X & Y skipping steps.

Hey Everyone,

I've been breaking my head on this for the last couple of days...
My prints seem to skip a step once in a while at random intervals.
I do have heatsinks and fans on my steppers and i've set the pot to 0.4V for +- 1A to my motors.
The motors feel warm but not hot , neither are the heatsinks.

I've already lowered my acceleration to 1000 max on Sprinter , Marlin and also tried Repetier but to no avail..
Also i've double checked if my belts don't slip and they don't.
Is there anyone that could help me out on this ? cause it's driving me crazy ....

I did notice that the layers always seem to skip towards the 0 point .. don't know if that could be any help

*edit:* oh , and also when the motors skip steps, i heard a loud 'pop'...

Thanks alot

Edited 1 time(s). Last edit at 08/07/2012 02:30PM by stefkeh.

Can be mechanical problem if FW acceleration do not help try:

1. is something blocking linear bearings (fergotten washer in my issue)
2. sliping geared wheel on motor
3. deformed or badly positioned linear rods.
4. something colide with one axix (pop sound) it happens once to me when one too long bolt uner bed colided with m8 theraded rod...

Assuming it's mechanical, the most common causes, are
Belt too tight, or binding somewhere, often on the washer on the outside of the bearing used as an idler.
Rods, not parallel, this usually caused binding at one end.
I'd also make lubricate any LM8UU's they can get quite stiff if they are dry.

If you're hearing a pop, I'd start by tracking down what it popping, sounds like something binding and breaking free to me.

Or the head hitting bobbles of printed plastic. Is your extruder calibrated? Try using z lift and retract.

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Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9

I've had similar issues when I first step my machine, only a week or two ago,

After calibrating and ruling out issue with the steppers and drivers.

First issue was with the hotend which was wobbling, wrapping it in kapton tape fixed this. (seemed like it was skipping on the Y axis only)
The second issue was with my pulleys, and the screws that were holding them onto the stepper, these where colliding with the motor mounts causing a nasty noise and causing skipped steps. This was resolved with grub screws.

Hey guys,

Thanks alot for all your suggestions, i will check them all when i get home later today and i'll let you know if any of these solved my problem

Thanks !

I had problems with mine when I first set it up (last week) during calibration. It would track fine and step off 5 or 6 10mm steps at a time and then jump ahead, or miss a few in a row.

When I swapped the driver boards around the problem moved, so for me it was the drivers (Ramps 1.4 with Pololu driver boards) and I had to reflow the solder on the pins of two of them. Even under a magnifying glass I couldn't tell what the problem pins were, but making sure they were all good and connected all around the pins did the trick.

Edited 1 time(s). Last edit at 08/08/2012 01:20PM by a_shorething.