Adding Remote Control To The Elegoo Mars Pro

October 30, 2020 by Tom Nardi 5 Comments

Recent price drops put entry level masked stereolithography (MSLA) resin 3D printers at around $200 USD, making them a very compelling tool for makers and hackers. But as you might expect, getting the price this low often involves cutting several corners. One of the ways manufacturers have made their machines so cheap is by simplifying the electronics and paring down the feature set to the absolute minimum.

So it was hardly a surprise for [Luiz Ribeiro] to find that his new Elegoo Mars Pro didn’t offer WiFi connectivity or a remote control interface. You’re supposed to just stick a USB flash drive into the printer and select the object you want to print from its menu system. But that doesn’t mean he couldn’t hack the capability in himself.

If this were a traditional 3D printer, he might have installed OctoPrint and been done with it. But resin printers are a very different beast. In the end, [Luiz] had to develop his own remote control software that worked around the unique limitations of the printer’s electronics. His software runs on a Raspberry Pi Zero and uses Linux’s “USB Gadget” system to make it appear as a flash drive when plugged into the USB port on the Elegoo Mars Pro.

This allows sending object files to the printer over the network, but there was a missing piece to the puzzle. [Luiz] still needed to manually go over to the printer and select which file he wanted to load from the menu. Until he realized there was an exposed serial port on control board that allowed him to pass commands to the printer. Between the serial connection and faux USB Mass Storage device, his mariner software has full control over the Mars Pro and is able to trigger and monitor print jobs remotely.

It might not offer quite the flexibility of adding OctoPrint to your FDM 3D printer, but it’s certainly a start.

DIY Monochrome LCD Hack Doesn’t Go As Planned

March 1, 2020 by Tom Nardi 41 Comments

Manufacturers of low-cost 3D printers that use the masked stereolithography (MSLA) process are able to build their machines so cheaply because they’re using repurposed smartphone or tablet LCD panels to mask off the UV backlight. Considering the quality you get out of even the entry-level MSLA resin printers, we certainly aren’t complaining about this bit of thrift. But as [Jan Mrázek] explains in a recent blog post, there’s certainly room for improvement.

The problem is that those repurposed LCD panels are, as you’d expect, color displays. After all, even the bottom of the barrel mobile devices moved away from monochrome displays decades ago. But in this case, that’s not what you really want. Since the printer operates on a single wavelength of light, the color filters inside the LCD are actually absorbing light that could otherwise be curing the resin. So an MSLA printer with a monochrome screen would use less energy and print faster. There’s only one problem: it’s not very easy to find high-resolution monochrome displays in the year 2020.

So [Jan] decided to see if he could take a replacement screen intended for his Elegoo Mars MSLA printer and convert it from color to monochrome by disassembling it and manually removing the color filters. If this sounds a bit crazy, that’s because it is. Turns out taking apart an LCD, modifying its internal layout, and putting it all back together in working order is just as difficult as you’d think.

But it was still worth a try. [Jan] pulls the display apart, removes the liquid crystals, scrapes off the color filters, and then puts it all back together again. His first attempt got him a monochrome display that actually worked, but with debris trapped inside the screen, the image was too poor to be useful. He tried again, this time trying harder to keep foreign material out of the crystals. But when he got it back together a second time, he found it no longer functioned. He thinks it’s possible that his attempt to clean up the inside of the display was too aggressive, but really there are so many things that could go wrong here it’s hard to pin down just one.

Long story short, manually creating monochrome displays for low-cost MSLA printers might not be a viable option. Until a better solution comes along, you might be interested in seeing some slightly less invasive ways of improving your resin print quality.

Prusa Introduces A Resin Printer At Maker Faire NY

September 22, 2018 by Brian Benchoff 35 Comments

For one reason or another, the World Maker Faire in New York has become the preeminent place to launch 3D printers. MakerBot did it with the Thing-O-Matic way back when, and over the years we’ve seen some interesting new advances come out of Queens during one special weekend in September.

Today Prusa Research announced their latest creation. It’s the resin printer you’ve all been waiting for. The Prusa SL1 is aiming to become the Prusa Mk 3 of the resin printer world: it’s a solid printer, it’s relatively cheap (kit price starts at $1299/€1299), and it produces prints that are at least as good as resin printers that cost three times as much.

The tech inside the SL1 is about what you’d expect if you’ve been following resin printers for a while. The resin is activated by a bank of LEDs shining through a photomask, in this case a 5.5 inch, 1440p display. Everything is printed on a removable bed that can be transferred over to a separate ‘curing chamber’ after the print is done. It’s more or less what you would expect, but there are some fascinating refinements to the design that make this a resin printer worthy of carrying the Prusa name.

Common problems with a masked SLA printer that uses LEDs and an LCD are the interface between the LCD and the resin, and the temperature of the display itself. Resin is not kind to LCD displays, and to remedy this problem, Prusa has included an FEP film on the bottom of the removable tank. This is a user-replaceable part (technically a consumable, at least to the same extent as a PEI build plate on a filament printer), and Prusa will be selling those as spare parts on their store. The LCD is also cooled; one of the major drawbacks of shining several watts of UV through an LCD is the lifetime of the display. Cooling the display helps, and should greatly increase the lifetime of the printer. All of this is wrapped up in an exceptionally heavy metal case with the lovely hinged UV-opaque orange plastic lid.

Of course, saying you’ve built a resin printer is one thing, but how do the prints look? Exceptional. The Prusa booth at Maker Faire was loaded up with sample prints from the machine, and they’re of the same high quality you would expect from the Form 3D printers that have been the go-to in the resin printer world. The Prusa SLA also works with big-O Open resins, meaning you’re not tied to a single resin vendor.

This is just the announcement of the Prusa resin printer, but they are taking preorders. The price for the kit — no word on how complex of a kit it is — is $1300, while the assembled printer is $1600, with the first units shipping in January.