INVESTIGATION OF THE PERFORMANCE OF DIFFERENT FACE MILLING INSERTS TO IMPROVE ROUGH MILLING OF SA508 GRADE 3 FORGINGS

摘要

The selection of cutting tool geometry and cutting conditions plays a major part in the planning of machining operations affecting the productivity. Although there are several classifications used by tool manufacturers, carbide inserts for face milling can be categorised according to their cutting edge angle. In this study, the material removal performance of square, round and high-feed inserts, which all have different cutting edge angles, was investigated through cutting trials conducted without coolant on forged SA508 Gr.3 C1.2. Predictive tool life models for round and high-feed inserts were developed by means of the response surface methodology and their adequacy was checked through the analysis of variance. Cutting speed versus feed per tooth contour plots are presented against predicted tool life values which facilitate the selection of cutting conditions ensuring desired tool life. The experimental data has demonstrated that using inserts with lower cutting edge angle would significantly improve cycle times especially in the rough milling stage where the surface integrity is not of primary interest. However, it should be taken into account that limitations exist mainly due to the process stability and capabilities of machine tools.