IJMERR Determination and Analysis of Working Diameters and Working Angle of the Torus Cutter Blade in Multi-axis Machining in the Aspect of Tool Wear

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Abstract

During multi-axis machining of sculptured surfaces using the torus milling cutter, the diameters at the characteristic points in the tool-workpiece contact zone are constantly changing, even when the toolpath is constant. There are two main reasons for this. Firstly, the normal vector of the machined surface is constantly changing along the toolpath. Secondly, a different value for the inclination of the milling cutter axis is deliberately introduced relative to the normal vector at set intervals, e.g. in time, thereby taking into account, for example, the wear of the active cutting edge segment of the tool. While the diameter of the cutter changes, the cutting parameters also change. This change affects both the tool life and the uniformity of the machined surface roughness. This paper presents the geometrical-kinematic basis for solving this problem, together with the necessary analyses by considering different kinematic variants of multi-axis cutting. This paper presents a derivation of the theory using transformations in a three-dimensional space with elements of direct tool mapping in a CAD/CAM environment. The geometric-kinematic problem of the cutting process is treated locally, where the general machined surface is replaced at each tool-workpiece contact point by its tangent plane at that point. Based on the results obtained, a method of selecting parameters for multi-axis torus milling was formulated that minimises the change in the instantaneous value of the effective diameter in the contact zone, thus providing more constant cutting parameters with taking into account the tool wear criterion.