Simulation Study On Cold Pressing Precision Forming Of Surface Texture

Surface texture is considered to be an effective means to improve the surface contact mode and lubrication state of the friction pair.The micro-surface texture processing through the coldpressing precision forming has the advantages of high processing efficiency,low cost and low equipment requirements.It is suitable for high volume production applications in industry.Surface texture during the cold forming process,the microstructure of the workpiece surface makes the data and information from the macro-scale deformation mechanics no longer fully valid,and scale effects will occur,resulting in significant differences in material properties.Therefore,in order to avoid and reduce the size effect,improve the quality of materials after forming,and reduce the cost and cycle of research,this paper uses the finite element method of crystal shaping through the secondary development of Abaqus and the combination of material user subprograms.The cold pressing precision forming of copper surface texture was studied by simulation.The main research contents and results of this paper are as follows:(1)The effect of grain size on deformation behavior during single-point surface texture microstructure processing was studied.As the grain size decreases,the strength and hardness of the workpiece surface will increase,and the load force required for processing will increase,resulting in higher elastic rebound at the end of processing.The surface of the workpiece after cold pressing will form a pile-up phenomenon in the 45° direction of the workpiece due to the flow of metal;and it is found that the workpiece with a grain size of 35μm shows a lower residual stress value after cold pressing,it has excellent mechanical properties and is most suitable for cold-pressed precision forming production.(2)The effect of friction coefficient on deformation behavior during surface microstructure machining was studied.The single-point microstructure cold forming is simulated.With the increase of the friction coefficient between the indenter die and the polycrystalline copper workpiece during the processing,the deformation load force increases,and the surface protrusion in the processing area will increase.When the friction coefficient is greater than 0.1,the processed polycrystalline copper workpiece shows lower elastic rebound.(3)The effect of the micro-indenter microstructure array size on the deformation behavior of the workpiece during surface texture processing is simulated and analyzed.Under the same indenter microstructure spacing,a smaller indenter size will reduce the interference phenomenon in the processing process and improve the performance of the workpiece.Affected by the reduction of the processing range,the grain refinement strengthening effect will also be weakened,and the overall strength and hardness of the machined surface will be reduced.The simulation results of micro-indenter microstructure array forming surface texture and singlepoint microstructure cold-pressing precision forming are compared and analyzed.Under the same indenter microstructure size,there is a multiple relationship between single-point texture cold pressing and multi-point texture cold pressing.(4)When the surface texture is formed,the microstructure spacing of the indenter has a great influence on the deformation behavior of the workpiece.As the surface texture microstructure spacing increases,the surface strength of the polycrystalline copper workpiece increases.,and the amount of protrusion decreases,and the interference phenomenon gradually weakens.When the surface texture spacing is 300μm,the influence of the processing interference between the microstructures basically disappears,and the surface quality is better.When the microstructure spacing is greater than 200μm,the load required for processing became stable.