JPS602948B2 - Vacuum die casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum die-casting apparatus which reduces the pressure inside a cavity and an injection sleeve to prevent the occurrence of blemishes.

The die-casting method is a well-established method that can efficiently mass-produce castings with complex shapes, but on the other hand, the air present in the cavity and injection sleeve may be drawn in when molten metal is injected. Furthermore, since the mold is press-fitted without completely exhausting the air inside the cavity, a large number of cavities occur, which deteriorates the strength, pressure resistance, skin, etc. of the casting. Therefore, as a general method for discharging air from the cavity, an overflow or air vent is provided in the mold, and the melted metal is press-fitted into the cavity to force air, gas, etc. out through the overflow or air vent. However, the shape of the runner is overflowing. It has been extremely difficult to determine the location, size, quantity, etc. of one in advance.
Vacuum die casting has also been devised as a method for reducing the pressure inside the cavity. Broadly speaking, there are two types: those in which only the mold is vacuumed, and those in which the mold is housed in a vacuum box. The latter type is called the Reed Prentes style.

The Cacks and Morton method is a method of creating a vacuum in the cavity from above the dividing surface of the die, but it is not sufficiently effective, and the Reed-Brentes method uses a hood to cover the mold and vacuum the inside of the hood. This method requires a large-scale device, making it difficult to put it into practical use. Another method is to wait for the rotatable sleeve valve to flow into the sleeve valve and pour the molten metal into it, and then the sleep valve moves to suck it in through the suction hole and then press it in. However, it takes a long time to inject the molten metal. It had the disadvantage that the temperature of the metal would drop and therefore it would have to be kept warm.

In view of the above drawbacks, the present invention eliminates the above drawbacks by providing a die casting molding device that uses a simple mechanism, eliminates time loss in the injection process, and creates a vacuum inside the cavity and injection sleeve to prevent the occurrence of mirror defects. An example of implementing the present invention will be described below based on the drawings.
Reference numeral 1 denotes a mold, which consists of a fixed mold 3 attached to a fixed plate 2 and a movable mold 4 corresponding to the fixed mold 3. An injection sleeve 7 suitable for this purpose is attached, and a plunger tip 10 attached to the tip of an injection plunger rod 9 of an injection cylinder 8 is housed inside the injection sleeve 7 so as to be slidable back and forth.

Reference numeral 11 denotes an injection port for a predetermined metal port wound A, which is provided immediately before the plunger tip 10 before injection starts, and is closed from the plunger tip 1 after injection starts. A sleeve-side suction hole 12 for sucking the air inside the injection sleeve 7 is provided in front of the injection sleeve 7, and the inner wall 23 of the injection sleeve 7 is fitted with the sleeve-side suction hole 12, and the width of the injection sleeve 7 is large groove 24
, thereby prolonging the depressurization time within the injection sleeve 7.

The sleeve-side suction hole 12 is connected to a vacuum pump 13, and a solenoid valve 15 for opening and closing the suction path 14 is interposed therebetween.

Reference numeral 16 designates a cavity-side suction hole provided in the rear part of the mold 1, which fits into the cavity 6 of the mold 1 and connects its suction path 17 to the vacuum pump 13 in the same way as the sleeve-side suction hole 12. They are connected via a solenoid valve 18 that is opened and closed. 19 is a switch lever attached to the injection plunger 9; 20, 21, 22 are limit switches operated by the switch lever 19, which open and close the solenoid valves 15, 18 in relation to the sliding position of the plunger tip 10. It is something.

Next, to explain the operation of the die casting molding apparatus according to the present invention, in FIG. After the melt A is injected into the sleeve 7, the injection plunger rod 9 is moved forward to inject the molten metal A into the cavity 6. During the process, the plunger tip 10 is inserted into the injection port 11 as shown in FIG. When the closing position is reached, the switch lever 19 attached to the injection plunger rod 9 operates the limit switch 20 to open the solenoid valve 15 of the suction path 14, and the sleeve-side suction hole 12 is opened in the injection sleeve 7. The remaining air is suctioned by reducing the pressure from the cavity 6, and the solenoid valve 18 of the suction path 17 is opened at the same time.
A vacuum is applied to the inside from the cavity side suction hole 16 to suck out the residual air inside the cavity 6, and the injection sleeve 7 and the inside of the cavity 6 are brought into a vacuum state.

Subsequently, the plunger tip 10 advances further and passes through the groove 24 as shown in FIG.
When the switch lever 19 operates the limit switch 21 to close the solenoid valve 15, the suction path 14 of the sleeve-side suction hole 12 is closed.
is closed. When the plunger tip 10 advances further and reaches the position where injection of the molten metal A into the cavity 6 is completed as shown in FIG. This closes the suction path 17 of the cavity side suction hole 16 and completes the injection process. In short, in the present invention, a sleeve-side suction hole 12 is provided in front of the injection row 1 of an injection sleeve 7 that is suitable for the cavity 6, a cavity-side suction hole 16 is provided in the rear part of the cavity 6, and a sleeve-side suction hole 12 is provided in the rear part of the cavity 6. The hole 12 and the cavity side suction hole 16 are connected to the vacuum pump 13, and solenoid valves 15 and 18 are interposed in the suction paths 14 and 17, respectively, and a switch lever 19 is attached to the injection plunger rod 9. 19, when the plunger tip 10 at the tip of the injection plunger rod 9 reaches the position where it closes the injection row 1, the suction paths 14 and 17 of both the sleeve side suction hole 12 and the cavity side suction hole 16 are closed. Since the limit switch 20 that connects the solenoid valves 15 and 18 is provided, as soon as the injection port 11 is closed and the injection sleeve 7 and the cavity 6 are sealed, the remaining air in these spaces can be efficiently sucked. is completed, and the plunger tip 10 is connected to the sleeve side suction hole 1.
2, the sleeve side suction hole 12 is closed.
The limit switch 2 opens the solenoid valve 15 of
1 is provided, after the suction from the sleeve-side suction hole 12 is completed, external air is prevented from being suctioned from the sleeve-side suction hole 12, and a decrease in the suction effect from the cavity-side suction hole 16 can be prevented. In addition, a limit switch 22 is provided that opens the solenoid valve 18 of the cavity side suction hole 16 when the plunger tip 10 reaches the injection completion position, thereby preventing the suction of falling sun from the cavity side suction hole 16. Thus, clogging of the suction path 17 can be prevented, and as described above, the opening/closing control of the suction action from the sleeve-side suction hole 12 and the cavity-side suction hole 16 can be automatically controlled in relation to the advancing position of the plunger tip 10. Therefore, it is possible to carry out vacuum casting under optimal conditions, resulting in a high-quality product with very few rust spots.Moreover, since there is no air that acts as a resistance to the penetration of molten moat A, the hot water circulation is good. This makes it possible to make the density uniform.

In addition, the inner wall 23 of the injection sleeve 7 has a sleeve-side suction hole 12.
Since the wide groove 24 is formed in the axial direction of the injection sleeve 7, it is possible to extend the depressurization time acting inside the injection sleeve 7, thereby further sucking the residual air inside the injection sleeve 7. It can be carried out effectively, and has great practical effects, such as being able to produce molded products of good quality.

[Brief explanation of drawings]

The figure shows an example of the implementation of the present invention, and FIGS. 1 to 4 are diagrams showing the operating state of the vacuum die-casting apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Mold, 6... Cavity, 7... Injection sleeve, 10... Plunger tip, 12... Sleeve side suction hole, 16... Cavity side suction hole, 24... Groove. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 A sleeve-side suction hole is provided in front of the inlet of the injection sleeve that communicates with the cavity, and a groove portion that is wide in the axial direction of the injection sleeve is formed in the inner wall of the injection sleeve that communicates with the sleeve-side suction hole, and the injection sleeve communicates with the cavity. A cavity-side suction hole is provided at the rear of the injection sleeve, and the sleeve-side suction hole and the cavity-side suction hole are connected to a vacuum pump, and a solenoid valve is interposed in each suction path. A switch lever is attached to the tube, and during the movement trajectory of the switch lever, when the plunger tip at the tip of the injection plunger rod reaches the position where it closes the injection port, the suction path of both the sleeve side suction hole and the cavity side suction hole is closed. A limit switch that opens the solenoid valve of the sleeve side, a limit switch that closes the solenoid valve of the sleeve side suction hole when the plunger tip reaches the position where it closes the sleeve side suction hole, and a limit switch that closes the solenoid valve of the sleeve side suction hole, and the plunger tip reaches the injection completion position. A vacuum die casting molding apparatus characterized in that a limit switch is provided for closing a solenoid valve of a cavity side suction hole when the vacuum die casting is performed.