Studies On Forming Mechanism And Control Methods Of Reverse Tonnage In Blanking Press

The blanking press,as one of a mechanical press,can offer several benefits in terms of low cost,strong bearing capacity and high efficiency.It has been widely used in punching,blanking and other cutting processing,and has great potential applications in the fields of automotive,appliances and aerospace.However,the cutting and blanking operations are always associated with large reverse tonnage,leading to violent vibration of blanking press and loud noise.At present,the reverse tonnage has become a key technical problem which severely limits the development of blanking press.In response to the problems above,the formation mechanism and control method of reverse tonnage have been systematically investigated in this work,original results with important theoretical and practical value have been obtained.The related research results have been applied to the JE31-1250 blanking press of the CAMC Co.,Ltd.The major research work and achievements are summarized as follows:A numerical simulation method of blanking process for blanking press has been proposed.Finite element analysis model of blanking process has been established,the variation rule of the maximum blanking force in the blanking process has been revealed.The affects of blanking speed,die clearance and plate thickness on maximum blanking force have been investigated.The approximate computing model of the maximum blanking force has been established by Central Composite Method.The fracture process of sheet metal has been studied and the formation mechanism of reverse tonnage has been revealed.The dynamic and kinematic model of blanking press has been constructed,and the mathematical model of reverse tonnage has been established.The influences of reverse tonnage on the vibration of crown and slide,the displacement of slide,and the strain of the connecting rod have been discussed,and the increase of frame stiffness cannot reduce the reverse tonnage has been found.The reverse tonnage tests of the blanking press were carried out,and the mathematical model of reverse tonnage has been proved as rational by the test.A reverse tonnage control method for blanking press has been proposed and hydraulic dampers have been developed.As a result,the reverse tonnage has been eliminated,vibration acceleration of the slide and crown has been reduced,and the section morphology of sheet metal has been improved by hydraulic dampers.The engineering application tests have been carried out to verify the work validity of the hydraulic damper.The influence of hydraulic damper force on reverse tonnage was studied,and the optimum working position of the hydraulic damper work was determined.This test has provided a factual basis for wide applications of the key technology in this paper.