Lead In motions let you make the tool approach an Automatic Cut motion (or another approach motion) tangentially along an arc of specified radius. The radius of the arc is determined by the HELICAL_DIAMETER parameter value, the lengths of the preceding linear segments—by TANGENT_LEAD_STEP and NORMAL_LEAD_STEP, the angle of the arc is defined by the ENTRY_ANGLE parameter value.

Lead Out motions let you make the tool exit from the current point tangentially to the Automatic Cut motion along an arc of specified radius. The radius of the arc is determined by the HELICAL_DIAMETER parameter value, the lengths of the linear segments—by TANGENT_LEAD_STEP and NORMAL_LEAD_STEP, the angle of the arc is defined by the EXIT_ANGLE parameter value.

The following diagram illustrates Lead In and Lead Out motions.