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Prusa i3 Bear Upgrade V2

Discussion in '3D printers' started by pek, Feb 8, 2018.

  1. jay3D

    jay3D New
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    I haven't. Thanks for sharing.

    Firmware: I like.
    Slic3r PE: finally...
    MMU - idea: cool.
    MMU - price: cool cool cool.
    MMU - wipe tower: they finally implemented this idea. Not originally from Prusa though. But I don't care. As long as it decreases the wipe tower, I am very happy.

    I was looking at the E6D Diamond Hotend for quite a while now. Much cheeper as the MMU. However, if they now got a better mechanical design still using the direct extruder, then I take it.
     
  2. jay3D

    jay3D New
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    The MMU prototype seems to be easily adaptable. There seems to be a removable base between Bowden and Frame. This would make it easy to put it anywhere on the Bear.
     
  3. xequtor

    xequtor New
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    FINLY! that was my idea from the beginning
     
  4. kabar03

    kabar03 New
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    Pek, are you happy using IGUS bearings?
     
  5. xequtor

    xequtor New
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    I removed my IGUS RJ4JP 01-08 wich were installed on X axis, I had problem with autohome and calibration almost ruined my Rubby nozzle due to wrong home detection.
    They are not sliding so easy as the original ones and have resistance which Trinamics detects as endstop on left side and if resistance on right side then error about X axis length, I I'll stay with the original bearings.

    For IGUS, best solution is to get the IGUS alu rods, they are coated with teflon or something similar.
     
  6. pek

    pek Journeyman
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    Yes easy to adapt, the v1.0 should be easy to add as well

    That is a very clever idea, love it!

    Yes but I do not like them :D , but Igus is doing very impressive and good products! They are more complex to install properly and Prusa printer is a pretty bad platform for that...

    I have first used RJZM-01-08 on X and Y axis with original rods. They were having too much play and, at that time, I also learned that Igus bearings need special rods because of their self-lubrication. I then switched to RJ4JP-01-08 which have less play (that what the datasheet says) and with Igus recommended aluminum rods. Still too much play. Plus, the aluminum rods are way too much flexible!

    I read few times that Igus "bearings" does not slide very well. However, if you take the time to perfectly align the rods and be careful with the way you mount them, then it is not true. They were sliding as good as the original bearing, maybe even better! They are also very sensitive to their own alignment, they need a good solid housing. After few prints they start to slide a bit better, certainly due to their self-lubrication.

    In conclusion, this is what I think about those bearings :
    • Igus products are very good and interesting, just not for a "single" 8mm shaft mount style
    • Igus bearings slide very well, they just need to be properly mounted
    • RJ4JP are better than RJZM because less play but difference is very low
    • Both bearings need a solid closed housing (not a 3D printed mount, tolerances and rigidity matters)
    • With Igus bearing you have to use Igus rods but just not the aluminum ones
    • Bearing mounts on Prusa Y carriage is a very very bad design, and even more for both RJ4JP and RJZM
    • Prusa Y carriage needs 4 bearings to reduce play and vibration with Igus bearings
    • Prusa X carriage with closed housing for bearing will be too bulky for me (and what about the weight?)
    • Z axis does not need Igus bearing (less vibration and noise than X and Y)
    This is my own conclusion and maybe I did something wrong with them because lots of people are very happy!

    They slide very well but it is almost impossible to get them right on the Prusa.

    In fact their rods are not smooth because they need to keeps plastic particles from the bearings (this is the self-lubrication things)!
     
    #126 pek, Mar 4, 2018
    Last edited: Mar 4, 2018
  7. jay3D

    jay3D New
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    Hast anyone tried to use Igus rails? Everyone is talking about Hiwin and Misumi. No one seems to use Igus. I wonder if the tolerance is considered to high.
    Igus has some nifty double rod rails and more.

    Pek, any thoughts?
     
  8. jay3D

    jay3D New
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    drylin_shop.jpg

    I like the 2nd from the left as well as the one in the middle.
     
  9. pek

    pek Journeyman
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    Did not try them, it is clearly the best solution for plastic bearings (you can adjust properly the play). I would like to try them, but maybe after Hiwin/Misumi/IKO... because they are more complex to install. Igus technology is very awesome!
     
  10. jay3D

    jay3D New
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    Igus is a supplier of our company. I might ask them if they have advice on which of their products would fit a 3D printer.

    Would be fun to do it differently than the usual blokes. ^_^
     
  11. pek

    pek Journeyman
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    https://www.igus.com/wpck/17736/3Dprinting

    As you can see, there is no Drylin R on their 3D printers (check videos)
     
  12. pek

    pek Journeyman
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    btw, what your company is producing?
     
  13. jay3D

    jay3D New
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    Defibrillators. :ROFL:
     
  14. pek

    pek Journeyman
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    You shocked me (sorry... :zipit:)
     
  15. kabar03

    kabar03 New
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    Ok, thanks for the detailed feedback, I'll search out good traditional bearings to install
     
  16. pek

    pek Journeyman
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    If you find something else than Misumi (in Europe they sells only if you are a company), then please share here. It will be very useful. I am going to try Motedis bearings with PTFE based oil (this is what Prusa support recommended me).
     
  17. pek

    pek Journeyman
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    MK2.5 manual is out!
    Original Prusa i3 MK2S to MK2.5 upgrade

    We are going to get the new textile sleeve for heated bed cables, nice! As expected from the Prusa Github, the new RAMBo case is much better, specially for cable wear (I did a piece to solve this on MK2s : Prusa Rambo Extruder Cables Protector by pekcitron ). However, I was hopping to get 3 more holes on the heated bed to be able to use the new Y carriage of the MK3, it's has a better mount of the heated bed (but still very bad on bearings).
     
  18. pek

    pek Journeyman
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    Be sure the day I will get a CNC I will mill a better Y carriage!
     
  19. jay3D

    jay3D New
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    I am planning a house right now so that I can have a CNC machine. :D
     
  20. jay3D

    jay3D New
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    I am will try to get around this with cable chains. Already printed and ready to be installed for a couple of weeks. Waiting for time to do the Bear Upgrade to get this done as well.

    Right now: printing the tennis dampers. This takes longer than expected. Slic3r PE says 10 h per print. It is more along the line of 16 h per piece. :banghead:
    I consider to buy 4 additional corners to get the build started and add the feet later.
     
  21. pek

    pek Journeyman
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    You are planing the house for the CNC machine, nice :ROFL:

    I heard about good material for feet, I will try to find them again!

    Some theory on how to use Igus : . Very interesting!
     
  22. jay3D

    jay3D New
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    TPU is a good vibration damper.

    What I find most interessting is the 2:1 rule. I think the Prusa is designed with clearance in mind so that you don't need (near) perfect alignment of the rods.
    However, it seems to be that no matter which linear motion system you design, you want to have a fixed and a floating side. Also, in the Prusa it would be easy to move the y-motor closest to the fixed size to get maximum performance.

    I remember in the the "Tune you xyz axis" threads, someone talked about restrcting the system of the z-axis in the same way. Either you define the smooth rod or the lead screw as fixed. The otherone needs to be floating = able to move.

    I wonder if a single Igus double W rail would be enough for the y-axis.
     
  23. jay3D

    jay3D New
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    Just ordered the missing joining plates. Lets see what is faster: parcel from Belgium or printing 3 additional feet. The race is on. I want to start building this thing. :D
     
  24. pek

    pek Journeyman
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    Yes the "design rules" is the interesting part of the video, all the rest is advertisement :-D

    The things I am not sure to understand correctly with the 2:1 rule is the motor position. In this diagram :
    drylin_t_kons_regel_5.jpg

    the motor is on the right (corresponds drive force), floating in 1 and fixed bearing in 2. In the case of the Prusa, the motor is in the middle, not on the right. Does it change something? If not then Prusa Y carriage does not obey to 2:1 rule.

    Yes I am thinking more and more of this Igus double W rail! The only problem is that the Y carriage is quite flexible, so not good to have the bearing too much in the middle.

    Looking forward to see your printer working, hope I did not do too much mistakes :D
     
  25. jay3D

    jay3D New
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    I'm seeing massive warping in my PETG prints. Installed the latest firmware yesterday and hat to reset everything. Not sure if it is a firmware, slicing or filament issue... Good thing I ordered the other plates. They will be my reference for squareness and not the printed parts.


    Regarding the Igus setup:
    The prusa has ~45 mm between the double bearings. (let's assume this is the fixed side). The distance to the belt is ~84 mm. So they are within the 2:1 rule.

    However, what people are doing is reducing the tolerance by using Igus bearings. The whole Prusa setup needs massive tollerances to work. I think that is why they abbendend linear rails. If the rails have a tolerance of 0.1 mm on the floating side then the distance between the rails is only allowed to have the same tolerance. And that is tough to achieve.

    That's why I like the double rail.

    I am considering having an asymmetrical design:
    - double W rails on one side = fixed side
    - y-motor close to that rail = best x:1 ratio
    - V-slot wheels on the other side = maximum tolerance. It's only there to take load and not for linear motion anyway.
     
  26. jay3D

    jay3D New
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    Oh, btw, I think the best ratio is a lead screw or belt driven actuator where the lead / belt is running through the V-Slot.
     
  27. pek

    pek Journeyman
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    I recommend brim on some part to avoid warping : prusa_i3_bear_upgrade/print_settings.md at master · gregsaun/prusa_i3_bear_upgrade · GitHub . 4 or 5mm is enough.

    You are right, my memory was wrong :D. I measured Y carriage, on MK2 there is 70mm between bearings and 85mm from bearing to center, same for MK3. Not bad

    I heard that as well for linear rails. It is almost impossible to achieve on a MK2 frame, however, on MK3 it is possible. But linear rail on MK3 will cost more and might increase support questions and frustration...

    With your asymmetrical design, you have to be careful to have V-slot wheel side at the same height as the Igus rail side. Might be difficult to achieve.

    Yes that is the best ratio :D
     
  28. pek

    pek Journeyman
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    Got this email from Prusa this morning :
    "Your order with the reference ********* just had label created, your order is to be packed and shipped within a few days."

    That is the MK2.5 upgrade \o/
     
  29. xequtor

    xequtor New
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    WAIT!, you will get the "sticker" PEI spring steel print bed, if you can wait then you will get the structured/powder coated one, but you have to email Prusa. I'm waiting, they will send powder coated by end of this month.
     
  30. pek

    pek Journeyman
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    Yes I know, but I do not want to wait. I would like to give you as soon as possible the confirmation that my kit works with MK2.5 upgrade kit. And as I would like to have both type of surfaces, then it is a better compromise as I will get a 10$ voucher for the powder coated steel sheet.
     

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