Injection molding apparatus

Abstract

An apparatus provided is capable of performing injection molding of a high-melting point metal. The injection molding apparatus comprises a mold, a sleeve disposed so as to be movable forward and backward toward a pouring gate of the mold, a plunger slidably disposed in the sleeve, a heating means for heating and melting a raw material lump supplied into a raw material accommodating part formed by an inside wall of the sleeve and the plunger mentioned above, and a raw material lump supplying means for supplying the raw material lump to the above-mentioned raw material accommodating part from above. For the purpose of ensuring that a melt of a metal which has been heated and melted hardly flows into a gap between the plunger and the sleeve, the above-mentioned plunger and/or sleeve is equipped with a cooling means.

1 . An injection molding apparatus, comprising a mold having a pouring gate, a sleeve disposed so as to be movable forward and backward toward said pouring gate of said mold, a plunger slidably disposed in said sleeve, and a heating means for heating and melting a raw material lump supplied into a raw material accommodating part formed by an inside wall of said sleeve and said plunger, wherein said plunger and/or said sleeve is equipped with a cooling means.  
   
   
       2 . The apparatus set forth in  claim 1 , wherein said plunger has an internal space formed therein and extending along its axial direction and a cooling medium supply pipe disposed in said internal space so as to leave a space portion around its leading end portion in the vicinity of a plunger head part and the circumference of a pipe wall, so that a cooling medium supplied through said cooling medium supply pipe may flow through the internal space of said plunger from its leading end.  
   
   
       3 . The apparatus set forth in  claim 1 , wherein said sleeve is provided at its outer peripheral surface with a cooling jacket having a flow path formed in the shape of bellows in its circumferential wall.  
   
   
       4 . The apparatus set forth in  claim 3 , wherein said cooling jacket is divided.  
   
   
       5 . The apparatus set forth in  claim 1 , wherein said plunger is formed from a metal or alloy having a melting point of not less than 800° C.  
   
   
       6 . The apparatus set forth in  claim 1 , wherein part or all of said plunger is formed from ceramic.  
   
   
       7 . The apparatus set forth in  claim 1 , wherein said plunger is provided with a piston ring disposed in the outer peripheral surface of a head part of said plunger.  
   
   
       8 . The apparatus set forth in  claim 1 , wherein said plunger has a main body part and a separate head part.  
   
   
       9 . The apparatus set forth in  claim 1 , wherein said sleeve is formed from ceramic.  
   
   
       10 . An injection molding apparatus, comprising a mold having a pouring gate, a sleeve disposed beneath said mold so as to be movable forward and backward toward said pouring gate of said mold, a plunger slidably disposed in said sleeve, a heating means for heating and melting a raw material lump supplied into a raw material accommodating part formed by an inside wall of said sleeve and said plunger, and a raw material lump supplying means for supplying the raw material lump to said raw material accommodating part from above, wherein said plunger and/or said sleeve is provided with a cooling means.  
   
   
       11 . The apparatus set forth in  claim 10 , wherein said plunger has an internal space formed therein and extending along its axial direction and a cooling medium supply pipe disposed in said internal space so as to leave a space portion around its leading end portion in the vicinity of a plunger head part and the circumference of a pipe wall, so that a cooling medium supplied through said cooling medium supply pipe may flow through the internal space of said plunger from its leading end.  
   
   
       12 . The apparatus set forth in  claim 10 , wherein said sleeve is provided at its outer peripheral surface with a cooling jacket having a flow path formed in the shape of bellows in its circumferential wall.  
   
   
       13 . The apparatus set forth in  claim 12 , wherein said cooling jacket is divided.  
   
   
       14 . The apparatus set forth in  claim 10 , wherein said plunger is formed from a metal or alloy having a melting point of not less than 800° C.  
   
   
       15 . The apparatus set forth in  claim 10 , wherein part or all of said plunger is formed from ceramic.  
   
   
       16 . The apparatus set forth in  claim 10 , wherein said plunger is provided with a piston ring disposed in the outer peripheral surface of a head part of said plunger.  
   
   
       17 . The apparatus set forth in  claim 10 , wherein said plunger has a main body part and a separate head part.  
   
   
       18 . The apparatus set forth in  claim 10 , wherein said sleeve is formed from ceramic.  
   
   
       19 . The apparatus set forth in  claim 10 , wherein said raw material lump supplying means comprises an accommodating device containing a plurality of raw material lumps, a means for transferring the raw material lump disposed in said accommodating device to an upper position above said device, and a means for transferring the raw material lump transferred onto the upper position of the accommodating device to a position above the sleeve.