Winter-Proof (And Improve) Your Resin 3D Printing

January 31, 2025 by Donald Papp 5 Comments

Was your 3D printer working fine over the summer, and now it’s not? With colder temperatures comes an overall surge in print failure reports — particularly with resin-based printers that might reside in outbuildings, basements, or garages. If you think this applies to you, don’t miss [Jan Mrázek]’s tips on improving cold-weather print results. His tips target the main reasons prints fail, helping to make the process a little more resilient overall. [Jan]’s advice is the product of long experience and experimentation, so don’t miss out.

With environmental changes comes the possibility that things change just enough to interfere with layers forming properly. The most beneficial thing overall is to maintain a consistent resin temperature; between 22 and 30 degrees Celsius is optimal. A resin heater is one solution, and there are many DIY options using simple parts. Some of the newer (and more expensive) printers have heaters built in, but most existing hobbyist machines do not.

Temperature control isn’t the only thing, either. Layer formation and build plate adhesion can all be improved by adding rest times between layers. Yes, this increases print time. It also allows resin to settle before the next layer, improving adhesion and preventing blooming (a rough texture caused by an imperfect cure.) Since resin flows less readily at lower temperatures, rest times can help improve results. The best setting depends heavily on your particular setup, so [Jan] gives tips on finding optimal rest times.

Most common knowledge and advice from well-meaning communities online focuses on increasing exposure time or blaming the build plate. [Jan] feels that these are ultimately the wrong way to go about addressing failures. Usually, an environmental change (like the arrival of winter) has simply pushed a printer that was not optimized in the first place outside of its narrow comfort zone. A little optimization can set things back on track, making the printer more resilient and reliable overall.

Keep Your Lungs Clean And Happy With A DIY Supplied-Air Respirator

July 9, 2024 by Dan Maloney 13 Comments

The smell of resin SLA printing is like the weather — everybody complains about it, but nobody does anything about it. At least until now, as [Aris Alder] tackles the problem with an affordable DIY supplied-air respirator.

Now, we know what you’re thinking, anything as critical as breathing is probably best left to the professionals. While we agree in principle, most solutions from reputable companies would cost multiple thousands of dollars to accomplish, making it hard to justify for a home gamer who just doesn’t want to breathe in nasty volatile organic compounds. [Aris] starts the video below with a careful examination of the different available respirator options, concluding that a supplied air respirator (SAR) is the way to go.

His homebrew version consists of an affordable, commercially available plastic hood with a built-in visor. Rather than an expensive oil-free compressor to supply the needed airflow, he sourced a low-cost inline duct fan and placed it outside the work zone to pull in fresh air. Connecting the two is low-cost polyethylene tubing and a couple of 3D printed adapters. This has the advantage of being very lightweight and less likely to yank the hood off your head, and can be replaced in a few seconds when it inevitably punctures.

Another vital part of the kit is a pulse oximeter, which [Aris] uses to make sure he’s getting enough oxygen. His O₂ saturation actually goes up from his baseline when the hood is on and powered up, which bodes well for the system. Every time we pick up the welding torch or angle grinder we wish for something like this, so it might just be time to build one.

Continue reading “Keep Your Lungs Clean And Happy With A DIY Supplied-Air Respirator” →

Mods Turn Junk UPS Into A Long-Endurance Beast

December 15, 2023 by Dan Maloney 36 Comments

If you’ve got a so-called uninterruptible power supply (UPS) on your system, you’re probably painfully aware that the “uninterruptible” part has some pretty serious limits. Most consumer units are designed to provide power during a black out only long enough to gracefully shut down your system. But with a few hacks like these, you can stretch that time out and turn it into a long-endurance UPS.

As many good stories do, this one starts in the trash, where [MetaphysicalEngineer] spotted an APC home office-style UPS. It was clearly labeled “broken,” but that just turned out to be a dead battery. While he could have simply replaced it with a 12-volt sealed lead-acid battery, [Meta] knew that his computer setup would quickly deplete the standard battery. A little testing showed him that a car battery would extend the run time significantly, especially if he threw in some extra cooling for the onboard inverter.

His final design uses a marine deep-cycle battery in a plastic battery box with the UPS mounted on top. The vacated battery compartment made a great place to add a cooling fan, along with a clever circuit to turn it on only when the beeper on the UPS sounds, with a bonus volume control for the annoying sound. He also added accessories to the battery box top, including a voltmeter, a USB charger, and a switched 12-volt power outlet. And kudos for the liberal use of fuses in the build; things could get spicy otherwise. The video below shows the entire build along with all the testing. [MetaphysicalEngineer] managed to triple the estimated runtime for the load he’s trying to power, so it seems like a win to us.

If your needs run more toward keeping your networking gear running through a blackout, you might want to check out this inverter-less DC UPS.

Continue reading “Mods Turn Junk UPS Into A Long-Endurance Beast” →

A 3D Printed Grinder For Printed Lens Blanks

November 16, 2023 by Dan Maloney 20 Comments

When one thinks of applications for 3D printing, optical components don’t seem to be a good fit. With the possible exception of Fresnel lenses, FDM printing doesn’t seem up to the job of getting the smooth surfaces and precision dimensions needed to focus light. Resin printing might be a little closer to the mark, but there’s still a long way to go between a printed blank and a finished lens.

That gap is what [Fraens] aims to fill with this homebrew lens grinding machine. It uses the same basic methods used to grind and polish lenses for centuries, only with printed components and lens blanks. The machine itself consists of a motorized chuck for holding the lens blank, plus an articulated arm to hold the polishing tool. The tool arm has an eccentric drive that wobbles the polishing tool back and forth across the blank while it rotates in the chuck. Lens grinding requires a lot of water and abrasive, so a large bowl is provided to catch the swarf and keep the work area clean.

Lens blanks are printed to approximately their finished dimensions using clear resin in an SLA printer. [Fraens] spent a lot of time optimizing the printing geometry to minimize the number of print layers required. He found that a 30° angle between the lens and the resin pool worked best, resulting in the clearest blanks. To polish the rough blanks, a lapping tool is made from polymer modeling clay; after baking it dry, the tool can hold a variety of pads and polishing compounds. From there it’s just a matter of running the blank through a range of abrasives to get the desired final surface.

Are the lenses fantastic? Well, they’re probably not going to make it into fine optical equipment, but they’re a lot better than you might expect. Of course, there’s plenty of room for improvement; better resins might result in clearer blanks, and perhaps degassing the uncured resin under vacuum might help with bubbles. Skipping the printed blanks and going with CNC-machined acrylic might be worth a try, too.

Continue reading “A 3D Printed Grinder For Printed Lens Blanks” →

Simple Hack Lets Smartphone Take Resin Printer Time-Lapses

October 26, 2023 by Dan Maloney 5 Comments

With how cheap they’re getting, everyone seems to be jumping on the resin printer bandwagon. They may not be able to fully replace your trusty old FDM printer, but for certain jobs, they just can’t be beaten. Sadly though, creating those smooth time-lapse videos of your prints isn’t quite as easy to do as it is on their filament-based counterparts.

Not as easy, perhaps, but not impossible. [Fraens] found a way to make time-lapses on any resin printer, and in a wonderfully hacky way. First, you need to find a smartphone, which shouldn’t be too hard, given how often we all tend to upgrade. [Fraens] recommends replacing the standard camera app on the phone with Open Camera, to prevent it from closing during the long intervals with nothing happening. The camera is triggered by any readily available Bluetooth dongle, which is connected via a simple transistor circuit to an Arduino output. To trigger the shutter, a light-dependent resistor (LDR) is connected to one of the microcontroller’s inputs. The LDR is placed inside the bed of the resin printer — an Anycubic Photon in this case — where light from the UV panel used to cross-link the resin can fall on it. A simple bit of Arduino code triggers the Bluetooth dongle at the right moment, capturing a series of stills which are later stitched together using DaVinci Resolve.

The short video below shows the results, which look pretty good to us. There are other ways to do this, of course, but we find the simplicity of this method pleasing.

Continue reading “Simple Hack Lets Smartphone Take Resin Printer Time-Lapses” →

Hackaday Links: February 12, 2023

February 12, 2023 by Dan Maloney 24 Comments

So, maybe right now isn’t the best time to get into the high-altitude ballooning hobby? At least in the US, which with the downing of another — whatever? — over Alaska, seems to have taken a “Sidewinders first, threat identification later” approach to anything that floats by. The latest incident involved an aircraft of unknown type, described as “the size of a small car” — there’s that units problem again — that was operating over Prudhoe Bay off the northern coast of Alaska. The reason that was given for this one earning a Sidewinder was that it was operating much lower than the balloon from last week, only about 40,000 feet, which is well within the ceiling of commercial aviation. It was also over sea ice at the time of the shootdown, making the chance of bothering anyone besides a polar bear unlikely. We’re not taking any political position on this whole thing, but there certainly are engineering and technical aspects of these shootdowns that are pretty interesting, as well as the aforementioned potential for liability if your HAB goes astray. Nobody ever really benefits from having an international incident on their resume, after all.

Continue reading “Hackaday Links: February 12, 2023” →

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

January 3, 2023 by Maya Posch 20 Comments

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])