Design And Numerical Analysis Of Sphericalarc Ultra-high Pressure Die

Due to the characteristics of a relatively stable high-pressure environment and strong holding capacity,the double-sided top mold has special advantages in the manufacture of high-quality synthetic diamond and cubic boron nitride.With the continuous scientific research and the improvement of industrial production level,there is now an urgent need for ultra-high pressure dies with both ultra-high ultimate pressure and large cavity volume.But then comes the challenge of a large size pressure cylinder and steel support ring difficult to manufacture and process.To solve the above-mentioned problems,this article improves the geometric structure of the traditional double-sided die cylinder to make it have high pressure bearing capacity and larger cavity volume without increasing the difficulty of manufacturing and processing.In this paper,we firstly analyze the theoretical stresses in the traditional single-and multi-layer thick-walled cylinders and come up with the optimal method for the design of two-sided top tooling,and then,based on the traditional two-sided top tooling,we change the geometry of the inner wall of the press cylinder from cylindrical to spherical-like spherical arc and design a super high-pressure tooling with spherical arc inner wall.This spherical arc mold solves the technical problem of conflicting pressure capacity and cavity volume of two-sided top mold so that the two-sided top mold can withstand both high pressure and large cavity volume.The DM module of ANSYS Workbench analysis software is used to build the geometric model of the ultra-high pressure mold,and the finite element analysis is carried out for the preload condition and working condition of the mold to verify the safety of the mold under these two working conditions.In this paper,the maximum equivalent stress and maximum shear stress of the cylinder are used as the evaluation indicators of the mold,and the spherical arc ultra-high pressure mold is analyzed.The results show that the proposed spherical arc ultra-high pressure mold reduces the equivalent stress by 15.43% and the maximum shear stress by23.4% compared with the traditional double-sided top mold,which proves that the spherical arc structure can effectively reduce the circumferential tension of the mold.Stress,improve the pressure-bearing capacity of the mold.In addition,a detailed analysis of the mold stress changes is carried out.The analysis results show that the stress distribution of the spherical arc structure is more reasonable.Then,according to the double-layer thick-walled cylindrical shrink sleeve theory,the optimal interference formula of the multilayer prestressed ring is derived and verified,and the main factors affecting the stress of the support ring and the filling method of the cavity volume are explored.Finally,by analyzing the influence law of the transition straight line,transition arc,spherical arc radius,and half cone angle of the spherical arc structure on the stress,the optimal parameter combination of the mold structure is obtained.