Examples - Siemens SINUMERIK 840D sl Function Manual

W1: Tool offset
18.5 Tool radius compensation 2D (TRC)
● At least two blocks must always be taken into consideration:
– The SAR block itself
– The block, which defines the approach or retraction direction
Further blocks can be programmed between these two blocks.
The number of possible dummy blocks is limited with the machine data:
MD20202 $MC_WAB_MAXNUM_DUMMY_BLOCKS (maximum number of blocks with no
traversing motions with SAR).
● If tool radius compensation is activated simultaneously in an approach block the first linear
block of the SAR contour is the block in which activation takes place.
The complete contour generated by the SAR function is treated by tool radius compensation
as if it has been programmed explicitly (collision detection, calculation of intersection,
approach behavior NORM/KONT).
● The direction of the infeed motion and the position of the circle plane or the helix axis are
defined exclusively by the active plane (G17 - G19) - rotated with an active frame where
appropriate.
● On approach, a preprocessor stop must not be inserted between the SAR block and the
following block which defines the direction of the tangent.
Whether programmed explicitly or inserted automatically by the control, a preprocessor
stop results, in this case, in an alarm.
Behavior with REPOS
If an SAR cycle is interrupted and repositioned, it resumes at the point of interruption on
RMIBL. With RMEBL, the contact point is the end point of the last SAR block; with RMBBL, it is
the start point of the first SAR block.
If RMIBL is programmed together with DISPR (reapproach at distance DISPR in front of
interruption point), the reapproach point can appear in a subblock of the SAR cycle before the
interruption subblock.
18.5.4.6

Examples

Example 1
The following conditions must be true:
● Smooth approach is activated in block N20
● X=40 (end point); Y=0; Z=0
● Approach movement performed with quadrant (G247)
● Approach direction not programmed, G140 is valid, i.e. because TRC is active (G42) and
compensation value is positive (10), the contour is approached from the right
● Approach circle generated internally (SAR contour) has radius 20, so that the radius of the
tool center path is equal to the programmed value DISR=10
1420
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions