Yet and another Y axis layer shift post. Help please!
So I'm pulling my hair out. I've been experiencing a Y-layer shift lately. Not every print, maybe every 3-5 prints. I can't diagnose it myself.
Printer history:
- The printer has a fair amount of hours on it. It's not plugged in, but I think it's around 180 days (I'll update the post when I plug it back in).
- I regularly do full maintenance every 200-300 hours, including cleaning and lubricating the smooth rods
- I'm running the 3D Que AutoFarm on this printer. The problem is more pronounced when the kit is installed and angled but still exists when the printer is on a level surface.
Symptoms:
- Layer shift happens pretty consistently after the first 5-7 layers
- The shift is always in the same direction (the print shifts closer to the back of the bed)
- The distance of the shift is pretty consistent, about 1-2cm
Things I've inspected with the belt still attached:
- Smooth rods are fine. No grooves.
- The smooth rods are not overly lubricated.
- The U bolts for the bearings are not loose or overly tight
- The bed slides smoothly with no binding spots.
I removed the belt and inspected the following:
- The Stepper motor spins freely
- The idler spins freely
- The belt has been visually inspected. It seems fine to me.
- The bed glides on the rails perfectly smooth.
Belt tension:
- I've set the tension according to the Prusa assembly manual (grabbing the stepper motor with pliers and pushing on the plate; the belt does not flex)
- I've checked that tension against the GT2 Belt tension gauge, and it's smack dead in the middle. (Granted, I printed this gauge a long while ago, so time and humidity might have altered its effectiveness.
- Plucking the belt makes a nice tone
I seriously don't know what to do or try next. Maybe replacing the belt because it has a flaw that I can see/feel?
RE: Yet and another Y axis layer shift post. Help please!
The one thing that I do not see listed in your remediation attempts so far, is checking the screws on the Y-motor pulley. If they are loose, the pulley can have some rotational play on the shaft which will usually show up as layer shift. See step 28 of the Y-Axis Assembly instructions.
The same issue can appear on the X-axis too, so it is worth checking both of those during your routine maintenance.
I hope that helps.
Cheers,
Tim
RE:
Thank you for the reply.
I had missed that I checked the set screws on the motor pully. When the best was removed, I loosened both screws and tightened them in the proper order.
I'll also check the X axis pully screws.
I broke it all down again and cleaned and re-lubed the bearings. I found a tiny, nonlinear scar on one of the rods. I made sure to align that spot to not come in contact with the bearing surfaces.
So far I've gotten 6 or 7 after the Y axis second breakdown and rebuild. So far so good. If anything print quality seems a bit better as well.
RE: Yet and another Y axis layer shift post. Help please!
Looks like that has sorted it!
Cheers,
Tim