Numerical investigation of advanced manufacturing processes

In metal machining field, turning and milling have been widely used to manufacture many types of mechanical components such as bearing and gears. In turning process, the work-piece normally is a tube or a cylinder. The work-piece rotates from the center point of the work-piece at certain speed, contacting cutting tools, and being cut by the tool to form to components with specific geometry. In milling process, the work-piece is held in position with the tool rotating from the center position of the tool at certain speed, contacting the work-piece, and finally being milled into component with specific geometry. In turning process, the rake face has high temperature and high stresses which will wear and eventually damage the tool. Because of this, many researchers are conducting optimization research in this manufacturing field to minimize the cutting force and temperature on the rake face in order to improve the cutting performance.;In the past, the laser assisted machining (LAM) has been used mainly on machinability studies of difficult-to-machine materials, such as titanium and nickel alloys, structural ceramics, and a variety of materials including metals, composites, ceramics, and semiconductors. Although laser preheating brings about the widely known benefits such as reduced long tool life, cutting force, improved surface finish, and high productivity, few studies concern energy efficiency in LAM or TAM. For LAM/TAM to become economically viable, its cost-effectiveness needs to be justified. In the present research, the energy utilization and efficiency in thermally assisted machining (TAM) of titanium alloy by using numerical simulation has been assessed. The software AdvantEdge FEM is also used to conduct the simulation of orthogonal machining of the workpiece. Thermal boundary conditions are specified to approximate laser preheating of the workpiece material. The effects of operating conditions (preheat temperature, cutting speed, depth of cut, and rake angle) on mechanical cutting energy, preheat energy, and energy efficiency are investigated.;Furthermore, the energy aspects in metal cutting and attempts to provide an overall assessment of energy consumption and energy efficiency against the operating conditions have been investigated. Specifically, the effects of tool geometry and cutting parameters in turning of ANSI 4140 steel are investigated through numerical experiments using finite element simulation. The variables considered include cutting speed, rake angle, nose radius, and edge radius. The effects of these parameters on cutting energy consumption and cutting efficiency are analyzed.;In addition, the effects of different variables (preheating temperature, edge radius, and rake angle) on ductile regime milling of a bioceramic material known as nanohydroxyapatite (nano-HAP) by using numerical simulation is assessed. Commercial software AdvantEdge FEM is also used to conduct the simulation of 2D milling mimicked by orthogonal machining with varying uncut chip thickness. Thermal boundary conditions are applied to approximate preheating of the work material. Based on the pressure-based criterion for ductile regime machining (DRM), the dependence of critical depth of cut on cutting conditions is investigated.;The performance of restricted contact cutting tool in dry orthogonal machining of mild steel (AISI 1045 steel) is also investigated by using finite element simulations. The rake face length of cemented carbide (WC/Co) cutting inserts is shortened. The aim of this research is to examine the effect of shortened tools on machining performance in terms of the main force, thrust force, and chip-tool contact length and to compare them with regular cutting tools. The following restricted tool parameters are examined: length of rake face, alpha angle (the angle between the rake face and the supporting face), and edge radius. At present, researchers are applying micro-textures on the tool rake face to create textured tool in order to optimize the cutting process. In this research area, most researchers have conducted experimental and numerical studies. Lei et al found that the contact length was decreased by using microholes textured tool in lubricated cutting environment. In 2013, Deng et al. (2012) and Wu et al. (2012) found different geometrical characteristics on the cemented carbide tool rake face to machine steel and Ti-6Al-4V.;Finally, in this research, the performance of microhole textured cutting tools in dry three-dimensional (3D) turning of Ti alloy (Ti-6A1-4V) has been investigated. The machining simulation software, AdvantEdge FEM, is used to model and simulate the results. Microholes are designed on the rake face of cemented carbide (WC/Co) cutting inserts. The Johnson-Cook model is used to describe the material behavior of the workpiece. The purpose is to compare the effect between microhole textured cutting tool and non-textured regular cutting tools on machining performance. Specifically, the following microhole parameters are tested: microhole diameter, microhole depth, edge distance (the distance from cutting edge to the first line of microholes), and microhole position pattern.