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Single Layer X-Shift  

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Yowzilla
(@yowzilla)
Member
Single Layer X-Shift

 

I have one of my two MK3S+ printers shifting in X-axis at random heights and at times not at all.    I spected a bad stepper motor and swapped the steppers but the issue remained.  Also with swap I did NOT mess with grub screws in shaft.    This printer has printed 100's of this same part with same code on SD card for over a year.

The shift remains after the following:

X-Axis stepper change

Lubrication of all rails 

Re adjustment of X-axis belt

I have been using Prusa printers for the past 4 years and am stumped with this one......

 

Posted : 31/05/2023 7:02 pm
Diem
 Diem
(@diem)
Illustrious Member

Hmmmm. The odd minor uneven layer suggests there is a belt problem as you suspected.

Have you tried:

https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

It MUST be printed in Prusament PETG or the spring tension will be wrong.

Cheerio,

Posted : 31/05/2023 10:57 pm
Yowzilla
(@yowzilla)
Member
Topic starter answered:
RE: Single Layer X-Shift

Now you have me thinking @Diem.   Both my Prusa printers have been non-stop for years.   Might be time to replace the BELTS!!   I will try that.

Posted : 01/06/2023 6:35 pm
Diem
 Diem
(@diem)
Illustrious Member

Get the tensions right first.  If the belts begin to fail and don't maintain the tension, then it's time to replace.

Cheerio,

Posted : 01/06/2023 10:50 pm
Yowzilla
(@yowzilla)
Member
Topic starter answered:
RE: Single Layer X-Shift

Again.   I have been running printers and this print for years and this is the first real challenge to address print quality.     I can only provide observations but print quality seems to be on a negative curve.  The direct link in the mechanical chain is belts.   Tensions are in zone from resistance values in control screens.     It feels logical that at 20,000 miles it is time to change the belts.   

Posted : 02/06/2023 1:59 am
Diem
 Diem
(@diem)
Illustrious Member

The belt tension figure is a measure of the resistance felt by the stepper when moving the axis. On a correctly set up machine this does equate, roughly, to belt tension.

But other things can affect mechanical resistance.

First, with the power off, move the axis by hand; is it smooth? Does the resistance stay the same over the whole range?

You have eliminated the smooth rods - and linear bearings?  Check the idler pulley is not clogged, out of line, or damaged (loosen the belt and try turning it with your fingertip, is it smooth?)

I would be surprised if the belts were failing UNLESS the idler has been out of line for a long time but it won't hurt to change them.

Cheerio,

Posted : 02/06/2023 12:15 pm
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