Workpiece punch-molding method and workpiece punch-molding device

Abstract

Provided is a workpiece punch-molding method and a workpiece punch-molding device capable of maintaining the thickness of a workpiece at a constant precision. Prior to the punch of a workpiece by a mold punch and a counter punch, the data denoting a relationship between a punch speed of the mold punch and a delay time of the depressurization of the counter punch is obtained. The counter punch is subjected to the depressurization at an early timing based on the obtained data.

1 . A workpiece punch-molding method for punching a workpiece having a predefined shape from a metal plate, comprising:
 a punching step of depressing a punching position of the metal plate being held on a die to punch the workpiece into the predefined shape by a mold punch;   the punching step being configured to include a counter punch pressing step of making a counter punch, which is disposed opposite to the mold punch and is configured to be freely movable in the vertical direction, to follow a punching motion of the mold punch while the counter punch is being pressed to contact the workpiece by a predefined counterweight, a counterweight setting step of generating a fluid pressure from a fluid pressure applying unit to be applied to the counter punch as the counterweight, and a depressurizing step of depressurizing the fluid pressure from the fluid pressure applying unit according to a descended position of the counter punch by a depressurizing unit;   a data obtaining step of obtaining data denoting a relationship between a punching speed of the mold punch and a delay time of a depressurizing motion of the depressurizing unit relative to the punching motion of the mold punch being disposed prior to the punching step; and   the depressurizing unit being actuated at an early timing on the basis of the data obtained by the data obtaining step in the depressurizing step.   
     
     
         2 . The workpiece punch-molding method according to  claim 1 , wherein
 a data storing step of storing the data obtained by the data obtaining step in a storing unit is disposed prior to the punching step, and   the data stored in the storing unit by the data storing step is used to actuate the depressurizing unit in the depressurizing step.   
     
     
         3 . The workpiece punch-molding method according to  claim 1 , wherein the counterweight setting step is configured to include
 a punching speed obtaining step of obtaining the punching speed of the mold punch, and   a fluid pressure adjusting step of adjusting the fluid pressure from the fluid pressure applying unit so as to depressurize the fluid pressure applied to the counter punch following the punching motion of the mold punch according to an increment on the punching speed obtained by the punching speed obtaining step.   
     
     
         4 . A workpiece punch-molding method for punching a workpiece having a predefined shape from a metal plate, comprising:
 a punching step of depressing a punching position of the metal plate being held on a die to punch the workpiece into the predefined shape by a mold punch;   the punching step being configured to include a counter punch pressing step of making a counter punch, which is disposed opposite to the mold punch and is configured to be freely movable in the vertical direction, to follow a punching motion of the mold punch while the counter punch is being pressed to contact the workpiece by a predefined counterweight, and a counterweight setting step of generating a fluid pressure from a fluid pressure applying unit to be applied to the counter punch as the counterweight; and   the counterweight setting step being configured to include a punching speed obtaining step of obtaining a punching speed of the mold punch, and a fluid pressure adjusting step of adjusting the fluid pressure from the fluid pressure applying unit so as to depressurize the fluid pressure applied to the counter punch following the punching motion of the mold punch according to an increment on the punching speed obtained by the punching speed obtaining step.   
     
     
         5 . A workpiece punch-molding device for punching a workpiece having a predefined shape from a metal plate, comprising:
 a die for holding the metal plate,   a mold punch for depressing a punching position of the metal plate being held on a die to punch the workpiece into the predefined shape,   a counter punch disposed to be freely movable in the vertical direction with respect to the mold punch and configured to follow a punching motion of the mold punch while being pressed to contact the workpiece by a predefined counterweight,   a fluid pressure applying unit configured to generate the counterweight by applying a fluid pressure to the counter punch,   a depressurizing unit configured to depressurize the fluid pressure from the fluid pressure applying unit,   a storing unit configured to store preliminarily obtained data denoting a relationship between a punching speed of the mold punch and a delay time of a depressurizing motion of the depressurizing unit relative to the punching motion of the mold punch, and   a depressurizing motion controlling unit configured to actuate the depressurizing unit on the basis of the data in the storing unit so as to depressurize the fluid pressure from the fluid pressure applying unit at an early timing in relation to the delay time of the depressurizing motion.   
     
     
         6 . The workpiece punch-molding device according to  claim 5  is further provided with a fluid pressure adjusting unit configured to adjust the fluid pressure from the fluid pressure applying unit so as to depressurize the fluid pressure applied to the counter punch following the punching motion of the mold punch according to an increment on the punching speed of the mold punch. 
     
     
         7 . A workpiece punch-molding device for punching a workpiece having a predefined shape from a metal plate, comprising:
 a die for holding the metal plate,   a mold punch for depressing a punching position of the metal plate being held on the die to punch the workpiece into the predefined shape,   a counter punch disposed to be freely movable in the vertical direction with respect to the mold punch and configured to follow a punching motion of the mold punch while being pressed to contact the workpiece by a predefined counterweight,   a fluid pressure applying unit configured to generate the counterweight by applying a fluid pressure to the counter punch, and   a fluid pressure adjusting unit configured to adjust the fluid pressure from the fluid pressure applying unit so as to depressurize the fluid pressure from the fluid pressure applying unit following the punching motion of the mold punch according to an increment on the punching speed of the mold punch.