抄録
Due to increasing demands for micro- and/or high-precision parts, ultra-micro cutting technologies have been developed at high speed. The importance of atmosphere in micro cutting has been recognized more and more in recent researches. This is because the effects of cutting environments and/or surface oxidation of a workpiece increase when the scale of cutting decreases. In this paper, based on the results of a series of cutting experiments, we discuss how the atmospheric molecules affect the performance of microcutting. The cutting force, critical depth of cut and scratches formed on the workpiece surface have been examined and compared between the results of cutting in air and those in vacuum environments. The workpieces are silicon mono-crystals that have been exposed to air for various lengths of time after being cleaned with RCA method. The experimental results show that brittle/ductile transition takes place with smaller depth of cut in air than in a vacuum. This implies that the brittleness of a silicon mono-crystal decreases in a vacuum. On the other hand, from the comparison of results obtained using a tool moving back and forth in air and in a vacuum, it has also been found that cutting force decreases if atmospheric molecules are sandwiched between a tool and chip during cutting. This could be because of the lubrication effect of the atmospheric molecules.
