Closing Method and Closing Machine

Abstract

In a closing machine ( 1 ) for closing an open end of a work piece ( 9 ) by pressing a die ( 4 ) heated by a high frequency heating device ( 2 ) against the work piece ( 9 ) rotating about an axial center, the die ( 4 ) comprises a die main body ( 601 ) which contacts the work piece ( 9 ) and a holder ( 611 ) which surrounds the die main body ( 601 ). The die main body ( 601 ) is formed from cemented carbide whereas the holder ( 611 ) is formed from a steel material. The holder ( 611 ) is subjected to induction heating by the high-frequency heating device ( 2 ), whereas the die main body ( 601 ) is heated by heat transfer from the holder ( 611 ).

1 . A closing method for closing an open end of a work piece by pressing a die heated by a high frequency heating device against the work piece rotating about an axial center,
 wherein   a die main body of the die, which contacts the work piece, is formed from a non-ferrous metal, whereas a holder surrounding the die main body is formed from a ferrous metal; and   the holder is subjected to induction heating by the high-frequency heating device whereas the die main body is heated by heat transfer from the holder.   
     
     
         2 . A closing machine for closing an open end of a work piece by pressing a die heated by a high frequency heating device against the work piece rotating about an axial center,
 wherein   the die comprises a die main body which contacts the work piece, and a holder which surrounds the die main body;   the die main body is formed from a non-ferrous metal;   the holder is formed from a ferrous metal; and   the holder is subjected to induction heating by the high-frequency heating device whereas the die main body is heated by heat transfer from the holder.   
     
     
         3 . The closing machine as defined in  claim 2 , wherein the die main body is formed from a cemented carbide. 
     
     
         4 . The closing machine as defined in  claim 2 , wherein the holder comprises a cylindrical die outer wall portion which surrounds the die main body, and an induction coil of the high-frequency heating device is provided so as to surround the die outer wall portion.