FANUC Series 16/18/160/180-Model C for Lathe Operator Manual

PROGRAMMING
B–62754EN/01
15. COMPENSATION FUNCTION
267
When a tool is moved to the measurement position by execution of a
command given to the CNC, the CNC automatically measures the
difference between the current coordinate value and the coordinate value
of the command measurement position and uses it as the offset value for
the tool. When the tool has been already offset, it is moved to the
measurement position with that offset value. If the CNC judges that
further offset is needed after calculating the difference between the
coordinate values of the measurement position and the commanded
coordinate values, the current offset value is further offset.
Refer to the instruction manuals of the machine tool builder for details.
When moving the tool to a position for measurement, the coordinate
system must be set in advance. (The work coordinate system for
programming is used in common.)
A movement to a measurement position is performed by specifying as
follows in the MDI, or MEM mode :
G36 Xx
a
; or G37 Zz
a
;
In this case, the measurement position should be x
a
or z
a
(absolute
command).
Execution of this command moves the tool at the rapid traverse rate
toward the measurement position, lowers the feedrate halfway, then
continues 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 outputs the measurement position reach signal
to the CNC which stops the tool.
The current tool offset value is further offset by the difference between the
coordinate value (α or β) when the tool has reached the measurement
position and the value of x
a
or z
a
specified in G36Xx
a
or G37Zz
a
.
Offset value x = Current offset value x+(α–x
a
)
Offset value z = Current offset value z+(β–z
a
)
x
a
: Programmed X–axis measurement point
z
a
: Programmed Z–axis measurement point
These offset values can also be altered from the MDI keyboard.
15.6
AUTOMATIC TOOL
OFFSET (G36, G37)
Explanations
D Coordinate system
D Movement to
measurement position
D Offset

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