Z-Axis threaded rods not centered on Z-axis-top part
 
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julio.m
(@julio-m)
New Member
Z-Axis threaded rods not centered on Z-axis-top part

Hello,
I have assembled MK2s Kit two weeks and I have been printing pretty good, however I have noticed Z-Axis threaded rod (right side) is not centered on Z-axis-top hole, In fact, it is touching quite hard the edge of the printed opening hole (frame side) when the X axis is close to the heated bed.

This situation seems not to be affecting the printing quality, however, vibrations are causing a loud noise.
I was about to design and print something like that:

https://www.stlfinder.com/model/don-t-use-prusa-i3-mk2-z-threaded-rod-center-cap-BD4Q79Cf/7579186

But I saw the bad comments.

I have followed carefully instructions and every screw is tighten.
Z-Axis threaded rod does not look bend, just not aligned.

Posted : 16/07/2017 6:13 pm
MPJ
 MPJ
(@mpj)
Active Member
Re: Z-Axis threaded rods not centered on Z-axis-top part

One way to adjust this is to loosen the black top nut on the threaded rod. There is a bit of wiggle room with these. I moved the rod to the center and then tighten the bolts up. That might be all you need, but if hitting a lot, then could be how the motor is mounted.

Posted : 16/07/2017 6:31 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Z-Axis threaded rods not centered on Z-axis-top part

there are two screws on the end of the rods of the Xaxis, (rIGHT HAND SIDE)

THEY MAY BE TOO TIGHT.
THEY SHOULD JUST TOUCH THE END OF THE RODS.

THEY ARENOTMEAN TTO TENSION THE x AXIS BELT.
REGARDS jOAN

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 16/07/2017 8:44 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Z-Axis threaded rods not centered on Z-axis-top part

Sorry for shouting...

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 16/07/2017 8:44 pm
julio.m
(@julio-m)
New Member
Topic starter answered:
Re: Z-Axis threaded rods not centered on Z-axis-top part

Thank you for your suggestions guys, but the problem persist...
here is a video of it

Posted : 18/07/2017 4:42 pm
AJS
 AJS
(@ajs)
Noble Member
Re: Z-Axis threaded rods not centered on Z-axis-top part

Shim the motor mount?

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 19/07/2017 1:57 am
cory.w
(@cory-w)
Estimable Member
Re: Z-Axis threaded rods not centered on Z-axis-top part

Ive had this problem as well since I got the printer. Rebuilt a few times and always looks the same. Even with new holders on the top. Let me know if you figure out a solution. Doesnt appear to cause issues but maybe since I've always had it that way I dont know any different. They do look fine though when Z axis is all the way up at least.

Posted : 20/07/2017 1:59 am
ABW
 ABW
(@abw)
New Member
Re: Z-Axis threaded rods not centered on Z-axis-top part

I had the same issue and, but it turned out to be easy to fix in my case. Had me worried for a bit though...

The symptom was that when the Z axis was lowered towards the bottom of the frame, the threaded rod was leaning against the top part, but when the Z axis was at the top of the frame, it was fine.

The key is that, next to the Z axis bearings, at the top of the Z assembly, there's a black mounting ring (called the trapezoid motor mount in the assembly manual, step 8, Z Axis assembly in my manual v2.03). It was necessary to adjust this ring. Here's what I did to fix it.

  • Turn on the printer and Go to Settings > Move Axis > Move Z and lower it as far as you can. You should now see the threaded rod is non-centered in the top part.

  • Loosen the 2 bolts holding the mounting ring on (the black "trapezoid motor mount").

  • Gently center the rod, and then while you hold it centered, tighten both bolts, so that when you let go, it stays in the center.

  • Test the fix, by going into Settings > Move Axis > Move Z all the way up and down again. It should not be touching the top part at any time.
  • You may need to do this on both sides if necessary.

    Good luck, hope this helps.

    Posted : 02/09/2017 6:52 pm
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