Now that rotary is becoming more mainstream and with the G93 function availability in a rotary post processor I thought I would post an explanation.
The technical definition:
Inverse Time Feed Mode (G93) feature specifies that all F (feedrate) values are to be interpreted as "strokes per minute." This is equivalent to saying that the F code value, when DIVIDED INTO 60, is the number of seconds that the motion should take to complete.
Rotary feedrates have never been easy to understand. Inches (or millimeters) per minute (second) converted into degrees per min/sec just adds to the rotary confusion. To make it even worse, various controllers handle the data differently when given the same feedrates.
In the example below, a 2" diameter blank is used and a vector is setup that spirals around the blank twice while traveling 10" in the axial direction.
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