3D Printing Prusa Mk3 Layer Shifting

I have a Prusa Mk3 that arrived in Jul 2018 and have printed a lot of PLA, PETG, Carbon PETG, etc and have had no real problems until about 3 weeks ago. It started as a minor layer shift on the Y axis on several prints and now it is every print at about 4-6% completion. There is a loud grinding noise and then the layer shift. I use Simplify 3D. I have changed a lot of settings as a lot of youtube videos suggest and still nothing. Belts are tight and today I just changed the bearing to the Igus Drylin bearings on the Y axis. Still didn't resolve the problem. I changed the orientation of the printed object 90 degrees and it printed out not great but with NO layer separation.
Any suggestions? Comments?

Check out the screws in the motor couplers and pulleys. It sounds like you are dropping steps causing the shift. It's also possible that you are getting something binding at some Z heights. That one would be more difficult to to troubleshoot, so hopefully it's just a loose set screw.

Sounds like your stepper motor is stalling. Could be motor driver, binding as suggested or motor.

Try printing at half speed as an experiment. Where ALL motions are half speed. From the pics it looks like the stalling isn't occurring during printing (when it is slower) but between layers when the motion is fast.

jderimig said:

Sounds like your stepper motor is stalling. Could be motor driver, binding as suggested or motor.

Try printing at half speed as an experiment. Where ALL motions are half speed. From the pics it looks like the stalling isn't occurring during printing (when it is slower) but between layers when the motion is fast.

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My normal speed is 4800mm/min. I am down to 600mm/min and still no fix. I read that someone slowed the x/y movement speed to 500 mm/min and I am currently trying that. It normally starts layer shifting with a grinding clunking noise at 4-6% completion.
The motor does not appear to be excessively hot but may be damaged internally.

Is this happening on all your prints , or just this one file? I wonder if you have a bug in your program around the 5 percent Mark. The grinding / binding may be caused by the machine trying to be in 2 places at once .

3stoogesrocketry said:

Is this happening on all your prints , or just this one file? I wonder if you have a bug in your program around the 5 percent Mark. The grinding / binding may be caused by the machine trying to be in 2 places at once .

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I have has some files do this. I had to reslice a few to avoid it.

Then I found this: https://forums.matterhackers.com/to...MI_LKswdH33wIVirbICh0k5wwNEAAYASAAEgLoN_D_BwE

I have resliced several times with Simplify 3D. Then I tried Cura and Slic3r Prusa. Same Problem. In my above comment the last thing I did was reduce the X/Y movement speed to 500mm/min. It is currently at 18% completion and NO layer shift BUT it will take about 9 hours (3 hours longer than normal) to complete.

Good luck. I had a 2-day print that shifted on the last 10 layers. I was ticked.

35% now and just tiny micro layer shifts. Not enough to complain about. Just doesn't look as pretty as the other stuff.

This is a far fetched question but can a loose 'X-Axis' belt affect the 'Y-Axis' print? And visa-versa?

Most layer shifts are due to belt being to loose or the set screw being to lose and letting the spindle skip.
Once print is completed go into setting and post your belt numbers 260-280 is the sweet spot for prusa belts, to loose and they will jump to tight and the "teeth" get stretched and can also jump.

Locksmith said:

Once print is completed go into setting and post your belt numbers 260-280 is the sweet spot for prusa belts.

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Where did you get those numbers 260-280 are the sweet spot? Prusa tech service told me anywhere from 240+-40 or 200-280 is ideal. Mine is 232 for the Y and 262 for the X. Still I have Y axis shifts.

I don’t have a 3D printer, but do have a couple robotic workstations for weighing samples in the lab. As they age, the stepper motor driver current needs to be tweaked up from time to time. That’s a pot on the driver board for us.

The symptoms sound really similar to yours - the motor makes an occasional loud grinding noise, the arm stutters, and is off of step count afterwards.

gorillamotors said:

Where did you get those numbers 260-280 are the sweet spot? Prusa tech service told me anywhere from 240+-40 or 200-280 is ideal. Mine is 232 for the Y and 262 for the X. Still I have Y axis shifts.

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Its from the Prusa support group, here is a guide from Chris if you dont know who he is basically the Yoda of MK3
https://prusacommunity.com/your-belt-status-and-you/
in short he says 255-280

gorillamotors said:

This is a far fetched question but can a loose 'X-Axis' belt affect the 'Y-Axis' print? And visa-versa?

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Absolutely.

Locksmith said:

Its from the Prusa support group, here is a guide from Chris if you dont know who he is basically the Yoda of MK3
https://prusacommunity.com/your-belt-status-and-you/
in short he says 255-280

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Thanks. I have never seen that.

Locksmith said:

Its from the Prusa support group, here is a guide from Chris if you dont know who he is basically the Yoda of MK3
https://prusacommunity.com/your-belt-status-and-you/
in short he says 255-280

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I added links to the tips.

gorillamotors said:

The motor does not appear to be excessively hot but may be damaged internally.

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Steppers run at constant current. If the motor is not that hot then you can safely bump up the current.

jderimig said:

Steppers run at constant current. If the motor is not that hot then you can safely bump up the current.

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How do I do this?

Depends on your electronics, if your stepper motor drivers have a pot then you can adjust it. If the current is set with a fixed resistor then you can't.

Also, check for any globbing of the 3d print material, this could drag as the head goes by and eventually result in a position error and layer shift.

I printed for 6 months with my MK3 and then suddenly had layer shifts in both x-y on every print. Checked belts and all the blog suggestions. I think the problem may have been that the heat block was sort of getting loose and wobbly over time. I replaced the heat block with a copper heat block, changed the thermistor to a PT100 sensor and amp, and built an enclosure. Between the 3 sets of changes, no more layer shifts (but I don't know which if the 3 was the fix, or if some combination fixed it).

When winter came, and the ambient basement temp dropped to 60, I had lots of problems, namely prints not sticking to the surface. The enclosed helped a lot.

curtisheisey said:

I replaced the heat block with a copper heat block, changed the thermistor to a PT100 sensor and amp

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What code in the firmware did you change to allow the use of the PT100 and amp?

gorillamotors said:

What code in the firmware did you change to allow the use of the PT100 and amp?

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Check out my post in "Prusa Mods" https://www.rocketryforum.com/threads/prusa-mods.150336/ Post #13. There is one line in a header file that you have to uncomment and compile.

I had this issue when I first started using my Qidi printer. I had it on one of those plastic cafeteria tables that you get at Costco. The table top on those can slide back and forth about 1/2". I moved the printer to a very solid work table and haven't had the problem since. has anyone had a similar experience?

I have a cr10s pro v2, I'm new to 3d printing so I'm struggling with this problem. I have a layer shifting problem occurring when a print is roughly above z-100. imprinting some large parts and they seem to always fail at the very end. when I print smaller objects it's perfect, but after z100 it seems to just fail. I've checked the z-axis leveling, leveled the bed. I've checked the XYZ axis to see if they were skipping, and all belts are correct, i can't figure this out, any help?