1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Y Axis Bearing Alternative

Discussion in 'Mods and Upgrades' started by WheresWaldo, Nov 28, 2015.

  1. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    This is a replacement / upgrade to the Robo3D R1 and the LM8UU linear bearings used to guide the Y Axis of the moveable bed. This model uses self-aligning self-lubricating sintered bronze bushings instead of ball bearings. Advantages are operation with less mess and little or no lubrication is needed along the rails. Quieter operation from the solid bronze bearings. No possibility of gouging the rails in the event of a bad or dry ball bearing.

    This pillow block uses 7Z41MPSB08M bearings available in the US from Ultibots.com
    [​IMG]

    Robo_Y-axis_Pillow_Block_(Clear).png Robo_Y-axis_Pillow_Block_(Solid).png

    Designed to be printed laying flat. When doing so support will assist the center hole stay round but is not absolutely necessary. Can also be printed from either end with no support.

    Please print this with ABS or other filament with a higher Tg (Glass Transition Temperature) because of the close proximity of the top of the pillow block to the bottom of the bed heater. Alternatively, insulating the bottom of the heater pad may also provide satisfactory results.

    There are a few significant differences between these blocks and the OEM Robo3D blocks.
    1. They are one single piece. Instead of using two pieces like the Robo, it is designed to hold the bearing without artificially compressing them while fastening the block to the printer.
    2. The holes for the bolts are recessed. To allow for more room under the bed, the screws are recessed and can use readily available socket head cap screws which allow for easier installation over phillips head screws.
    3. Uses self-aligning/lubricating bearings over LM8UU. Bronze bushings provide longer life, less maintenance and quieter operation over ball-bearings.
    4. As a result of bearing design and placement, the effective support length is actually increased without increasing the size of the block itself.
    The model as well as 3D solid source files, in a variety of formats, can be found on Thingiverse. Autodesk Fusion 360 was used to create this model.

    X Axis bearing replacement thread located here.
     
    #1 WheresWaldo, Nov 28, 2015
    Last edited: Feb 8, 2016
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    Installation notes:

    In order for these larger in diameter bearings to fit within the pillow blocks, there were a few things you should make note of during assembly. This model raises your bed approximately 1 to 1.5 mm. You need to make sure that your Y Axis belt runs straight with no binding. This gave me an opportunity to adjust things properly. Please note that the Chinese man or woman who assembled your Robo3D only cares about how many they can put together during a shift. You on the other hand, as a Robo3D R1 owner care much more about reliability and print quality. Here are some things to look for when substituting these bearings.
    1. The two idler bearings under the bed will likely need an additional washer under the bearing to move the bearings up. Most 8 mm washers are 1.2 to 2.0 mm thick so one should suffice, alternatively you could pre-print a 1.5 mm spacer.
    2. The Y stepper GT-2 gear will also likely need to be raised on the motor shaft.
    3. The Y Axis Belt Tensioner (you know the part that sometimes comes broken in the box) can be swapped around so the the solid edge is up, this will lower the belt approximately 1 mm. You need to have these five items aligned for smooth operation.
    4. There will be a break-in period for these bearings so things will get smoother with use as the bearing deposits a micron level layer of material on your rods through use. Tim Rastall has a video that in part shows how to speed up the break in process:
    5. Your bed will need re-leveling, please follow the guides on this site for doing the paper level.
    6. Z Offset will likely change, you are moving the bed in relation to where the stepper motor thinks that full steps are, this will change the relationship between actual height and desired height of the extruder (Z Offset).
     
    #2 WheresWaldo, Nov 29, 2015
    Last edited: Nov 29, 2015
    Geof likes this.
  3. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    Testing:

    Here is a video of the bed moving after final assembly. Most of the noise you hear is Fan and Motor noise:


    Here are a couple of pictures. Excuse the quality and white balance, these were cell phone pictures:
    [​IMG]
    [​IMG]
     
  4. danzca6

    danzca6 Well-Known Member

    Joined:
    Jul 27, 2015
    Messages:
    2,161
    Likes Received:
    1,074
    Holy cow....that's quiet. This might be a reason for me to reprint an x carriage if you ever incorporate it into that design. I like what you did here Waldo. Never heard of these bearings before. Great job on the mod. I have it on my list to try out.
     
    #4 danzca6, Dec 4, 2015
    Last edited: Dec 4, 2015
  5. sesl

    sesl New Member

    Joined:
    Nov 19, 2015
    Messages:
    15
    Likes Received:
    9
    This looks great and sounds super smooth! Great job man! This will probably end up being my first upgrade to my RB1+ The bed noise has been annoying me and I've been trying to figure out how to further tighten down the stock clamps on the bearings since that seems to be what's been causing it.
     
  6. danzca6

    danzca6 Well-Known Member

    Joined:
    Jul 27, 2015
    Messages:
    2,161
    Likes Received:
    1,074
    Yeah, I'll be upstairs and know when the print is done because I can here the Y axis home and then push out. So darn loud. $18 for 4 bearing sounds steep, but man, this might be moving up my mod list quick. Waldo does great work. Very creative.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,338
    Likes Received:
    7,035
    You can get smoother and quieter linear bearings, they just cost more.
    Even so they will not be as quiet as these :)
     
  8. Printed Solid

    Printed Solid Volunteer Admin
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    1,605
    Likes Received:
    1,001
    Cool upgrade. I'm looking at doing something similar.
    I bought some IGUS bearings that were advertised as LM8UUs. Of course I now find that IGUS doesn't actually make LM8UUs and the details of the listing said that they aren't actually quite the same size and don't fit in the stock bearing blocks. Anyone know if someone else has already designed a mount I can just print?
     
  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    The problem with the Igus bearings is that they are designed to be compressed, so they are oversized, I am not a fan of the split pillow blocks with plastic bearings either. They have a tendency to squash the bearings into an oval shape, That is why I like these better. LM8UU are 15 mm OD, these are 15.9 mm OD. I don't remember what the nominal (compressed) OD of the IGUS are.

    @Printed Solid, you could still download my pillow block design as I included STEP, IGES, SAT, SMT as well as Fusion 360 files along with the STL, easy enough to modify.
     
    Printed Solid and mark tomlinson like this.
  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    @danzca6 I am in the process of doing the same for X, but after printing out a few carriages and not really liking the results, here is what I ended up with:

    1. Took the X Carriage completely apart, including removing the old LM8UU bearings.
    2. Walked to my drill press, chucked up a HSS 5/8" bit and drilled out the holes (5/8" is something like 15.82... mm, close enough)
    3. Used Acetone to clean up the holes and smooth them a bit.
    4. Press fit the new bearings and did the break-in procedure in the video above.

    Still not up and running as I broke my thermistor and one of the wires into the E Stepper in the process and I need to solder a couple of leads.

    PS - In case anyone wants to know, the steppers use a JST-PH 6-pin connector.
     
    #10 WheresWaldo, Dec 4, 2015
    Last edited: Dec 5, 2015
  11. danzca6

    danzca6 Well-Known Member

    Joined:
    Jul 27, 2015
    Messages:
    2,161
    Likes Received:
    1,074
    Interesting discovery on these bearings. Come to find out that there is no difference in outer dimensions for the 8mm and the 10mm sizes. So, if you wanted to say upgrade your rods from 8mm to 10mm you could use this same pillow block. The max RPM rating is about 2400 lower on the 10 vs the 8. Not sure if that would make a difference or not. Since I was going to do this mod, I have been thinking why not upgrade to 10mm rods and redesign the end caps to except the new rod size. I have that model redesign complete. Now it's up to me to decide which would be best to go with. I would think going 10mm on the Y might be an improvement over the stock rods. Actually, doing the same on the X might be a good upgrade as well. No price difference in the bearings between the two sizes.

    Sintered Bronze Pressbearings.PNG
     
  12. Nathanfish

    Nathanfish Active Member

    Joined:
    Aug 6, 2015
    Messages:
    306
    Likes Received:
    34
    I have an STL file of y axis brackets modified for 10mm rods if you're interested.
     
  13. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    Go ahead and add it to this thread. I probably won't do this upgrade but others could be interested. My Robo is now good enough for my own personal use with 8 mm rails but 10 mm will make it just a little bit more rigid.
     
  14. danzca6

    danzca6 Well-Known Member

    Joined:
    Jul 27, 2015
    Messages:
    2,161
    Likes Received:
    1,074
    I did update the design for the pillow block as well for the 10mm rods. The center hole was only 10mm so I made it 12mm. I have the Y brackets redesigned as well. I can post all that tonight when I get access to Fusion 360 again. Having a hard time finding a good source for 10 mm rods to do the upgrade, but once I do find one, I will go forward with it. I figure it would be a good project to do along with the new bearings.
     
  15. KTMDirtFace

    KTMDirtFace Well-Known Member

    Joined:
    May 18, 2015
    Messages:
    1,247
    Likes Received:
    461
    How much infill are you using on your block?

    I have been doing 100% on my carriage in PLA. Don't think I will need that much on the Y block but curious what you used.
     
  16. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    40% rectilinear
     
  17. KTMDirtFace

    KTMDirtFace Well-Known Member

    Joined:
    May 18, 2015
    Messages:
    1,247
    Likes Received:
    461
    Cool thanks, I printed one in PETG on its end.. Only because I wanted the bearing holes more round. Bearings get here tomorrow.
     
  18. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,817
    Likes Received:
    3,539
    Exactly how I printed one set. Two at once on end.
     
    #18 WheresWaldo, Feb 15, 2016
    Last edited: Feb 16, 2016
  19. KTMDirtFace

    KTMDirtFace Well-Known Member

    Joined:
    May 18, 2015
    Messages:
    1,247
    Likes Received:
    461
    I outta wait to see if the bearings will fit before i print anymore. Thanks though!
     
  20. danzca6

    danzca6 Well-Known Member

    Joined:
    Jul 27, 2015
    Messages:
    2,161
    Likes Received:
    1,074
    some sanding with a dremel sanding cylinder or hitting it with a drill bit (if you have one big enough) should fix any tight issues. Some tape will help with any loose issues.
     

Share This Page