Do you know how to switch the feed rate mode from PERMIN to PERREV for Rigid Tapping?

Rigid tapping cycles perform the following sequence of actions: the tool plunges at cutting feed, reverses the spindle, retracts at cutting feed and reverses the spindle again. If the CAM programmer uses proper best practices, whenever a tapping cycle is programmed, the feed rate should be expressed in units per revolution (PERREV). However, situations may arise where tapping cycles are programmed with the feed rate expressed in units per minute (PERMIN). In such a case, you can write the following two user-defined macros to switch the feed rate mode from PERMIN to PERREV.


Below is an illustration of the output codes with the feedrate input in PERMIN in the input file.


Benefit to User:
During rigid tapping, ensure that the machine feed rate is synchronized to match the specific thread pitch as the rigidly-mounted tap is quickly driven in and out of a hole.

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