In order to find out the contact pressure intensity distribution and its effects on the workepiece flatness error in plane polishing with retaining ring,the contact model and the boundary conditions are built up based on the axial symmetric elastic contact theory.The pressure intensity distribution is calculated and analyzed with the help of the Hankel transform theory and the constructing solution method of Chebyshev orthogonal polynomials.And then,the effects of the dimensionless ring-workpiece gap,the load ratio of the retaining ring and the dimensionless ring width on the contact pressure intensity distribution are obtained.Finally,based on the distribution theory of material removal volume,the effects of the pressure intensity distributions on the flatness errors of polished workpiece are also investigated experimentally.The results show that the contact pressure intensity distribution becomes more uniform and the better profile of polished workpiece can also be obtained,if the dimensionless ring-workpiece gap is reduced,the load ratio is selected as 0.6 to 0.85,and the dimensionless ring width is taken as 0.13 to 0.40.
In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by the use of electroplating technology, and also its polishing ability for JGS-2 wafer was investigated by polishing experiments. The research results show that the phyllotactic parameters of the polishing pad influence the arrangement density of the tin fixed abrasive blocks, the polishing pad with phyllotactic pattern is feasibly fabricated by the use of electroplating technology, and the good polishing result can be obtained by using the polishing pad with phyllotactic pattern to polish a wafer when the diameter D of the tin fixed abrasive block is between Φ1.3 mm and Φ1.4 mm, and the phyllotactic coefficient k between 1.0 and 1.1,respectively.
