Research On Ultrasonic Micro-drawing Technology Of Metal Sheet Flexible Punch

With the increasing miniaturization of products,traditional machining methods such as rigid stamping have been difficult to meet the processing and manufacturing requirements of micro parts.At present,the micro-forming processes for metal sheets mainly include laser,electromagnetic and viscous medium pressure forming.The flexible punch is used to replace the rigid punch to solve the problem of die centering and difficult processing of the punch.Flexible punching metal sheet micro-stamping is an emerging micro-forming technology.It is by adding EVA plastic powder between the punch and the metal material,and then applying high-frequency ultrasonic vibration to it,causing it to collide violently,friction and The temperature rises to form a flexible punch,and under the force of the ultrasonic head,the metal sheet is pushed into the die to form a micro-punched part.This process will skillfully combine ultrasonic vibration and viscous medium pressure forming,so that it can reduce the flow stress of the material,postpone the contraction,reduce the friction,and improve the micro-drawing,micro-bulging and micro-punching of the metal sheet.Forming limit,etc.This article applies the process to the micro-drawing of thin metal sheets.The main contents of the research are:(1)The early stage is mainly to familiarize with the structural characteristics and working principle of the improved ultrasonic welding machine.Secondly,master the influence of ultrasonic time,pressure holding time,punch pressure,punch position H and ultrasonic amplitude on the ?1.0mm cup drawing deformation,so as to preliminarily determine a set of optimal process parameters.(2)The micro-drawing experiment explores the influence of process parameters on the drawing deformation.In this paper,T2 red copper sheet with a thickness of 50?m and annealed at 450? is used as the forming material to investigate the influence of punch pressure,amplitude and punch position H on the center deviation t.The research results show that when the pressure is 0.1MPa,the deep-drawn part is bowl-shaped.When the pressure is greater than 0.2MPa,the center deviation t increases as the pressure increases.Effect of amplitude on center deviation.It shows that it decreases first and then increases,and the amplitude is the best when the amplitude is 6 130 V.The impact of the punch position H on the center deviation is smaller first and then increases.When H is 0.25 mm,the forming quality is the best.(3)Annealing T2 copper with different plate thicknesses,observing metallography and measuring grain size.Using T2 copper thin sheet with a thickness of 50?m and annealed at300?,375?,450?,525?,600? and 675? as the micro-drawing material,the thickness/grain size of the drawn sheet and the morphology and thickness distribution of the drawn part were studied Impact.The experimental results show that when the plate thickness/grain size is 7.68,the shape of the deep-drawn part is bowl-shaped,and as the plate thickness grain size gradually decreases to 3.05,a ?1.0mm cup-shaped part is successfully pulled out.When the plate thickness/grain size continues to decrease,the deeper the drawing part is,the easier it is to pull.The drawing and thickness measurement of the deep-drawn parts showed that the bottom of the cup was the most severely thinned.As the plate thickness/grain size decreased,the amount of thinning became larger and larger.