MakerBot Conveyor Belt

As previously mentioned, Kapton is a candidate material for a conveyor belt build platform. I did a small test with a Kapton belt and heated build platform. The results are promising.

The image below shows the mechanism I’m using for testing. Two steel shafts are held apart by an acetal structure. Acetal is used directly rather than acetal bushings in wood. The platform snaps directly to the CupCake y-stage like the regular build platform. A kapton belt made from Kapton tape is looped around the shafts. Two Kapton layers were placed together with the sticky sides facing each other. The design files are available in subversion.

I would appreciate any ideas from the community in the comments below.

EDIT 2010-03-17-0626: So far I’ve only tested with what you see in the video, a mall thin ABS exrusion. The kapton does not seem to expand when heated. It’s also not very elastic, so I’m considering adding tension springs to hold down the tension bar. Right now the bar is just screwed down to keep the belt flat. I’ll plan on testing with a belt made from wide kapton film rather than a bunch of tape. I’ll also be testing to see how large of an object can be printed with this method.

EDIT 2010-03-17-1435: The springs I have in mind would sit between the tensioning rod and the screws that push the rod down. I’d want this so a fairly constant force is exerted on the belt if it were to expand when heated. Below is a side-view drawing of the conveyor mechanism.


24 thoughts on “MakerBot Conveyor Belt

  1. Looks very nice, are you having any problems with thermal expansion of the kapton causing buckling? How are you keeping the belt flat? I’d be very interested if this can survive the warping forces of larger, thicker objects, have you tested any yet?

  2. It does look nice, but I have to wonder about the idea of springs, unless they’re very strong. I’d think you would want the kapton under as much tension as it can reasonably stand to keep it flat under warping (since there’s nothing holding it down. Or to try and combine this with some kind of vacuum-frame thing…

    1. Replace the tension bar with a silicone covered friction belt driver. Look at how makerbot drives the toothed belt and drive it in a similar fashion with a friction drive.

      1. Would you link to an example of the silicone covered friction belt driver you mention?

        Do you mean to have the tension bar replaced by a roller that would drive the Kapton belt?

        I’m not sure what you mean by “friction drive.” It’s my understanding that the belts are driven by toothed timing pulleys.

        1. It’s similar to how printers move paper around with silicone rubber rollers. A belt dive is used to give indexed positioning, however because it isn’t necessary to know the precise placement of the belt as long as it doesn’t run into the completed print, you can use a pulley system that uses friction between a motor driven roller and the kapton belt. This has the advantage of being easy to build and interface with the kapton belt.

          Yes I do mean to have the tension bar replaced with a silicone covered rod that acts in a similar fashion of providing tension while also driving the kapton belt. The reason this works is because when you kink the belt for tensioning, your also providing the perfect conditions to increase the surface area for a friction drive silicone rubber belt drive. Thus, you can combine both the tension device and the drive device into the same structure.

          I hope this clarifies and helps.

  3. How about cutting holes on the edges like in film or even using strips of film with holes taped on edges and using sprockets for movement?

    1. That reminds me of the paper used in dot matrix printers. That sounds like a good way to guarantee the Kapton belt moves. It might otherwise slide over the two shafts. I’ll test without sprockets first and see if that’s good enough. Since Kapton is laserable, making sprcket holes in a sheet would be fairly trivial.

  4. What about doing away with the y axis and driving the belt directly for the y axis. You’d reduce part count.

    1. You need 2x the size of flat platform in the Y direction to make that work. Keeping that flat and rigid might require some serious reconstruction.

    2. That’s an idea I was considering until the bowden extruder became a real option. With a bowden style extruder the print head(s) would have little enough mass such that it would be easier to move than the build platform. In a future MakerBot version the build platform will likely only move along the z-axis.

      An advantage of moving the build platform in only the z-axis is that the printed object wouldn’t wobble around during printing.

    1. Nozzle tempreature of 220C. This test is the only time I’ve printed with a heated platform, which I pretty warm, but cool enough to touch. I’ll get the platform working properly and do more testing this weekend if I scrape enough time together.

  5. Nice work, very impressive and a step in the right direction.

    Probably best way to motivate your conveyor could be to make the conveyor with standard timing belts down each edge. (Just wider than you build platfor so that the Kapton stays flat) Then add timing gear pulleys to the ends of your rollers (cut the flanges off or get them flanged only on the out side edge.) Add a motor assembly to one of your roller/pulley assemblys.

    Do away with the axis drive in the direction your conveyors goes and drive your conveyor motor with this output.

    A conveyor bed is definitely the way to go.

  6. Thanks. It’s just one of many steps by many others. It certainly will help achieve one requirement in the $80,000 Personal Manufacturing Prize (

    “The capacity to print a full set of parts for a complete replica of itself within 7 days, including the time for reloading, and clearing of printer head jams.”

    It will be great to queue up print jobs and leave the printer to its business.

    I’ll look into finding a timing bealt that is wide, thin, and flexible enough for what you’re describing.

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    in a new way. FuzzyBase can be found on cydia. This is the way most Comfort fashion people behave.

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