Nagy, Peter Victor
M.S. (Master of Science)
Department of Mechanical Engineering
Metal-cutting--Simulation methods; Time-domain analysis
Global competitiveness is forcing manufacturing companies to make a critical review of every aspect of their businesses. In most machine shops, the profit margin is typically quite low. Optimized processing is required to ensure a profit. Simulation of metal-cutting processes provides substantial opportunities for enhancing throughput, decreasing costs and improving product quality. The use of computer simulations to avoid unstable cutting processes is one area where significant gains can be realized. Time domain simulation models were developed for both plunge feed turning and slender endmilling. Simulations were conducted using C++ computer programs. Chatter (i.e., excessive tool vibration) is shown to exist beyond a stability limit of chip width for both cases. Sinusoidal varying tool displacements are demonstrated to contribute to regenerative surface waviness (i.e., causing varying chip thickness) for all chip widths. A nominal tool displacement that is proportional to chip width arises due to the tool compliance and force exerted on the tool. When chip widths are below a limiting size for stability, displacement amplitudes decay towards the nominal tool displacement value. For chip widths at the stability limit, a constant amplitude of the tool displacement around the nominal value occurs. A constant growth of the displacement amplitude occurs for chip widths above the stability limit. Generally, the growth rate in the amplitude is fester for larger amounts of excessive chip widths. However, the amplitude growth is limited when the tool momentarily and repeatedly leaves the cut corresponding to chatter. Experimental verification was performed utilizing a Kistler force dynamometer, a Tektronix data acquisition system, a Renault lathe and a Mori-Seiki machining center. Good correlation was achieved between experiments and simulations.
Hoefler, Brian, "Time domain simulations of metal-cutting systems with experimental verification" (1997). Graduate Research Theses & Dissertations. 6466.
viii, 102 pages
Northern Illinois University
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