Interesting Simplify3D Slicing Issue (Shifted Layers)

[BDub]

The crowbar on the left in both pictures has shifted to the right(first image)/left(second image) in the middle at layer 28. You won't see it in the preview, but it prints that way every time. I tried all kinds of speed decreases, even modifying the travel acceleration and xyjerk setting to no avail! After I simply rotated the part -90 instead of 90, it sliced and printed perfectly.




Here are the crowbar files:
Sketchup
STL
Bad Slice
Good Slice

How to reproduce:
Import into Simplify 3D and rotate on Z axis 90 degrees for the bad slice.
Import into Simplify 3D and rotate on Z axis -90 degrees for the good slice.

If anyone is a GCODE wizard and can tell me what's gone wrong at layer 28, please let me know

[CompoundCarl]

I looked through that whole "bad" gcode file, and I don't see anything wrong with it. It definitely isn't the gcode coordinates in the file that are causing the shifting.

Perhaps it's just coincidence or it's something with the firmware or the machine that happens in a similar location each time.

Watch it really closely when it's printing that layer next time. Maybe you can spot what happens.

Either way, the gcode you posted looks perfectly fine and correct

[BDub]

Thanks for looking through the code. The strange thing is lowering the overall speeds of everything from 60mm/s max to 40mm/s max did not change anything. I also tried lowering the piece into the bed by -4mm so that the problem would occur at layer 8 instead of layer 28, and it does every time. I think I printed 7 of these all with the same results and changing the slicing settings every time. I also printed several shorter pieces of the middle hex portion of the crowbar and they printed fine. I watched these all VERY closely trying to figure out when the shift happens exactly, and I never ended up seeing exactly when.. just the layer at which this happens. Only when I finally flipped the part before slicing did it fix the problem. Maybe I should try 20 or 10mm/s and see if it still does it. This is the first time I've seen shifted layers like this on my printer, printing hundreds of things with 3 different slicers.

[BDub]

I originally posted this issue on my own forum over here:
http://zeeproforums.technobly.com/t/int ... layers/391

Since then there have been updates... but I'm still stumped on what's wrong.

[BDub]

Problem solved http://zeeproforums.technobly.com/t/int ... ers/391/13

Turns out the Y-endstop was being "kissed" right on the center layer of the part... how lucky!! See above for pictures and other thoughts on how to make Simplify3D better (i.e. idiot proof )