The application of an inclined end mill machining strategy on 3-axis machining centres

An inclined end mill machining strategy offers an effective machining method for manufacturing low curvature free-form surfaces. The machined surface profile is a close match to the required surface geometry, and standard end mills are available at competitive prices. The amount of surface finishing work is therefore reduced, and the inclined cutting action prolongs the tool life. Although this machining strategy has these advantages, it is not commonly used in manufacturing industry, because it needs the facilities of costly 5-axis machining centres and appropriate post processors are required to generate the NC codes for these advanced machine tools. This paper proposes a simple method which extends the machining capability of the conventional 3-axis machining centre to give the same specifications as a 5-axis machine, and therefore allow the inclined end mill machining strategy to be used on 3-axis machines. The method involves tilting the workpiece instead of tilting the end mill during the machining process. The tool paths are determined by the workpiece rotation and cutter contact point offset equations. The amount of excess material on the machined surface is minimized by choosing optimum pitching and rolling angles at the work set-up stage. The experimental results indicate that the quality of the machined surfaces is improved in comparison with the surfaces machined by ball-nosed cutters, e.g. the resulting cusp volume is reduced by 64%. The research suggests that the need for advanced and expensive 5-axis machining could be satisfied in a more economical machining environment. As a result, the machining cost of the products may be significantly reduced.