Die-cast manufacturing method and die-cast manufacturing apparatus, and pressurization means

Abstract

A die-casting method and a die-casting apparatus effectively prevent backward flow of molten metal, and enable additional pressurization to a product injected within a cavity when pressurization of a runner is performed after molten metal injection by a plunger. An injecting portion including first pressurization means that injects a molten metal to a die-casting metallic mold, second pressurization means that pressurizes a runner communicated with the cavity, and an orifice formed on a surface corresponding to a rising runner portion directly connected to the cavity in the runner is provided. When the second pressurization means performs second pressurization through the runner directly connected to the cavity after the first pressurization means injects molten metal, the second pressurization means pressurizes while preventing the molten metal from flowing backward with the orifice in a pressurization passage of the second pressurization means.

1 . A die-cast manufacturing method comprising:
 injecting a molten metal from a sleeve by first pressurization means;   subsequently pressurizing a runner by second pressurization means;   using a pressure pin of the second pressurization means to allow an oxygen supply passage provided in the pressure pin to supply oxygen through a distal end valve; and   after the pressure pin of the second pressurization means is preliminarily moved to project into the runner, filling the cavity with the oxygen via the distal end valve to draw the pressure pin, and subsequently injecting the molten metal with the first pressurization means through the sleeve, and afterwards, performing the runner pressurization by the second pressurization means.   
     
     
         2 . The die-cast manufacturing method according to  claim 1 , wherein
 providing an orifice in a middle of a runner pressurization passage of the pressure pin of the second pressurization means to prevent a gas and the molten metal from flowing backward.   
     
     
         3 . A die-cast manufacturing method comprising:
 injecting a molten metal from a sleeve by first pressurization means after molds are clamped;   pressurizing a runner portion directly connected to a cavity by second pressurization means;   providing an orifice in a runner pressurization passage of a pressure pin of the second pressurization means to allow preventing a gas and the molten metal from flowing backward;   before the injection by the first pressurization means from the mold clamping starts, operating the pressure pin of the second pressurization means to move to a runner advance limit and preventing the gas from flowing backward with the orifice while supplying oxygen to the cavity with an oxygen supply valve disposed in the pressure pin to return the pressure pin; and   after the molten metal injection by the first pressurization means, causing the orifice with the second pressurization means to prevent the molten metal from flowing backward, and performing runner pressurization.   
     
     
         4 . A die-cast manufacturing method comprising:
 injecting a molten metal from a sleeve by first pressurization means after molds are clamped; and   pressurizing a runner portion directly connected to a cavity by second pressurization means, wherein   the method performs steps of:
 an oxygen supplying operation to the cavity from an oxygen supply valve disposed in a pressure pin of the second pressurization means while an orifice prevents a gas from flowing backward, together with a mold clamping starting operation; 
 a molten metal injection operation by the first pressurization means via the sleeve; and 
 a runner pressurization operation by the second pressurization means by the pressure pin while the orifice prevents the molten metal from flowing backward. 
   
     
     
         5 . The die-cast manufacturing method according to  claim 1 , wherein
 the pressure pin of the second pressurization means is provided with a poppet-type valve at a distal end portion, and a valve opening/closing operation thereof opens and closes an oxygen supply passage formed in a center portion.   
     
     
         6 . The die-cast manufacturing method according to  claim 5 , wherein
 the poppet-type valve has a diameter smaller than an outer diameter of the pressure pin, and is opened and closed on a top end surface of the pressure pin.   
     
     
         7 . The die-cast manufacturing method according to  claim 1 , wherein
 the orifice is formed on a surface corresponding to a runner portion directly connected to the cavity in the runner to prevent the gas or the molten metal from flowing backward.   
     
     
         8 . The die-cast manufacturing method according to  claim 1 , wherein
 the molten metal is injected into the cavity via a plurality of branching runners, and the orifice is formed on a rising runner portion of a selected branching runner or on a surface corresponding to a neighboring portion of the rising runner portion to prevent the gas or the molten metal from flowing backward.   
     
     
         9 . The die-cast manufacturing method according to  claim 1 , wherein
 the pressure pin of the second pressurization means has a moving direction that is a direction intersecting with a plunger operation direction of the first pressurization means.   
     
     
         10 . The die-cast manufacturing method according to  claim 1 , wherein
 the pressure pin of the second pressurization means has a moving direction that is a direction parallel to a plunger operation direction of the first pressurization means.   
     
     
         11 . The die-cast manufacturing method according to  claim 1 , wherein
 a new branching runner coupled to a portion where a density improvement is desired performs second pressurization to the cavity.   
     
     
         12 . A die-cast manufacturing method comprising
 when second pressurization means performs second pressurization through a runner directly connected to a cavity after first pressurization means injects a molten metal to clamped metallic molds,
 using the runner as a gas purge runner of the cavity by the first pressurization means; 
 after mold clamping starts, operating a pressure pin of the second pressurization means before the injection by the first pressurization means and preventing a gas from flowing backward with an orifice while supplying oxygen to the cavity by an oxygen supply valve disposed in the pressure pin to return the pressure pin; and 
 after the pressurization by the first pressurization means is terminated, operating the second pressurization means to pressurize the cavity from the gas purge runner. 
   
     
     
         13 . A die-cast manufacturing apparatus comprising:
 first pressurization means that injects a molten metal to a die-casting metallic mold;   second pressurization means that pressurizes a runner communicated with a cavity;   an oxygen supply passage formed with a pressure pin of the second pressurization means as a hollow pipe structure; and   a valve disposed at a distal end of the pressure pin that opens and closes the oxygen supply passage.   
     
     
         14 . The die-cast manufacturing apparatus according to  claim 13 , further comprising
 providing an orifice formed on a surface corresponding to the runner directly connected to the cavity, the pressure pin being inserted through the orifice.   
     
     
         15 . A die-cast manufacturing apparatus comprising:
 first pressurization means that injects a molten metal to a die-casting metallic mold;   second pressurization means that pressurizes a runner communicated with a cavity;   an orifice formed on a surface corresponding to the runner directly connected to the cavity, a pressure pin of the second pressurization means being inserted through the orifice;   an oxygen supply passage internally formed as a hollow pipe structure of the pressure pin and a valve disposed in a distal end portion of the pressure pin, the valve opening and closing the oxygen supply passage.   
     
     
         16 . The die-cast manufacturing apparatus according to  claim 13 , wherein
 the orifice is formed at proximity of a boundary between a sprue core runner portion leading the molten metal injection from the second pressurization means to the cavity and a rising runner portion.   
     
     
         17 . The die-cast manufacturing apparatus according to  claim 13 , wherein
 the runner is formed of a plurality of branching runners, the orifice is formed on a surface corresponding to a selected branching runner, and a valved pressure pin of the second pressurization means is insertable into the orifice.   
     
     
         18 . The die-cast manufacturing apparatus according to  claim 13 , wherein
 the valved pressure pin of the second pressurization means has a moving direction that is a direction intersecting with a plunger direction of the first pressurization means.   
     
     
         19 . The die-cast manufacturing apparatus according to  claim 13 , wherein
 the valved pressure pin of the second pressurization means has a moving direction that is a direction parallel to a plunger direction of the first pressurization means.   
     
     
         20 . The die-cast manufacturing apparatus according to  claim 13 , further comprising
 a new branching runner in the first pressurization means, the new branching runner being coupled to a portion where a density improvement is desired; and   second pressurization means having a valved pressure pin that moves in a direction identical to a direction of a flow of the molten metal within the new branching runner.   
     
     
         21 . A die-cast manufacturing apparatus comprising:
 first pressurization means that injects a molten metal to a die-casting metallic mold;   second pressurization means that pressurizes a runner communicated with a cavity;   the runner serving as an auxiliary runner disposed at a position where the molten metal filling the cavity by the first pressurization means overflows;   an orifice through which a pressure pin of the second pressurization means is inserted, the orifice being formed on a surface corresponding to the runner directly connected to the cavity in the auxiliary runner;   an oxygen supply passage internally formed as a hollow pipe structure of the pressure pin and a valve disposed in a distal end portion of the pressure pin, the valve opening and closing the oxygen supply passage; and   control means that controls a sequence of operations of: after mold clamping starts, and before the injection by the first pressurization means, operating a pressure pin of the second pressurization means and preventing a gas from flowing backward by the orifice while supplying oxygen to the cavity by an oxygen supply valve disposed in the pressure pin to return the pressure pin; and after the pressurization by the first pressurization means is terminated, operating the second pressurization means to pressurize the cavity from the auxiliary runner.   
     
     
         22 . (canceled)