X Axis Stall

[Neale]

Couple of thoughts.

First - 48V and NEMA34 motors don't really go together. The high-inductance motors need a fair bit of volts to get them going. It's possible that things have tightened up a bit or moved slightly out of aligment since first building the machine, so more friction, so more likelihood of stalling? Does it still happen if you reduce acceleration and max speed? Try low values just for testing purposes.

Second - and possibly linked to first. Sounds like you are using a switch-mode power supply. These are really not ideal for stepper motors. Steppers need high pulse currents even if the average is low, and it's possible that these peak currents (possibly increased because of a bit more friction as above) are tripping the over-current limits on the PSU. Ideally, you should be looking at about 68V from a linear power supply - details and how to build are available on this site!

[JAZZCNC]

This going to be one of two things IMO,
#1 slippage of couplings/pulleys or friction due to mechanical wear/failure.
#2 Lose or breaking/ trapped wire

However, everything Neale mentions is correct and could very likely be a cause of trouble and most certainly will be straggling performance, so I 100% agree with him that you should up the volts for the Nema 34 and go with a toroidal type supply. But first I would try to identify the cause of this issue if it as been working ok for a lengthy time, the simplest way to check the PSU would being just running the X-axis with the other axis unpowered.

My suggestion would be to write some G-code with 1000's of short moves at full rapid speed but just long enough to let the motor reach full speed before changing direction. Zero and Mark the axis before starting the run and finish by having it come back to Zero.
If it returns to zero, then repeat but this time run the other axis at the same time, if it then drops steps then it's a power issue.!

[dazp1976]

Couple of thoughts.

First - 48V and NEMA34 motors don't really go together. The high-inductance motors need a fair bit of volts to get them going. It's possible that things have tightened up a bit or moved slightly out of aligment since first building the machine, so more friction, so more likelihood of stalling? Does it still happen if you reduce acceleration and max speed? Try low values just for testing purposes.

Second - and possibly linked to first. Sounds like you are using a switch-mode power supply. These are really not ideal for stepper motors. Steppers need high pulse currents even if the average is low, and it's possible that these peak currents (possibly increased because of a bit more friction as above) are tripping the over-current limits on the PSU. Ideally, you should be looking at about 68V from a linear power supply - details and how to build are available on this site!

I was disappointed with my mill Z 34 stepper max speed on 60vdc. Accel was quick but rpm lacking.
I've recently swapped driver to a dm860t https://www.omc-stepperonline.com/download/DM860T.pdf and powering it off a new 80vdc.
Haven't got into fully testing yet.

[JAZZCNC]

I was disappointed with my mill Z 34 stepper max speed on 60vdc. Accel was quick but rpm lacking.
I've recently swapped driver to a dm860t https://www.omc-stepperonline.com/download/DM860T.pdf and powering it off a new 80vdc.
Haven't got into fully testing yet.

You won't see a massive difference in speed with only 20V difference, if you want real speed with large 34 motors then you really need mains-powered drives. These give high speed and torque.

[dazp1976]

You won't see a massive difference in speed with only 20V difference, if you want real speed with large 34 motors then you really need mains-powered drives. These give high speed and torque.

Probarbly not. Maybe an extra 400mm/min ish. Not much, but there'll be a lesser risk of skips/stalls if left at the present settings.
I was looking at the Leadshine DM2282 but..... For around another £100 I could get a basic 1kw AC servo set instead.
That's my future route so I'll make the most of what I've got until then.

[JAZZCNC]

I was looking at the Leadshine DM2282 but..... For around another £100 I could get a basic 1kw AC servo set instead.
That's my future route so I'll make the most of what I've got until then.

What mill have you got that you think a 1Kw servo is a correct choice.? I've got an Hurco BM40M milling machine that weighs 8 tons and is the size of a transit van that is only fit with 1.5Kw servos.. . Remember bigger doesn't; always make it better, often just more expensive with lower performance than a correctly sized motor.