LittleRP, The Latest Of The Resin Printers

LitleRP Over the last few years, a few resin / stereolithography printers have been made a few headlines due to print quality that cannot be matched by the usual RepRap style filament printers. These used to be extremely expensive machines, but lately there have been a few newcomers to the field. The latest is the LittleRP, an affordable DLP projector-based resin printer that can be put together for under a kilobuck.

Instead of proprietary resins, the LittleRP is designed to use as many different formulations of UV curing resin as possible, including those from MadeSolid and MakerJuice. These resins are cured with a DLP projector, providing a print area of 60x40x100mm with the recommended 1024×768 projector, or 72x40x100mm with the alternative 1080p projector.

This isn’t the only resin printer that’s come out recently; SeeMeCNC recently announced their cleverly named DropLit resin printer kit, going with the same ‘bring your own projector’ idea as the LittleRP. With the price of the printer, both of these kits should cost less than $1000 USD. With the price of UV resin dropping over the last few years, it might be just the time to get in the resin printer game.

26 thoughts on “LittleRP, The Latest Of The Resin Printers

  1. looks all right but im left wondering why so many people build these with projectors and not something a bit simpler? im sure many of u have seen the peachy printer? $100 instead of 1k seems far more tempting

    1. Galvo driven laser is the traditional way of doing this, especially on the early 3D printers in the late ’90s. The problem is that you need a good servo system for precise prints, and there’s no cheap off the shelf way to do this and print at any reasonable speed.

      Projector cured SLA doesn’t have a precision or speed problem because of the projector’s fixed pixel array. Since this tradeoff is mostly a cost issue, the target hacker market is more likely to be comfortable sourcing and hacking a second hand projector.

      Many projectors use costly HID lamps with short lifetimes, so it’s not uncommon to see these available used for cheap. For SLA purposes, where only a narrow wavelength is needed, the light source can be replaced with a high power blue LED module for much less than the cost of the HID replacement.

      1. Why not a driver system with piezo disks / benders and mirrors. You get micrometer resolution and high speeds. If you don’t go to the strong force piezo actuators you can build them cheap (even with amplification mechanism) wiht relativly cheap driver (for example opa544)?

        More time would be nice to try this stuff…

        BTW I like the mechanical desing of this printer except that there would be a possibility to reduce the mechanical loop slightly.

        1. Galvos are easy to make. Servo’d galvos with the precision needed here are hard. I imagine servo control for those piezos would have the same difficulties plus the smaller deflection.

          1. The good things with piezos is that the voltage is proportional to the deflection. Next with high reduced deflection should also not be that big problem (also with galvos) because the gain combined with the optical path. Another advantage with small deflections is a high bandwidth.

        2. Since the light is coming from only one point with a laser, you have to play with the angles of the beam. In this case, this would give less accuracy when you get a larger angle. You have to compensate this. Not with a projector.

    1. Its only $100, if you buy everything else. As I recall, the kit was really $600+.
      While this is a novel idea, the resolution is horrible.
      Please stop saying this printer is only $100!

      1. Where did you get $600 from?
        All that’s missing is a computer and some tubs for water. Assuming a backer ordered from a computer, I can’t imagine spending $500 for a couple Rubbermaid bins.
        After that, you’re just looking at cost of supplies (resin).

        The only things I’m seeing for more than a hundred or so are beta testers, pre-assembled units, or the higher end version.

    1. I was thinking about that. This is done in chip lithography, where a mask for one chip or a subset of the wafer is “stepped” across the wafer in multiple exposures.

      A laser cutter type arrangement of mirrors on an XY table could be used to do this, though the beam spread would need to be kept in check.

    2. The trouble is that it defeats the purpose of using a projector somewhat.
      Using the projector lets one forget about the precision xy movement, and just leaves us to build a precision z axis. Having to step around would increase the cost significantly.

      They do it in silicon, as chango says, but there the relative positions of the panels don’t matter so much. Each panel has many, many chips on it, so it’s not a big deal if the steps don’t quite line up.

      1. I would agree that your average FDM printer is not up to the task of milling anything. That said you could probably modify a decent CNC Mill to do a fairly decent 3D printing job. The biggest problem is finding a happy medium between the two in the Z-axis. Since CNC Mills really don’t tend to have a lot of Z range and 3D printers rely on a lot more Z-axis freedom.

  2. Resin printers are fascinating, just the level of detail they can achieve is awesome. I just wish there were some resins out there with better physical properties. FDM printers might be a little on the rough side but they tend to be far more utilitarian.

  3. Can resin printers print acceptable lenses yet?
    Actually where would I go to get help in designing/prototyping/manufacturing a plastic lens array for a project I have in mind?

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