Optimization of machining strip width using effective cutting shape of flat-end cutter for five-axis free-form surface machining

Abstract

Tool postures of the flat-end cutter can make a huge difference to both machining strip width and machining efficiency in five-axis end milling. Most of current methods evaluate the machining strip width and implement a tool orientation optimization by finding two intersection points between the effective cutting profile of a flat-end cutter and the offset surface profile which represents machined surface. However, real machining strip width and real residual height should be formed between two adjacent cutter contours. As the results, two problems of current methods cannot be avoided: (1) Machining strip width computed on a single cutter location cannot accurately represent the distance between two adjacent tool paths and (2) excessive overlap or larger span length between two adjacent cutter contours leads to unsteady residual height, which causes surface quality differences. In order to solve the above problems, a more suitable method for computing machining strip width is presented and proved in this paper. A flat-end cutter is adopted and the analytical model of effective cutting shape for this kind of tool is constructed firstly. Later, a geometric foundation to achieve optimization is established by investigating the impact of different flat-end cutter postures on the machining strip width. Furthermore, the reasonable strip width is obtained and optimized by implementing an iterative and optimization approach under the given scallop height. A three-dimensional centrifugal compressor blade is used as a numerical example to verify the approach presented in this paper. To prove the superiority of the involved method, the research gives a comparison with UG method with the same cutting parameters. Numerical experiment suggests that machining efficiency of the paper’s method improves by 37.85%. Finally, a machining simulation is performed in the VERICUT software to testify that a uniform error distribution is created.