The value of the Plunge Clearance parameter is the distance between the start point and the end point of a plunge move. This distance is measured along the axis of the tool when the tool moves toward the part. The start point of the plunge move is the end point of a vertical rapid move. The end point of the plunge move is the start point of the first feed move (or cut move).
5 Axis Only
There are two plunge moves in 5 Axis operations, one after the other. The Plunge Clearance value is the distance between the start point and the end point of these two moves. The second plunge move is the plunge move that is defined in the first part of this definition. SURFCAM uses the first plunge to decrease the tool speed before the tool axis is changed at the bottom of a rapid move.