Alarm Behavior; Intersection Procedure For Polynomials - Siemens SINUMERIK 840D sl Function Manual

18.5.11

Alarm behavior

Alarm during preprocessing
If a tool radius compensation alarm is output during preprocessing, main-run machining stops
at the next block end reached, i.e. usually at the end of the block currently being interpolated
(if Look Ahead is active, once the axes have come to a stop).
Alarms for preprocessing stop and active tool radius compensation
Tool radius compensation generally requires at least one of the following traversing blocks
(even more for bottlenecks) to determine the end point of a block. Since the preprocessing
stop of such a block is not available, traversing continues to the offset point in the last block.
Correspondingly, the offset point in the start point is approached in the first block after a
preprocessing stop.
The contour obtained may deviate considerably from the one that would result without
preprocessing stop. Contour violations in particular are possible. Therefore the following
setting data was introduced:
SD42480 $MC_STOP_CUTCOM_STOPRE (alarm response for TRC and preprocessing
stop).
The response of the tool radius compensation remains unchanged compared to the previous
status, and/or an alarm is output for preprocessing stop during active tool radius compensation
and the program is halted, depending on the value.
The user can acknowledge this alarm and continue the NC program with NC start or abort it
with RESET.
18.5.12

Intersection procedure for polynomials

Function
If two curves with active tool radius compensation form an outside corner, depending on the
G code of the 18th group (corner behavior with tool compensation; G450 / G451) and
regardless of the type of curves involved (straight lines, circles, polynomials):
● Either a conic is inserted to bypass the corner
Or
● The curves involved are extrapolated to form an intersection.
If no intersection is found with G451 activated, or if the angle formed by the two curves is too
steep, switchover to insert mode is automatic.
The intersection procedure for polynomials is released with the machine data:
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
18.5 Tool radius compensation 2D (TRC)
W1: Tool offset
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