Gradual Lead In/Out for Thread Mill

The new Gradual option for Thread Mill toolpaths generates lead-in and lead-out moves that coincide with tool manufacturer recommendations. The strategy engages the radial depth of a Thread Mill operation through a helical motion that gradually engages the tool throughout a 180-degree arc sweep. Throughout the arc sweep motion, the tool will engage 1/2-pitch deep before achieving full radial and axial thread depths. In short, the Gradual option provides a more precise lead-in and lead-out strategy that promotes better tool life and proper tool engagement.

The following image depicts the minor diameter of an ID thread using a red dotted circle. The tool motion (shown in green) will begin 180 degrees from the start point of the thread. A helical motion, traveling 1/2 pitch axially, will gradually engage the tool throughout the gradual lead-in. For the lead-out strategy, the same motion is reversed. That is, the tool will gradually exit 180 degrees radially from the last point of full engagement while traveling 1/2 pitch.

When you activate the Gradual option, Mastercam activates the associated Engagement percentage parameter. Use this parameter to specify the distance the tool will be from the minor diameter for an ID thread and the major diameter for an OD thread before engagement begins. Tooling manufacturers suggest using the quotient of the minor/major thread diameters.