Detailed Description
2.4 Tool: Tool radius compensation 2D (TRC)
Tool Compensation (W1)
2-50 Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
• DISR: Specifies the length of a straight approach line or the radius of an approach arc.
On approach/retraction along a straight line, DISR specifies the distance from the cutter
edge to the start point of the contour, i.e., the length of the straight line with active TRC is
calculated as the total of the tool radius and the programmed value of DISR.
An alarm is output on approach and retraction with straight lines:
– If DISR is negative and the amount is greater than the tool radius
(the length of the resulting approach line is less than or equal to zero)
With circles, DISR always specifies the radius of the tool center path. If tool radius
compensation is activated, a circle is generated internally, the radius of which is
dimensioned such that the tool center path is derived, in this case also, from the
programmed radius.
An alarm is output on approach and retraction with circles:
– If the radius of the circle generated internally is zero or negative
– If DISR is not programmed
Or
– If the radius value ≤ 0.
• DISCL: Specifies the distance from point P
2
to the machining plane.
If the position of point P
2
is to be specified by an absolute reference on the axis
perpendicular to the circle plane, the value must be programmed in the form DISCL =
AC( ....).
If DISCL is not programmed, points P
1
, P
2
and P
3
are identical with G340 and the
approach contour is mapped from P
1
to P
4
.
The system checks that the point defined by DISCL lies between P
1
and P
3
, i.e., in all
movements, which have a component perpendicular to the machining plane (e.g., infeed
movements, approach movements from P
3
to P
4
), this component must have the same
leading sign. It is not permitted to change direction. An alarm is output if this condition is
violated.
On detection of a reversal of direction, a tolerance defined by the machine data:
MD20204 $MC_SAR_CLEARANCE_TOLERANCE
is permitted.
However, if P
2
is outside the range defined by P
1
and P
3
and the deviation is less than or
equal to this tolerance, it is assumed that P
2
is in the plane defined by P
1
and/or P
3
.
Example:
An approach is made with G17 starting at position Z=20 of point P
1
. The SAR plane
defined by P
3
is at Z=0. The point defined by DISCL must, therefore, lie between these
two points. MD20204=0.010. If P
2
is between 20.000 and 20.010 or between 0 and -
0.010, it is assumed that the value 20.0 or 0.0 is programmed. The alarm is output if the Z
position of P
2
is greater than 20.010 or less than -0.010.
Depending on the relative position of start point P
0
and end point P
4
with reference to the
machining plane, the infeed movements are performed in the negative (normal for
approach) or positive (normal for retraction) direction, i.e., with G17 it is possible for the Z
component of end point P
4
to be greater than that of start point P
0
.
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