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Problem with 90 degrees angles  

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vladimir.aubrecht@me.com
(@vladimir-aubrechtme-com)
Active Member
Problem with 90 degrees angles

Hi, I just got my Průša XL, but since first print I started to notice, something is off…

 

I managed to identify, that printer is losing accuracy with change of Z axe for some reason. Specifically, I start the print and higher it gets, dimensions in X and Y are more and more off…

I tried to print calibration cube of 20x20x20 mm, it has exactly this dimesion on one side in Z axe, but in another one it has 20.1x20.1x20 mm.

I tried to google the problem, but cannot find anything and don’t know even how to name problem properly… 

 

I also tried to calibrate belts with using Průša Belt app, but no luck with that.

Anybody any clue what to do with it? Thanks!

Posted : 01/10/2023 8:36 pm
jF
 jF
(@jf-2)
Trusted Member
RE:

but in another one it has 20.1x20.1x20 mm.

That's actually a pretty good result...

You should try the homing tower test here instead

https://help.prusa3d.com/article/adjusting-belt-tension-xl_401793

Also, check that the motor pully on the x/y belt is not loose, I had an issue with one of them being completely loose and I'm pretty sure it would have manifested as your exact issue if was just barely loose compared to just crashing the tool in my case.

This post was modified 5 months ago 2 times by jF
Posted : 03/10/2023 1:34 am
vladimir.aubrecht@me.com
(@vladimir-aubrechtme-com)
Active Member
Topic starter answered:
RE: Problem with 90 degrees angles

Thank you for pointers! 😊 Unfortunately no improvement, but few new discoveries … 😊

I checked all motors and they hold very well. Also I tried to print 70% of the tower and no accuracy / layer shifting issues pop up there (see photo). Thou what is interesting is, that the dimensions of the tower are identical in any point of Z axe even thou it was much taller then calibration cube or the main model I am trying to print (keyboard case I designed, there should be right angle between walls and base of case, but I can see that it’s actually getting tighter closer to base, so angle is more something like 85 degrees there - it’s visibly not a straight wall and it should be).

Also starting to thing problem could be somehow related to stringing problem I have. Originally I did not put much attention to it as considered it less important, but basically everything is extremely stringing… Any model I am printing, with any material (PLA or PETG), even when it’s just freshly unpacked Prusament printed with Prusament profile in slicer.

I was watching the extruder and it seems that it’s oozing when traveling. During the traveling it manage to ooze 3-5 mm string and that one typically end up as a string. I tried to polish Prusament profiles in slicer, but got to conclusion that there is some real problem there as it was stringing even when I printed PETG on 215 C (much less, but I started to hit problems with underextrusions and considering that temperature is already too low, I did not consider it right way…)

Any more ideas? 😊 

Posted : 04/10/2023 11:34 pm
vladimir.aubrecht@me.com
(@vladimir-aubrechtme-com)
Active Member
Topic starter answered:
RE: Problem with 90 degrees angles

Forgot to mention, I printed also temperature tower and stringing was everywhere. Lowest temperature (220C) looked best, that’s why I followed up with 215 C for PETG.

Posted : 04/10/2023 11:50 pm
vladimir.aubrecht@me.com
(@vladimir-aubrechtme-com)
Active Member
Topic starter answered:
RE: Problem with 90 degrees angles

I finally managed to solve the issue with help of Průša support (btw they were great, fast, helpful and we had nice communication). There was some problem with hotend (probably thermistor). Průša provided me new one and it works without any issues now 😊 

Posted : 20/10/2023 12:56 am
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