Influence of machining inclination angle on surface quality in ball end milling

Summarization: In the cutting process with ball end milling tools, especially for free-formed surfaces, the cutting velocity varies according to the contact position of the cutting edge with respect to the workpiece. Taking into account that the cutting velocity of the cutting edge centre is zero, when the cutting tool axis is normal to the cutting plane, the machined surface produced can be rough and it has low quality. As this paper can prove, a machining inclination angle between the cutting tool and the workpiece can improve the quality of the milled surface. The paper presents an analytical model, which was developed in object oriented C++ language and describes the geometry of the milling process with various tools, applied in ball end tools. The model determines quantitatively the topomorphy of the produced surface and the resulting surface roughness. The description of the cutting part is based on the analysis of the workpiece in a number of finite linear segments, the so-called needles. The model takes into account the orientation of the cutting tool, with respect to the workpiece, offering the possibility to alter the tool inclination angles. On the other hand it can support the alternative processing strategies, resulting from these contact angles with respect to feed direction. Herewith, the model is utilized to calculate the influence of various cutting parameters and especially of the milling strategy due to machining inclination angle, in the resulting surface roughness. In addition, the specific software may be used to determine the optimal cutting conditions in multi-axis milling, whereas it has been experimentally evaluated through cutting experiments carried out with the aid of a reliable 5-axis Machining Center.Presented on