Research On The Effect Of Friction Stay And Springback Law Of Cylindrical Part In Hydrodynamic Deep Drawing

With the development of science and technology,the demand for light-weight thinwalled and complex curved forming parts is rising linearly,and also the requirements of forming accuracy are getting higher.Hydrodynamic deep drawing has a good forming effect for the thin-walled complex components.This is due to the convexity in the liquidfilled drawing process.A close contact between the mold and the blank,hich establishes beneficial friction,that is,friction retention effect.The existence of this effect is conducive to providing the forming limit of the formed part.At the same time,the formed part has a higher forming accuracy.The forming accuracy is related to the reduce of the springback of the formed partThis parper establish the relationship among the axial tension of the straight wall area and the liquid pressure and the friction coefficient of the punch through the Hooke's law.It can be seen that the increase of the pressure and the friction coefficient of the punch can reduce the axial tensile stress from the equation.At the same time,through the finite element simulation of 5A06 aluminum alloy,it was found that the pressure below 15 MPa,the wall thickness reduction decreases with the increase of the pressure of the liquid chamber,which plays a role in maintaining friction.Study the influence of the pressure and the roughness of the punch to the friction retention effec.Through the mesh and the static strain shooting,we can found that the reduction in wall thickness and the maximum axial stress and strain decrease as the liquid pressure increases.The punches with different roughness are processed,and it is found that when the roughness is small,the increase of the roughness is conducive to reducing the thickness of the wall,but when the roughness is too large,it will increase the thickness.Based on the traditional bending springback,we explain the liquid pressure can reduce the springback of the punch fillet of the cylindrical part.At the same time,dynaform is used to calculate the rebound of the side wall and the angle of the punch fillet,and the diameter of the die.The rebound decrease with the increase of the pressure,and the bottom surface is uneven.The degree increases as the liquid pressure increases.Conducted experiments on the resilience of the cylindrical part with liquid-filled deep drawing,designed molds that can measure the height of the side wall in real time and the springback of the side wall after unloading.And study the influence of different blank holder forces,materials,thicknesses and the gaps between the molds to the side wall springback effects.At the same time,the punch fillet is performed outside the mold,and the concave mold fillet is near the barrel.The diameter and flatness of the bottom surface were measured.It was found that the resilience of the cylindrical part decreased with the increase of the liquid pressure,and the shape freezing of the cylindrical part gradually became better.At the same time,the larger the yield strength,the smaller the plate thickness,the bigger the gap between molds,the greater the rebound.It is also found that the flatness of the bottom surface becomes worse with the increase of the liquid pressure.