Eleksdraw jamming and stopping
Hello friends. Fourth day of operation of one of our Eleksdraws.
After a couple of lines the machine jams, starts drawing squiggly lines or straight diagonals for a while and then stops completely or jams again for good. To reset the motors to a functional state we have to turn the machine off and back on, and even then after a couple of lines the problem presents itself again.
We've troubleshot software and firmware issues to no avail, it's mechanical. I'm thinking about sending the machine back to the vendor if it's a defective or dead part, but maybe I'm missing something.
Thanks in advance
@xanthicism It sounds like a mechanical issue (friction) but it could be the stepper driver current limit isn't set correctly. The reference voltage should be 0.3~0.4VDC for each driver.
If the limit is set too high you will notice the motor and drivers getting hot or sounding rough, perhaps even jumping rather than smoothly stepping. If it's too low you will just lose steps, which on a CoreXY machine like the EleksDraw usually results in diagonal steps (as only 1 motor is running).
Thank you for the prompt response.
The motors return to a functional state after unplugging and plugging the machine back, even though just for a couple of lines. There is no friction whatsoever while manually operating the machine through software control, the issues arise after sending code to it. Also, the machine has worked impeccably with the same settings for four days, nothing has changed on that front.
I'll try setting the current limit to the ranges you indicated if I find out how Thank you very much
@xanthicism Don't move the axis manually (by hand) with the motors connected as that will damage the drivers, but if they work when cooled down then that suggests they are overheating but how it worked for several days is confusing if nothing has changed.
The motors have less torque at higher feed rates but if you haven't changed anything then it should still work.
Search current limit A4988 drivers and you'll find videos and tutorials.
No I never moved the axis by hand, by manually I meant by giving them directions through software one by one.
I will try to set the drivers to the right voltage ranges, still, it's very sketchy they started to behave after days of working flawlessly. Could it be a PSU/wall plug problem? Like dirty power?
@xanthicism The controller (Nano) is powered from the USB port, only the motor power is from your mains and it would be unlikely one motor would continue moving while the other stopped.
I guess I'll try with the voltage range thingy and if that fails I'll ask for a refund.
Thanks, you've been very helpful
Both controllers measure around 1.7V to the dot (measured on the screw itself). Do I have to touch anything? The fact that both steppers are on the same settings is sketchy, since the diagonal lines make it seem that only one stepper goes bad at a time.
Do I keep tinkering with it? Do I just refund?
Thank you very much
@xanthicism That is WAY too high, actually that sounds like it's at max current which would require heat sinks and a fan on the drivers. They will be overheating and shutting down which is what causes the issue. Reduce both to a safe level (0.4VDC is sufficient) and see if that fixes it.
Make sure you aren't pressing the wiper (screw) down with the meter probe as that will short it out causing a high reading, but if it really is set to max then just reducing it should resolve the issue unless it's damaged something.
I've now tried 0.35 and 0.40, the issue persists.
By the way, I think I was indeed pressing on the screw while taking measurements before, disregard the 1.7 reading entirely.
Another interesting evolution: the machine seems to plot just fine at very slow speeds.
EDIT: nvm it freaked out again. I guess I'll just ask for a refund or for a new board.
@xanthicism It's just friction overcoming torque, I doubt there's anything wrong with the machine except for adjustments or settings but if you've had enough and want to get a refund / replacement I understand that.
What feed rates are you using?
Stepper motors have the greatest torque at slow speeds, so you are more likely to have problems when using higher feed rates.
Due to the pen I'm using for the current project i usually plot at 700mm/min, but before the issues started I plotted at 1000 with no problem whatsoever. The slower I go with the plot speed the longer it takes for the issue arise and for the machine to jam.
Honestly I'd do everything to avoid a replacement procedure from a random Aliexpress vendor, but after reflashing the original firmware, checking the voltage control thing, using different software, different power supplies, different usb cables, power outlets I honestly don't know what's left to check.
@xanthicism If it's not electrical (stepper driver) then it has to be mechanical, have you checked the belts?
Yes I did and they are fine, I could disassemble the machine and check them out to see if they're damaged in any way but they're straight and they keep the right tension. I mean, I could disassemble and reassemble the machine completely just 'cause and see if anything changes.