森田 昇

An atomic force microscope (AFM) can trace surface roughness using a contact probe in a similar manner to a stylus instrument, and the AFM has the advantages of high lateral resolution and low contact force because of its very soft cantilever and a feedback controller that keeps the contact force constant (less than 10-8N). However, such features can cause measuring errors characteristic of an AFM. In this study, a standard sample was measured using an AFM under certain conditions in order to extract the errors from the results. The distortion of the cantilever was also observed using a microscopic interferometer. As a result, it was clarified that the cantilever was bent unexpectedly by a lateral force which acted on the tip of the probe. The feedback controller could not trace the surface geometry precisely because the precision angle sensor using an optical lever mistook the force which acted on the tip.

In this study, which is aimed at understanding machining characteristics and tribological phenomena in vacuum, a machining system in a vacuum chamber which pressure is 6.0 × 10-5Pa, is developed and diamond cutting experiments using a aluminum workpieces are carried out. The cutting system is a face turning composed of a high speed spindle with a magnetic bearing, that revolves at 22 000 rpm in vacuum, and a diamond tool with rake angle 0 deg and flank angle 5 deg. Cutting behaviors in vacuum are similar to those in argon gases, and also those in air and oxygen are in a similar way. For instance, the cutting force in vacuum and in argon gases is larger than that in air and oxygen, and phenomena like a built-up edge generate in air and oxygen, but that is not observed in vacuum and argon gases. The similarity depends on the pressure or absence of oxygen. It is found that those results depend on the pressure or absence of oxygen.