Volumetric Compensation System (Vcs) - Siemens SINUMERIK 840D Manual

3.8
Types of VCS
compensation
76
Key functions for 5-axis machining
3.8

Volumetric compensation system (VCS)

As far as the production of large workpieces is concerned, e.g. structural parts on gantry-type
milling machines, it is very difficult to achieve the necessary level of machine positioning accu-
racy due to the large dimensions of the working area. Errors due to sagging, buckling, etc. in par-
ticular can only be remedied mechanically with a great deal of effort.
The volumetric compensation system for the SINUMERIK is a tool for correcting geometric dis-
tortions of the machine mechanics. It reduces the impact of machine errors on the tool center
point (TCP) systematically, thereby increasing the accuracy of the machine.
As part of this process, the machine errors are detected on the basis of measurements and an
error file is generated. VCS then implements the compensation values automatically. To increase
the level of accuracy, calibration and testing with the compensation values can be performed
using an iterative method. VCS automatically compensates the detected errors in conjunction
with TRAORI.
As regards the VCS commissioning process and machine calibration, please contact your
machine manufacturer.
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Below are some examples of the kinds of
error source that can be compensated:
Linear position deviation
Straightness of axes
Unintentional axis rotations
Roll, pitch, and yaw
Squareness of axes in relation to one
another
Tool orientation errors involving swivel
heads