Prediction of Surface Profile Evolution of Workpiece and Lapping plate in Lapping Process

Lapping has a history of hundreds of years, yet it still relies on the experience of workers. To improve the automaticity and controllability of the lapping process, a modeling method of friction and wear is developed to predict the surface profile evolution of the workpiece and lapping plate in the lapping process. In the proposed method, by solving the balance equations of resultant force and moment, the inclination angles of the workpiece can be calculated, thus more accurate contact pressure distribution of the workpiece/lapping plate interface can be calculated. Combined with the material removal rate model, the continuous evolution process of the workpiece and lapping plate can be predicted in the lapping process. The modeling method was validated by a lapping test of a flat optical glass (Φ 100 mm) with a composite copper plate. The results show that the proposed method can predict the evolution of the surface profile of the workpiece and lapping plate with high accuracy. Consequently, the lapping plate can be dressed at the right time point. Benefit from this, in the validation test the PV value of the workpiece (with 5 mm edge exclusion) was reduced from 5.279 μm to 0.267 μm in 30 min. The proposed surface profile evolution modeling method not only improves the lapping efficiency but also provides an opportunity to understand the lapping process.

Theoretical modeling and experimental research on the depth of radial material removal for flexible grinding

Abrasive belt flap wheel has large elastic deformation, which can better fit the surface of aero-engine blades. Reasonable control of the depth of radial material removal can effectively improve the grinding efficiency and profile accuracy of the blade surface. The depth of radial material removal for flexible grinding was studied through the process parameters in this article. First, the material removal rate model was established based on Hertz elastic contact theory and Preston equation. Then, according to the principle of equivalent material removal volume, a noval approach to determine the depth of radial material removal was proposed. Finally, the experiments for both plane and surface were implemented on a vertical machining center. The results indicate that the proposed method can improve the accuracy and consistency for flexible grinding.

The Experimental Study on Mechanical Polishing on Materials with Hydrolysis Reaction

The hydrolytic properties of LiAlO2 (LAO) are important factors for its applications on LED fabrication. During soft pad polishing process, the H2O in the slurry is deleterious for LAO surface polishing results. The current study develops a material removal rate model for materials with hydrolysis reaction to predict the result of polishing process.The current research conducts the experimental studies to investigate the material removal rate and its mechanism during the soft pad polishing process. In the experimental study, the hydrolytic properties of LAO have been tested to understand the hydrolysis speed with different operation parameters to assist the development of the theoretical model. Also the material removal rates of LAO with hydrolytic property have been measured under different soft pad polishing operating conditions. The experimental results provide the hydrolytic properties of LiAlO2 to understanding of the mechanism on polishing process.