Strange Problem - Layer shift only on top and bottom layers
I have printed two 25mm calibration cubes on opposite sides of the build plate. The cube at the back right seems to print well. The cube at the front left has the bottom and the top layer shifted on the x-axis just a little. It's the same model printed at the same time. I have lubricated all the rods and z-screws, z-calibrated and tried different temperatures. At a loss. Belt problem maybe? Any help appreciated.
RE: Strange Problem - Layer shift only on top and bottom layers
the layer shift, appears to be the same distance to the right at the bottom and the left at the top.
equal layer shifts in opposite directions, are odd,
Perhaps the grub screws on the toothed wheel on the motor shaft, are loose... there should be one screw fastened firmly against the flat on the motor shaft, and the other screw should be firmly fastened against the the curved side of the shaft.
If the screws are loose, the toothed wheel moves a little in one direction when obstructed, and than the same amount in the opposite direction when it hits an obstruction from the other side...
good luck,
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Strange Problem - Layer shift only on top and bottom layers
Thanks for the reply @JoanTabb. It's a good suggestion. I checked the grub screws and the belt tensions. I can't detect any movement or slop. I also checked the gcode and the perimeters start at the same x-y coords on each layer, so it's not a slicing problem. I'm now testing just the left cube to see if it prints correctly when the gantry doesn't move back and forth.
RE: Strange Problem - Layer shift only on top and bottom layers
The print turned out much better when only printing one cube, although it printed a lot slower because of the minimum layer time. I'm going to play around with acceleration and jerk settings.
RE: Strange Problem - Layer shift only on top and bottom layers
I slowed down acceleration from 1000 to 700 and lowered jerk from 8 to 7. The layer shifting seems more random now on both cubes. Not sure what else to do. Stepper motor problem?
