
B-63782EN/01 NC FUNCTIONS 7.COORDINATE SYSTEM
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7.6 ROTARY TABLE DYNAMIC FIXTURE OFFSET
The rotary table dynamic fixture offset function saves the operator the
trouble of re-setting the workpiece coordinate system when the rotary
table rotates before cutting is started. With this function the operator
simply sets the position of a workpiece placed at a certain position on
the rotary table as a reference fixture offset. If the rotary table rotates,
the system automatically obtains a current fixture offset from the
angular displacement of the rotary table and creates a suitable
workpiece coordinate system. After the reference fixture offset is set,
the workpiece coordinate system is prepared dynamically, wherever
the rotary table is located. The zero point of the workpiece coordinate
system is obtained by adding the fixture offset to the offset from the
workpiece reference point.
Y
Y
Y
F
0
F
θ
0
θ
Z
W
Machine coordinate
system origin
W : Workpiece origin offset value
θ
0
: Reference angle
F
0
: Reference fixture offset value
θ : Rotation axis angle
F : Fixture offset value
C
Rotation axis
center
Fig.7.6 Fixture offset
- Fixture offset command
When command G54.2 Pn is specified, a fixture offset is calculated
from the rotary axis angular displacement and the data of n. The fixture
offset becomes valid.
If n is set to 0, the fixture offset becomes invalid.
- When a move command is specified for a rotation axis in G54.2 mode
When a move command is specified for a rotation axis related to fixture
offset in G54.2 mode, vector calculation is performed using the
coordinates of the rotation axis at the end point of the block, and
movement is made to the specified position pointed to by the vector on
the workpiece coordinate system.