Mechanism And Experimental Study On Cold Pressing Forming Of Copper Alloy Surface Texture

Surface texture refers to a surface with specific functions through active design and manufacturing that produces micron or submillimeter-scale structures arranged according to certain rules.Surface texture has shown good application prospects in many fields such as anti-friction,anti-wear,vibration reduction,and anti-adhesion.Modern industrial technology provides a variety of processing methods to build different surface textures,such as laser surface micro-modeling technology,surface shot peening technology,photolithography technology,etc.However,the traditional processing technology has many limitations,such as laser surface micro-modeling technology,expensive equipment,serious processing ablation,and a large amount of molten material is formed around the micro groove,causing the groove edge to bulge.Furthermore,these techniques are not always applicable due to severe constraints on materials,cost,processing time,methods and chemical treatments.Aiming at the problems of high cost and low efficiency existing in traditional surface texture processing methods,a high-efficiency and low-cost surface texture processing method,surface texture cold pressing,was studied.The mechanism of surface texture cold pressing was analyzed,and the effects of different loads,spacing and grain size on the results of surface texture cold pressing were studied.The process parameters of cold-pressed surface texture were determined experimentally,and the feasibility of cold-pressed micro-dimple texture to prepare functional surface texture was verified.The main research contents and results of this paper are as follows:(1)The forming mechanism of surface texture cold pressing is analyzed,and the plastic deformation mode of polycrystalline metal materials is introduced.A mechanical analysis of cold forming is performed,stress and strain are introduced,as well as the yield criterion for the material to enter a plastically deformed state.It is found that the surface texture cold pressing can be analyzed and studied by the contact mechanics theory.The contact model consists of a loading phase and an unloading phase.The loading stage can be roughly divided into elastic loading stage,elastic-plastic loading stage and fully plastic loading stage based on the contact deformation form.(2)Self-designed and developed surface texture cold forming system.Load the platform to set the fixture,which can install different molds.The system is loaded by springs,and the loading springs with suitable stiffness can be replaced according to the needs of different loads.A mobile platform is set on the worktable,and the sample to be processed can be accurately moved on the X-axis and Y-axis on the mobile platform.The system is equipped with displacement sensor and load cell,which can realize real-time monitoring of load and displacement during processing.(3)Through the self-developed surface texture cold press forming system,the surface texture cold press forming experiments of circular pits were carried out on copper alloys.Circular pit textures with a diameter of Φ336.0-720.6 μm and a depth of 27.33-110.10 μm were fabricated on the surface of H62 copper alloy.The three-dimensional morphology and size data of the texture were obtained by ultra-depth-of-field microscopy.(4)The effect of different loads on the results of surface texture cold pressing was studied.The results show that the depth of the cold-pressed texture and the diameter of the deformation-affected zone increase with the increase of the imprinting load.(5)The effect of different distances on the cold pressing results of surface texture was studied.Metal flow between cold-formed textures interacts.When the texture spacing is small,the inter-texture metal material will sag downward,lower than the original plane,and form a height difference with the original plane.As the spacing increases,the height difference decreases.(6)The effect of different grain sizes on the cold forming results was investigated.The results show that the change of grain size will affect the depth of cold-pressed texture and the diameter of deformation-affected zone.Under the same imprinting load,with the increase of grain size,the depth of cold-pressed texture and the diameter of deformation-affected zone The diameter increases accordingly.