STEPPERS Will Someone Please Help!!!

[bill south]

Hey Guys and Gals!
I'm in the process of setting up a sherline system with steppers. I'm using STMD stepper drivers (kit assembled and tested on the bench) and on the bench, everything spins well and functions OK with step and direction.
The system I'm working on an old D&M 4 which started life as an educational CNC trainer. However, is used old technology from the eighties.
I gutted the thing and kept the power supply (50V) and motor control board for the spindle. I'm using mach 3 with a cnc4pc parallel port interface card and charge pump and as I said, the STMD driver boards.
Everything seems to work fine but when I try to move the axis, they seem to be slipping. The motor sounds like it's spinning but the spindle is not turning. I don't think there is a gear or anything inside but it sounds like it's spinning but the motor just does not turn.
I have the STMD driver set for 2 amps and am using the motors which were on the system but wired and running bi polar with the new drivers. I don't know anything about the motors since they have no identification but the manufacturer which is now defunk.
All my experience is with servo systems but this stepper system is just, well, different. Whats happening guys and do I need to add more juice to the system. Right now I have it set for 2 amps but I can take it to 3 amps. However, w/o knowing the motors, I'm afraid I'll fry something. BTW, the motors are wired for 4 wire bipolar and I have them wired to use the full 2 coils on each side.
Is this enough information????
Help if possible.
Bill

[bill south]

Of the many many folks out there with experence with steppers, can't I get some advice. Help folks. Does this make sense??? Please help!
Bill

Mike, have you seen this with steppers???
Me

[ger21]

Try lowering the acceleration in Mach3 by half and see if that helps.

[homebrewCNC]

I am not an expert, but these may be some reasons why you are having trouble.

1. What frame size are the motors you are using? If they are slipping and the axis is not moving the motors may be too small.

2 . Look in mach 3 under config--->motor tuning, and make sure the motor tuning is set up so the motor are not accelerating too quickly.

3. The motors may not be wired correctly.

Hope this help.

[aggie_67]

Need to clarify your problem. I'm just a newbie but know a lot of the problems getting answers here is how the question is phrased. You have mentioned axis and spindle in your problem; two entirely different pieces. Then at another point you say the motor sounds like it's spinning...but the motor isn't turning??? Not sure I understand what your problem is. The axis are X, Y, & Z. Is the problem that none of them move at all, or does the spindle (motor control board / motor) not turn, an entirely different entity. Are you using a break out board to transmit the MACH3 signal to the motor control board.?

[bill south]

Thanks Guys;
I lowered the acceleration rate and the motors locked up and ran beautifully. Thanks for the tip, Ger21. I'm still loosing a bunch of steps but I'll figure it out. More motor tuning Ithink.
I tried to run some code and the zaxis was getting lower and lower every pass, in air so no tool damage.
After working with servos for so long, this is a totally new ball game. And, not sure I like steppers!
Thanks Again.
Bill