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Prusa i3 Bear Edition

Discussion in '3D printers' started by pek, Sep 21, 2017.

  1. pek

    pek Well-Known
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  2. pek

    pek Well-Known
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    Hi all,

    I am new here but reading OB since few months now (and waiting for the Apex and maybe new CNC machine? :-D) . Thanks to all the OB team for your impressive work! I am really happy to have a project to share here.

    As I am new I need your help about the brackets/plates I used for this project. What do you thing? Z axis will be strong enough? Too much brackets or plates? Or not enough?

    Thanks in advance for your help
     
    MaryD likes this.
  3. Fits Nugly

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  4. pek

    pek Well-Known
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    Yes I know it, it is mentioned in my description :)

    This project is very good however there are too many things to update from Prusa i3 MK2/MK2s, like the rods or the RAMBo cover. 3030 extrusion is good but OB offers a single and simple platform where you can find all the hardware (not only extrusion and t-nuts) you would need to build/customize this frame.
     
  5. pek

    pek Well-Known
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    Update : description to better reflect why another conversion kit :)
     
  6. pek

    pek Well-Known
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    I have added the screen mount and the vslot end caps (yes with a tiny bear :-D ).

    However I put this project on hold for now because Josef Prusa has just announced the new MK3 which solve the problem of the frame, plus some other awesome features!!!
    Check this out: Original Prusa i3 MK3 is out! And it's bloody smart! - Prusa Printers

    I still have some idea with this project but I will wait until my MK3 arrive :)
     
  7. p.builds

    p.builds New
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    Maybe MK3 will arive, but the MK2s stays for sure!!
     
  8. pek

    pek Well-Known
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    Yes and the MK2.5 upgrade does not include the new frame. I am currently working on another project, cheaper to make more sense for MK2.5 users. I will post it soon :)
     
  9. pek

    pek Well-Known
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    Here is my new idea :

    home_left.png home_right.png right.png front.png bottom.png

    PROS :
    - cheaper : less part to build and to print
    - less part to print (z axis bottoms and tops, RAMBo cover hinges)
    - reuse original frame ( eco :-D )
    - less measurement during building

    CONS :
    - need to drill the frame (I have designed a drilling helper)
    - less rigid in Z (not sure about this for a 3D printer)
    - less customable
    - 8 threads to tap


    What do you think?
     
  10. p.builds

    p.builds New
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    We are at the same frequency!!!

    Your design is amazing!
    The frame itself is very rigid. The two 10mm screws are bending and are responsible for the unstable construction. So I think your design will be super stable!

    Also, I want to reuse too the original frame, because it is signed by the Joseph himself.

    Although I imaging it a little different:

    I think to keep the big 10mm screws and just wear the 20x40 profile over them. One part from the front and another one from the behind. The 10 mm screws fit in the inner gap at the core of the profile. I will screw them tightly from both sides. If it is not stable enough, I could screw underneath them another single piece of 20x40.

    Or I would follow your idea! I really like your designs. What tool do you use?
     
    #10 p.builds, Sep 28, 2017
    Last edited: Sep 28, 2017
  11. pek

    pek Well-Known
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    Thank you p.builds, I really appreciate your comment :)

    I took time to check what is moving on the frame and yes you are right the 10mm screws are bending. However, the frame is also bending where the 10mm screws are tighten on the aluminum frame, it is more visible on the left (RAMBo cover side). This part of the frame is quite small and the nuts and screw seems to not support this part enough. Maybe it is only mine that is like this...

    I was first thinking of something like you describe but after this observation I decided to go for a stronger option.

    I am using Fusion 360, really recommend it! Files of the project with original frame will be available soon (Fusion 360 project as well), the other one is available on my github.
     
    #11 pek, Sep 28, 2017
    Last edited: Sep 28, 2017
  12. pek

    pek Well-Known
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    I did analyze the price of both builds :
    • With the original frame : around 80€
    • Full openbuild frame : around 120€
    I think it makes more sens to continue with the original frame in regard of the MK2.5 upgrade and MK3 prices. What do you think?
     
  13. p.builds

    p.builds New
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    Let's do it!

    The only difference from the MK3 will be the electronics and the trinamic drivers.
     
  14. p.builds

    p.builds New
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    My idea of covering the 10mm screws with 2040 and then tighten them completely at the two edges, didn't result in a solid object.

    I'm not sure if we can connect tight enough the original frame with 2040 extrusions.

    The more i think about it, the more I tend to believe that your first design is more doable. Perhaps, after building it, we could fasten the original frame in front of the vertical 2040 frame. This way we keep the original X and Z axis (and the frame with Josef's signature :)). Then we need to print the Y axis, the RAMBo and the power supply holders.
     
  15. pek

    pek Well-Known
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    I have updated the project page :)


    Exactly :)

    Interesting, could you explain why we could not connect tight enough to the original frame? This is what Prusa is doing with the MK3 and with only 20x20 extrusions (and a smaller lower part of the frame).

    I was thinking about adding in front of the original frame. The problem is that all electronics will be more in the back and the heat-bed cable might be too short
     
  16. kyle fossum

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    Aww, I just finished printing the parts for the first design.. Well I'm gonna have to just go for it and build V1. Are there any significant advantages of the newest version over the first one?
     
  17. pek

    pek Well-Known
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    The first one will be stronger so go for it, it is just more expensive and so does not make big sense against the MK3. You will be the first one to build it, please give some feedback :)

    All files are still available on my github from previous version here : GitHub - gregsaun/prusa_i3_bear_upgrade at bd46df00bfdc56512b5bfc0410671e9ca4d9f05f

    Sorry, a bit messy, I should have done version ( never push to master :-D )

    2017.10.01 - 18:19 Update : links
    2017.10.01 - 18:26 Update : links ... again
     
    #17 pek, Oct 1, 2017
    Last edited: Oct 1, 2017
  18. pek

    pek Well-Known
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    For now I do not have time to work on both projects at the same time. However, if you think it can be useful then I can publish it separately.
     
  19. Jeepguy42

    Jeepguy42 Well-Known
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    From what I can tell with this design you would need the attached BOM to build this (the tap is only if you don't have a 5MM tap). I like this design and am really considering doing this upgrade to my printer after I get the 2.5 upgrade (when its available).
     

    Attached Files:

  20. pek

    pek Well-Known
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    Thank you to helping me. I am very happy you consider building one :)

    I think you missed few screws, here is mine : bom on my github . What do you think?

    How deep we can go with the OB drill tap? Will it be enough for the 30mm screws?
     
  21. Jeepguy42

    Jeepguy42 Well-Known
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    I assume it would be fine. It doesn't need to go in the full 30mm since you will have 6mm of the aluminum frame plus the corner bracket. Not sure exactly how long the tap is so mine is only a guess. The 20mm in theory will only be into the extrusion by 12mm or so and I assume you'd want a little more than that to hold.

    I did miss the motor mount screws.
     
  22. pek

    pek Well-Known
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    Ok let's go with 30mm :)
     
  23. Thomas Sexton

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    do you have the STL's done for the LCD holder yet?
     
  24. pek

    pek Well-Known
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  25. Jeepguy42

    Jeepguy42 Well-Known
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    Just added a comment to your thingiverse but figured I drop an image here so you cans ee what I am seeing with your new file

    Interference.JPG
    [​IMG]
     
  26. Itamar Bonneau

    Itamar Bonneau Well-Known
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    looks really cool - following this and considering going this way. had my eye on a z/haribo but I have different extrusions then the parts they have and there are a lot of changes to be done if you want to go zaribo way (firmware etc...). so I think this is the way for me.

    could be an option to reuse the 10mm threaded rods as stiffeners on the back the Z plate - would require printing adapters for the PSU and Rambo - just a thought
     
  27. guysnover

    guysnover New
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    Pek,

    I just bought 2 kits weeks before they announced the MK3! Y-axis frame is the worst part and I put it together as carefully as I could. I want to try your build. I thought of a simple part that will really help.
    Can you create printed drilling template for the necessary holes in the main Z axis frame? Something that fits snug around the frame edge and just has holes where you need to drill. Small holes, because it would be best to use a center punch to mark the locations, double check the locations with calipers, then drill.
     
  28. pek

    pek Well-Known
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    Fixed, thanks again for your help :)

    Thank you so much, really happy you consider building it!

    Before reinforcing the Z axis I would to first see how it is like this. Then I have few ideas if it is not strong enough.

    Sorry for you to have missed the MK3, however, you will get reduction to upgrade to MK2.5...

    I have a 3D printed drilling template, but use with caution, I did not test it yet :
    drilling_helper.stl

    There is also a PDF to show you the position of the holes :
    frame_drilling_dimensions.pdf

    Let me know if you need something more
     
    #28 pek, Oct 7, 2017
    Last edited: Oct 7, 2017
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  29. kyle fossum

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    I will be assembling the original design as soon as I get my aluminum cutting sawblade, I am excited to build it!
     
  30. pek

    pek Well-Known
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    I hope everything will be fine. I am excited to see it in real!

    Be sure to check all printed pieces on the rails before disassemble the printer ;)
     

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