Key Technology Research Of CNC Hydraulic Die Cushion

With the understangding and explorating on the die cushion via technical status ans development trend in home and abroad,it is observed that when the die cushion is selected for middle and large-size mechanical press,the pneumatic die cushion is with priority,however,with the development of automotive,shipbuilding industry,etc.,the mechanical press develop towards long-stroke,large-tonnage and high-speed.CNC hydraulic die cushion is the core-component for press development,and the CNC hydraulic die cushion is desigened for solving the problems such as punching efficiency,punching quality,noise-reducing during the production of press;hence take the function design of CNC hydraulic die cushion as example,to carry out the study on structure function of pre-acceleration,changing press,die cushion interlocking,which can give an effective help for the design of CNC hydraulic die cushion in series;thus it has a certain reference value.In this paper,we aimed at the key function of the hydraulic tension pad,the pre acceleration.First of all,to determine the position of the starting position of the pre accelerated motion of the stretching pad,the speed of the contact between the stretching pad and the sliding block is respectively analyzed for the pressure fluctuation peak and the stable time of the main hydraulic cylinder.Using AMESim software simulation and MAC8 calculation,the control of the numerical control hydraulic pad of the pre acceleration value,determine the numerical control hydraulic stretching pad of the relative coefficient of the relative sliding speed in 80%.No pre acceleration function,system pressure fluctuations occurred earlier,and the two step,peak pressure,stationary time in 370ms;pre acceleration under the condition of pressure fluctuation in contact with the slider,and no two step change,change of pressure peak pressure is low,stable time 140ms;thus,determine the hydraulic NC cushion pre acceleration function using velocity and position feedback control scheme.Study on the principle of the changing blamk holder force of CNC hydraulic die cushion and confirm its structure and capacity;the design of blank holder force and the confirmation of its control scheme can be carried out by means of the analysis of funcition of changing blank holder force.The locking function of hydraulic NC cushion position feedback,the cushion to the limit position in the punching slider motion,can lock the real return to the slider reset after 500 ms.The design principles do not follow the movement of the slider return;through the cushion locking free,down and down atresia atresia analysis several cases have a reclaimer,pressure curve,provides a solution to solve the position feedback of hydraulic NC cushion locking problem.