See Related Parameters.
This value specifies the plunge rate in inches per minute or millimeters per minute depending on the selection made in the Options > Units submenu. This is the rate at which the tool will feed if it is moving directly down at the beginning of a cutting cycle, or as it moves between passes in feed and bidirectional retrace modes.
The Plunge Rate is calculated by SURFCAM to be half the Feed Rate. If you override this value, the value of the Plunge Chip Load will be re-calculated as you enter the new value for the Plunge Rate.
The IPM / MMPM or IPR / MMPR selection in the second column of Feed Rate also applies to Plunge Rate. That selection determines the Post output code for the plunge rate.