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No more end cap friction on Ultimaker Originals

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As many other UMO owners I was looking for a clever way to fix the 8mm x/y rods without getting a lot of abrasion resulting in black greasy dust at the endcaps and no play of the rods.

The solution was actually presented in 2013 by Ultimaker on the UM2. The pulleys fix the rods with spacers from the inside. In order to make this working the bearings have to be kept in place by the side panel. The panels on the UM2 have an opening just large enough to let the rod pass at assembling.

The UMO frame is different. There is just one big hole for the bearing and nothing that would keep the bearing in place - except the end caps. Sometimes the distance between the two end caps of one rod is larger than the rod itself. The result is significant play which ruins print quality. Quite a number of modified end caps deal with the problem by using e.g. screws to fix the rod from the outside. But even with special screws which have a ball at their tip one always gets abrasion.

What do you need?

1. A little bit of time ;)

2. Printed spacers

3. 'End caps' with an opening for the rods

How do you do it?

1. Measure the distance between the outermost pulleys and the inner wall of adjacent wodden panel. This gives you eight numbers.

2. Add 0.7-0.8mm to each of them. This is the difference in thickness of the bearing and the wodden panels.

3. Scale the length of the spacer to these eight modified lengths and print them.

4. Print eight exemplaries of the open end caps (you may try to use the wodden end caps with hole you mounted on the inside of the wodden pannels, then you just need another two; if you have a direct drive which keeps two of the eight bearings in place from the outside, you don't even need any of the open end caps).

5. Remove the print head and all rods but leave the bearings in their holes.

6. Clean the rods (if your rods rather ressemble bananas, this might be a good time to replace them ;))

7. Dismount any endcaps which may be still mounted to the wodden frame.

8. Mount the open end caps on the outside of the wodden panels. Do not mount any open end cap on the inside!

9. Re-assemble the rods:

  a) Slide a rod in from one side

  b) Slide the first spacer over the rod on the inside of the bearing (make sure you take one with correct length for this position)

  c) Slide a pulley over the rod; don't forget the timing belt! It should look now like this:


  d) Slide the corresponding x/y block over the rod.

  e) Complete the 'sandwich' with the pulley on the opposite side and the corresponding spacer.

  f) Push the rod into the bearing on the opposite side.

10. Fix the rods by fixing the pulleys and re-mount the print head.


And then, enjoy friction-less and accurate printing... ;)



Edited by Guest
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I printed and installed them instantly when I saw your design on YM - I really recommend it to everyone ;)

These are the dimensions i use now, i hope that helps someone (at least as a first orientation):

back: 35mm

front: 14mm

right: 19mm

left: 19mm

But... My rods are driven directly, therefore your back spacers may differ.

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I will raise my priority on making these things for my printer as well. Last weekend I was printing and I heard some new sounds coming from the printer and I found out that one of the axis on one side was loose. The object was a little bit effected but while continuing printing I re positioned the Y axis and got the endcap on one side fixed again. The print was saved but I really need to implement this modification to get this solved.

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I made some "C" shaped spacers. They seem to work great and you don't have to take much apart to install (I did have to loosen a bearing on one side to squeeze the second spacer in.)

Sorry, I didn't publish them just because I am not using the normal sprockets and didn't want to confuse anyone. They are pretty simple to make.


Edited by Guest

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Ha I did the modification while I had to replace my xy blocks. Ofcause when I measured my distances I made a 3mm error so when I installed the cilinders there was too much room:( Nothing a hobbiest can't fix but I could not print at time since my printer was missing some xy parts... So I drilled some 8mm holes in some rings to fill the gap. Now everything fits nicely.


I upgraded to the mooncactus xy blocks and they do their job well




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