Browsing by Subject "Turning--Mathematical models."

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Machining conditions optimization, tool allocation, and tool magazine arrangement on a CNC turning center
(1993) Avcı, Selçuk
In the view of the high investment and tooling cost of a CNC machining center, the cutting and idle times should be optimized by considering the tool consumption and the non-machining time components for an effective utilization. Therefore, it is necessary to develop a new module as a part of the overall computer-aided process planning system, which will improve both the system effectiveness and provide consistent process plans. In this thesis, it is proposed to build a detailed mathematical model for the operation of a CNC lathe which will include the system characterization, the cutting conditions and tool life relationship, and related constraints. Then an algorithm is presented to find tool-operation assignments, machining conditions, appropriate tool magazine organization, and an operations sequence which will result in a minimum production cost.
Unknown
Modeling and optimization of multi-scale machining operations
(2012) Yılmaz, Fevzi
Minimization of production time, cost and energy while improving the part quality is the main goal in manufacturing. In order to be competitive in today’s global markets, it is crucial to develop high precision machine tools and maintain high productive operation of the machine tools through intelligent and effective selection of machining parameters. A recent shift in manufacturing industry is towards the production of high value added micro parts which are mainly used in biomedical and electronics industries. However, the knowledge base for micro machining operations is quite limited compared to macro scale machining processes. Metal cutting, which allows production of parts with complex shapes made from engineering materials, constitutes a large portion in all manufacturing activities and expected to remain so in upcoming years. In this thesis, modeling and optimization of macro scale turning and micro scale milling operations have been considered. A well known multi pass turning problem from the literature is used as a benchmark tool to test the performances of Particle Swarm Optimization (PSO) technique and nonlinear optimization algorithms. It is shown that acceptable results can be obtained through PSO in short time. Micro scale milling operation is thoroughly investigated through experimental techniques where the influences of machining parameters on the process outputs (machining forces, surface quality, and tool life) have been investigated and factors affecting the process outputs are identified. A minimum unit cost optimization problem is formulated based on the pocketing operation and machining strategies are proposed for different machining scenarios using PSO technique.