UM2 skipping multiple layers in a print?

[fourier 2]

For a reason I can't determine, this has happened a couple times already. I come to check in on a print, and the print is perfect up to a point, at which point it's spaghetti, and the buildplate is WAY lower (like sometimes nearly a centimeter) than it's supposed to be. I have no idea what's causing it. I've checked the g-code thoroughly in multiple viewers and the slicer itself (Simplify3D) and there doesn't seem to be any such issue in the g-code.

I am printing from SD card, by the way. The printer's only about a week old, so I am really hoping it's not something hardware related.

Edit: it's a plain UM2 by the way.

Edited December 11, 2015 by Guest

[gr5 2,167]

There's several possibilities. For example maybe it stopped extruding for 20 minutes and started back up. Much more likely though the Z axis slid down. You don't say which printer but the metal beds on the UMO+ and UM2 and UM2ext are quite heavy and if the Z stepper loses power it's common for the bed to slide down a bit and the stepper driver will cut power if it gets too hot. This has been a problem for many people with boards made in the last year and the solution is to lower the Z stepper current down to 1000ma. You should be able to set it from the front panel but will lose the setting on power cycle unless you save with I believe an M500. Try it first and if this fixes the problem ask how to save the setting permanently.

[fourier 2]

Yeah I mentioned it's a UM2 in the topic, but didn't in the post.

I will try lowering the power. I'm familiar with Mxxx codes (I also have a Printrbot Simple Metal, an M500 + M501 is practically a daily operation for using it!), so I'll do that. I wasn't keeping track, but from memory, it would make sense that it is overheating. The prints I recall them failing on were fairly long (3+ hour) prints. There was also a bit of clicking, which initially I associated with the extruder, but never made much sense since the print wouldn't have issues. Might have been the z-stepper losing power for a brief moment!

BTW, M500 = save, M501 = recall saved settings (to confirm they saved correctly).

Edited December 11, 2015 by Guest
More detail.

[gr5 2,167]

Well if you like gcodes you can do it all through that:

M907 Z1000

sets the Z driver to 1000ma max.  default I believe was 1300ma for a while (and on my printer)  and newer software are at 1100ma default for Z I believe.  I thinK default is now:

M907 X1300 Y1300 Z1000 E1250

Edited December 11, 2015 by Guest

[fourier 2]

Thanks again, I've tried the new power settings and the failed print did not fail this time, and I do not hear the clicking I couldn't narrow down before. So for the time being, I believe the problem is fixed!