Denford Software & Machines

TRIAC PC
1992
VR MILLING V2.31

When trying to interpolate a G02 or G03 circle cut at very low feed rates, 5 inches per minute or lower, the machine looses the part datum. And the machine resonates when moving.

Straight lines, squares, angles, diamond shapes no problem. Only circles.

At higher feed rates, 12 inches and above, the machine runs perfect.

Any ideas on what to look at?

Thanks

Hi,

It sounds like the stepper motor is resonating. This can happen with Stepper motors at low speed if they are not under load. The load on the motor damps the stepper motor.

It sounds like the motor is not under the correct load.

This could be because:

1 The slides need adjusting to tighten the up the travel (check the Gib strips)
2 There is backlash on the belt drive so it has a small period where there is no load

Circles will cause the problem as the motor moves through a range of feeds and will pass through the resonant frequancy.

Good Luck