JPS5843178B2 - Method of filling molten metal in vertical die casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for filling molten metal in a vertical die casting machine.

More specifically, the molten metal is stored in a storage chamber below the sleeve so that the level of the molten metal is equal to or lower than the bottom surface of the entrance of the hot water into the cavity, and then the upper part of the storage chamber is The molten metal is moved into the cavity by activating the plunger located in the cavity, filling it under pressure, and preventing air from being drawn in. 1. The present invention relates to a method for filling molten metal in a vertical die-casting machine, which suppresses the occurrence of casting defects such as sink marks and makes it possible to obtain sound die-cast products.

The filling method of molten metal generally adopted in conventional die casting machines of this kind is to receive and store the poured molten metal while sealing it with a counter located below to prevent it from entering the cavity during pouring. This is dealt with by installing a molten metal shutoff valve in the runner.

In such conventional means, it is necessary to synchronize a counter and a shut valve at a preset timing and speed with the operation of a plunger during injection and filling of molten metal.

However, in reality, it is very difficult to completely synchronize the two for each shot due to variations in the amount of poured metal, variations in set timing values, etc.

For example, assuming that a large amount of molten metal is poured, the plunger contacts the molten metal and pressurizes the molten metal before the counter lowers the command, and the pressure causes the molten metal to enter the sliding part between the sleeve and the plunger and exit the machine. This may cause problems such as hot water blowing out or solidifying on the sliding parts, impeding operability.

Also, if the amount of molten metal is small, the counter operates to open the runner opening before the plunger catches up and the molten metal flows into the cavity and fills it, but it takes too much time for the plunger to pressurize and fill it. , hot spots, cavities, sink marks, etc. occur, which adversely affect the quality of the cast product and reduce the product yield.

The present inventors have devised the present invention in view of the above-mentioned problems in filling a vertical die-casting machine with molten metal, and to effectively solve the problems.

The object of the present invention is to inject and store hot water into the storage chamber so that the level is the same as or lower than the bottom surface of the hot water inlet into the cavity, and then activate the plunger located above the storage chamber. By moving the molten metal into the cavity and filling it under pressure, it prevents air from being entrained, and prevents cavities, hot spots,
To provide a vertical die-casting machine which suppresses and prevents the occurrence of casting defects such as sink marks as much as possible, thereby making it possible to obtain sound die-cast products at a high yield.

Another object of the present invention is to simplify the structure of the machine itself and reduce costs, without requiring a counter or a shut valve, and therefore without the need for complex means such as a synchronization mechanism, thereby improving the above-mentioned yield. The present invention also provides a method for filling molten metal in a vertical die-casting machine, which also contributes to reducing product costs.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

This will make the advantages of the invention even more apparent.

Each of the drawings is a longitudinal sectional view of a vertical die-casting machine used to carry out the present invention, and shows operations in the order of steps.

The die casting machine 1 consists of an upper mold 2 and a lower mold 3, and the mating surfaces 2a and 3a of each mold 2 and 3 are provided with a protrusion 2b and a recess 3b which form a product cavity 4 in the mated state.

In the illustration, the recess 3b is provided below the mold mating surface 3a of the lower mold 3, while the cavity 4 is provided on the mold mating surface 2a of the upper mold 2.
A runner 5 is formed which communicates with the runner.

A concave molten metal reservoir 6 is formed in a portion of the lower mold 3 adjacent to the cavity 4, while a protrusion 7 that protrudes somewhat downward is formed in the upper mold 2, facing this portion 6. Part 7
A molten metal storage chamber 8 having a volume larger than the volume of the cavity 4 is formed between the molds and the recess 6 in a mold-matched state.

This chamber 8 communicates with the above-mentioned runner 5 at the upper level through a communication passage 9 extending diagonally upward, and the chamber 8 is located at a lower level than the runner 5.

A sleeve 10 is fitted into the protrusion 7, and the sleeve 10
is open to the ceiling of room 8 and communicates with it.

A plunger 11 is installed on the sleeve 10 so as to be able to move up and down so as to be slidably fitted thereto, and the sleeve 10 is movable up and down.
A molten metal pouring socket 12 faces a part above 0.

In the drawings, reference numeral 13 indicates an extrusion pin such as a cast product.

Next, let us explain how to fill cavity 4 with molten metal.

When the upper and lower molds 2 and 3 are aligned, a storage chamber 8 is formed below the inlet of hot water into the cavity 4, that is, the runner 5.

The plunger 11 is located above the sleeve 10 and the socket 12
The molten metal M is injected from above the sleeve 10, and the molten metal M
is stored in chamber 8.

The liquid level of the hot water M is set at the same level as the runner 5, or lower than this, and is set to such a level that the hot water M does not flow into the cavity 4, and there is no problem even if there is variation within that range.

Of course, the amount of hot water M needs to be sufficiently larger than the volume of the cavity 4.

FIG. 1 shows the storage state after pouring the molten metal.

Next, the plunger 11 is lowered, fitted into the sleeve 10, and slid down (see FIG. 2).

Due to the downward movement of the plunger 11, this 11 finally comes into contact with the molten metal M located below the sleeve 11, and the molten metal M is transferred to the plunger 11.
As it descends, it is pressed, pushed out and moved, and flows into the cavity 4 via the communication path 9 and the runner 5 and is filled.

In this case, the hot water is pushed out and moved only by the descent of the plunger 11, and flows into the cavity 4 to fill it.Since there is no counter or shaft valve, it is necessary to adjust the plunger, its speed change, synchronization timing, etc., and these mechanisms. I don't.

Regardless of whether the amount of hot water M is large or small, filling with hot water is started only when the plunger 11 comes into contact with the hot water.

Therefore, there is no occurrence of hot water, and the plunger 1
Since hot water is pushed out and moved in step 1, filling is performed quietly and smoothly, and air entrainment and the formation of cavities caused by this can be suppressed and prevented as much as possible.

Then, the filled hot water is pressurized near the H corner of the filling downward stroke of the plunger 11, completing pressurized filling.

In this case, the hot water level in the sleeve 10 in FIG. 2 is maintained internally, and finally enters the reservoir chamber 8 when the plunger 11 descends, thus preventing impurities such as air oxides from entering the cavity 4. It is possible to prevent this from getting caught.

This is shown in Figure 3. After solidification of the hot water, the upper die 2 is moved upward to open the lower die 3, and then the ejection pins 13 are activated to eject the product M1'.

This is shown in Figure 4. As is clear from the above, according to the present invention, the movement of the hot water starts when the plunger touches the top surface of the hot water stored in a stationary state, and there is no pressure applied to the hot water or no movement before the plunger starts moving. Entrainment of air, etc. is prevented, and there is no entrainment of oxide films, etc., and there is no generation of hot water spots, and filling can be performed smoothly to obtain a cast product without cavities, sink marks, etc.

The device that carries out the above does not need to be equipped with a counter, shut valve, etc., and the device and injection control system are simpler than before, making it possible to obtain good quality and sound castings with a simple and inexpensive device. .

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and the drawings are longitudinal cross-sectional views, with Fig. 1 showing the molten metal storage state, Fig. 2 showing the plunger descending state, and Fig. 3 showing the plunger descending limit. Fig. 4 shows the completion of filling, and Fig. 4 shows the product dispensing. In the drawing, 1 is a vertical die casting machine, 4 is a cavity,
5 is an inlet for hot water, 8 is a storage chamber, and 11 is a plunger.

Claims (1)

[Claims] 1. The molten metal is poured into a reservoir chamber formed below the runner of the mold cavity in the mold below the plunger sleeve provided vertically in the mold, below the lower surface of the entrance of the hot water into the cavity. The molten metal is injected and stored so as to reach a surface level of , and then a plunger is lowered into the plunger sleeve located above the storage chamber to move the molten metal into the cavity and fill it under pressure. A method of filling molten metal in a vertical die-casting machine.