15. COMPENSATION FUNCTION
By issuing G37 the tool starts moving to the measurement position and
keeps on moving till the approach end signal from the measurement
device is output. Movement of the tool is stopped when the tool tip
reaches the measurement position.
Difference between coordinate value when tool reaches the measurement
position and coordinate value commanded by G37 is added to the tool
length offset amount currently used.
A (Start position)
Measurement position is commanded
B (Deceleration position)
C (Measurement position)
The tool stops when the approach end
signal goes on.
Compensation value = (Current compensation value) + [(Coordinates of the
point at which the tool is stopped) – (Coordinates of the programmed measure-
Fig15.2(a).Automatic tool length measurement
G92 IP_ ;Sets the workpiece coordinate system. (It can be set
with G54 to G59. See Chapter 7, “Coordinate System.”)
Hff; Specifies an offset number for tool length offset.
G90 G37 IP_ ; Absolute command
G37 is valid only in the block in which it is specified.
IP_ indicates the X–, Y–, Z–, or fourth axis.
Set the workpiece coordinate system so that a measurement can be made
after moving the tool to the measurement position. The coordinate system
must be the same as the workpiece coordinate system for programming.
Specify the absolute coordinates of the correct measurement position.
Execution of this command moves the tool at the rapid traverse rate
toward the measurement position, reduces the federate halfway, then
continuous to move it until the approach end signal from the measuring
instrument is issued. When the tool tip reaches the measurement position,
the measuring instrument sends an approach end signal to the CNC which
stops the tool.
D Setting the workpiece
D Specifying G37