Investigation On Ultrasonic Vibration Assisted Plastic Deformation Behaviours And Micro-blanking Mechanism Using Pure Copper Foil

Along with the continuous development of micro-electromechanical systems,higher requirements is made for the quality of micro-foil parts. the more complexshapes, dimensional accuracy and high surface quality requirements of thesemicro-foil parts presents certain challenges for the development of micro-formingtechnology. The paper proposes a new technology of using the ultrasonic vibrationassisted micro-punching to improve the quality of micro-punching process. Metallicmaterials under ultrasonic vibration conditions show a special mechanicalproperties, and ultrasonic vibration assisted micro-stamping is exactly using suchmechanical properties and changes in state of stress during the forming process toimprove the quality of parts. It is important for forming a high precision,high-quality micro-foil parts.To study the effect of ultrasonic vibration on plastic deformation behavior ofcopper plates, paper developed ultrasonic vibration assisted uniaxial tension devicewhich is composed of universal testing machine, ultrasonic vibration system and aconnection device components. The ultrasonic transducer modal analysis is study toensure vibration performance, designing vibrator ends in0.2mm wide,10mm longslot for holding the sample.The paper conducts uniaxial tensile test using with different grain sizes ofcopper plate ultrasonic vibration assisted mechanical testing device. The studyfound that the ultrasonic vibration reduce the yield strength and tensile strength ofcopper plates in the experiment, showing a softening effect of ultrasonic vibrationon metallic materials. Under the ultrasonic vibrations, copper material hardeningexponent increases, annealed copper plate has slightly lower elongation. Rolledcopper plate elongation increased by8%. Fracture of the tensile specimens wereanalyzed showed that under ultrasonic vibrations conditions, the grain has moreintense deformation, and more dimples.Vibration-assisted micro-punching finite element analysis was conducted usinga unilateral gap thickness ratio of6%-20%, respectively, five different blankingclearance in the presence or absence of vibration loading conditions were simulated.The results show that the gap8%is the clearance to blank the best quality. Stress onthe foil plate during the blanking is analyzed, the vibration ease the stressconcentration during blanking, increasing the compressive stress to the hydrostaticpressure in the larger deformation, crack initiation is suppressed. Developed a ultrasonic vibration assisted micro-punching die, studied theinfluence of ultrasonic vibration under different grain sizes and different speedsduring the blanking, the results indicate that the whole blanking cross section isbright band with the annealed state copper foil, but when loading ultrasonicvibration blanking cross section is smooth, lower roughness. When blanking withrolled copper foil, the length of bright band of the blanking cross section increaseswith speed, and ultrasonic vibration increase the length of bright band of blankingcross section. Study the initiation and development of crack during blanking, underthe ultrasonic vibration crack has later initiation, smaller angle tear, flatter tear tapeover the surface, so that the quality is improved.