Research On Formability Of Ultrasonic Assisted Hydraulic Deep Drawing Micro-parts

Based on the hydraulic drawing of sheet metal,ultrasonic vibration is applied in the process of drawing.The maximum forming limit of sheet metal obtained by hydraulic drawing is greatly improved and the wall thickness distribution of sheet metal is more uniform.The addition of ultrasonic vibration changes the forming performance of ultrasonic assisted sheet metal hydraulic drawing,and the formability of sheet metal can effectively reflect the drawing process of sheet metal.Due to the research of ultrasonic assisted hydraulic deep drawing is rare,in the process of sheet metal drawing,due to the improper selection of technological parameters,will make the sheet metal wrinkle,fracture and other defects,in order to eliminate these defects and further improve the sheet metal forming performance,it is necessary to carry out relevant research.In this paper,the forming properties of sheet metal assisted by ultrasonic were studied by combining finite element simulation and experiment.Based on the characteristics of ultrasonic vibration and the principle of sheet metal hydraulic deep drawing,an ultrasonic assisted sheet metal hydraulic deep drawing forming platform was built.At the same time,the ABAQUS finite element simulation is compared with the experiment to verify the accuracy of the finite element simulation.Through conducting relevant tests on T2 copper plate with outer diameter of 10 mm and thickness of0.3 mm under different ultrasonic application duration,ultrasonic application time,ultrasonic amplitude and punch drawing speed,and comparing with ordinary hydraulic drawing test,analyzing the influence of ultrasonic vibration on the fluctuation of drawing force and fluid pressure required for sheet forming.The influence of ultrasonic vibration on the maximum drawing height and wall thickness distribution is also analyzed.The experimental results show that :(1)the application of ultrasonic vibration can effectively improve the forming limit of sheet metal hydraulic drawing,can obtain a higher maximum drawing height,and the wall thickness distribution is more uniform.(2)The reasonable process parameters of T2 copper plate with diameter of 10 mm and thickness of0.3 mm in ultrasonic assisted sheet hydraulic drawing are: blank holder force of 300 N,fluid pressure of 2 MPa,punch drawing speed of 2 mm/min,ultrasonic amplitude of 16 μm,ultrasonic application time of the whole process.(3)With the application of ultrasonic vibration,the drawing force required by plate drawing is far less than the conventional hydraulic drawing force;The fluctuation amplitude of fluid pressure in ultrasonic test is larger than that in non-ultrasonic test.With the increase of the amplitude,the fluctuation amplitude of fluid pressure increases first and then decreases,and the fluctuation amplitude is the largest when the amplitude is 18 μm.(4)With the increase of ultrasonic amplitude,the maximum drawing height of the same specification plate also increases;The average wall thickness of the plate shows a trend of gradually increasing,the uniformity coefficient of the wall thickness of the plate shows a trend of gradually decreasing,the wall thickness is more and more uniform.