Die-casting mold structure for thin-walled zinc alloy shells for electrical connectors

Abstract

The present invention discloses a die-casting mold structure for a thin-walled mini zinc alloy shell. The mold structure includes a longitudinal runner, a transverse runner, an end runner, and a mold cavity all connected serially to provide a path for a liquid metal. The end runner and the mold cavity are connected through an in-gate. The liquid metal flows through the in-gate and enters the mold cavity at an incidence angle of approximately 30 to 45 degrees. The liquid metal is incident on the mold cavity near the rear end surface of the mold cavity. The direction of the liquid metal flow is controlled as the liquid metal flows through the runners and into the cavity so as to reduce the amount of air mixed into the liquid metal. The result is that the liquid metal can fill the mold cavity more satisfactorily, reducing casting defects and increasing product yield.

What is claimed is: 
     
         1 . A die-casting mold structure for a thin-walled metal casting, comprising:
 a runner;   a mold cavity; and   an in-gate that connects the runner and the mold cavity;   wherein the runner provides a path for a liquid metal to flow into the mold cavity, wherein the cross sectional area of the runner and the cross-sectional area of the in-gate are progressively smaller in a direction of flow of the liquid metal, wherein the runner connects with the mold cavity at an incidence angle that is not a right angle, and wherein the in-gate is near a rear end surface of the mold cavity.   
     
     
         2 . The die-casting mold structure of  claim 1 , wherein the incidence angle is subtended by the runner and a plane of the in-gate. 
     
     
         3 . The die-casting structure of  claim 1 , wherein the incidence angle is approximately 30 to 45 degrees. 
     
     
         4 . The die-casting mold structure of  claim 1 , wherein the runner comprises a longitudinal runner, a transverse runner, and an end runner, wherein the longitudinal runner, and transverse runner, and the end runner are serially connected, and wherein the end runner connects to the mold cavity at the in-gate. 
     
     
         5 . The die-casting mold structure of  claim 4 , wherein the cross-sectional area of the longitudinal runner, the cross-sectional area of the transverse runner, the cross-sectional area of the end runner, and the cross-sectional area of the in-gate are progressively smaller in the direction of flow of the liquid metal. 
     
     
         6 . The die-casting mold structure of  claim 4 , wherein a connection between the transverse runner and the end runner forms an arc, and wherein the arc has an arc radius of approximately 10 mm to 15 mm. 
     
     
         7 . The die-casting mold structure of  claim 1 , wherein the distance between a mid-point of the in-gate and the rear end surface of the mold cavity is approximately 2 to 3 mm. 
     
     
         8 . The die-casting mold structure of  claim 1 , wherein the metal is a zinc alloy and wherein the die-casting mold structure produces a thin-walled mini zinc alloy casting. 
     
     
         9 . The die-casting mold structure of  claim 1 , wherein a wall thickness of the thin-walled mini zinc alloy casting is between 0.1 mm and 0.5 mm. 
     
     
         10 . The die-casting mold structure of  claim 1 , wherein the thin-walled mini zinc alloy casting has little or no surface flow mark. 
     
     
         11 . A method for die-casting a thin-walled metal casting, comprising:
 flowing a liquid metal into a mold cavity from a runner, wherein an in-gate connects the runner and the mold cavity;   increasing a speed of the flow of the liquid metal by gradually decreasing a cross-sectional area of the runner in a direction of the flow of the liquid metal;   configuring an incidence angle of the flow of the liquid metal into the mold cavity to be other than a right angle; and   configuring the position of the in-gate to be near a rear end surface of the mold cavity.   
     
     
         12 . The method of  claim 11 , wherein the incidence angle is subtended by the runner and a plane of the in-gate. 
     
     
         13 . The method of  claim 11 , wherein the incidence angle is approximately 30 to 45 degrees. 
     
     
         14 . The method of  claim 11 , wherein the runner comprises a longitudinal runner, a transverse runner, and an end runner, wherein the longitudinal runner, the transverse runner, and the end runner are serially connected, and wherein the end runner connects to the mold cavity at the in-gate. 
     
     
         15 . The method of  claim 14 , wherein the cross-sectional area of the longitudinal runner, the cross-sectional area of the transverse runner, the cross-sectional area of the end runner, and the cross-sectional area of the in-gate are progressively smaller in the direction of flow of the liquid metal. 
     
     
         16 . The method of  claim 14 , wherein a connection between the transverse runner and the end runner forms an arc, and wherein the arc has an arc radius of approximately 10 mm to 15 mm. 
     
     
         17 . The method of  claim 11 , wherein the distance between a mid-point of the in-gate and the rear end surface of the mold cavity is approximately 2 to 3 mm 
     
     
         18 . The method of  claim 11 , wherein the metal is a zinc alloy to produce a thin-walled mini zinc alloy casting. 
     
     
         19 . The method of  claim 11 , wherein a speed vector of the liquid metal at the in-gate has a sub-vector component parallel to a plane of the in-gate. 
     
     
         20 . The method of  claim 11 , further comprising determining a shape and dimension of the runner in accordance with a weight and shape of the thin-walled metal casting.