An accuracy model for the peripheral milling of aluminum alloys using response surface design

Abstract

In the peripheral milling process, the helical end mill is deflected easily by cutting forces, which results in inaccuracy of the machined surface of the workpiece. Since the cutting conditions involve various cutting parameters and working materials, how to model the multi-variable cutting process and select the appropriate cutting conditions which satisfies the accuracy requirement is an important problem in the present work. A dimensional-accuracy model for the peripheral milling of aluminum alloys under dry and down-milling conditions is presented. The model is postulated as a second-order equation and developed in terms of the Brinell hardness of the workpiece, the cutting speed, the feed, radial and axial depths of cut. To build the quadratic model and minimize the number of experiments for the design parameters, response surface methodology (RSM) with an orthogonal rotatable central composite design is used. By means of variance analyses and additional experiments, the adequacy of this model is confirmed. The model will be very useful in selecting cutting conditions to meet the accuracy requirement in peripheral milling operations. Using the model, the effect of each of the cutting parameters on the dimensional accuracy is analyzed. It is shown that the peripheral milling accuracy will be reduced with increasing values of workpiece hardness, feed, radial and axial depths of cut, but increased when a high cutting speed is employed. It is found also that the radial and axial depths of cut have the most significant influence on the accuracy in the peripheral milling aluminum alloys.