The need throughout the machining industry for cost reduction and increases in productivity have contributed to new interest in high-speed machining. Even though, many model for machining exist, most of them are for low-speed machining, where momentum is negligible and material behavior is well approximated by the quasi-static laws. In machining at high speeds momentum could be large and the strain rate can be exceedingly high. For these reasons a uid mechanics approach to understanding high-speed, very high-speed and ultra-high-speed machining is attempted here. 德國LaVision PIV/PLIF粒子成像測速場儀