Prusa i3 Y axis occasionally gets stuck

I'm curious as to whether anyone else has seen this problem.

On a couple of fairly large prints, usually taking up much of my XY surface (this is a Prusa i3 6 I got from MakerFarm 4-5 years ago), I've had an issue where the Y axis gets stuck and the print continues but is skewed by around 5-10mm on the Y axis.
I've printed several reels of ABS on this machine and have not had problems apart from wearing out my Z-axis threaded rod and needing some occasional adjustments.
I'm using Arduino Mega with RAMPS 1.4 and Marlin firmware. I have a direct feed extruder running 3mm ABS.

It will continue printing and usually adheres to the skewed layer, and will often skew a second time if I am not around to stop it. I cannot find any obstructions, traps or potential cable jams or blockages, and my filament is spool-fed.

This morning I had a print fail while I was nearby and I heard a loud clunk. I went to investigate and it had skewed but I could not see what happened. This was about 90 minutes into the print. I'll post pictures when I get home tonight.

My next step will be to set up a video camera to record (I also have the timelapse on Z change from Octoprint but obviously this happens while on the layer).

Possible causes I can think of:
1. Y axis stepper motor is failing intermittently (it is getting used heavily and was very hot)
2. Motor driver for Y axis is failing intermittently
3. Arduino Mega is failing to communicate with the driver but continuing with a missed Y move (seems very unlikely, I would think it will just stop)
4. Some other mechanical issue I didn't notice.

Any thoughts, suggestions or experiences with this?

If the T motor is getting hotter than the others, maybe the drive current is set too high which could cause the driver to over heat and shut down for a moment.

Good idea, I'll take some temperature measurements...

I started another print this morning which was not covering a huge amount of area, and this time it got stuck on an X-axis movement and became skewed.
My strongest suspicion is that either the drivers or other regulator components on the RAMPS board are failing. I was not expecting a failure so did not have temperature measurement running but all of my motors were too hot to touch when I cancelled the print.
A replacement RAMPS 1.6 board was fairly cheap so I'm going to try that. This rev is also supposed to handle more current than the RAMPS 1.4. At worst I'll be out $10 and will have an extra RAMPS board

Edited 1 time(s). Last edit at 04/05/2019 01:45PM by papergeek.

Quote
papergeek
I started another print this morning which was not covering a huge amount of area, and this time it got stuck on an X-axis movement and became skewed.
My strongest suspicion is that either the drivers or other regulator components on the RAMPS board are failing. I was not expecting a failure so did not have temperature measurement running but all of my motors were too hot to touch when I cancelled the print.
A replacement RAMPS 1.6 board was fairly cheap so I'm going to try that. This rev is also supposed to handle more current than the RAMPS 1.4. At worst I'll be out $10 and will have an extra RAMPS board

If the motors were all way hot, you need to adjust your current settings on your "stepstick" drivers, it is set too high. These are the "mini" boards mounted on the RAMPS board. Google to see which ones you have, then get out your DVM and check your numbers. I'll bet they are too high.

DLC

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@dlc60 Thanks for the suggestion. I did indeed do that while running. As a result I have my motors running a tiny bit quieter and I still have not taken readings of the motor temperatures.

As it turns out this was a problem with one particular model I was printing, sliced for 0.3mm layers. (download from thingiverse [www.thingiverse.com] )
The large flat piece with an irregular notched hole in the middle at the coarse (faster) slicing setting of 0.3mm with ABS resulted in some slight vertical protrusions in the middle notched part. The hotend would sometimes collide with these (this was the clunk I sometimes heard but did not have the patience to set up a camera for), and the piece being very thoroughly stuck to the print bed it simply caused skew in either the X or Y axis (usually Y).
There was (apparently) no failure of any electronics involved.
I will try at a finer setting perhaps 0.1.
My 5yo will be happy when I finally get this printed. i actually had a similar problem printing one of my own designs here [www.thingiverse.com]
which was what he's been saving coins in. I'll also try that one at a finer pitch.
So, I believe this case is nearly closed...