by RetireeJay » 2018-Apr-Mon-19-Apr
Are the blue sample and the gray sample oriented the same way, i.e. is the base at the right in both examples? And are both of these samples taken after all your rebuilding work?
I ask because although the pattern seems to repeat every 10 layers, it the samples are oriented the same way then the first skip in the gray sample is after layer 4 whereas the first skip in the blue sample is after layer 10. If both samples are oriented the same way, then this tells us that the "repeatable" pattern of a glitch every 10 layers has a non-repeatable initiation. That, in turn, seems to suggest that the problem is not a mechanical interference with the vertical motion in Z. However, it could be related to rotation of the Z screw.
Does your bed have more slope to it than it used to, causing the Z axis to move more and more to compensate (I'm assuming the Simple has a probe and does "bed leveling".)?
It might be worthwhile to check the coupling between the Z motor and your Z screw. Are the grub screws or other fastening components firmly seated, with the motor's coupling seated against the flat on the motor shaft? Is there anything interfering with smooth rotation of the coupling through a full 360 degrees of turning, like friction against a stationary object or a projection that runs into a stationary object? There should be at least a little clearance between the coupling and the motor body.
What kind of thread is on the Z screws on your Simple Metal? Have you changed (or verified) the steps per millimeter? Does the total height of your test pieces match what you specified in the model?
Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3, upgraded to MK3S