Ultraprecision cutting tests were performed on single crystal silicon doped with various elements, and the effects of doping on cutting mechanism were investigated. Raman spectroscopy was used to measure the changes in lattice defects in silicon due to doping, and nanoindentation was used to investigate the changes in material hardness caused by doping. Cutting experiments were performed using a single crystal diamond tool under various conditions. Ductile-brittle transition was determined by the presence/absence of microcracks on the cut surface, and the corresponding maximum undeformed chip thickness was compared. The results showed that element doping decreases the critical chip thickness for ductile-brittle transition and lowers the ductile machinability of silicon.

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Large reflective aspherical optical components with high-precision free-form surfaces and a maximum length exceeding 100 mm are widely used for optical parts of automobile Head-Up Display (HUD) systems, focusing devices for X-ray or neutron beams, etc. On-machine measurement on ultrahigh precision machine tools is an effective method for high precision and rapid manufacturing of large free-form optics. An on-machine surface profile measurement system has been developed for high-accuracy surface profile measurement of free-form optics using a laser auto-focus probe with 1 nm resolution linear scale and high-speed displacement acquisition system. The system enables high-speed and damage-less surface measurement of fabricated optical surfaces made of aluminum or other soft metal materials.

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The substrate material of semiconductor chips is sliced by a multi-wire saw. This processing method involves use of a slurry suspended abrasive grains in base oil. The slurry enters between the wire and workpiece, and the grains in the slurry process the workpiece by scratching or rolling actions. However, the grain actions at the processing part are not clear. Therefore, this study was performed to clarify the processing mechanism of multi-wire saw from the grain actions at the bottom of the sliced groove. The grain actions at the bottom of the groove were observed by high-speed camera. The relations between the grain actions at the bottom of the groove and the processing characteristics were clarified.

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