Effects of AFM tip wear on evaluating the surface quality machined by ultra-precision machining process

In this paper, the influences of tip wear of atomic force microscope (AFM) on evaluating the surface quality were studied. Three typical ultra-precision machined surfaces respectively machined by ultra-precision grinding, ultra-precision turning, and ultra-precision polishing were chosen, and the silicon tips with different wear degrees, the new tip, the moderately worn tip, and the badly worn tip, were employed to scan these three surfaces. By analyzing the AFM scanning results from different tips, each type of surface was characterized with the methods of 3D surface texture parameters and power spectral density (PSD). It was found that the tip wear would mainly degrade the ability of tip on measuring the valley structure and cause more artifacts when measuring the peak structure, which resulted in the effects on evaluating surface roughness parameters and identifying the high-frequency harmonic components. Moreover, due to the different topography characteristics of these three ultra-precision machined surfaces, the influences caused by tip wear on the evaluation of the surface quality were reflected in different aspects.