Z-Axis Pulsing

My Z axis pulses, I don't know how else to describe it.

It runs fine for a distance, then begins to pulse. Its not loosing direction but no longer moving in any smooth fashion.

I have tried changing the min/max speeds and feedrates as well as varying the pot on the driver, and come up with nothing. It didnt seem to do this before, so Im assuming Ive changed something to cause this.

Any ideas?

Im using Tonokip firmware with RepSnapper and just performing manual movements trying to dial in the calibration

For one, it's always interesting which type of electronics you're using.

For two, this sounds like a overheating stepper driver. Reduce the current and see wether it gets better. If yes, and you need the current to avoid step losses (unlikely on the Z axis), mount a heatsink.

---

Generation 7 Electronics	Teacup Firmware	RepRap DIY

Good point, Its running RAMPS 1.3 with
Drivers
Motors

The drivers have heatsinks and a small computer case fan blowing across them. The Z-current is pretty high, but the driver only gets warm to the touch.

If the over-current protection is kicking in, the driver won't get hot. Over-current causes the pulsing you are experienceing. Take a magnifying glass, and have a look at the trim pot on the Pololu for the Z-Axis, looking for the flat spot on the side of the trim. It can rotate from the 7:00 to 5:00 position. It should be between 8:00 and 10:00. You don't need more than this.

Well that took care of it nicely. I thought I had checked that...
Not sure about your clock reference, but I turned the pot to 50%~60% of its travel and it works like a champ.

Thanks for the help

7:00 = South West
5:00 = South East
8:00 to 10:00 = West

Your 50%-60% = North (This is probably too much, but does not usually cause overheating on z axis, since it is off when idle).