Research On Thin Sheetmetal Tensile With Ultrasonic And The Effect On Ultrasonic Gas Film Of Micro Bulging

Sheet metal micro-forming process has been widely concerned in the field of manufacturing because of its advantages such as simple process,low cost,high efficiency and energy saving.In order to investigate the mechanical properties of sheet metal during forming,many scholars at home and abroad have done some research on it.In the aspect of ultrasonic tensile,this paper explores the mechanical properties of T2 copper sheet under ultrasonic vibration;in the aspect of sheet metal micro stamping,a new method named Micro instantaneous Viscous medium Ultrasonic thin sheet metal Forming(Micro-VUF)has been presented.Through ultrasonic micro bulging experiment,the main effect of the pressure of ultrasonic head and ultrasonic amplitude and ultrasonic loading time of ultrasonic effect of gas film in film thickness.has been research on this forming process.It is of great significance to further study the sheet metal forming theory.The main research work and conclusions are as follows:(1)The thickness / grain size ratio of T2 copper sheet at different annealing temperatures was investigated.The experimental results show that when the thickness of the copper sheet decreases to a certain extent,the grain size is greatly affected by the thickness of the plate.At the same temperature,with the increase of copper sheet thickness,the grain size of samples is also increased with the increase of thickness / grain size ratio increases;for the same thickness of copper plate,with the increase of heat treatment temperature,the grain size increases,the thickness / grain size ratio decreases with the increase of temperature.When the heat treatment temperature reach to 600?,the thickness / grain size ratio decreased gradually leveled off.(2)The mechanical properties of T2 copper sheet under ultrasonic tensile condition were studied.The results show that when the thickness / grain size is lower than 1,the increase of yield strength increases with the decrease of thickness / grain size ratio,and the deformation resistance decreases with the decrease of thickness / grain size ratio.Compared with no copper sheet annealing,the T2 copper sheet after annealing treatment,its yield strength,tensile strength and elongation were decreased in different degree,which shows the obvious effect of "softening".(3)In the process of Micro instantaneous Viscous medium Ultrasonic thin sheet metal Forming,the effect of pressure on the film is negatively correlated.The influence of ultrasonic amplitude on the thickness of the film shows the law of the first decrease and then increase.With the increase of the ultrasonic loading time,the thickness of the film decreases.For copper sheet thickness of 30?m,heat treatment temperature of 600 ? on micro bulging experiment,ultrasonic head pressure is 3.8MPa,ultrasonic amplitude is 36.54?m,ultrasonic loading time is 1.2s,can be the gas film thickness control between 0.8-2.2?m.