Another DIY Motion System (Cheap&dirty)

Discussion in 'Motion System' started by fantasmag0ria, Nov 6, 2020.

  1. fantasmag0ria

    fantasmag0ria Member

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    Hello everyone!

    The idea is to build the motion system with cutting corners wherever possible, using parts I already have laying around and to fabricobble as many custom stuff as possible myself. As a added side benefit the plan is to learn something in CAM and Machining.

    It wont be a quick project. But I have time.

    2020-11-06 13_42_27-a.jpg ‎- Zdjęcia.png

    Starting with a few parts I already ordered:
    • Top and bottom alu plates: laser-cut. Decent quality, bit warped but good enough.
    • bed under-plate modified to accommodate my bed assembly I'm using currently.
    • bed bracket: also laser-cut
    • 3060 profiles I found the cheapest online.
    • belts, linear rails, pulleys - sourced from Aliexpress. Not the cheapest but also not original.
    • side, rear PC panels I want to replace with MDF or plywood for two reasons: 1. its cheaper 2. I want to have it lit inside and not to illuminate the whole room i will keep it in.
    so far I spent like 200Euro for all the parts I ordered/made.

    MS-X-bar-alu:
    My CNC router has work envelope of 300x200mm so I won't be able to machine it in one piece. Idea is to do it in 3pieces and bolt it together. I'll see how it goes. I'm 90% done on this part.
    20201105_182939.jpg

    Stepper stand-offs:
    'Lathed' out of aluminium round stock I had laying around.
    20201105_183409.jpg

    I will keep you guys updated.

    PS. I wanted to add some more pictures but I have no idea why I get errors that I cant. I'll try again later.
     
  2. fantasmag0ria

    fantasmag0ria Member

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    Update on the 3 part x-bar: finished.
    Looks really good. Its straight and dimensionally accurate.

    20201108_175117.jpg
     
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  3. fantasmag0ria

    fantasmag0ria Member

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    Update!

    Still lots of 3dprinted parts instead of machined. But its good for now. I think.

    Next step is to check if its working. I'm using duet board in my current printer and don't want to disassemble it. But I think I have a SKR board somewhere. For testing should be good.
     

    Attached Files:

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  4. Greg Holloway

    Greg Holloway Administrator
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    Looks good. I love the X-Bar

    One thing I would say, if you are going to use a printed bracket for the Z-Axis motor, modify it to have some bracing at it is likely to warp and bend under all the weight.

    Something like this.

    upload_2020-12-16_15-5-47.png
     
  5. fantasmag0ria

    fantasmag0ria Member

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    Yeah, the plan is to have it machined in the end. Right now the stepper is laying directly on the bottom plate so it wont move down from the weight of the bed assembly. it might move up a bit during fast bed acceleration ;)
     
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  6. fantasmag0ria

    fantasmag0ria Member

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    It's alive! Default skr mini marlin build. I only changed coreXY kinematics. That's fastest I can reliably run it without drivers overheating at 24VDC and the carriage slamming into Z axis rail ;) I wont bother tuning it now, will do on the duet board.

     
  7. Greg Holloway

    Greg Holloway Administrator
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  8. fantasmag0ria

    fantasmag0ria Member

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    I agree! Thanks.
     
  9. Dejay

    Dejay Member

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    Wow really awesome fantasmag0ria! Any progress? :)

    Can you expand on the 3D printed tool plate? How does the matching plate look like? Are there other discussions about "fabricobbling" a toolchanger?

    Are your registration points precise / stiff enough? I assume more important that absolute precision is how repeatable the registration works once you have it calibrated.

    I've had the idea of possibly using PCB as tool changing plates that you can order cheaply and that come presumably quite precision milled. And then soldering some kind of hardware to make the registration points (screw heads?).
     
  10. fantasmag0ria

    fantasmag0ria Member

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    Progress? Some. I didn't have much time recently. Mostly electronics. I got duet and expansion board mounted and half-wired. Still waiting for the psup.

    regarding 3d printed parts: it's a temporary solution. I don't intend running it like that.

    The idea of PCB tool plate seems really interesting. You can use pogo-pins as a electric interface. One thing might be an issue: some more current hungry device like heaters. Pogo pins are not designed (usually) to carry much current. And also it stops the system from preheating tools. Maybe you can go hybrid? pogo + separate wire for high current? Regarding mechanical interface: you can go the same way E3D went with aluminium. Bore some holes and press-fit/glue-in a ball bearings.

    I have a prototype tool-plate. Machined out of PA9, press-fit ball bearings and acetal (POM) insert (why acetal? because its nice to machine, durable, low friction and I have a literal drawer of small pieces ;) )
     

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  11. Dejay

    Dejay Member

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    Really nice! Maybe I just need a CNC haha. But what do you mean the prototype is missed out of PA9? Isn't the picture showing aluminium?

    And it seems you went with simple holes instead of "slits" to register the opposite of the bearing balls. I wonder how that compares.

    I'm thinking balls from bearings and some bigger needle of needle bearings could work well.
     
  12. fantasmag0ria

    fantasmag0ria Member

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    Machined out of PA9. PA9 is a harder aluminium alloy. Also knows as 7075.
     
  13. Dejay

    Dejay Member

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    Sorry typo, meant to write machined haha. And thanks, didn't realize it was an aluminium alloy, thought it was a polyamid / nylon grade.
     

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