
OPERATION
B–63014EN/02
11. SETTING AND DISPLAYING DATA
877
In general, the tool length offset value can be defined in either of the
following two ways. Both methods are based on the same concept: The
difference between the tip position of the tool and that of a reference tool
is used as the tool offset.
(1)Definition 1
The first method involves using the actual tool length as the tool length
offset. In this case, the reference tool is an imaginary tool which has
its tip at the machine zero point when the machine is positioned to the
Z–axis machine zero point. The difference between the tip position of
the tool to be measured and that of the reference tool, that is, the
distance along the Z–axis from the machine zero point to the tip of the
tool when the machine is positioned to the Z–axis machine zero point,
is defined as the tool length offset.
Tool
T02
Tool
T03
Refer-
ence
tool
(Reference tool
tip position)
Tool
T01
Machine zero
point
OFSL03
OFSL02
OFSL01 : Tool length offset for tool T01
OFSL02 : Tool length offset for tool T02
OFSL03 : Tool length offset for tool T03
OFSL01
Also, with this function, the tool is manually moved by means of jog
feed until its tip touches the top surface of the workpiece or reference
block. This surface is called the measurement surface. Assume that
the top surface of the machines table is set as the measurement surface,
although this is actually not allowed because the machine would be
damaged. In such a case, distance L from the machine zero point to
the machine table top surface is specific to that machine. Set distance
L in a parameter (No. 5022). Assume Zt to be the machine coordinate
of the tool at the position where it would touch the machine table top
surface if that surface were set as the measurement surface. The tool
length offset (OFSL) can then be easily calculated from L and Zt.
Because the machine table top surface cannot actually be used as the
measurement surface, however, that surface is defined as the base
measurement surface and the distance from the base measurement
surface to the actual measurement surface, that is, the height of the
workpiece or reference block (Hm) must be set. The tool length offset
value (OFSL) can thus be obtained from the formula shown below.
Explanations
D Definition of tool length
offset value