Commenting to see when someone finds a solution (Hopefully!)
I had such a behaviour as result of a overheated stepper motor for the x axis (would be similar with overheated stepper driver) I accidently used a differnt type of nema17 for the one axis.
Check if one of your steppers is significantly hotter than the others.
Stretching - but bad trace on the PCB? If it sporadically moves in the wrong direction, the DIR line might be compromised when the STP pulses come into the driver.
It could be a buffering problem, as in the gcode is not getting to the printer fast enough so lines get missed, or your custom marlin has a bug in the buffer reading code which causes it to miss some code, or the buffer memory is faulty. Or none of the above.
Is there any chance that cables of XY motors be interfered by high current carrying cables?, You can check it easily by wrapping cables with aluminum foil or keep distance with hand during printing.
Baud rate is what I would change. What are you running.
I seem to remember reading that overheating stepper motor drivers can cause something like this.
If you suspect a USB comms problem try connecting with a laptop running on battery. That will eliminate ground loop problems.
Printing-wise, does this happen at random heights in the print or after a certain amount of time? Trying to determine if it’s a power or time (temperature) related issue.
So here’s what I have so far.
Drivers are quite warm
This happens at completely random times:could be second layer and could allow the same 25 min print to finish.
I swapped out the cable and there was no change.
Stepper motors have not been crazy crazy hot
Accel and jerk are at crazy low values.
No ground loop as I ran it off a battery and no cigar.
This issue is quite odd!
It almost reminds me of what a stepped driver going into thermal shutdown would be like. I don’t hear the motor skipping steps but if the driver collapses then the motor has the ability to just keep sliding a little before it can get current back through it again from the driver.
Oh I love constant current drivers haha.
@Mark_Rehorst it’s a printrboard so the drivers are mounted drive fly. But I can swap the boards on the two printers and see if it makes a difference.
I had this problem with my Arduino board and ramps board. I had to turn down the potentiometer on the driver board. I was giving too much juice to the motors.
@Griffin_Paquette have you tried printing with the SD card instead. Try a good that works on the first printer… I’d it persists it might actually be a card issue. Is the entire kit from Brooks started kits? If so talk to the and see if you can send it in for testing…
Do you have the end stops enabled for all moves, or just homing moves? I’m with the other person who suggested end stops. Looks like it tried to move across, received an end stop hit signal and continued on.
Could be caused by a loose wire or broken solder joint if your switches are wired to the NC position on the switch, motion of the carriage could aggravate a broken wire or a loose plug on the board.
My endstops are both wired on the outer two so I would assume that normally open?
Do you have another board, not installed in anyachinr, that you could switch it and test and see if it does the same thing?
I do @Diego_Pablos . That’s the first thing I’m gonna try. I am unfortunately out of town until Sunday though so I have to wait until then to test. Lots of good ideas that make me think it’s not a torque issue from the motors which is a good sign. If we can work through it the other kiddos can get theirs on the way even faster!
Just wanted to give everyone a heads up. The issue is resolved. It turned out to be a faulty printrboard as I switched the one from the good orange and black not to this one and it printed flawlessly. Just put another new on I had lying around in it and it has gone hours without an issue. Glad the motors aren’t the problem.