Is A LEGO 3D Printer By Definition Self-replicating?


LEGO parts are plastic. 3D printers make parts out of plastic. So the transitive property tells us that a LEGO 3D printer should be able to recreate itself. This one’s not quite there yet, mostly because it doesn’t use plastic filament as a printing medium. Look close and you’ll probably recognize that extruder as the tip of a hot glue gun. If all else fails you can use the machine as a precision hot glue applicator.

The instructions to make your own version include the design reference and a few ideas for getting the most out of the glue dispenser. For the design phase [Matstermind] used LEGO Digital Designer. It’s basically CAD with the entire library of LEGO parts available as building blocks. from there he assembled the machine which is controlled by an NXT brick. He goes on to link to a few different printing mediums. There’s instructions for using crayons to make colored glue sticks, as well as a method of printing in sugar using the hot glue extruder.

We remember seeing one other LEGO 3D printer. That one didn’t use an extruder either. It placed blocks based on the design to be printed.

[Thanks Bryson via Prosthetic Knowledge]

35 thoughts on “Is A LEGO 3D Printer By Definition Self-replicating?

    1. Also the accuracy of Lego blocks themselves is extremely high (two micrometres) so this has a looong way to go before approaching anything like self-replication. Still, awesome build, eh?

        1. Nah, let’s not. As someone who’s had 2 or 3 of my own projects featured on HAD I can confirm that no matter what you do there will be an army of haters out there ready to trash it interspersed with an army of insanely intelligent people who actually know what they’re talking about and who raise all kinds of interesting issues that go far beyond whatever it is your cute little project is about. On HAD the articles are the hook but the comments are where you learn the important stuff. I for one have learned more from this site’s comments sections than any other, and I would hate to see HAD reduced to nothing more than an ego-boosting circle-jerk.

    1. Just use Metal and copper glue sticks to print the motors and controller DUH….
      I’m having trouble finding the fiberglass and solder gluesticks for the circuitboard.

  1. This whole “self replicating” thing has gotten completely out of control.

    A Lego 3D printer is made of Legos and a bunch of other stuff, none of which can be produced by the machine. Just like a RepRap is made out of some 3D printed plastic bits and a whole bunch of other stuff that can’t be printed. It doesn’t even come *close* to the definition of self replicating.

    A drill press can make a few holes in metal, and drill presses require holes in metal. Does that make it self replicating? Likewise a milling machine can make some of it’s own parts. Still not self replicating.

    I know self replicating is a really neat phrase and it would be super cool if it was actually true, but please, stop.

    1. +1 again.

      Even improperly redefining “self replicating” as a machine that can merely generate *some* of the parts required to build another, this machine can’t do it. The accuracy/strength of the produced parts is woefully inadequate.

      But hey, outrageous editorial claims always produce more comments. I guess the editors don’t mind if we’re busy correcting their misinformation instead of focusing on the actual hack. Just as long as we keep running up the post count and ad views…

    2. Your last point, is it about this project being true to self replication or just in general because nano-tech is getting closer to self replication. I agree that this build isn’t self replicating. I did find some humor in a Lego based 3d printer is making more Legos

      1. I own a metal lathe and have lots of experience using it. This statement always bothers me too. Has anyone actually made a lathe using only a lathe? I suppose you could use simple- (bushings) instead of ball-bearings, but what about the ways?

  2. Even though this is somewhat off-topic, I just realized that it seems like you can tell the difference between designers and hackers from what they build using LEGO. Not by what they build, but by the colors of the bricks they use.
    However, this could also be the difference between lazy and OCD…

  3. People can’t even look past the title (albeit an incorrect one) to appreciate what the guy did. You people have such a strange sense of cynicism that you just love to flaunt.

    1. We can look past the title…but it really isn’t the most impressive thing. It is a hot glue gun mover that produces results that are not as good as hand control, and the lack of cross-brick bracing in the design means it will probably fall apart after 5 minutes of use (not that it would ever get it). If it is a prototype and the plan is to move to plastic printing I’ll be more impressed…obviously still not self replicating, but at least it might be as close as EVERY OTHER 3D PRINTER.

    2. The title does pose a question though… and it’s kinda obvious that it’s meant to be dissected in the comments. So it’s not surprising that most of the comments deal with the question posed.

  4. Finally an article that isn’t so prudent when it comes to the inventions, no “With this amount of work, they -should- go the extra mile” BS, can we get more articles like this one please and not the other?

  5. Also to be honest the lego way is much more work than just building one of the reprap’s nowadays. The wallace++, prusa variation (wallebot v2 for instance) and prusa i3 can all be printed in 24hours and assembled in 1 day by the owner!

    The only difference is that you’ll use stepper motors which are much better than the lego steppers. You have printed plastic parts (like lego) but you combine it with some m8 threaded rods (cheaper and stronger than beams of lego blocks).

    If you have a reprap you can make a new one in 2-3 days using your own reprap. True, it’s not self replicating in the sense that the machine builds itself. It’s more machine + it’s owner has the potential to build new ones using some electronics and steppers and a hot-end for the price which is a factor 10 to 100 times less than the commercial machines that where available before Adrian Bowyer released the first reprap into the open source world…

  6. These are just my iterations:

    But the whole open source world is also doing this constantly by the time I finish my next 3d printer, there’s already hundreds of new iterations and improvements done by others too… Your comment is a bit like comparing the first linux to what android is today. Same was true for the first repraps they weren’t that great. But the print quality has drastically improved in just a few years. And even just in the last months due to slic3r’s improvement and better marlin&repitier firmware, we’re basically beating the available commercial machines nowadays ;)

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