Re: Rigid Tapping--How is this accomplished?

This is done with an encoder on the spindle, and the z speed
is adjusted to follow at the same pitch.

Depending on the nature of your tapping, you may be able to
get by with some tap drivers that engage the square on the
tap shanke. There is often enough slide in/out to compenstate
for z-inconsistencies and most importantly accel/decel.

-d

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jmorrphd2" <jmorrphd@s...>
wrote:

> Dear Fellow Group Members:
> I would like to know how rigid tapping is implemented. I know
> that the Z-axis feed and the rpm are synchronized such that the
> Z-axis feed (in distance per minute) is equal to motor rpm x thread
> pitch. How does the drive motor "measure" its angular displacement
> or speed? Is the Z-axis speed adjusted continuously as a function
> of motor speed variation? Or, is the motor angular momentum such
> that there is no appreciable decrease in speed over the length of
> the cutting of threads?
> Finally, I imagine that there is more than one way to implement
> rigid tapping. Any comments appreciated. Thanks, Jim