Die Casting Mold and Improved Vent Structure Used Therein

Abstract

A die casting mold includes a resistance member ( 17 ) disposed in a vent passage ( 16 ) to reduce a flow velocity of molten metal as the molten metal advances along the vent passage. The resistant member comprises a plurality of discrete protrusions ( 24 ) arranged in staggered relation to one another in both a longitudinal direction and a transverse direction of the vent passage so as to define therebetween a labyrinthine part ( 34 ) extending between an inlet side and an outlet side of the vent passage.

1 . A die casting mold comprising:
 a fixed mold member;   a movable mold member movable toward and away from the fixed mold member to define therebetween a die cavity when the die casting mold is closed;   a vent passage formed in a mating surface of one of the fixed mold member and the movable mold member and extending in communication with the die cavity to allow for escape of residual air and/or gas from the die cavity when a molten metal is charged into the die cavity; and   a resistance member disposed in the vent passage to reduce a flow velocity of the molten metal as the molten metal advances along the vent passage, wherein the resistance member comprises a plurality of discrete protrusions arranged in staggered relation to one another in both a longitudinal direction and a transverse direction of the vent passage so as to define therebetween a labyrinthine part extending between an inlet side and an outlet side of the vent passage.   
   
   
       2 . The die casting mold as claimed in  claim 1 , wherein the other of the fixed mold member and the movable mold member has a mating surface including a flat portion adapted for abutment with top surfaces of the protrusions. 
   
   
       3 . The die casting mold as claimed in  claim 2 , wherein the top surfaces of the protrusions are flat and engageable flatways with the flat mating surface portion of the other mold member. 
   
   
       4 . The die casting mold as claimed in  claim 1 , the labyrinthine part of the vent passage including a plurality of parallel spaced first grooves extending in the longitudinal direction of the vent passage and a plurality of parallel spaced second grooves extending in the transverse direction of the vent passage, the second grooves being deeper than the first grooves. 
   
   
       5 . The die-casting mold as claimed in  claim 1 , wherein the resistance member is formed by a separate member structurally independent from the one mold member and removably mounted to the one mold member, the resistance member including a flat plate-like base detachably mounted to the one mold member with the protrusions formed on one surface of the flat plate-like base. 
   
   
       6 . A chill vent structure for a die casting mold, comprising:
 a flat plate-like base; and   a plurality of discrete protrusions formed on one surface of the flat plate-like base and arranged in staggered relation to one another so as to define therebetween a vent passage of labyrinthine structure.   
   
   
       7 . The chill vent structure as claimed in  claim 6 , wherein the protrusions have flat top surfaces. 
   
   
       8 . The chill vent structure as claimed in  claim 6 , wherein the vent passage includes a plurality of parallel spaced first grooves extending in a longitudinal direction of the vent passage and a plurality of parallel spaced second grooves extending in a transverse direction of the vent passage, the second grooves being deeper than the first grooves.