W1: Tool offset
18.8 Incrementally programmed compensation values
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
1539
Supplementary condition
If the behavior is set such that the offset remains active even after the end of the program and RESET (MD20110
$MC_RESET_MODE_MASK, bit6=1), and if an incremental path is programmed in the first part program block,
the compensation is always traversed additively to the programmed path.
18.8.2 Machining in direction of tool orientation
Typical application
On machines with toolholders with orientation capability, traversing should take place in the tool direction
(typically, when drilling) without activating a frame (e.g., using TOFRAME or TOROT), on which one of the axes
points in the direction of the tool.
This is also true of machines on which a frame defining the oblique plane is active during oblique machining
operations, but the tool cannot be set exactly perpendicular because an indexed toolholder (Hirth tooth system)
is restricting the setting of the tool orientation.
In these cases it is then necessary - contrary to the motion actually requested perpendicular to the plane - to drill
in the tool direction, as the drill would otherwise not be guided in the direction of its longitudinal axis, which,
among other things, would lead to breaking of the drill.
MOVT
The end point of such a motion is programmed with MOVT= .... The programmed value is effective
incrementally in the tool direction as standard. The positive direction is defined from the tool tip to the toolholder.
The content of MOVT is thus generally negative for the infeed motion (when drilling), and positive for the retraction
motion. This corresponds to the situation with normal paraxial machining, e.g., with G91Z ....
If the motion is programmed in the form MOVT=AC( ...), MOVT functions absolutely. In this case a plane is
defined, which runs through the current zero point, and whose surface normal vector is parallel to the tool
orientation. MOVT then gives the position relative to this plane:
Note
With this configuration, part programs must always begin with absolute programming.
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