Widia GTD

Widia GTD CNC Thread Mill Programming

 

Compensating the Program Feed Rate For the Centerline of the Tool

This third and most important element is why 80% of canned cycles do not work. A helical tool path takes an enormous amount of data processing capacity for even the latest microprocessor hardware. Many controllers that employ automatic feed and tool diameter compensation features bypass these formulas when a true helical move is programmed.

For this reason, Widia GTD recommends programming controlled feed rates within the program for the centerline of the spindle (or tool). Using this method assures absolute feed control of the tool through the entire thread milling operation.

Referring to the drawing below, a tool representing 70% of a 1/2" major thread diameter to be milled will have a centerline tool path that is 30% of the thread produced. Therefore the programmed feed rate for the centerline must be 30% of the intended IPM to be achieved for the periphery of the mill.