Effect of various assisted machining technique applications on cutting performance of quartz glass milling

摘要

The three stage experiments including without assistance, uniaxial ultrasonically assisted and biaxial ultrasonically assisted machining systems on quartz glass milling were constructed in this study in order to verify the assisted effect on cutting performance and to compare the merit and limitations among them. First of all, the milling experiment without assistance was performed to investigate the variations of cutting performance. Next, uniaxial ultrasonically assisted system (y direction oscillation) and a biaxial ultrasonically assisted system with simultaneous dual-axis oscillations (x and y directions) were subsequently introduced at the second to the third stage experiments, respectively. At each stage experiment, the effects of process parameters on the variations of the machined surface quality and cutting-tool wear are investigated. It is expected that the machinability of this high brittle material can be promoted resulting in good cutting performance and smaller cutting-tool wear. A biaxial ultrasonically assisted machining system is designed, fabricated and mounted on a machine-tool worktable. At the meantime, a long-term oscillation test including calibration and detailed adjustment is conducted repeatedly until the normal manipulation of the whole system is assured. Under these assistances, milling experiments of quartz glass by cutting-tool of extra-fine particle tungsten carbide with nACo® coating were conducted. And the full factorial experiments of process parameter combinations such as feed rate, cutting velocity and radial depth of cut were also planned. During the experiments, dynamometer is used to monitor the variation of cutting force. Tool wear, edge-indentation and side surface morphology of the quartz glass will be measured by tool-microscope off-line. Surface roughness measurement through a probe contact type instrument is also performed. The results show that the milling experiment with a biaxial ultrasonically assisted machining system with simultaneous dual-axis oscillations has the better results than those experiments without assistance and with uniaxial ultrasonically assisted. Because the use of this biaxial ultrasonically assisted system, the cutting performance of tool wear and surface roughness are improved significantly.