steppers on a Bridgeport

[thespindoc]

Can anyone advise me what motor I might successfully use in a Bridgeport Boss 6 retrofit. I have a 2:1 gearing throught the timing pulleys and belts to a 5 pitch ball screw. The current Anaheim Automation high torque (3100 oz*in) motors just will not mover faster than 20 ipm with the CNClite and their stepper board. Has anyone successfully used this board with a large mill and can you recomment a particular motor. I hate to keep buying motors that don't work. I am using a Gecko 210 drive and have a 75v 16 amp DC powersupply for the motors. The computer supplies the 5vDC and 12vDC power to the stepper board and Gecko drives. A standalone step pulse generator that bypasses the stepper board and computer moves the x axis at about 120 ipm with no problem so I do not believe there is a mechanical problem or a problem with the drives or powersupply.

CamSoft is wracking their brains to try to help me as is Mariss at Gecko.

thanks for any input.

Keith Clark

[Jim Cooper]

Keith,

I don't know Mariss and I have not used the stepper board from CamSoft. I have used the Galil boards with CNC Lite on Bridgeport knee mills.

I have got better than expected feedrates and rapids from this package.

There is a setting in CNC Lite that caps the maximum rapidspeed. It is called RAPIDSPEED for each axis. The system won't go any faster than this speed. CamSoft must be aware of this because it is the first thing I thought of.

Other than that all that stands out is the 5 to 1pitch and 2 to 1 belt ratio. I think Anaheim Automation only sells stepper motors so it may be the motor is stalling at higher travel speeds with this gear factor. Stepper motors will commonly stall at higher RPMs.

Power especially voltage affects speed. Check if your getting 75 V out of the gecko drive.

Jim

[thespindoc]

Jim,

I appreciate you positive experience. I have been manipulating all the speed parameters in setup including RAPIDSPEED, ACCEL, and DECEL, but can not get better than 20 ipm. It looks like the stepper board acts like a Galil card. I hope you might be able to tell me what motors you were able to use successfully? I am able to run the motors I have quite nicely with a step pulse generator from Anaheim that bypasses the stepper board so I think the powersupply and Gecko drives are working fine. It seems to be a problem with how the step pulses are configured and issued by the stepper board.

I am just to the point where I was hoping someone who had done a Bridgeport could tell me that they used motor x brand and model and are satisfied since there are supposedly many out there who have done it.

Thanks,

Keith Clark

[Jim Cooper]

Keith,

The motors were already on the machine. I think they were sigma brand. The machine was a retrofit I helped someone do and the dirt bag still owes me money. Both of us were satisfied with the result, but my travel time should of been paid too.

Their 4 axis $395 stepper board said it is rated 45,000 pulses per second that is 2,700,000 per minute. Depending on how many steps it takes to move one inch on your machine this would determine IPM after diving it by your ball screw pitch and belt.

Jim

[HillBilly]

Keith,

Your test definitly points to the pulse generation section of the motion control board.
I would try 1k terminating resistors at the Gecko inputs to ground. It sounds like your cable is ringing at higher frequencies (an oscilloscope would verify this).

HillBilly