7 path contours — spline interpolation, Function – HEIDENHAIN TNC 426 (280 476) User Manual
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HEIDENHAIN TNC 426, TNC 430
173
6.7 P
a
th Cont
ours
—
Spline Int
e
rpolation
6.7 Path Contours — Spline
Interpolation
Function
If you wish to machine contours that are described in a CAD system
as splines, you can transfer them directly to the TNC and execute
them. The TNC features a spline interpolator for executing third-
degree polynomials in two, three, four, or five axes.
Example: Block format for two axes
The TNC executes the spline block according to the following third-
degree polynomials:
X(t) = K3X · t
3
+ K2X · t
2
+ K1X · t + X
Z(t) = K3Z · t
3
+ K2Z · t
2
+ K1Z · t + Z
whereby the variable t runs from 1 to 0. The incrementation of t
depends on the feed rate and the length of the spline.
Example: Block format for five axes
You cannot edit spline blocks in the TNC. Exception: Feed
rate F and miscellaneous function M in the spline block.
7 L X+33.909 Z+75.107 F MAX
Spline starting point
8 SPL X+39.824 Z+77.425
Spline end point
K3X+0.0983 K2X-0.441 K1X-5.5724
Spline parameters for X axis
K3Z+0.0015 K2Z-0.9549 K1Z+3.0875 F10000
Spline parameters for Z axis
9 SPL X+44.862 Z+73.44
Spline end point
K3X+0.0934 K2X-0.7211 K1X-4.4102
Spline parameters for X axis
K3Z-0.0576 K2Z-0.7822 K1Z+4.8246
Spline parameters for Z axis
10 ...
7 L X+33.909 Y-25.838 Z+75.107 A+17 B-10.103 F MAX
Spline starting point
8 SPL X+39.824 Y-28.378 Z+77.425 A+17.32 B-12.75
Spline end point
K3X+0.0983 K2X-0.441 K1X-5.5724
Spline parameters for X axis
K3Y-0.0422 K2Y+0.1893 K1Y+2.3929
Spline parameters for Y axis
K3Z+0.0015 K2Z-0.9549 K1Z+3.0875
Spline parameters for Z axis
K3A+0.1283 K2A-0.141 K1A-0.5724
Spline parameters for A axis
K3B+0.0083 K2B-0.413 E+2 K1B-1.5724 E+1 F10000
Spline parameters for B axis with
exponential notation
9 ...