RE: RP & T by B-spline machining

From: Geoff Donohoo (
Date: Thu Dec 04 1997 - 00:36:30 EET

>Besides our Stratasys, Helisys, Kira and Actua machine we make use of
>3, 4 and 5 axis milling techniques.
>In a few days we will order our new High Speed Milling machine from
>Mikron, the HSM 700. We heard that some controlers for such a machine
>like Siemens, Fanuc and Heidenhain/ATEK-HS-plus can use B-spline
>machining for making the product. My question:

>Is there anybody out there who knows anything about B-spline

Yes, but only a little. This ability of the CAM software and the controls on the M/C tool will give much better quality surface finish, smaller NC file sizes and faster cut times

>What is the input for such a controller and which CAD-CAM system van
>make such a input?

Jan, Unigraphics V13.0 supports NURB output, (up to order 4 cubic splines). A UG file looks like this before postprocessing.


>Is there anybody out there who knows anything about the Siemens,
>Fanuc or Heidenhain/ATEK-HS-plus controllers.
These are the three that I know of who currently support this type of interpolation. Some examples follow:-


     N0100 G05 P10000
     N0110 G06.2 P4 K0. X-1.6953 Y-.75 Z-.2358 F10.
     N0120 K0. X-1.6544 Z-.2313
     N0130 K0. X-1.5752 Z-.2225
     N0140 K0. X-1.4053 Z-.2067
     N0150 K.0313 X-1.3031 Z-.1982
     N0160 K.0781 X-1.1215 Z-.1847

     N0330 K.9063 X1.7085 Z-.2373
     N0340 K.9688 X1.75 Z-.2421
     N0350 K1.
     N0360 K1.
     N0370 K1.
     N0380 K1.
     N0390 G01 Y-.7188 Z-.238

Siemens B-Spline

     N0090 X-1.6953 Z-.2358
     N0100 BSPLINE SD=3 PL=0. X-1.6544 Y-.75 Z-.2313 F10.
     N0110 PL=.0313 X-1.5752 Z-.2225
     N0120 PL=.0469 X-1.4053 Z-.2067
     N0130 PL=.0469 X-1.3031 Z-.1982
     N0140 PL=.0313 X-1.1215 Z-.1847

     N0300 PL=.0625 X1.6138 Z-.2263
     N0310 PL=.0313 X1.7085 Z-.2373
     N0320 PL=0. X1.75 Z-.2421

Heidenhain Polynomial

     L X-1.695 Z-.236
     SPL X-1.587 Y-.75 Z-.224 K3X-.0135 K2X.013 K1X-.108 K3Y0.
     K2Y0. K1Y0. K3Z-.0012 K2Z.0005 K1Z-.0111
     SPL X-1.418 Y-.75 Z-.208 K3X.0224 K2X-.0381 K1X-.1531 K3Y0.
     K2Y0. K1Y0. K3Z.0018 K2Z-.0041 K1Z-.0137
     SPL X-1.277 Y-.75 Z-.196 K3X-.026 K2X.04 K1X-.155 K3Y0.
     K2Y0. K1Y0. K3Z-.0022 K2Z.0024 K1Z-.0119
     SPL X-1.164 Y-.75 Z-.188 K3X.0084 K2X-.0073 K1X-.1138 K3Y0.
     K2Y0. K1Y0. K3Z.0007 K2Z-.001 K1Z-.008

>I really like to hear anything from somebody!!!!!

>All the best from Holland and more specific Delft

>Jan Willem Gunnink

Hope this helps. Also you might like to try our web site at

All the best from Australia and more specifically Sydney!

Geoff Donohoo
EDS Australia

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