The CLEARP Command [ML]

This command is used to define a clearance plane. CLEARP is used with the RETRCT command to withdraw the tool tip to the specified plane. This retraction plane remains in effect until changed by a new CLEARP command, or a CLRSRF command. This command is valid for lathes and 3-axis+ mills.

There are three possible ways in which CLEARP can be programmed. The first format can be used for lathes or mills. The second and third formats are only valid for mills.

\textbf{CLEARP / } d

\textbf{CLEARP / } a,b,c,d

\textbf{CLEARP /} \begin{pmatrix}\begin{array}{l} \textbf{XYPLAN} \\ \textbf{YZPLAN} \\ \textbf{ZXPLAN} \end{array}\end{pmatrix} ,d

\textbf{CLEARP / NOMORE}

For the first format, GENER calculates the correct retraction plane depending on the d value programmed and on the type of lathe (whether it is a horizontal or vertical lathe). When this format is used on a mill, the d value is the distance above (or below) the XY plane.

The second format defines the clearance plane using the canonical form of a plane a,b,c,d. The variables a,b,c specify the unit vector that is normal to the plane and d specifies the distance of the clearance plane from the part coordinate origin in the direction of the plane normal unit vector. Symbolic planes can generally be used by the APT programmer.

The last format uses the minor words XYPLAN, YZPLAN and ZXPLAN. They indicate the plane normal to an axis in the part coordinate system (for example, YZPLAN is normal to the X axis). The d value in this format specifies the distance from the origin normal to the indicated plane.

Note that the CLEARP command only defines the clearance plane, a RETRCT command is needed to position the tool tip on the defined plane. See “The RETRCT Command” for more information on tool retraction processing.

NOMORE removes the definition of the clearance surface that was defined by CLEARP or CLRSRF commands. It is an error to code RETRCT without a defined clearance surface.