JPH05123847A - Secondary pressurizing method in die casting machine - Google Patents

Abstract

PURPOSE:To provide a secondary pressurizing method in die casting machine so as to apply the secondary pressurization to molten metal during solidification by utilizing ejecting pins in an ejecting mechanism. CONSTITUTION:The tip parts of the ejecting pins 2 in the retreating limit of the ejecting movement of the ejecting cylinder 1 are immersed in the thickness direction of the die from the surface of a cavity in the die 5, 4, and during the solidification of the molten metal after the molten metal (m) is injected and filled up into the cavity 5 in the die, the ejecting cylinder 1 is worked and the ejecting pins 2 are shifted to advance so as to apply the pressure to the molten metal (m) during the solidification.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary pressurizing method for a die casting machine, and more specifically, it applies a pressure to the molten metal during solidification in addition to the pressure when the molten metal is injected into the mold cavity. The present invention relates to an improvement in a secondary pressing method for stabilizing the metal crystal structure of a product molded by molding, that is, homogenizing crystal grains.

[0002]

2. Description of the Related Art Conventionally, a secondary pressing method of this type is such that a pressing cylinder is installed on the back surface of a mold, and the tip of a pressing pin connected and supported by this cylinder rod is attached to the surface of the mold cavity. It is placed in the same plane as the stand-by, and the pressure cylinder is operated during the solidification of the molten metal after the molten metal is injected and filled, and the pressure pin is moved forward to apply pressure, that is, secondary pressure to the molten metal during solidification. I was doing However, in the conventional method, since the pressurizing cylinder protrudes from the back surface of the mold, the installation location is compromised by many cooling pipes installed in the mold from the back surface of the mold. It is not possible to set up the installation place as expected due to the restrictions of the above and interference with the cooling hose connected to the cooling pipe. Therefore, not only can effective secondary pressurization not be expected due to variations in pressure applied to the molten metal in the mold cavity due to restrictions on the installation location,
Since new processing such as providing an insertion hole for inserting and installing the pressure pin in the mold itself is required, the mold manufacturing cost becomes high and the structure becomes complicated and the mold mounting work is performed. It had many problems such as adversely affecting.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional circumstances, and a technical problem to be solved by the invention is to use molten metal being solidified by utilizing an extrusion pin of an extrusion mechanism. An object of the present invention is to provide a secondary pressurizing method for a die casting machine in which secondary pressurization is applied.

[0004]

To achieve the above object, the technical means taken by the present invention is that the tip of the extrusion pin is moved in the thickness direction of the die from the cavity surface of the die in the retreat limit of the extrusion operation of the extrusion cylinder. It is characterized in that it is placed so that it is immersed, and that the extrusion cylinder is operated and the extrusion pin is moved forward to apply pressure to the molten metal during solidification after the molten metal has been injected and filled into the mold cavity. .

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The drawings show an example of a die casting machine for carrying out the secondary pressurizing method of the present invention (hereinafter referred to as the present method). In the extruding operation retreat limit, the tip of the extruding pin 2 is immersed in the mold thickness direction from the cavity surface 3a of the movable mold 3 in the illustrated example, and the movable mold 3 and the fixed mold 4 are molded. When the molten metal m is injected and filled into the cavity 5 formed by the cavity surfaces 3a and 4a of the two dies 3 and 4 by the combination (mold clamping), the extrusion cylinder 1 is operated and the extrusion pin 2 is cavities during the solidification of the molten metal. The surface, in the figure, the push-out pin 2 is incorporated in the movable mold 3 so that the cavity surface 3a of the movable mold 3 is disposed.
It is configured to move forward to apply pressure (secondary pressure) to the molten metal during solidification.

The length of the push-out pin 2 is such that the tip of the push-out pin 2 is recessed in the die thickness direction from the cavity surface 3a of the movable die 3 in the retreat limit of the pushing operation of the pushing cylinder 1, that is, from the cavity surface 3a into the pin insertion hole 6. Is formed with an appropriate depth so as to be immersive and standby, and the rear end of the extrusion plate 7 is fixedly supported by the extrusion plate 7 and is connected to the extrusion cylinder 1 through the extrusion rod 8 so that the cylinder 1 can be extruded and retracted to the retracted limit. The tip surface of the extruding pin 2 and the pin insertion hole 5 ensure that the depression 9 into which the molten metal having the secondary pressurizing capacity enters at the time of filling is secured, and the molten metal m is extruded during solidification of the molten metal after being injected and filled. When the cylinder 1 starts to operate and the push-out pin 2 moves forward to the cavity surface 3a, the pressure corresponding to the volume of the molten metal in the recess 9 that is pushed into the cavity 5 is generated during the solidification. And it constitutes as applied to the Activity 5 in the molten metal m. The pressurizing forward stroke at the time of the secondary pressurization by the push-out pin 2 is the same as that of the push-out pin 2, and the tip end surface of the guide pin 10 whose rear end is slidably supported by the push-out plate 7 is the fixed mold 4. Until it hits the surface of the patent. That is, the guide pin 11 stands by at a position where the tip end face of the push-out pin 2 is recessed into the pin insertion hole 6 and forms a recess 9 at a position where the tip end face thereof is separated from the parting face of the fixed mold 4. Form to length.

Next, the control method of the extrusion cylinder 1 from the start of secondary pressurization after the molten metal is filled to the extrusion and removal of the product after the movable and fixed molds 3 and 4 are opened will be described. A not-shown timer for instructing and controlling the switching operation timing of the direction switching solenoid valve 12 connected and provided in the middle of the pipeline connecting the hydraulic pump 11 and the pushing cylinder 1 is connected to the solenoid valve 12. Placed and placed, the injection mechanism 13 (plunger rod, tip is shown in the drawing) high-speed injection limit switch or the operation is started by the signal of completion of filling, and after that time, the solenoid valve
The operation command is output to 12 so that the solenoid valve 12 is switched to the position 12a for sending the hydraulic oil to the forward side 1a of the extrusion cylinder 1, and again after the secondary pressurization is started by the operation start of the extrusion cylinder 1. Then, after the time is up (compression time is completed), an operation command is output to the solenoid valve 12
Releases the hydraulic oil on the forward side 1a and the backward side 1b of the extrusion cylinder 1, that is, releases the operating pressure and pushes out the extrusion cylinder 1
Set the timer in advance so that it switches to the position 12b that keeps the neutral state. Both movable and fixed molds 3, 4
The extrusion advance of the extrusion cylinder 1 at the time of extruding the product M after the mold opening and the backward movement after the completion of the extrusion of the product M are performed by well-known control.

Thus, according to the present method constructed as described above, when the molten metal m is injected and filled after the movable and fixed metal molds 3 and 4 are aligned with each other, the extrusion pin 2 is pushed back by waiting the retracting waiting of the extrusion cylinder 1. The tip 9 of the movable mold 3 is kept in the pin insertion hole 6 at a proper depth with respect to the cavity surface 3a of the movable mold 3 to stand by to secure the structure of the recess 9 and to fill the cavity 5 with the molten metal m. The molten metal m enters the depression 9 (see FIG. 1). Injection mechanism 13 with the start of injection of molten metal 13
Direction switching solenoid valve due to the time-up of the timer that started operation by the signal output from the high-speed injection limit switch of
12 is a position where the hydraulic oil is sent to the forward side 1a of the extrusion cylinder 1.
When switched to the 12a side, the extrusion cylinder 1 operates to advance the extrusion pin 2 to push the molten metal m in the recess 9 into the cavity 5 (see FIG. 2). Thereby, the depression 9
The pressure corresponding to the internal molten metal volume is applied to the molten metal m in the cavity 5 during solidification, and the molten metal m is further pressurized. Then, the solenoid valve 12 releases the hydraulic oil between the forward side 1a and the backward side 1b of the extrusion cylinder 1 by the time-up of the timer which started the operation again after the start of the secondary pressurization by the operation start of the extrusion cylinder 1, and the position 12b side. Then, the secondary pressurization is completed, and the movable and fixed molds 3 and 4 are opened. After the movable and fixed molds 3 and 4 are opened, the solenoid valve 12
Is a position 12 for sending hydraulic oil to the forward side 1a of the extrusion cylinder 1.
It is switched to the side a again and the extrusion cylinder 1 operates to extrude and demold the product M (see FIG. 3), and at the same time, the solenoid valve 12 sends the hydraulic oil to the backward side 1b of the extrusion cylinder 1 12c.
The push pin 2 is retracted by switching to the side, and the tip of the push pin 2 is set in the pin insertion hole 6 and stands by.

Therefore, according to the present method, it is possible to apply a pressure to the molten metal m in the cavity 5 which is being solidified by the forward movement of the respective extrusion pins 2 which are scattered over the entire surface 3a of the cavity and incorporated in the movable mold 3. It is possible to pressurize the molten metal m uniformly and effectively with a pressure without variation.

[0010]

The secondary pressurizing method for the die casting machine of the present invention is constructed as described above, and therefore has the following effects.
Extrusion operation of the extrusion cylinder The tip of the extrusion pin is immersed from the cavity surface of the die in the thickness direction of the die at the backward limit, and the extrusion cylinder is moved during the solidification of the molten metal after the molten metal is injected and filled in the die cavity. Since it was operated and the extrusion pin was moved forward and pressure was applied to the molten metal during solidification, new processing such as providing an insertion hole for inserting and installing the pressure pin and the mold structure like the conventional method Without causing complication, the extruding pin can be advanced to uniformly and effectively pressurize the molten metal in the cavity during solidification with a pressure without variation.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an example for carrying out a secondary pressing method of a die casting machine of the present invention, showing a state before a secondary pressing operation.

FIG. 2 is a vertical sectional front view showing a state in which a secondary pressure is applied to the molten metal in the cavity during solidification.

FIG. 3 is a vertical cross-sectional front view showing a demolded state of a product.

[Explanation of symbols]

1 ... Extrusion cylinder 2 ... Extrusion pin 3 ... Movable mold 3a ... Cavity surface 4 ... Fixed mold m ... Molten metal

Claims (1)

[Claims] 1. The solidification of the molten metal after the tip of the extrusion pin is immersed from the cavity surface of the mold in the thickness direction of the mold in the direction of the backward movement of the extrusion cylinder and the molten metal is injected and filled into the mold cavity. A second pressurizing method for a die casting machine, characterized in that an extruding cylinder is operated to move an extruding pin forward to apply pressure to the molten metal during solidification.