Influence of Steady Vibration with Small Amplitude upon Surface Roughness in Diamond Machining

Abstract

Steady vibrations with small amplitude and low frequency usually remain in precision diamond machine tools even supported on air mounts, and inevitably deteriorate cut surfaces roughness. Analysing an enveloping curve of feed marks disturbed by such a steady vibration, the surface roughness is estimated as the function of both the ratio of vibration amplitude to theoretical roughness, and the phase lag of the vibration to work rotation. This makes it clear that the roughness can be reduced to 20-30% of the sum of the theoretical roughness and a vibration amplitude at optimal cutting conditions. The analytical results are proved in experiments cutting A1 alloy with straight and round tools. The lathe used for the experiment was oscillated at 5.8 Hz frequency, 0.03µmP-p relative amplitude between a tool and a workpiece, by the disturbance from the floor. These results show that straight tools are more effective for improving surface roughness than round ones, and provide a surface roughness within 0.01 µmRmax during the above-mentioned vibration. © 1987, The Japan Society for Precision Engineering. All rights reserved.