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aurik94
(@aurik94)
Active Member
X-axis sticking?

So today I started having problems with a lot of crashing issues.  In fact, the printer is now crashing when doing the 3x3 mesh bed leveling before a print.  It gets the first 4 points just fine, but when the head moves leftwards across the X-axis, it stops and makes the horrendous "the motor is moving but I'm not" noise.  So I went ahead and tried turning the printer off and tried moving the X-axis slowly by hand.  When I move it to the right, it moves nice and smooth.  When I move it to the left, I get an inch or two, and then the amount of resistance jumps significantly.  So it's definitely a hardware problem of some sort, but I'm not sure where to look.

This isn't a new build -- I've had this printer up and running for about 3 months now.  This IS a new problem though.

Any ideas as to what can be causing this?

Posted : 22/11/2019 12:38 am
rmm200
(@rmm200)
Noble Member
RE: X-axis sticking?

Loosten the drive wheel on the stepper so it spins freely.

Try your drag test again. Still binds, it is bearings. Either linear or idler. They are cheap.

No bind - stepper is likely culprit. Contact support Chat.

And don't forget to tighten the drive gear again.

Posted : 22/11/2019 12:41 am
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(@)
Illustrious Member
RE: X-axis sticking?

Loosen the extruder case screws near the X bearings. See if that allows easier movement.

Also - the bearings are not shipped with proper lubrication - the bearings need to be greased before installation onto the rods.  The shipping oil they do have evaporates once the bearings are removed from the seal bags the ship in.  If the bearings become dry, they will seize and destroy the rods.  If you did not pack the bearings, then add a few drops of a light machine oil on the rods, work the extruder and bed back and forth to get some oil inside the grease seals.  This is to stave off more damage until you get a chance to do it right.

This post was modified 2 years ago by --
Posted : 22/11/2019 12:43 am
aurik94
(@aurik94)
Active Member
Topic starter answered:
RE: X-axis sticking?
Posted by: @robert-rmm200

Loosten the drive wheel on the stepper so it spins freely.

Try your drag test again. Still binds, it is bearings. Either linear or idler. They are cheap.

No bind - stepper is likely culprit. Contact support Chat.

And don't forget to tighten the drive gear again.

Well, it's definitely the bearings.  Is this something I can order off Amazon, or do I need to order them directly from Prusa?

Posted : 22/11/2019 1:04 am
rmm200
(@rmm200)
Noble Member
RE: X-axis sticking?

Well first follow Tim's advise. Loosen the bearing mount on the extruder and see if that helps.

Lubricate your current bearings or the new ones.

LM8UU (double check that part number) bearings are bog standard. No advantage ordering from Prusa.

Check your rods for wear marks. Bad bearings cut grooves.

Oh - also - make sure you check your idler bearing. Easy to forget.

An example of a dozen bearings for under $10:

https://www.amazon.com/AUEAR-LM8UU-Linear-Bearing-Printer/dp/B07V6JZQ6F/ref=asc_df_B07V6JZQ6F/?tag=hyprod-20&linkCode=df0&hvadid=388767351524&hvpos=1o3&hvnetw=g&hvrand=7031421748455360795&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033152&hvtargid=pla-838212153575&psc=1&tag=&ref=&adgrpid=83520103830&hvpone=&hvptwo=&hvadid=388767351524&hvpos=1o3&hvnetw=g&hvrand=7031421748455360795&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033152&hvtargid=pla-838212153575

Not that I recommend those - I would get them from a 3D printer supply house.

This post was modified 2 years ago by rmm200
Posted : 22/11/2019 1:11 am
aurik94 liked
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(@)
Illustrious Member
RE: X-axis sticking?

If the rods have been scored, rods and bearings are needed.  If the rods are not scored, the bearings might be salvageable.   Try the oil trick, even motor oil is worth a shot.  Many folk have used oil to improve friction - some even use oil routinely and forego grease. 

If you do oil, oil regularly, and protect the print sheet with cardboard when dripping on the oil to avoid a cleanup mess.

 

When my OEM bearing went dry and scored the rods, I bought Misumi LMU8's directly from Misumi... greased them and put them on the OEM rods, even though the rods were lightly scored.  They worked for quite a while, much longer than the OEM's took to wear out.  

 

This post was modified 2 years ago by --
Posted : 22/11/2019 1:15 am
aurik94 liked
aurik94
(@aurik94)
Active Member
Topic starter answered:
RE: X-axis sticking?
Posted by: @tim-m30

If the rods have been scored, rods and bearings are needed.  If the rods are not scored, the bearings might be salvageable.   Try the oil trick, even motor oil is worth a shot.  Many folk have used oil to improve friction - some even use oil routinely and forego grease. 

If you do oil, oil regularly, and protect the print sheet with cardboard when dripping on the oil to avoid a cleanup mess.

 

When my OEM bearing went dry and scored the rods, I bought Misumi LMU8's directly from Misumi... greased them and put them on the OEM rods, even though the rods were lightly scored.  They worked for quite a while, much longer than the OEM's took to wear out.  

 

So I went ahead and dipped a q-tip in some motor oil wiped a bit on the x-axis, ran the extruder over it a few times, and then wiped it off with a clean paper towel, and miraculously things started working immediately.  I've ordered an extra set of bearings in the event that they die on me, but the motor oil trick seems to have worked.  Thanks!!

Posted : 25/11/2019 4:14 pm
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