A Study on Diamond Turning of Al-Mg Alloy — Generation Mechanism of Surface Machined with Worn Tool

Abstract

It is well-known that the roughness of machined surfaces in diamond turning can be improved with increase of cutting length in comparison with that of the initial stage. This seems to result from an apparent increase in the wear of the diamond tool with cutting length. In this paper, the effect of diamond tool wear on surface roughness is examined for the turning of an Al-Mg alloy. The following results are obtained. (1) The tears generated on the leading end cutting edge of a straight tool deteriorate the surface roughness at a positive tool setting angle. Conversely, the tear marks decrease as the tool wear grows. (2) The surface roughness has a strong correlation with the cutting edge recession of the worn tool. (3) A residual stock removal is generated at a cutting edge recession of more than 0.3μm. Since uneven residual stock removal with tear marks is cut off by the trailing end cutting edge, the surface roughness is improved after a certain cutting length.