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X axis belt too tight  

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Ken
 Ken
(@ken-5)
Active Member
X axis belt too tight

I just finished assembling my new MK3S, and other than a few minor stumbles (all my fault, of course), everything is working well. I’ve done several prints, some off the web and some of my own design, and I’m pretty happy with the result. That said, I’m wondering about the X axis belt tensioning. Running the belt test, the Y axis shows 280, which I’m thinking is fine (should be between 240 and 300?). The X axis tension, on the other hand, seems to be a bit too tight with a value of 139-146 If this is indeed too tight, then the obvious solution would be to disassemble the E axis back and loosen the belt. Although I think I can do this with no issue, it does look to be a bit of a pain to do considering all the wiring is in place and nicely tied up.

So, with an X axis belt tension of 139-146, is it worthwhile taking the time and effort to tear into things and loosen the belt? If my prints look fine now (to my untrained eye), what’s the down side of a belt that is too tight? Also, will I have to go through a full calibration and live Z adjust after doing this?

Thanks in advance for any tips…

 - Ken

Posted : 29/07/2020 6:54 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: X axis belt too tight
Posted by: @macbates

I just finished assembling my new MK3S, and other than a few minor stumbles (all my fault, of course), everything is working well. I’ve done several prints, some off the web and some of my own design, and I’m pretty happy with the result. That said, I’m wondering about the X axis belt tensioning. Running the belt test, the Y axis shows 280, which I’m thinking is fine (should be between 240 and 300?). The X axis tension, on the other hand, seems to be a bit too tight with a value of 139-146 If this is indeed too tight, then the obvious solution would be to disassemble the E axis back and loosen the belt. Although I think I can do this with no issue, it does look to be a bit of a pain to do considering all the wiring is in place and nicely tied up.

So, with an X axis belt tension of 139-146, is it worthwhile taking the time and effort to tear into things and loosen the belt? If my prints look fine now (to my untrained eye), what’s the down side of a belt that is too tight? Also, will I have to go through a full calibration and live Z adjust after doing this?

Thanks in advance for any tips…

 - Ken

Hello and welcome here in the Prusaforum,

Which firmware do you use? In 3.9.0 the values seem to have changed compared to 3.8.1. For fine tuning see Step54 in this manual: https://help.prusa3d.com/en/guide/5-e-axis-assembly_28536/#30816

also here: https://help.prusa3d.com/en/article/adjusting-belt-tension-mk3-s_112380

If the printer works properly (without layershifts or other errors), I would not change anything for the time being.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 29/07/2020 7:10 pm
Ken
 Ken
(@ken-5)
Active Member
Topic starter answered:
RE: X axis belt too tight

@karl-herbert

Thanks for the quick response, Karl. The motor adjustment didn't help since I suspect the belt was way too tight. I didn't know about the second link, and that adjustment procedure doesn't look to be as difficult as I had imagined. I'll wait a few more days to see how the printing goes, and then maybe tackle the belt loosening procedure you pointed me to.

Thanks again,

 - Ken

Posted : 29/07/2020 7:16 pm
Ken
 Ken
(@ken-5)
Active Member
Topic starter answered:
RE: X axis belt too tight

The belt adjustment was actually quite easy. It seems very loose to me, and the lower portion of the belt rests on the bottom slot of the extruder, but the belt test shows 246, which is within the stated limits. Good to go!

 - Ken

Posted : 29/07/2020 11:04 pm
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