Modeling and optimization of turn-milling processes for cutting parameter selection

Official URL: http://risc01.sabanciuniv.edu/record=b1606668 (Table of Contents)

Turn-milling is a relatively new machining process technology offering important advantages such as increased productivity, reduced tool wear and better surface finish. Because two conventional cutting processes turning and milling are combined in turn-milling, there are many parameters that affect the process making their optimal selection challenging. Optimization studies performed on turn-milling processes are very limited and consider one objective at a time. In this work, orthogonal turn-milling is considered where spindle and work rotational speeds, cutter (tool-work axes) offset, depth of cut and feed per revolution are selected as process parameters. The effects of each parameter on tool wear, surface roughness, circularity, cusp height, material removal rate (MRR) and cutting forces were investigated through process model based simulations and experiments carried out on a multi-tasking CNC machine tool. Tool life and surface roughness are formulated including cutter offset for the first time in this present work. Also, for the first time, turn-milling process is defined as a multi-objective problem and an effective method is proposed to handle this optimization problem. Minimum surface error, minimum production cost and minimum production time are aimed at the same time, and results are generated for selection of optimal cutting process parameters. After optimal parameter sets are found, they are compared with the parameters proposed by tool suppliers in machining tests. In addition, orthogonal turn-milling process is compared with conventional turning process comprehensively in order to demonstrate the process advantages.