Proposal of a Ball Burnishing Method with Forced Rotation

Abstract

In this report, a new ball burnishing process in which the ball is forced to be rotated is proposed. A ball rolling friction test apparatus in which the rotational speed of the ball can be controlled was developed. Controlling the rotational speed of the ball can generate any slip speed at the ball and workpiece substrates. It is found that the friction force produced by the slip speed improves the surface roughness of the workpiece. The lubricant oil, which remains at contacting interface, can act a factor to rough the workpiece surface. However, with the proposed process, even in lubricated condition, the processed surface is obtained the similar surface that was observed in dry condition. If the slip speed is not zero, the lowest surface roughness becomes 0.017 μmRa. This result is better than the case of free rotation (the slip speed is zero). Minus rotation (the slip speed is minus) effectively vanish valley parts of the surface. From the spectrum analysis, in minus rotation, the peaks at wide range of wavelength are disappeared.

Keywords

• ball burnishing
• surface finish
• rolling friction
• slip speed
• spectrum analysis