Accuracy problem

Hi, i finished my printer today and already printed a little part. Everything worked well, had some minor problems (1 wrong bolt, 2 missing nuts, hate to solder such small parts,…) Dokumentation is very good.

The Extruder Motor didn’t manage to feed enough Filament, i rised the temperature to 205°c (for PLA) and it works better now.

But there is one problem i have. When i measured the printed part, every outer dimension was 0,4 mm to large, every inner dimension was 0,4mm to small (the height is of course OK).

There are two possibilities i can imagine:

  • To much material.
  • A little warp between the layers, for example one layer is 0,25mm more left, another one is 0.25mm more to the right.

What can i do? Is there a possibility to add some Offset (in slic3r), so that the walls of the part are printed a little smaller?


Are you measuring on the bottom layers? these are always a bit to big.

You can enter a scaling factor in Repetier when you load an .stl file.

Hi, I dont think scaling will solve the Problem, making it smaller will make the inner dimensions even smaller. when I try to measure a single layer, the Dimension seems to be OK, maybe the layerd do not fit exactly. I try to post some Pictures, this will say more than words…

Hi here are the pics, I hope it works.

Hi, me again. Another idea: Could this be a problem with the z-axis. Th total height of the object is 15mm, the pitch of the M8-spindle is 1,25mm -> 15/1,25=12 which seems to be the number of the bulges or beads (dont know the right word). If the z-axis moves a bit less, the layer thickness will be less and there will be to much plastic, if it moves more the will be less plastic, resulting in a smaller diameter ? By the way, the spindle is wobbling a bit, i dont know how big is the effect.

I know I’m annoying, but see…

what can I do?

This seems a Z axis related problem. I also had problems with the Z axis because the threaded rod was bent, I had to level it carfuly. I also changed the mechanical design for the attachement of the rod to the motor.

Try this: Move the Z axis in manual mode in repetier and watch the Z motor. Does it wobble?

Hello 3dp,
yes i think ist a problem with the z-axis.
move the z-axis up and down (z-home) by manual control and i thingk you will se the z-stepper wobble.
jonas had postet this video

If you have this problem it is because the threaded Z rod has become warped. Because of this problem it will print thin layers than thicker layers then again thin layers, then thick, and so on giving you the Z banding you see.

You can remedy this problem by making sure the bottom of the Z motor cannot move (attach it to the frame) this will force the threaded rod straighter, the Z motor can handle the extra sideways stresses.


thanks for all your tips and hints. Aligned the threaded rod, fastend the z-Motor really hard to the Frame, put some grease to all rods. Results are much better now, toleranzes within 0.05 to 0.1 mm wich i can live with.

Thanks a lot again.