Research On Machining Deformation And Surface Quality Control Of AA5083 Al Alloy Thin-walled Parts

The automobile cubing is a 1:1 model made by milling metal materials according to the digital model.It is the basis of car body manufacturing and inspection,which is used to check the assembly quality of the car body,the position relationship between parts,the gap,the height difference of surfaces etc and judge whether the design requirements have been met.The use of automobile cubing can help to ensure the matching of automobile parts or functional modules in the assembly process and the later vehicle interchangeability in the maintenance process.It plays an important role in designing and manufacturing process`of vehicles.AA5083 aluminum alloy is widely used in industry has many outstanding characteristics,such as strong plasticity,good strength,low price,good corrosion resistance,less fuel consumption and little impact on the environment.As the substitute of steel and cast iron,AA5083 aluminum alloy is demanded greatly in the field of automobile cubing manufacturing.However,due to the thin thickness of the body wall and the large amount of material removal,the processing technology of milling AA5083 aluminum alloy mainly depends on the experience of the engineer,which is easy to cause quality problems such as excessive machining deformation and poor surface roughness.To solve the above problems,the main study contents of this master’s thesis are as follows: 1.According to the generation mechanism of residual stress,the residual stress of workpiece after machining is analyzed by using the finite element software Advant Edge FEM,and the deformation of workpiece caused by the release of residual stress is simulated by ABAQUS software.Then the distribution of residual stress and the variation rule of the maximum deformation of workpiece caused by the rake angle,relief angle and helix angle of the cutter are studied.In order to get minimum deformation of the workpiece,the geometric parameters of the cutter were optimized by the Taguchi method,and the suitable geometric parameters of the cutter for milling AA5083 aluminum alloy thin-walled parts were selected.2.Taking the thin-walled parts of the automobile fender cubing as research object,the 3D finite element simulation prediction model of the milling deformation of the thin-walled parts was established through the discussion of the key technology in the simulation process.Then,the influence of three cutting modes(reciprocating milling,following parts and following peripheral)and four types of machining sequence on the deformation of thin-walled parts were studied,which was applied to find the most suitable processing technology for the thin-walled parts of the cubing.3.The milling experimental of thin-walled parts was designed through the Design-Expert experimental design software.According to the measurement results,the response surface method(RSM)was used to propose a second-order prediction model based on the control factors(cutting parameters)and the response parameters(surface roughness,machining deformation),and the analysis of variance(ANOVA)was used to analyze the influence of the control factors on the response parameters.Then,the RSM optimization function and the artificial bee colony(ABC)algorithm were used to optimize the surface roughness and machining deformation at the same time.The optimal cutting parameters were obtained by comparing the optimization results.4.Milling experiments were done to validate the effect of cutter angle,machining method and cutting parameters on the deformation and surface quality of thin-walled parts.Then the control scheme was proposed.According to the optimization scheme,the thin-walled parts of the automobile fender cubing were machined,and the deformation value of the cubing after the processing was measured.Compared with the original processing technology,the measurement results showed that the machining deformation of the thin-walled parts of the cubing after the optimization of the processing technology was reduced by about 35%,which can met the manufacturing requirements of the main engine plant better.