Abstract
In this paper, turning experiments on a single crystal silicon substrate under atmospheric and high hydrostatic pressure are conducted. And their surface roughness is compared. Generally, hard/brittle materials, such as glass and silicon, are difficult to be machined. However, it has been found that such materials can be machined in ductile manner when high hydrostatic pressure is applied. In order to utilize this effect, we developed precision machining device that works in high pressure environment up to 250MPa. The experimental equipment consists of high pressure vessel, gate-shaped frame for storing and suppressing the pressure vessel, pump system, NC machining device, and a controller. Turning experiments are carried out under atmospheric and 150MPa environment. The surfaces of the machined specimens were observed by laser microscope and their surface roughnesses were compared. We confirmed that the surface roughness of silicon substrate was enhanced by applying high hydrostatic pressure.
