max 60 ipm before motors stall?!

[bikedude987]

Hi, I'm finishing setting up an old prolight1000 with keling 4030 drivers keling 425oz-in stepper motors (8 lead bipolar running parallel). everything is working, but no matter what microstep setting I set the drivers to, i can only achieve about 60ipm before the motors lose steps or stall.

machine specs:
5 rev/in ballscrew
2:1 reduction on the motors
C10BOB
36V 9.7A power supply
running EMC2 software.

I think I should be able to achieve a faster rapid rate, but I don't know. How fast (rpm) should these motors be able to achieve?

Thanks in advance!

[TaK]

Probably need more info.

What rate is your parallel port set to and what is the max frequency of your drivers?

If you are micro-stepping at 10 and those are 200 step/rev motors with 5tpi and a 2x reduction thats 20,000 steps per in. So if your parallel port is set to 25kHz, that's pretty close to 60 ipm. And 36V probably isn't the most efficient operating point of those steppers, depending on what configuration you are using.

If i did that right...

[bikedude987]

where would i find the frequency of the parallel port?

the max step rate is given at 44kHz in the stepconfig wizard.

the power supply is set at 36V, the drivers are set at 2.7A. what would likely be a better voltage to adjust to?

[george4657]

The 36 volt supply at the inductance of these motors limits their speed.
Your driver has a max of 40 volts so you have little room for improvement by changing.

Why do you have the reduction of 2:1 on your drives. This gives more power at low speed but requires higher RPM. Steppers run better at low RPM. You should try 1:1 ratio and see if this gives better overall performance.

|George

[bikedude987]

the reduction is what comes stock on the prolights, and we wanted this to be a direct bolt on. Personally, I would like to make it direct drive, but it's not up to me (school project...)

[jharvey407]

Did you ever get this problem resolved?

I am working on a very similar issue, 425 oz motor, 5 tpi screw. Direct drive and max 80 ipm.

I am considering gearing upto 1:3 to get 1250 rpm on the screw at just a little over 400 rpm on the motor.

[stevespo]

I've used those same motors in the past. You'll need much higher voltage to sustain higher RPMs.

Wired bipolar parallel, the inductance is 6.8mH, so the ideal voltage would be more like 32*sqrt(6.8) = 83V.

I used a 72VDC PSU and had pretty good results driving my machine (ballscrews) at 5:1 ratio and 1250 RPM. Rapid speeds to 250 IPM were reliable.

Definitely make sure you're not being limited by your CPU or Mach settings.

Gearing up to 1:2 or 1:3 could be a nice solution, but I never tried that. Went to BLDC servos instead...

Steve