Research On CNC Machining Technology Of Easily Deformable Thin-walled Shell Parts

Thin-walled shell parts are light in weight and low in stiffness.When processed by a multi-axis CNC machining center,deformation is easy to occur,resulting in the dimensional accuracy of thin-walled parts failing to meet the design requirements,resulting in the scrapped workpiece.The milling process parameters are one of the main reasons that affect the quality of CNC machining of parts,and most of the technicians on the actual machining site are determined by consulting the machining manual or relying on personal experience.This method often ignores the influence of machining deformation on machining accuracy and cannot achieve the ideal.Effect.In this paper,aiming at the milling deformation problem of a thin-walled shell part of a mechanical equipment,the problem is studied through two technical routes: special fixture design and milling process parameter optimization,so that the dimensional accuracy of the processed parts can meet the design requirements.First of all,in view of the large cutting amount and low rigidity of the thin-walled shell parts,which are prone to deformation,a special tooling is designed in order to improve the supporting rigidity of the parts and reduce the deformation amount under the conditions of facilitating the assembly and disassembly of the parts and the processing of chip evacuation.Compared with the traditional fixture,the splint and the special tooling splint have the characteristics of less clamping times and large deformation suppression.The traditional fixture and the special tooling splint are analyzed by finite element analysis,and it is found that the deformation of the latter is reduced by 79.1%.Then,the ABAQUS software is used to analyze the cutting process of aluminum alloy materials,and the milling force,milling temperature and deformation amount of the part during the milling process are obtained,and the variation law of the milling force is studied.Secondly,taking the milling force as the optimization target,through the Isight platform,an optimization method of milling process parameters based on the Kriging-MIGA algorithm was proposed.The sample data between the milling parameters and the milling force was designed by the optimal Latin hypercube test method,and the Kriging approximation model between the milling process parameters and the milling force was constructed by using the sample data,and the multi-island genetic(MIGA)algorithm was used for For the optimal solution of the Kriging approximation model,a set of milling parameter combinations that can minimize the milling force is obtained and the predicted value is obtained.The research results show that the milling process parameters optimization based on the Kriging-MIGA algorithm reduces the milling force by 39.37%compared to the one before optimization,and the deformation is effectively controlled.Finally,when the fixture design and milling parameter optimization are completed,the CNC machining process is compiled,and the thin-walled parts are processed and processed.The dimensional accuracy of the processed parts meets the technical requirements after quality inspection.It is verified that the proposed method has certain feasibility and practical application significance.