Abstract: A method for generating tool paths for a profile milling task uses straight line (lacing) tool paths toward and away from the exterior boundary of a part to cover a first inset of a machining region. Recess areas which are difficult to reach with straight line access are blocked off, algorithmically, and closed loop tool paths are used for these regions. The remainder of the machining region having relatively regular boundaries are covered with lacing tool paths which are line segments followed by an arc following the part contour. Lacing eliminates the need for predrilling and takes advantage of the fact that most tools perform better when following straight paths. Information supplied by means of charts that assure the safety of milling successive tool paths without retraction, coupled with retraction requirements (also supplied), provide the parameters needed for automated optimal milling.

Abstract: A method is presented to generate 2D tool paths and to optimize the ordering of these tool paths for 21/2 axis milling of cavities for molds and dies. All motion of the cutting tool is dictated and the number of retractions is reduced to a minimum without violating a prechosen set of ordering guidelines. Predrill locations for tool plunges are specified. A 3D solid model of the cavity region with optional islands, avoidance and containment regions is constructed and a planar section through the model forms a closed curve with nested and disjoint loops. Successive inset curves are taken until there are no arcs in the curve. An ordered list of roughing tool paths is generated with a retraction indicated when necessary to prevent gouging, and finishing tool paths are augmented with tangential approach and exit arcs and milled last.