X-Belt Tension Adjustment  

Re: X-Belt Tension Adjustment

You got it mostly right. Read step 18 of the Z-Axis assembly in the manual carefully ( http://manual.prusa3d.com/Guide/4.+Z-axis+assembly/509?lang=en )

The angled bolt is the tensioner - slightly loosen the three motor bolts and then turn that tensioner bolt in until the belt reaches the designated tightness. If turning this bolt all the way in doesn't give you the desire tightness, you have to go back to step 13 and move the belt in one tooth to make it 'shorter'. Then redo the steps back to step 18, and give it another shot. Once you get the belt tension correct, tight the three motor bolts down to "lock it in".

Re: X-Belt Tension Adjustment

Thanks for the help. Had to move the belt 3 teeth. The tensioner bolt adjustment seems to have very little effect.

Re: X-Belt Tension Adjustment

Thanks for the help. Had to move the belt 3 teeth. The tensioner bolt adjustment seems to have very little effect.

If you read the comments I left on step 18 you'll see I broke that part trying to tighten it. I really don't know if that adjustment does ANYTHING! I waited two weeks for a replacement part that I purchased because I had the kit.
I've since printed replacement parts in case anything else breaks.

Re: X-Belt Tension Adjustment

It absolutely does change the tension, provided you set things up right. If you loosen the three motor bolts and pull the motor toward the extruder, then set the belt in the x-carriage such that it is reasonably taut. Now if you screw the tensioner bolt in, it slowly rotates the motor away from the extruder, tightening the belt as you go. You don't have much movement- so it's critical you get close with the belt in the x-carriage first.

Re: X-Belt Tension Adjustment

Thanks for the help. Had to move the belt 3 teeth. The tensioner bolt adjustment seems to have very little effect.

It does have one effect: it boogers up the screw it is pushing up against (one of the 3 screws attaching the motor). Like many things MK3, one wonders "how did this make it past the first meeting?"...

Re: X-Belt Tension Adjustment

It absolutely does change the tension, provided you set things up right. If you loosen the three motor bolts and pull the motor toward the extruder, then set the belt in the x-carriage such that it is reasonably taut. Now if you screw the tensioner bolt in, it slowly rotates the motor away from the extruder, tightening the belt as you go. You don't have much movement- so it's critical you get close with the belt in the x-carriage first.

So you're saying it's not completely useless, just next to useless?

Re: X-Belt Tension Adjustment

Didn't say that at all. Take what you will from it I guess.

Re: X-Belt Tension Adjustment

I needed (still need?) to adjust the X belt that was in 281. After going all the way I could go by screwing that screw before I break the plastic .... I went down to ... chan chan ... 277. Not much of a gain. Unless I did this wrong. The screw (facing forward) that sits on the top left corner is now pushed all the way to the left . Not much benefit but at least I'm now "in range".

This was a pre-optimization since I was not having issues. If I run into issues due to not having the X belt tight enough then I will need to play with the belt behind the extruder. Hope I can avoid that.

Re: X-Belt Tension Adjustment

For Gaston : in the "User Manual for 3Dprinters" at chap 13.4 Loose X- and/or Y-axis belts it say =>
values 240 +- 40 are good ; so for you it is near. Don't touch to adjust.
Note : low value correspond to high tension, high value to less tension of the belt

Re: X-Belt Tension Adjustment

For Gaston : in the "User Manual for 3Dprinters" at chap 13.4 Loose X- and/or Y-axis belts it say =>
values 240 +- 40 are good ; so for you it is near. Don't touch to adjust.
Note : low value correspond to high tension, high value to less tension of the belt

Totally agree with this, but you should know that Prusa support is telling people (in email) they need to get closer to 240. I know this because they told me this. Because the belt tension estimate is very inaccurate, this led to a situation where I tightened the belts to the point that a plastic part was damaged.

Re: X-Belt Tension Adjustment

Be careful with trusting the belt status indicator. It can show you complete rubbish. I would suggest tensioning by feel.

Re: X-Belt Tension Adjustment

For newbies like me, can someone post a video showing what to expect as tension? Sound would help. Pressing belt not so much since I cannot see force I guess. Sound will show bouncing/vibrations. Thanks

As I said, I’ll leave x belt as is unless I run into issues.

Re: X-Belt Tension Adjustment

For newbies like me, can someone post a video showing what to expect as tension? Sound would help. Pressing belt not so much since I cannot see force I guess. Sound will show bouncing/vibrations. Thanks

As I said, I’ll leave x belt as is unless I run into issues.

E string of a bass guitar? mine sounds closer to G 😀

Re: X-Belt Tension Adjustment

The audio is not great (recorded with phone)
https://www.dropbox.com/s/1xws0w3nqwdzx82/VID_20180523_120638.mp4?dl=0

Re: X-Belt Tension Adjustment

Thanks. My Y sounds close to that. They sound very different from Toms video though. I can print just fine so no more tuning for now and instead more printing. 😎