Study On The Optimization And Application Of The Removal Function Form Of Abrasive Water Jet Polishing

Die steel has outstanding advantages such as high hardness and high stability,and plays an important role in compression molding technology,which is one of the mass production technology of aspherical optical components.Ultra-precision polishing technology is the last process in the manufacturing process of die steel and it is of great significance to improve the surface precision and quality of die steel.Because of that,Fluid Jet Polishing(FJP)has become one of the important ultra-precision polishing methods for die steel due to its high processing quality,freely adjustable removal funetion,low edge effect,and high-steep cavity machining.However,FJP still has problems such as the obscure incident removal mechanism,the difficulty in obtaining the Gaussian removal function,and the lack of the preferred function of the removal function,which restricts the application of FJP in the polishing of the die steel.In order to solve those problems,this paper firstly optimizes the three-dimensional removal model of abrasive particles,and establishes a mathematical model of rotary polishing.After that,the FJP experiment platform is optimized.Based on the platform,the morphology of the Gaussian-type removal function is explored.The law and its regulation method were established.Then the planar polishing roughness prediction model is established and the shape of the Gaussian-type removal function is optimized.Finally,those models and method are verified by polishing the 40CrMnMo7 die steel.The research work of this thesis enriches the theory of abrasive water jet polishing,which is beneficial to promote the application of FJP in polishing mold steel.The major research efforts include the following points.1.Aiming at the physical process of the Gaussian-type removal function which generates the center symmetry removal function from the static oblique incidence removal function by nozzle rotating in FJP,the three-dimensional removal model of oblique incidence is optimized and the corresponding rotational sweep mathematical model is established.After that,the law of morphology of the Gaussian-type removal function under different parameters is explored.2.According to the characteristics and requirements of the FJP,the FJP experimental platform is optimized.Combined with the FJP experimental platform and mathematical model,a rapid method of generating Gaussian-type removal function and the Gaussian removal function topography control method based on nozzle height adjustment are proposed.3.Based on the Gaussian-type removal function of many different topography obtained in the previous research,a unified shape evaluation standard is proposed.the roughness mathematical model of grating line processing is established.The simulation results of different morphology of removal functions are simulated.Base on this prediction results,the morphology of the Gaussian-type removal function is optimized.4.Based on 40CrMnMo7 die steel,the feasibility of cerium oxide abrasive in polishing this kind of die steel was preliminarily explored.Experimental verification of the above mathematical model,roughness model,morphology control method.