what would cause a shift change like this

what would cause a shift change like this

loose pulley?

just checked the set screws and there tight

maybe my belts slipping then

I just oiled it yesterday so i wouldn’t think that would be it. The print just finished and it got worse as it went on, kept shifting in the same direction.

Check you trimpots. Your Y-axis is heavy with that glass. Are you cooling your stepper drivers with a fan? If not, point a fan at them - it may help. But definitely check that you have Vref set corrrectly.

Intermittent lost steps maybe? Try turning down the max feed rate or acceleration a little and see if the problem changes or is eliminated.

The last time mine did something like that it was because one of the plastic, y-axis pulleys was rubbing on a supporting bolt, which occasionally stiffened the mechanics, causing a skip. Make sure you can move everything smoothly by hand.

I had problems like this from the beginning. In the end it whas the motor driver turned up too high, as i just bought a new more powerfull supply for the printer.

Just turn the pot on the motor driver to 0 and then gradually turn it up untill the motor is moving steady (even with higher speeds).

I’ve had this problem due to an overly heavy y bed combined with too high acceleration. Quickest way to check is turning down your x-y acceleration to, say 1000mm/s^2 and see if the problem stops. If it does, your options to resolve the issue will include:
-Increasing the current to your y stepper
-Decreasing the weight of your y bed assembly
-Keeping your acceleration values lower.

Also worth checking your y belt clamp to make sure the belt isn’t slipping there.

another thing to check is that the wires for your heated bed are not catching on anything as the Y axis moves back and forward.

Loose nozzle, missed steps, etc etc

Think i do need to check the trimpots because sometimes i hear a winding up noise then it goes away for a while. Then sometimes when the z-axis has to move a long distance it turns off for a bit and back on but most of the time it doesnt do that. Im not really sure how to set them correctly. I do know that i hear a high pitched winging noise when im printing.

Do you already have heatsinks and a fan on the stepper drivers? If they are on the edge of thermal overload protection they might drop out briefly.

only one stepper driver has sinks ive felt them and they all seem really cool not even hot. the only thing thats getting really hot is the mosfet for the hot bed

If they’re not hot your trimpots are too low. Ramps?

Ok ill have to turn them up then. The bad thing is when i turn them up a high pitched noise is comes from my motors


I’ve gotten something like that with intermittent communication problems, too. Mine were a combination of an almost bad USB cable and leaving Repetier-host open on the print visualization screen (clicking off onto any other tab fixed it).

Mine did that when the set screw on the y axis wasn’t on the flat part of the axle, so it slipped.