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Hi
Did something stupid the other day - misinterpreted a gcode and went out for a coffe - when I heard some crazy sounds from the machine. The bit had jammed in the workpiece and the machine was jammed while motors crying out…not a nice experience!!
After this I have issues with motor stalling on the X and Y axis. I have replaced the stepper drivers (and the cnc shield just to try), tried to adjust the potentiometer on the drivers, but no effect. The motors stall on both X and Y if I gently hold back the z-gantry. It seems like the motors just do not get the power they need.
So I wonder what it could be. As I have tried to adjust the current on the stepper drivers I do not think the issue is here. Is it possible that I have “fried” my motors? Can they be damaged? Anybody have experience here?
It is hard to tell but that sounds almost mechanically grinding to me.
I would try isolating the motor. Loosen and slip the belt off of each and run it slow, using hand pressure on the pulley to try to stall it.
That will at least tell you if the issue is in the motors or the gantry.
Hi and thanks all
I use polulu A4988 drivers. I will try isolate the motors next when I have time on the Y and check. Hopefully i have some time tomorrow evening. Will get back to the thread then, thanks for helping me out so far!
These stepper motor drivers are a bit wimpy for the X-carve.
If you have NEMA 17 stepper motors they are generally rated at about 1.6 amps per phase.
If you have NEMA 23 stepper motors they are generally rated at about 2.8 amps per phase.
The A4988s can only deliver about 1 amp per phase, a little more with sufficient cooling.
Since the Y axis has two motors in parallel that would only give you about 1/2 amp per phase from the A4988 drivers for each of the stepper motors on the Y axis.
Thanks, they have worked good so far but agree. I have a g-shield lying around - can try that instead. Also there is room to use the last slot on the cnc shield for an extra stepper driver. Just need time here to test… Not easy with kids all over the place
Switched to a gShield and behold, all axes are firm and powerful - no steps missed! That is great… And strange since I have used a4899 drivers for a good nine months. Why they suddenly can’t keep up Is a mystery to me. I have ordered some drv8825’s to replace them with since these give more power. If anybody have experience with them please give a comment on how they are performing.
Thanks for all the support, wish you all a happy Easter. Now it’s time to do some carving - and please don’t leave your machines carving without keeping attention - I won’t do the same mistake again!!
