Speed related fail: skipped steps

[edward]

This post is simply to show off my fail over the weekend. Actually I had two like this, same part. I was on a mad mission to get as many 3DR parts printed this weekend as possible, and I nearly finished them all.

The part in the photo was one of the Top Electronics mounts. Pushing the print speeds have been of interest to me lately (see: http://forum.seemecnc.com/viewtopic.php?f=54&t=2571), and I just went a bit too far.

I wasn't present when the skip happened, but I'm guessing that it was related to having my rapid speed and/or acceleration set too high. I think I had it at something like 250 mm/s and my acceleration for all axes at 4000 mm/s^2. With my jerk at 80 (mm/s), it must have been too much.

I successfully re-printed the parts, finishing all of the 3DR bottom and top mounts, after tweaking the rapid speed to 200 mm/s and accleration to 3500 mm/s^2.

[img]http://i.imgur.com/T4Ag34Z.jpg[/img]

Click for full-res version: http://i.imgur.com/T4Ag34Z.jpg

Here are some shots of the rest of the parts, all printed GREAT!

Bottom mount:
[img]http://i.imgur.com/Bv11klX.jpg[/img]
http://i.imgur.com/Bv11klX.jpg

Top Mount:
[img]http://i.imgur.com/comJj1Z.jpg[/img]
http://i.imgur.com/comJj1Z.jpg

Top Caps:
[img]http://i.imgur.com/wG7wN8J.jpg[/img]
http://i.imgur.com/wG7wN8J.jpg

Modified Gregs Extruder:
[img]http://i.imgur.com/alnvtLJ.jpg[/img]
http://i.imgur.com/alnvtLJ.jpg

Extruder gears (printed at 0.125mm layer height):
[img]http://i.imgur.com/45M8GxH.jpg[/img]
http://i.imgur.com/45M8GxH.jpg

Gears again:
[img]http://i.imgur.com/x9gfgSs.jpg[/img]
http://i.imgur.com/x9gfgSs.jpg

My only complaints any longer are those little retraction hairs that I just can't seem to kick, and still some bed level issues. I'm slowly narrowing down both...

Also, I'll be receiving some UHU glue from Amazon later today. Last night I let a plater of a pair of Top and Bottom mounts run in black ABS (8hr print) and everything was great except for some first layer curl that has, while not rendered them trash, made them look pretty terrible. I'm hoping that it will clear up my occasional large-print adhesion issue.

[geneb]

Edward, try bumping up the digipot values in the firmware a bit and run it at the same speed. The digipot values control how much power the steppers are being fed - I run mine at about 130, but I don't push the speed envelope very hard.

g.

[edward]

RAMPs.

I set the current with a cable that has one of the wires broken out to run through a DMM. If you step through in small enough increments you'll eventually see a maximum, then adjust that to the limit of your steppers.

I appreciate the idea, though.

[geneb]

I keep forgetting you've got a Franken MAX.

g.