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muttstang

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Posts posted by muttstang

  1. Or just increase the gear reduction some more depending on if the motor is capable of the RPM's at whatever the load ends up being. The bigger the gear reduction, the more that the relative rotation will be minimized. You can pretty easily get some 64 pitch worm gears and see a 60:1 reduction without a lot of size. You will likely have to buy the gears as the teeth would be getting a bit small for printing, especially with the higher friction loss that you get from worm gears

     

  2. Has anyone tried using a push to connect type of tube on an extruder upgrade by chance?

    I have a design and left provisions for a 1/8" NPT fitting and am trying to figure if a push to connect will work instead of a compression type of fitting.

    A push to connect fitting will generally allow the tube to be pulled out slightly so I don't know if this would cause issues. A compression fitting will be more of a rigid connection.

     

  3. You could do a single drive with a gear reduction while using a knurling tool head.

    I'm pressing these onto roll pins.

    There is a tube so that you can run a cleaning brush in there and clean off the feeder wheel.

    the tensioning arm can be released with a simple over-center arm. Not much for adjustment on the spring of the tensioning arm at this point. I might have something in mind for it though.

    The blue wheels are gears, the small one being pressed onto the stepper motor.

    I believe the gear reduction is 6.35:1

    .375" gear to 1" gear, down to .75" knurl wheel divided by 8mm/25.4 (od of original knurled wheel)

    singledriveextruder_zpsdb49bc6f.jpg

     

  4. Welp, MB approved the return of the Z18, though they are looking to charge the 10% restock fee on a printer that never worked right in the first place.

    The company is going to fight that a bit.

    Either the engineers at makerbot weren't admitting to the problems they were having, or else the exec's there ignored the engineers' advice and went to market with a defective product.

     

  5. I might skip the 3 knurling wheels. That requires some pretty complex gearing and I'd rather keep it simple. I'm going to try just a gear reduction to get more power out of the motor and use a larger knurling tool as the drive wheel.

    Though the flex shaft idea has me interested. I might have to pick up a nice flex shaft from mcmaster and do some of my own testing

     

  6. that depends on if you can adjust the rpm on the stepper and where the peak torque of the stepper is. I'm guessing that the peak torque on the stepper is at a higher RPM then it currently operates. So you would gain some power by spinning the stepper faster to get the proper rate of rotation on the extruder. Now if you are direct driving those wheels then you will have to spin the stepper even more slowly and will lose torque from the larger diameter as well. I wouldn't want to direct drive the bigger wheel. Direct drive may be simpler and make for lower part count, but it does not allow the stepper to operate at it's most efficient speeds.

     

  7. I still think just going to a pair of driven wheels of a larger diameter will make a huge difference.

    A quick sketch shows it has a lower angle for the filament to enter so loading would be easier. There is also 20% more contact area on each side. To keep the stepper rotating at the same rate there would have to be a matching gear reduction prior to hitting the drive sprockets.

    2wheeldiametercomparison_zps186c59b7.jpg

     

  8. I ordered the UM2 today and MB is sending a packing kit for the Z18 :)

    I did figure out that the thermocouple on my UP! was bad so I ordered a new one of those. I should be up to 2 printers soon :)

    I have a novel idea for a new feeder that I'm planning to put together using 3 straight knurling tools.

     

  9. Could someone use a knurling tool head? something like mcmaster part 3330A32?

    you could potentially use 2 of these (one on each side of the filament) spring loaded together and then linked with a single gear attached to the drive motor. That way you can set up the gear ratio to match the original diameter of the knurled piece on the stepper?

    I have something in mind but I have to sketch it out.

     

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