Bicubic Patch Surfaces for High-Speed Numerical Control Processing

Parametric bicubic patch surfaces have been used for some time in manufacture and design. It is convenient to have such surfaces available as standard numerical control surfaces using the APT programming language. A major drawback is that they are costly to use for data processing of numerical control programs. If, however, nonparametric bicubics are used, computer time, and hence cost, can be reduced dramatically. This paper details a strategy and algorithms for this purpose. Experimental data suggest that computer costs are comparable to, or somewhat lower than, the costs for processing tabulated cylinder surfaces.