Siemens SINUMERIK 840D sl Programming Manual page 600

Work preparation
3.7 Special motion commands
Spline type
B spline
600
Properties and use
B spline
Check polygon
P3
P2
P1
P1 to P7: specified coordinates
Properties:
● Does not run through the specified intermediate points along the curve, but
only close to them. The intermediate points to not attract the curve. The curve
characteristic can be additionally influenced by weighting the intermediate
points using a factor.
● The curve characteristic is tangential with continuous curvature.
● Does not generate any undesirable oscillations.
● The area of influence of changes to intermediate points along the curve is local.
This means that a change to an intermediate point along the curve only affects
up to max. 6 adjacent intermediate points.
Application:
Their B spline is primarily intended as interface to CAD systems.
P6
P7
P4
P5
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming