vnks

I've come to the conclusion that in my case there's oil-soaked wood dust in the linear bearings, that needs to be cleaned out. I haven't had a chance to actually do it yet, and won't for a while, but it makes a lot of sense to me. The printer was sitting in a pretty dusty wood shop, and I can see the grime inside the bearings. When I oil the rods, everything is smooth for a while, but a few hours in the dust absorbs the oil, and everything binds up. I'm going to disassemble everything and soak in WD-40 or something along those lines to get it all clean, and keep it away from wood dust in the future. Hopefully that'll be it.

So, after getting branded black Polulu stepper drivers, and replacing all of them, I have the same exact problem - skipped steps on the X-axis during long prints (6+ hours). Current is set to 1.15 amps, no heatsinks (per documentation, none are needed for this current level with active cooling). I noticed that all the skips are in the same direction - it keeps shifting towards the left, if looking at the printer from the front. Is this data point ringing a bell for anyone? I have nothing else left to try other than replacing the main board on a whim :(

Ah, too bad. In my case it probably happened a while ago with a larger model running into the same issues as yours. I think I'll try getting good quality stepper drivers instead of the cheapos I have now, there's some timing support for this being the problem...

Here's one weird thing I noticed, the head bearings are shifted on the X-axis, same axis that's skipping - http://imgur.com/sdX2dkZ . There's a matching gap on the other side. Could this be a symptom of a hardware issue? Everything feels very smooth, especially after oiling.

Yeah, I've been doing it for close to two months now with no progress. I was hoping someone has experienced this with a unique root cause - I've already tried all the common ones.

Hi, Any other ideas? I have a very expensive paperweight at this point :(

That would show up on the Ulticontroller, right? Nothing like that is showing.

That would be quite involved, I'd either have to re-wire everything or cut and re-splice the wiring... I'm not sure it's possible for a stepper motor itself to cause this - they're basically solid state. I certainly haven't been able to find any confirmation that it could be a potential cause.

1.15, as per the documentation. I tried lower and higher as well, it's skipping at all settings.

I've swapped the drivers around, and have a bunch of new StepSticks I've tried as well, no difference - it keeps happening on the same axis.

The fan is running fine, it's oiled and produces plenty of airflow. Additionally, whenever I catch it in the act of lots of skipping, if I shut down the print and take off the cover, the driver heatsinks are barely warm.

Hi all, I have an Ultimaker Original that started skipping steps on long prints (10+ hours) a few months back. Since then, I've tried everything I could think without making much of a difference. Pretty much the only thing I haven't tried is swapping the steppers. When it skips, it's a bunch of steps at once, like the driver overheats and shuts down. My test case is a 20+ hour print, slow, at 40 microns, so that I don't waste too much filament. I always oil the axes first, movement is smooth all over, no obvious binding. It always skips on the X-axis. - Replacing the stepper drivers, swapping X & Y - no change, same problem on the X axis. - Tuning stepper drivers, lowering or increasing the current, no noticeable difference until it's raised too much and it skips more. - Loosening the belts, long ones and short ones. - Marking the bushings and rods, to make sure nothing slips - they're not slipping. At this point I'm out of ideas, I'd swap the steppers if it wasn't such a pain, but I'm not even sure it's possible for the stepper itself to cause this. I did build my own firmware a while back (custom heated bed), but this was long before the problem started and I haven't touched it since. Any ideas? At this point I'd probably hook up a thermistor to stepper driver heatsinks and start logging the temperature, just to confirm that the drivers are really overheating.