Siemens SINUMERIK 840D sl Programming Manual page 179

Description
CAD/CAM systems normally produce linear blocks, which meet the configured accuracy
specifications. In the case of complex contours, a large volume of data and short path
sections can result. The short path sections restrict the processing rate.
The compressor allows a certain number (max. 10) of short path sections to be combined in
a single path section.
The modal G code COMPON or COMPCURV can be used to activate an "NC block
compressor". This function collects a series of linear blocks during linear interpolation (the
number is limited to 10) and approximates them within a tolerance specified in machine data
via a 3rd-degree (COMPON) or 5th-degree (COMPCURV) polynomial. One traversing block
is processed by the NC instead of a large number of small blocks.
COMPCAD
COMPCAD is processor and memory-intensive. It should only be used if surface quality
enhancement measures cannot be incorporated in the CAD/CAM program. Features:
• COMPCAD produces polynomial blocks with a continuous acceleration.
• With adjacent paths, deviations head in the same direction.
• A limit angle can be defined with setting data $SC_CRIT_SPLINE_ANGLE; COMPCAD
• The number of blocks to be compressed is not limited to 10.
• COMPCAD eliminates poor surface transitions. In doing so, however, the tolerances are
• The rounding function G642 can also be used.
COMPON, COMPCURV and COMPCAD extensions
The compressors COMPON, COMPCURV and COMPCAD are extended in a way that even
NC programs for which orientation was programmed via directional vectors, can be
compressed respecting a specifiable tolerance.
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
will leave the corners from this angle.
largely adhered to but the corner limit angle is ignored.
5.4 Compressor (COMPOF/ON, COMPCURV, COMPCAD)
Special Motion Commands
5-15