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MK3 (dis)assembly question  

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JLTX
 JLTX
(@jltx)
Reputable Member
MK3 (dis)assembly question

My printer arrives next week. So I am reading through the assembly instructions. Y axis looks way better than MK2S. Though I think I preferred the old belt holder style. I'll wait to see.

But I am perplexed by the new extruder design. Why did.they add a back plate? Now I have to disassemble all the wiring just to adjust the belt?

Posted : 17/12/2017 7:38 pm
Lloydcr
(@lloydcr)
New Member
Re: MK3 (dis)assembly question

Once you get the belt tensioned, any adjustment can be made by the X motor.

Posted : 17/12/2017 8:05 pm
Paul Meyer
(@paul-meyer)
Honorable Member
Re: MK3 (dis)assembly question


Once you get the belt tensioned, any adjustment can be made by the X motor.

How do you increase the belt tension at the x-motor? I assembled the belt as per instructions with the x-motor swinging on one screw, and then tension was placed on the belt as I swung it back into position and screwed it in. I don't see how I can adjust tension at the x-motor, however. It's in a fixed position with accurately sized screw holes.

If I want to increase tension, it seems like I'd need to:

  • release 3 x-motor screws to release tension

  • tighten the belt one full tooth on the extruder mount

  • swing x-motor back
  • Am I missing an easier adjustment? This is my first prusa, so it's quite possible.

    Posted : 17/12/2017 8:09 pm
    Mike
     Mike
    (@mike-8)
    Estimable Member
    Re: MK3 (dis)assembly question

    There is no good reason to constantly readjust the tension of the belt.
    The i3 is not a core xy.

    But you are right, if you whant to readjust the tension (more than a tooth), you have to disassembly it.

    Posted : 18/12/2017 10:51 am
    JLTX
     JLTX
    (@jltx)
    Reputable Member
    Topic starter answered:
    Re: MK3 (dis)assembly question


    There is no good reason to constantly readjust the tension of the belt.
    The i3 is not a core xy.

    But you are right, if you whant to readjust the tension (more than a tooth), you have to disassembly it.

    A couple times I removed belt on my MK2S for maintenance or upgrades. MK2S design was better. Not sure why they changed it. It looks like you can’t just unscrew it either. You have to cut all the zip ties to get any slack in the wiring to pull the plate off. I’ll be redesigning that.

    Posted : 18/12/2017 2:47 pm
    Athruz
    (@athruz)
    Eminent Member
    Re: MK3 (dis)assembly question

    So how can you adjust it one tooth? Is the hope that the belt would slip the one tooth while still inside the housing?

    My X-axis belt reads 246 and 270 on the Y. It is really a poor design to have to disassemble the extruder housing just to adjust the belt.

    Posted : 23/01/2018 4:27 am
    Area51
    (@area51)
    Member
    Re: MK3 (dis)assembly question

    I know of two solution to ease access to the MK3 x-axis belt, Thingiverse:

    https://www.thingiverse.com/thing:2731484
    https://www.thingiverse.com/thing:2727523

    Both solutions is replacements for the stock back-plate and easiest to assemble when building the kit, but takes more effort to replace after wires are mounted in the electronics.

    Have a look at my models on Printables.com 😉

    Posted : 23/01/2018 4:54 am
    Laurent's Lab
    (@laurents-lab)
    Eminent Member
    Re: MK3 (dis)assembly question

    There is this related statement in today's blog post:

    We are also continuing to develop the parts to remove some of the annoyances. Among upcoming updates are reworked X-carriage with belt holder system similar to the one on Y-axis and X-end-motor with the integrated belt tensioner. Once these parts get through our testing, they will be put into production and available on our website.

    https://www.prusaprinters.org/original-prusa-i3-mk3-2-months/

    Posted : 23/01/2018 5:35 am
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