A process planning strategy was proposed to suppress the wear effect of tool in a polishing of axially symmetrical work. This strategy can keep machining rate of tool to be constant. In study, we need to design the proper dwelling time distribution for tool to remove error of axially symmetrical surface and use computer to simulate. Observe the residual error on surface of work. Analyze the outcome of experiment and estimate feasibility of the strategy. According to the way of motion of tool, it could cause two difficulties: 1.To design the dwelling time distribution of tool will be more difficult. 2.The load of tool will be unstable. In order to solve this first difficulty, in a new strategy of working, the dwelling time distribution of tool must be a multiple of integral of the period of work rotation. And experiment to prove it, analyze and discuss the outcome of experiment. Second problem cause the load of tool to be unstable in experiment. To improve the load of tool, a new strategy was proposed to control load and to verify effectiveness for the strategy. Finally, analysis and discuss the outcome of experiment, and estimate the practicability of the strategy.

Abstract The tool wear characteristics of the hydrodynamic polishing process under various lubricating conditions are examined in this study. Both the experimental and theoretical studies will be done in this paper. In the experimental study, the relationships between tool wear and its possible influential factors will be examined. In the theoretical study, the mathematical model will be established to interpret the qualitative and quantitative relationships between tool wear characteristics and various operating parameters. For the experimental study, a series of experiments will be done to investigate the effect of various factors on the tool wear and machining rate, under non-contact or semi-contact lubricating condition. The factors may include the tool¡¦s angular speed, the applied load, the tool¡¦s surface irregularities, the slurry viscosity, and the properties of tool, workpiece and abrasive particle (such as surface energy). To establish the mathematical model, the principle of dynamics, law of minimum potential energy and elasto-hydrodynamic lubricating theorem of hydrodynamic polishing process are adopted to derive the removal rate model of a particle under differential contact conditions or under various material parameters (such as surface energies or speed constants) from the energy point of view. In addition, the wear rate of tool is to be analyzed. To deal with the random nature of tool¡¦s surface irregularities, the probability theory is applied to calculate the average wear rate of tool, under semi-contact or non-contact condition or under various material parameters. It is shown that both the tool waviness and radius of tool curvature changed and had specific trends in the wear process. Especially, the wear rate of tool under semi-contact lubricating condition was not necessarily large than that under the non-contact one. The experimental data indicated that the effects of tool wear on machining rate highly depended on the lubricating condition of tool. The trend of machining rate versus accumulated machining time under non-contact lubricating condition was very different from that under the semi-contact one. A mathematical model relating the removal capability of an abrasive particle at the tool¡¦s or workpiece¡¦s surface and various operating parameters are proposed. The qualitative properties of removal capability the under different material parameters and various contact conditions are obtained by the computer simulations. The analysis indicates that the relationships between the removal capability and various material parameters (such as surface energies of adhesion or operating conditions) are not monotonic. Under the contact condition, it is shown that the tool¡¦s surface energy of adhesion and the speed constant has a negative effect on the removal capability at tool¡¦s surface. On the other hand, the surface energy of adhesion on work and the speed constants have a positive effect on the removal capability at tool¡¦s surface. For the workpiece, the converse implications are also true. Three types of patterns for removal capability at tool¡¦s surface due to the degree of embedding of a particle were obtained. There are increase or first increase then decrease or decrease directly, respectively. Under non-contact condition, it is shown that the removal capability has a negative relationship with local film thickness. In addition, a mathematical model relating the tool or work piece wear rate and various operating parameters are also proposed. The qualitative properties of tool wear rate under various lubricating conditions are obtained by the simple statistic analysis. The analysis indicates that the relationships between tool and workpiece wear rate and various parameters are also not monotonic. Under non-contact condition, the tool or workpiece wear rate will first increase then decrease due to the tool periphery speed increase. The magnitude of wear rate will decrease or increase due to the material parameters. Under the semi-contact condition, the up-and-down trend is also occurred in the relationship between tool or workpiece wear rate and the tool periphery speed. Accordingly, the relationships between wear rate and tool periphery speed, in a lubricating range covering the non-contact and semi-contact conditions, will reveal a twin-peak pattern. Generally, the workpiece wear rate under the semi-contact condition is not less than the non-contact one. However, the tool wear rate under the semi-contact condition is not necessarily large than the non-contact one. For a specific condition, under the semi-contact condition, the magnitude of the tool wear rate under different speed will increase or decrease by choosing different tool¡¦s surface adhesive energy and speed constant and the relationship between tool wear rate and tool speed will become complex. The wear rate could increase or decrease significantly. In other word, the tool wear rate under the semi-contact condition may be smaller or large than the non-contact one. Hence, a tool with large surface adhesive energy and speed constant should have a lower tool wear rate or higher work wear rate under certain lubricating regime. Finally, the experimental study tests that the proposed model is closely related with the experimental data. The study showed that the qualitative trends of experimental data are consistent with the analytical predictions. Some of the qualitative relationships between tool wear and machining rate could be properly explained from the elasto-hydrodynamic lubrication theorem and the proposed wear theorem for hydrodynamic polishing process.

Abstract The removing efficiency of surface roughness for the hydrodynamic polishing process under semi-contact lubricating condition was investigated in this thesis. The experimental relationships between surface roughness and polishing were first examined. From the relationships, the potential influential factors of the removing efficiency and the magnitude of surface roughness were identified. Finally, a mathematical model that was related to the removing efficiency and the magnitude of surface roughness was proposed. Based on the experimental study, it was shown that the surface roughness would be rapidly reduced at the beginning by polishing process and then hardly improved afterward. This trend implied that surface roughness would not be completely removed during the polishing process. It was proposed that the amplitude and wavelength of surface roughness would affect the removing efficiency of surface roughness. Further, the removing efficiency was not sensitive to the tool velocity. From the mathematical model, several points were concluded. First, the removing efficiency was positively proportional to the amplitude of surface roughness. Second, the removing efficiency was inversely to the amplitude of surface roughness. Third, the removing efficiency was inverse proportional to a waviness of tool surface. Fourth, the removing efficiency was not sensitive to tool velocity. Finally, there existed an achievable minimum surface roughness for a surface with specific wavelength. The magnitude of a minimum surface roughness was shown to be proportional to the wavelength of work surface.

The ultimate value of surface roughness and its characteristic for the polishing process was investigated in this thesis. To find out the nature of ultimate surface roughness by means of the hydrodynamic polishing process and can be used for all polishing method. A preliminary mathematical model that was proposed to explain the ultimate surface roughness proceedings and a series of experiments was planed to verify suitable of this model. Starting with the rule for ultimate surface roughness happened. The assumption that abrasive particle at roughness peak and valley machining capability differ less than one atom, the ultimate surface roughness be attained. We can propose the mathematical model of ultimate surface roughness based on this rule and the previous study of hydrodynamic polishing process. Following by useing the computer simulation to help us exploring ultimate surface roughness characteristic and testing experiments fit for the forecasting. Finally, we explain reasons that cause the experiment results not agree with the model anticipation and propose better lubrication condition to polish the optimum surface.

In this thesis, several machining strategies to remove axially symmetric form error with small wavelength by Hydrodynamic Polishing process (abbreviated as HDP) were proposed. Three strategies were proposed progressively in the study so as to remove axially symmetric form error with small wavelength. The first and second tactics were based on a basic algorithm, say, directly solving of a set of simultaneous equations. In the first strategy, a set of simultaneous equations was constructed by relating the total machining action of each dwelling point to the corresponding initial error. Subsequently, a set of dwelling time was obtained by directly solving the simultaneous equations. The second strategy evaluates solutions in a similar way like the first one but more restrictions were concerned in solution evaluation. The third strategy is an optimal based method. A set of dwelling time was obtained by minimizing an objective function with given constraints. A series of computer simulations were conducted to estimate the residual error and examine the validity of the strategies. From the computer simulation, the first and second strategies were confronted with negative-time problem, so that merely limited improving of form precision was obtained. The proposed optimal strategy was shown to have high potential for improving the machining precision by the HDP process. Based on the proposed strategies, a better form precision of the work surface with small wavelength can be obtained.