Trouble printing motor gear

I've hit a bit of a bizarre problem. I've tried printing the motor gear 3 times and its like it is skipping steps at the exact same place every time. The first time I thought it was just a skipped step (despite efforts to fine-tune the drivers and throwing in a PSU fan blowing directly on the electronics). The 2nd time (at really what looks like the exact same spot) I thought there must be something wrong with the gcode, so I opened up KISS and just for fun dropped the infill settings a bit (just so something would have changed). Saved that printed it and again it failed at the exact same spot. Attached is the first and second attempts (first on the right that I stopped when I saw the skew, second on the right that I didn't see finish). The third looks identical to the second.

I don't think it's a coincidence that it's right after it finishes the herringbone layers, but nothing in the sliced model in KISS indicates a problem. Any ideas?

Edit: attached image

Edited 1 time(s). Last edit at 01/23/2014 12:52AM by maik.

I really have no answer other than it looks like it happens when it is doing the solid infill along the top of the gear portion just before the hub. The only thing I can think is happening is the rapid small infill is causing it to skip steps. To work around it you could slow down the entire print or just the solid infill or reduce the X/Y jerk. You could also try using more or less perimeter loops, this should change the way the rapid small infill is generated. You could also try turning the gear in Kisslicer after slicing so it changes the direction of the infill relative the machines axis. Last thing is do not over look the grub screws on the current gears. Although it happened at the same point on both prints it could just be a result of the motors taking that long to get warm and causing the grub screws to come loose.

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I ended up slowing it down to 15 mm/s and rotated the model 30 degrees in KISSlicer which seemed to do the trick. Should probably have only changed one variable to pin it down, but oh well. Thanks for the help.`

In Kisslicer I set jitter to 360 when printing gears. It makes for a more even print as alll your start points are not on the same tooth.