| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 90 === The multi-axis machining of complex surface is not only a fast and accurate method but also reduces errors of workpiece set-up. However, engineers usually determine set-up orientation by experiences and often they cannot finish complex surfaces at one set-up. If there is a rational evaluation for the workpiece orientation and the configuration of machine tool before planning of toolpath, it would increase the efficiency of process development.
Adapting the visibility cone together with workspace analysis, the selection module for the optimum workpiece orientation and the suitable configuration of machine tool was constructed in the thesis. First, the configurations of 3,4 and 5-axis machine tools were synthesized and then, the workspace was analyzed using form-shaping function. The position and normal vector of each point along u, v directions in the machining surface were got to calculate the visibility range as the point of the visibility cone. In 3-axis machining, all normal vectors of surface were projected on a unit sphere. All normal vectors had to be in the visibility range of the ball mill cutter as the workpiece set-up orientation changed. In 4-axis machining, the most intersection between the visibility cone of each point and the workspace was found by changing the set-up orientation. In 5-axis machining, according to different workspaces of 5-axis machine tools, the visibility range of machining surface was determined to find the most intersection between the visibility cone and the workspace by changing the workpiece orientation.
This thesis proposed a method of manufacturability evaluation to obtain the optimum workpiece set-up orientation and the suitable configuration of machine tools. The tool interference with surface can be avoided to improve the planning of toolpath. For manufacturing, it can reduce cost by changing to optimum set-up orientation. For selection machine tool, it can also avoid the use of unsuitable configuration of machine tool.
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