic realtor is not autonomous; it only lets a remote realtor interact with potential homebuyers without having to travel to multiple homes. It seems a little gimmicky to us, but the robots are reported to have made 25 sales in their first year on the job.

We’ve been seeing a lot of cheap resin printers these days, enough to make us want to jump into the market and start playing with them. But the cheap ones are all cheap for the same reason — they’re so dang small! They all use LCD screens from phones to mask off the UV light used to cure the resin, and the resulting print volume is tiny. Clem Mayer from MayerMakes has bigger ideas, though: he wants to make a giant resin printer using an LCD monitor as the mask. It’s not as simple as using a bigger screen, though; the film used between the screen and the resin, a fluoropolymer film called FEP, gets deformed when used on larger screens. So Clem is looking at a new built-plate interface that floats the resin on a layer of denser, immiscible liquid. It’s an interesting idea that is still clearly in the proof-of-concept phase, but we look forward to seeing what progress Clem makes.