Automatic Print Ejector For All 3D Printers

Way back in 2010, Makerbot released the Automated Build Platform, a neat heated conveyor belt for the Cupcake or Thing-O-Matic that would spit parts out when a print was done. It’s a great invention if you need to produce 20 of something, and the perfect invention if you want to sit on a patent and not innovate anything ever.

You won’t need to wait until the year 2030 to get a device that automatically removes a print from a print bed. The folks at MatterHackers came up with an Automatic Print Ejector that removes a print in the most [Rube Goldberg]-ish way possible: with a boxing glove.

The Automatic Print Ejector is pretty much taken straight out of a [Buster Keaton] movie. It’s a series of scissor mechanisms with a 3D printed boxing glove on the end, driven by a stepper motor. When the print finishes, the boxing glove simply punches a print off the bed of a printer.

Does it work? It does, brilliantly. Check out the video below.

20 thoughts on “Automatic Print Ejector For All 3D Printers

    1. If you scripted the printer to turn off the heatbed and wait 10-20 minutes you could punch objects off just as easily, when the plastic contracts it unsticks for the mostpart. This of course assumes use of a heated bed.

  1. Over a year ago I saw a demo of a 3d printer which was continuously printing easter eggs as a demo.
    Each time an egg was finished it used the printing head to push the egg of the build platform.The eggs sprung away for more than a meter when the attachment to the platform broke.
    This demo was in maker/hacker/whatever space in Electon, Breda, Netherlands.

    Why use new hardware when you’ve already got a moving 3-d machine?
    This is/was very similar to the pick and place machine which used te pickup head to pull the tape with smd components through the machine.

    1. This was more of a fun/silly way to do automatic print ejection and I’ll be honest the second I saw the pic at the top of the article I laughed.

      Personally I don’t think it would really be good for the printer in the long run to use the print head to dislodge prints. Most 3D printers just weren’t designed to exert a lot of force. Things are going to bend/break or become unaligned in short order. Since just after they are done printing if things are working well prints should be quite firmly adhered to the print bed. Given the time to let the bed cool down prints should effectively pop themselves off the bed.

      Course it probably doesn’t help that I don’t think I would ever trust a hobby level 3D printer to queue things up on its own. The farthest I’d trust them would be to complete a long print generally unattended with some checking now and then. Lest you run the risk of turning one spaghetti print gone wrong into a whole roll of fused pasta and possibly a fire :P

      1. Personally I don’t think it would really be good for the printer in the long run to use the print head to dislodge prints. Most 3D printers just weren’t designed to exert a lot of force.

        Maybe aren’t designed NOW to exert a lot of force. If I were going to upgrade a 3D printer to use the print head to knock prints off the table, this is what I would probably do:

        Add a small plate to the side of the print head, to be used to contact the freshly printed object. This will also protect the more delicate parts of the print head.
        Increase the size of the stepper motor that controls the dimension in which the object will be knocked.
        Beef up the carriage rods, if they aren’t up to the task (and if they aren’t, they were probably too small to begin with (stupid cost cutting measures)).

        That should probably do it. Am I missing anything else? I am fairly certain that there is, as I have never even used a 3D printer, much less built one. Yes, I do understand that these small changes may require a complete reconstruction of some specific printers, but are trivial changes in basic printer design and construction.

        1. The problem is all that mass has to be moved around to print everything. Bigger motors and bigger mechanisms means more mass, which leads to more wear and either to more durable (expensive) parts or to more maintenance. It’s all way over-engineered for the simple task of squirting hot plastics, which is 100% of what the moving bits are actually responsible for.

          To avoid that cost, a dedicated part remover makes sense. Whether or not it should take the form factor of a boxing glove is more a matter of taste.

          1. I knew there were things I weren’t considering. Besides, I never said using the print head to knock parts off was a GOOD idea, I was just saying that it could be implemented without quickly trashing the printer.

        2. You’d probably also want to upgrade the belts on whatever axis the printer moves along when dislodging prints. Most printers use 5mm timing belts or fishing line, I’d be very concerned about stretching.

  2. when using a heated bed however, parts tend to stick really well however., easpecially when using glue on the plate. You break and wear way too much. Now using a clean heated glass plate (alcohol works wonders to clean a plate) the print still sticks, until it cools down. Once cooled the part almost falls off. Granted, it does take much longer for the glass is cooled off. But thats the only way id see this work.

    1. Now that’s a good idea. If you don’t have to have the heating elements directly connected to the glass (either glued, epoxied, or integral to the plate), all you need is a second plate of glass that will “swap out” for every print. I imagine that the glass would cool enough to allow a part to fall off before the next part is completed (3d printers are NOT known for their speed). And if you do include the heating elements in the second bed, it should be warmed back up to proper temperature by the time it is swapped back.
      This is all assuming reasonable print lengths, and printed parts that have relatively small footprints. Even if the part isn’t removed automatically, swappable beds make sense. The first part can be transferred out while the second part starts printing.

  3. Hmmm… What about using a bi-metal bed? It would be pre-flexed until heated enough for the plastic, then, when heated more (or less) as is necessary at the end, it would flex and automatically break any adhesion. Add a few ultrasonic transducers, tilt the bed, and prints would just slide right off.

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