A parametric and accurate CAD model of flat end mills based on its grinding operations

Abstract

End mills are widely used in CNC machining. However, the complex structures of end mills make it difficult to define the CAD model which determines the quality and performance of virtual cutting tests. This paper presents an accurate CAD model of end mill through analyzing kinematic models of grinding processes. Initially, a common parametric representation of grinding wheel is given. Base on the given wheel profile and the design parameters of cutters including the rake angle, core diameters and pitch angle, the representation of helix flute surface is first calculated using contact theory and also the formulation of rake angle and pitch angle are investigated. Next, four design parameters are used to control the shape of the gash which is formed via Boolean operation between the given wheel and end mill. Similarly, the peripheral edges and end edges are swept using grinding simulation. Finally, integrating all the above processes, a parametric CAD model of end mill is represented. The simulation results showed that the proposed CAD model could achieve 1e-3 mm and 2e-2 deg. in accuracy, which can be used to evaluate the grinding process or improve the future FEA analysis of end-mills.