JPH071098A - Die casting method - Google Patents

Abstract

PURPOSE:To improve the quality of a formed product by replacing the air in a die cavity and an injection sleeve with inert gas before pouring molten metal into the injection sleeve. CONSTITUTION:In the condition of abutting the upper end part of the injection sleeve 30 on the lower part of the die, a passage introduced to the cavities 11a, 12a from an inert gas supplying source 85 at the outside of the die is opened by action of a valve, and after replacing the air in the die cavity and the injection sleeve with the inert gas, the molten metal is poured into the injection sleeve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting method for injecting a molten metal from directly below a mold after pouring the molten metal into the mold cavity and the injection sleeve for the inert gas.

[0002]

2. Description of the Related Art A conventional vertical casting die casting machine is further classified into a vertical clamping type and a horizontal clamping type according to the clamping direction thereof, and these are both vertically tiltable or horizontally movable. A mold injection device is provided directly below the mold. When injecting a molded product, after clamping the mold, the injection device is tilted or moved to supply the molten metal into the injection sleeve, and after returning to the injection position of the injection device, the upper end of the injection sleeve is placed under the mold. And the molten metal is injected into the cavity of the mold.

[0003]

By the way, when die casting is performed using such a conventional vertical casting type die casting machine, the space from the cavity formed between the molds to the injection sleeve of the vertical injection device. Air trapped in the space when the vertical injection device is tilted to pour the molten metal into the injection sleeve page (2) and when the molten metal is cast into the mold cavity while air is retained in the space. Reacts with and oxidizes, or burns depending on the molten metal used,
There is a problem that impurities such as oxides are mixed in the molded product and the quality of the molded product as a product deteriorates.

In view of the above-mentioned conventional problems, the present invention replaces the air in the mold cavity and the air in the injection sleeve with an inert gas before pouring the injection sleeve to improve the quality of the molded product. It is intended to provide a casting method.

[0005]

In order to achieve the above object, the method of die casting according to the present invention is a vertical casting method capable of pouring molten metal into the injection sleeve with the upper end of the injection sleeve being in contact with the lower part of the mold. Using a die casting machine with a mold injection device, after clamping the mold, contact the upper end of the injection sleeve with the lower part of the mold,
Next, the passage from the inert gas supply source provided outside the mold to the cavity inside the mold is opened by the action of the valve to replace the air inside the mold cavity and the injection sleeve with the inert gas, and then inside the injection sleeve. It was designed to be poured and injected.

[0006]

[Function] After the mold is clamped, with the upper end of the injection sleeve in contact with the lower part of the mold, the air in the mold cavity and the injection sleeve is completely replaced with the inert gas, and the molten metal is poured into the injection sleeve from the pouring port. After that, the molten metal is cast into the mold cavity. For this reason, the oxidation of the molten metal is small and the time from the completion of pouring to the casting is shortened.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the die casting method according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a side view of a vertical casting die casting machine, FIG. 2 is an enlarged sectional view of an essential part of the embodiment, page (3) FIG. 3 is a plan view taken along the line AA of FIG. 4, and FIG. The vertical injection apparatus which concerns on an Example, FIG. 5 is explanatory drawing which shows the die casting casting method of this invention, and FIG. 6 is explanatory drawing which shows the die casting casting method of this invention. In the figure, a pit 1 having a rectangular shape in plan view is provided below the floor surface, and both ends of the pit 1 are
A pair of machine bases 2 framed by steel plates or shaped steels extend upright on the floor surface, and one end of each machine base 2 has a fixed platen formed in a substantially square shape. 3 is placed and its leg portions 3a are fixed by bolting.

An end platen 4 is erected and fixed to the other end of the machine base 2 so as to be movable and adjustable. The fixed platen 3 and the end platen 4 are formed by four tie rods 5 at four corners. After being connected and adjusted for movement, they are fixed with a nut 6. Numeral 7 is a movable platen which is fitted into the tie rods 5 at the four corner holes so as to be able to move forward and backward with respect to the fixed platen 3. The movable platen 7 is provided between the piston rod 9 of the mold clamping cylinder 8 and the toggle mechanism 10. The piston plate 9 is moved forward and backward by hydraulic pressure to move forward and backward with respect to the fixed platen 3.

A fixed mold 11 having cavities 11a and 12a and a movable mold 12 are mounted on the fixed platen 3 and the movable platen 7, respectively, and the movable platen 7 is opened by being driven by a mold clamping cylinder 8. By advancing from the state, the mold is clamped as shown in FIG.

Next, a vertical casting type injection device 13 arranged in the pit 1 will be described. The vertical injection device 13 of this embodiment includes an injection sleeve 30, an inner plunger 28,
It has an outer plunger 38 and is configured to be slidable with respect to each other. 20 is a seat 1 fixed to the bottom of the pit 1.
8 is an injection cylinder rotatably supported by a pin 19 through a pin 19, and an injection plunger 24 is connected to a piston rod 22 thereof via a coupling 26.
The hydraulic pressure of the injection cylinder 20 causes the injection plunger page (4) 24 to move up and down.
Is fixed to the upper end surface of the injection plunger 24 and slidably engaged with the inside of an outer plunger 38 described later. The molten metal poured into the injection sleeve 30 is supplied to the inner plunger 2
The inner plunger 28 and the mold sleeve 14 are coaxially arranged so that the inner plunger 28 ascends while sliding in the mold sleeve 14 when casting into the cavities 11a, 12a by the rise of 8. ing.

Further, the docking frame 32 having the injection sleeve 30 fixed to the upper end surface has a hole at the lower end engageable with the plunger coupling 26, and the injection cylinder 2
0 is supported by fitting a pair of docking rams 34 that are diagonally planted on the upper surface of 0 (FIG. 3) into the ram holes, and a pressure oil chamber 36 provided in the docking frame 32 is provided.
Pressure oil and plunger coupling 26 introduced into
The docking frame 32 is configured to move up and down by moving up and down.

When the injection sleeve 30 moves up,
When the injection sleeve 30 is brought into engagement pressure contact with the lower parts of the fixed mold 11 and the movable mold 12 and the docking frame 32 is lowered, the injection sleeve 30 is separated from the lower parts of the mold. Further, an outer plunger 38 is slidably provided on the inner circumference of the injection sleeve 30 described above. A plunger frame 40 in which the outer plunger 38 is fixed to the upper end surface
Is a pair of plunger rams 44 that are spaced apart by a plurality of support rods 42 that are planted on the upper surface of the bottom plate 32a of the docking frame 32 and that are planted on the bottom plate 32a as shown in FIG. The plunger frame 40 is supported by being fitted in the hole, and is configured to move up and down by the pressure oil introduced into the pressure oil chamber 46 provided in the plunger frame 40 and the lowering of the plunger coupling 26.

A tilting cylinder 48 is provided on the side wall of the pit 1.
Is pivotally supported by a seat 47 and a pin 49 so as to be tiltable, and a rod 51 connected to a piston 50 of the tilting cylinder 48 has an end thereof connected via a joint 53 and a pin 55 to an injection cylinder. It is pivotally attached to the side of page (5) 20. Further, both the docking frame 32 and the plunger frame 40 are lowered, and the tilting cylinder 48 is operated to move the piston rod 51 forward and backward while the frames 32 and 40 and the lower portions of the molds 11 and 12 are separated from each other. As a result, the vertical casting injection device 13 as a whole is configured to stand and tilt between the tilted lubricant spray position shown by the chain line in FIG. 4 and the standing pouring and injection position shown by the solid line. .

As shown in FIG. 2, a mold degassing device 52 is arranged on a discharge passage communicating from the cavities 11a and 12a of both molds 11 and 12 to the outside of the molds 11 and 12, and the mold gas is discharged. The extraction device 52 is connected to an inert gas supply container 85, which is an inert gas supply source, through a pipe 81, a pipe 82, a solenoid valve 83, and a pipe 84. On the other hand, a pipe 86 and a solenoid valve 87 are connected by branching from a pipe 81 and a pipe 82 which are a part of a pipe connecting the mold degassing device 52 to the inert gas supply container 85. A pipe 88 and a pipe 89, which are further branched from 87, are connected. The pipe 88 is connected to a vacuum pump 93 via a vacuum tank 91 and a pipe 92, and the vacuum pump is driven by a motor 94. On the other hand, piping 8
A solenoid valve 90 is connected to the valve 9.

Reference numeral 62 denotes a molten metal holding furnace. A hot water supply pipe 64 is provided above the injection sleeve 30 from the molten metal holding furnace 62, particularly above the outer plunger 38 slightly separated from the inner plunger 28, and an outer plunger is provided. A pouring port 68 is opened above 38, and an induction heating device (not shown) is provided on the outer peripheral portion of the hot water supply pipe 64 so that the molten metal temperature does not decrease due to heat dissipation when the molten metal 70 is poured. In addition, an inert pressurizing gas 5 is supplied from above the molten metal holding furnace 62.
7 can be blown into the molten metal holding furnace 62 to press the surface of the molten metal into the injection sleeve 30 through the hot water supply pipe 64. Further, a slide valve 66, which is fixed to the cylinder device 72 and is openable and closable, is arranged at the upper end of the injection sleeve 30 in order to completely shut off the outside air from the inside of the injection sleeve 30. Reference numeral 73 is a lubricant spraying device. Page (6)

The operation of the die casting machine configured as above will be described. After the movable platen 7 is advanced by the mold clamping cylinder 8 to clamp the molds 11 and 12, the piston rod 51 of the tilting cylinder 48 is advanced and tilted to the chain line position as shown in FIG. The lubricant is spray-supplied from the lubricant spraying device 73 to stand up the injection cylinder 20. Next, when oil is sent to the pressure oil chamber 36 of the docking frame 32 via a pipe (not shown), the docking frame 32 starts to rise at a predetermined speed, and the injection plunger 24 contacts the coupling 26 with the bottom plate of the docking frame 32. As a result, the docking frame 32 and the plunger frame 40 start to rise integrally.

At the upper limit of the injection sleeve 30, both molds 1
At the end of charging into the step portions 1 and 12, the inner plunger 28 and the outer plunger 38 have the pouring port 6 shown by the solid line in FIG.
It has reached a position close to 8. Next, cylinder device 72
Pressure oil is supplied to the slide valve 66 to close it, and the solenoid valve 87 and 90 are turned on with the solenoid valve 83 kept off to activate the motor 94 of the vacuum pump 93.
In this way, through the degassing device 52, the cavity 11a,
12a is electrically connected to the mold 11 and 12 and the injection sleeve 3
Aspirate the air in 0. Cavity 11 for a certain time
After the air suction inside the a and 12a is performed and the air is removed, the solenoid valve 87 is turned off and the motor 94 of the vacuum pump 93 is stopped. Next, the solenoid valve 83 is simultaneously turned on to turn off the inert gas supply container 85 and the cavity 11.
Compressed inert gas is passed through the a and 12a parts to make the cavity 1
While blowing into 1a and 12a for a certain period of time, the slide valve 66 is opened so that the cavities 11a and 12a and the injection sleeve 30 are filled with an inert gas atmosphere.

After the exhaust gas is completely replaced with the inert gas, the solenoid valve 83 is turned off (the solenoid valves 87 and 90 remain in the off state), and immediately the inert pressure gas 57 is blown into the molten metal holding furnace 62 to hold the molten metal holding furnace. A molten metal in 62 is poured through a hot water supply pipe 64 to a pouring port 68.
From page to injection sleeve 30, start pouring (7) hot water (Fig. 5 (1)). After the pouring is completed, pressure oil is introduced into the cylinder device 72 to close the slide valve 66 (FIG. 5 (2)). Then, the supply of the compressed inert gas is stopped, and the pressure oil is introduced into the pressure oil chamber 46 to simultaneously raise the inner plunger 28 and the outer plunger 38 and raise the molten metal 70 into the mold sleeve 14 (FIG. 6).
(1)).

Finally, pressure oil is introduced into the injection cylinder 20 to further raise the inner plunger 28 to move the cavity 11
Molten metal 70 is injected into a and 12a (FIG. 6 (2)).
At the time of injection, the inert gas in the mold cavities 11a and 12a is discharged from the solenoid valve 90 into the atmosphere through the mold degassing device 52, the pipes 81 and 86, the solenoid valve 87, and the pipe 89. At this time, the inert gas in the mold cavities 11a and 12a may be discharged into the atmosphere by turning on the solenoid valve 87 and vacuum suction by driving the vacuum pump 93. Wait for the molten metal 70 in the cavities 11a, 12a to solidify, then lower the injection plunger 24, the docking frame 32, and the plunger frame 40, open the molds 11, 12, and take out the castings in the cavities 11a, 12a. This completes one casting cycle.

[0021]

As is apparent from the above description, the die casting method according to the present invention is a vertical mold capable of pouring molten metal into the injection sleeve with the upper end of the injection sleeve being in contact with the lower part of the mold. Using a die casting machine with an injection device, after clamping the mold, the upper end of the injection sleeve is brought into contact with the lower part of the mold,
Next, the passage from the inert gas supply source provided outside the mold to the cavity inside the mold is opened by the action of the valve to replace the air inside the mold cavity and the injection sleeve with the inert gas, and then inside the injection sleeve. By pouring and injecting
Since the generation of oxides is small, it is possible to produce high quality die cast moldings. Further, since the vertical injection device is poured while standing upright, the time from pouring to injection is short, the occurrence of a solidification layer is reduced, the holding temperature of the molten metal is lowered, and the energy cost and maintenance cost of the holding furnace are reduced. You can save. Page (8)

[Brief description of drawings]

FIG. 1 is a side view of a vertical casting die casting machine according to the present embodiment.

FIG. 2 is an enlarged sectional view of a main part of the embodiment.

FIG. 3 is a plan view taken along arrows AA of FIG.

FIG. 4 is a vertical casting injection device according to the present embodiment.

FIG. 5 is an explanatory view showing a die casting method of the present invention.

FIG. 6 is an explanatory view showing a die casting method of the present invention.

[Explanation of symbols]

 4 End Platen 5 Tie Rod 7 Movable Platen 10 Toggle Mechanism 11 Fixed Die 12 Movable Die 13 Vertical Casting Injection Device 14 Die Sleeve 20 Injection Cylinder 24 Injection Plunger 26 Plunger Coupling 28 Inner Plunger 30 Injection Sleeve 32 Docking Frame Page ( 9) 34 Docking ram 36, 46 Pressure oil chamber 38 Outer plunger 40 Plunger frame 44 Plunger ram 48 Tilt cylinder 52 Mold degassing device 62 Molten metal holding furnace 64 Hot water supply pipe 66 Slide valve 68 Pouring port 70 Molten metal 73 Lubricant spray Device 83, 87, 90 Electromagnetic valve 85 Inert gas supply container 91 Vacuum tank 93 Vacuum pump

Claims (1)

[Claims] 1. A die casting machine having a vertical injection device capable of pouring molten metal into the injection sleeve in a state where the upper end of the injection sleeve is in contact with the lower part of the mold, and the upper end of the injection sleeve is clamped after the mold is clamped. After replacing the air inside the mold cavity and the injection sleeve with an inert gas, the valve opens the passage leading from the inert gas supply source provided outside the mold to the cavity inside the mold. A method for die casting, comprising pouring molten metal into an injection sleeve and injecting it.