| With the development of modern science and engineering technology,especially in the field of microelectronics,the field of optics and their related technologies,the demand for super smoothing surface is increasing day by day,and its surface quality index is becoming higher and higher.The super smoothing polishing method based on loose abrasive is the main method to manufacturing the super smoothing surface.However,the research of the technology is still in the semi-empirical stage,which is greatly influenced by the operator’s experience.Therefore,it is beneficial to establish the appropriate material removal rate model,which could drive super smoothing polishing technology based on loose abrasive from semi-empirical to precise cvontrol.The macro scale model represented by Preston is only concerned with the control of the experimental parameters,and the role of abrasive particles in the polishing process is not carefully considered.Moveover,the micro-mechanism model,which is represented by the model of Jianfeng Luo,molecular dynamics simulation,the atomic force microscopy scratches experiment,seriously consider and analyze the material removal effect of the abrasive particles.However,the external boundary conditions and the experimental parameters in the actual polishing can not be well connected so that these models can not be well proved in the actual polishing experiments.Therefore,on the basis of the mechanism of material removal proposed by the predecessors,this paper proposes the concept of media scale,builds a theoretical model and does experimental research on this scale.It has made breakthrough progress in the following aspects:(1)Based on the differences between the object and the model parameters,the concept of macroscopic scale,microscopic scale and mesoscopic scale for the mechanism of material polishing removal are put forward,and the material removal mechanism of ultra-smooth surface polishing is fully researched.Scale range and research object.The significance of the model of polishing and the mechanism of material polishing on the mesoscale scale are analyzed.(2)On the macro-dimension of media scale,the material removal mechanism is proposed based on the macro scale mechanism of the former scientistes.On the micro-dimension of media scale,the abrasive wear material removal mechanism is proposed for the liquid-storing and non-liquid-storing pad, respectively.Material removal mechanisms/models under the two dimensions for media scale are discussed,and several important factors such as polishing mold / workpiece hardness,pressure and speed are given.The relationship between these two dimensions for media scale is analyzed.(3)The BK7 glass wear experiments were carried by using microtribometer for steel polishing flat,polyurethane polishing pad and pitch polishing pad.Experiment results show the removal mechanisms for these three polishing pads are different.(4)The material removal experiments were carried out at different pressures and velocities of the polyurethane polishing surface based on microtribometer.The experimental results show that the material removal rate is square proportional to the pressure,which is proportional to the velocity.(5)With the aid of the orthogonal experiment method,five factors with three levels were tested by bowl feed polishing,and the removal rate and surface roughness were analyzed.The super smoothing surface with roughness of 0.2076 nm was obtained using the optimized parameters.A range method for PSD curve was proposed and it was used on the 5 factors with 3 levers orthogonal experiments.The PSD curve was divided into three parts and each part was analyzed for maximum and minimum influence factor which is explained by material removal mechanism. |
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