Effect of tool path generation when machining mold-cavity

Abstract

Studies on the tool path generation for free form surface have been conducted extensively and most of these studies were focused on the effect of tool path generation on the tool wear and surface texture. In this study, the effect of tool path generation on tool wear, surface finish, machining time and dimensional accuracy were evaluated during ball end milling of a mold cavity. UGS CAD/CAM software was used to simulate the tool path and actual during machining at various cutting parameters was conducted on CNC machining centre to machine a concave shape of the mold-cavity component. Work piece of 6061 aluminium alloy and HSS ball end mill were used in this study. Four types of tool path strategies were investigated; they are Follow Periphery, Parallel Line, Concentric Arc and Radial Lines. Result showed that the highest value of 0.04pm flank wear was obtained when using Concentric Arc and the lowest value of 0.01pm was recorded with Parallel Line. Follow Periphery tool path strategy demonstrates the shortest machining time of 115 min and radial line recorded the longest machining time of 352 min. Radial Line and Follow Periphery recorded the lowest and highest surface roughness of 0.95pm and 2-76pm respectively. In average, the smallest error value in dimension was from Radial Line strategy with 0.04% while the biggest error was recorded using Follow Periphery with 0.6%. Based on the result obtained, it can be concluded that Parallel Line and Radial Line produce lower tool wear, smaller error in dimensional accuracy and better in surface finish but longer in cutting time while Follow Periphery and Concentric Arc produce shorter cutting time, higher tool wear, bigger error in dimensional accuracy and poor in surface finish.