Multi-spectrum analysis of surface roughness formation in ultra-precision machining

The formation of surface roughness in ultra-precision diamond turning is investigated using a multi-spectrum analysis method. The features on a diamond turned surface are extracted and analyzed by the spectrum analysis of its surface roughness profiles measured at a finite number of radial sections of the turned surface. It is found that the tool feed rate, the spindle rotational speed, the tool geometry, the material properties, as well as the relative tool-work vibration are not the only dominant components contributing to the generation of surface roughness. The material induced vibration caused by the variation of material crystallography is another major factor. The vibration causes a significant variation of the frequency of the surface modulation of the machined surface. With the use of the multi-spectrum analysis method, it is possible to conjecture the patterns of this vibration as well as to evaluate the properties of the workpiece materials.