Modelling Topology of Freeform Surfaces with Ball-end Milling

Machining of freeform surfaces, viz. dies, moulds, blades, etc. is one the most difficult processes nowadays. Ball-end milling having either the constant tool pitch for flat and oblique surfaces or the variable tool pitch for freeform surfaces is required to improve the surface quality before the final machining. Among other parameters of the surface quality is the surface topology which is described in the paper. Various strategies of the pre-final working passes in ball-end milling of three different types of the machined freeform surfaces (oblique, convex, concave) of three strategies - "along the trace", "across the trace" and "at an angle to the trace" of the rough machining passes are investigated, six different models representing the combination of the freeform surfaces and the trace shape of the topology of the surface before machining are offered. The calculated dependencies allow forecasting of cutting forces, and, hence, the predictability in obtaining the surface accuracy. (C) 2016 The Authors. Published by Elsevier Ltd.