Improved Spiral High-Speed Machining of Multiply-Connected Pockets

We introduce a geometric heuristic for decomposing an arbitrarily complex pocket with or without islands into simpler sub-pockets that are better suited for efficient spiral high-speed machining. Within every sub-pocket we apply a second heuristic for selecting a “good” start point of the spiral tool path. Several machining parameters such as the step-over distance and the engagement angle are considered as measures and indicators for a good tool path. Our heuristics are based on the Voronoi diagram of the pocket contours, and we can handle contours consisting of straight-line segments and circular arcs. The resulting new algorithm for high-speed spiral pocket machining was implemented and tested successfully on real-world data. Our experiments provide strong evidence that our heuristics reduce the total length of the tool path, while also reducing the variation of the curvature and of the engagement angle over the entire tool path, and decreasing the ratio between the maximum and the minimum step-over di...

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