Slug float-up preventing method and punch tool

Abstract

Provided are a slug float-up preventing method and a punch tool in performing a punching process on a plate-shaped workpiece (W) by cooperation between a punch tool ( 1 ) and a die tool ( 25 ), in which the workpiece is pressed onto an upper surface of the die tool by use of a plate holder ( 7 ) provided on the punch tool, part of the workpiece is punched out into a die hole ( 27 ) in the die tool by use of a punch blade ( 13 ) provided on the punch tool, a large amount of fluid is blown from a portion of a hole already processed on the workpiece toward a lower side of the punch blade ( 13 ) when the punch blade ( 13 ) is being lifted and is located above a lower surface of the workpiece and below an upper surface of the workpiece, and a small piece of slug located below the punch blade is dropped into the die hole ( 27 ).

1 . A slug float-up preventing method in performing a punching process on a plate-shaped workpiece by cooperation between a punch tool and a die tool, comprising the steps of:
 pressing the workpiece onto an upper surface of the die tool by use of a plate holder provided on the punch tool;   punching a part of the workpiece out into a die hole in the die tool by use of a punch blade provided on the punch tool;   blowing a large amount of a fluid from a portion of a hole already processed on the workpiece toward a lower side of the punch blade when the punch blade is being lifted and is located above a lower surface of the workpiece and below an upper surface of the workpiece; and   dropping a small piece of slug located below the punch blade into the die hole.   
   
   
       2 . The slug float-up preventing method according to  claim 1 , wherein a direction to blow the fluid is a blowing direction directed from around the punch blade toward a central part of the die hole. 
   
   
       3 . The slug float-up preventing method according to  claim 1 , wherein the fluid is formed into a flow which hits the upper surface of the die tool and is directed toward a center of the die hole. 
   
   
       4 . The slug float-up preventing method according to  claim 2 , wherein the fluid is formed into a flow which hits the upper surface of the die tool and is directed toward a center of the die hole. 
   
   
       5 . A punch tool for performing a punching process on a plate-shaped workpiece in cooperation with a die tool, comprising:
 a cylindrical punch guide including a plate holder at a lower end thereof; and   a punch body provided to be vertically movable inside the punch guide and including a punch blade at a lower end thereof, wherein   the plate holder includes a through-hole in which the punch blade is vertically movable,   fluid jet holes not communicating with the through-hole are provided in a plurality of positions around the through-hole, and   the plurality of fluid jet holes are directed obliquely downward so as to concentrate the fluid to a central part of a die hole provided on the die tool.   
   
   
       6 . The punch tool according to  claim 5 , further comprising:
 second fluid jet holes communicating with the through-hole and located in a plurality of positions around the through-hole, wherein   the plurality of second fluid jet holes are directed obliquely downward so as to concentrate the fluid to the central part of the die hole provided on the die tool.   
   
   
       7 . A punch tool for performing a punching process on a plate-shaped workpiece in cooperation with a die tool, comprising:
 a cylindrical punch guide including a plate holder on a lower end thereof; and   a punch body provided to be vertically movable inside the punch guide and including a punch blade at a lower end thereof, wherein   the plate holder includes a through-hole in which the punch blade is vertically movable,   fluid jet holes communicating with the through-hole are provided in a plurality of positions around the through-hole, and   the plurality of fluid jet holes are directed obliquely downward so as to concentrate the fluid to a central part of a die hole provided on the die tool.