JPS63192547A - Method for preventing casting fault by inserting metal foil - Google Patents

Abstract

PURPOSE:To prevent pressure leakage and oil leakage, etc., to outer part from inner part of a cavity without using exclusive ins serting piece and pressurizing pin mechanism by setting a metal foil at a position developing the pressure leakage in the casting of the cavity in the die. CONSTITUTION:At the time of opening the die, the metal foil 1 sets an ejector pin 3, so as to insert the ejector pin 3 at a space with a fixed die 4 or entwine with the ejector pin 3. Next, the die is closed by moving a moving die 5 and a die base 7, and the molten metal is injected from a sleeve 6 and is filled in the cavity 2. In the case of setting the metal foil 1, the metal foil 1 is inserted in the inner part of the casting. Therefore, in the intermediate part of the product, as the fine film of the metal foil 1 is formed, the pressure leakage is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a cast product free from casting defects such as pressure leakage due to metal foil inserts.

(Conventional technology) In the casting method, in which molten metal is injected into a mold and solidified,
Molten metal has the property of shrinking when it solidifies, so when a die-cast casting becomes thick, the surface is a dense layer of about 0.5 to 1.0 mm, but the interior is a sponge-like space that is easily affected by solidification and shrinkage. It has a coarse texture.

Therefore, if the surface layer of a thick die-casting is processed, or if the surface is scratched or peeled off, pressure may leak from the inside of the casting to the outside. In products that require hydraulic pressure, oil inside the case may seep out or leak. Techniques for preventing such casting defects in thick-walled parts of die castings generally include an insert method, a pressurization method, and the like.

In the insert method, as shown in Fig. 6 (a) and (b), the product is inserted into the thick part of the cavity 2 of the mold consisting of a fixed mold 4 and a movable mold 5 according to the shape and size of the part. An insert piece 9 of the shape and size is made of iron or aluminum and attached to the casting pin 3 and set in the mold to reduce the filling space of the molten metal in the cavity 2 and to prevent the molten metal poured into the cavity 2 from solidifying. This is a method of reducing the amount of shrinkage, and involves inserting a wire mesh-like charging body as an insert piece (@Kokai No. 51-54833). A method using a structured insert (Japanese Patent Application Laid-Open No. 51-148
Publication No. B), a method of rolling and inserting metal fibers (Japanese patent application No. 1)
No. 31-272713 Iren) etc. have also been proposed. The pressurizing method is a method in which pressure is applied during solidification using a pressurizing bottle 1O to replenish the molten metal for shrinkage during solidification, as shown in FIGS. 7(a) and 7(b).

(Problem to be solved by the invention) However, in the method using an insert piece as described above, it is necessary to manufacture a special insert piece with a shape suitable for the place of use, and if the insert piece falls during mold clamping, the mold The mold may be damaged if it gets caught in the mold, so
It is necessary to set it securely in a position where it will not fall.
Limited use. In addition, the method using pressure pins has a large mechanism, which limits the areas where it can be applied, and requires space to install the mechanism that operates the pressure bottle, and it is not possible to actively remove heat from the molten metal. Due to overheating (
There is a problem in that it is impossible to prevent the dense chill layer on the surface of the product from sticking to the mold and peeling off.

The present invention was made in view of the above-mentioned conventional problems, and does not require a dedicated insert piece or pressure pin mechanism.
The present invention provides a method for preventing pressure leakage, oil leakage, etc. from the inside of a cast product to the outside.

(Means for Solving the Problems) That is, the present invention provides a method for installing a metal foil in a region where pressure leakage occurs in a cast product of a mold cavity, or by covering the inner surface of the mold at the region where pressure leakage occurs. By wrapping the metal in foil and then injecting molten metal into the mold and solidifying it, the fine metal foil is systematically inserted into the coarse structure of the cast product to prevent pressure leakage from the inside of the cast product to the outside. It's a method.

The metal foil used in the present invention is a foil of metal such as aluminum, copper, or zinc, and its thickness is 0.02 to 0.5 m.
It is preferable that the metal foil is about
or similar is preferably used. The metal foil is used in a size that can block leakage areas and is matched to the shape of the product.

(Function) The metal foil inserted into the cast product acts to prevent pressure and oil leaks from the inside of the cast product to the outside. Furthermore, when the mold is wrapped in metal foil for casting, the metal foil also has a cooling effect like a cold metal.

(Example) Hereinafter, the present invention will be explained by way of examples with reference to the drawings.

FIG. 1 is a cross-sectional view of a mold in which metal foil is installed, and FIGS. 2 and 3 are enlarged views of part a in FIG. 1.

In the MS1 diagram, l is a metal foil, 2 is a cavity part, 3 is a cast-out pin, 4 is a fixed type, 5 is a movable type, and 6 is a sleeve (
(hole for injecting molten metal), 7 indicates a gooey base.

When the mold is opened in FIG. 1, the metal foil 1 is inserted into the space between the casting pin 3 and the fixed die 4, as shown in FIG.
or wrap it around the cast pin 3 as shown in Fig. 3. Next, the movable mold 5 and die base 7 are moved to close the mold, and the molten metal is injected from the sleeve 6 to fill the cavity 2 with the molten metal. metal foil l
When set as shown in FIG. 2, the metal foil l is inserted inside the casting. Therefore, in the middle of the product,
A dense film of metal foil 1 is formed, and pressure leakage can be prevented by this film.

Further, when the metal foil is wrapped around the cast pin 3 as shown in FIG. 3, a product with the metal foil 1 attached or welded to the surface is obtained. In this case, the metal foil prevents contact between the mold and the molten metal, which prevents the fine chill layer on the surface of the product from peeling off, and the foil itself also acts as a fine film, so the casting surface due to seizure is prevented. Roughness and pressure leakage can be prevented.

Additionally, if the metal foil attached to the surface of the product is harmful, it can be removed, creating a kind of cold metal effect. The thickness of the foil used should be thicker when removing the foil or when using it as a cold metal to achieve a cooling effect on the product, to prevent surface baking and mere pressure leakage. Thin pieces are used when the product is suitable for being cast.

Figures 4 and 5 show how the metal foil is installed inside the cavity, and Figure 4 (a) is A-A in Figure 1.
A sectional view, FIG. 4(B) is a BB sectional view of FIG. 4(A),
FIG. 5(a) is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 5(b) is a cross-sectional view taken along the line CC in FIG. 5(a). In FIG. 4, a cast-out pin 3 is covered with a metal foil 1, and holes are made at both ends of the metal foil to connect the cast-out pins 3', 3 adjacent to the cast-out pin 3.
The metal foil 1 is set in the cavity 2 by wrapping the metal foil 1 into the cavity 2 by wrapping it around the cast-out pins 3' and 3'' at both ends, as shown in FIG. , is set so as to block the space between the casting pin 3 and the movable mold 5.

(Effects of the invention) In the present invention, commercially available metal foil can be used as the insert material, and there is no need to make a special piece for the insert, so the production cost is low, and the insert material can be used during mold clamping. Even if it falls and gets caught in the mold, it will not damage the mold.

Furthermore, even when defective products are remelted, the insert material can be made of the same material as the product, so there is no need to take out the insert part, which is economical. and,
Since the insert material is in the form of foil, the size, shape, and position of the insert can be freely selected, and it can be inserted anywhere. Furthermore, even if inserting is not possible, by using thick foil, it can be separated after casting.

Furthermore, when the mold surface is wrapped with metal foil, seizure can be prevented without using a mold release agent, and the casting cycle is shortened because it has a cooling effect similar to that of a chilled metal.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the mold with metal foil installed, Figures 2 and 3 are enlarged views of section a in Figure 1, and Figure 4 (a) is a cross-sectional view taken along line A-A in Figure 1. Figure 4 (b) is a cross-sectional view taken along line B-B in figure 4 (a), Figure 5 (a) is a cross-sectional view taken along line A-A in figure 1, and figure 5 (
B) is a sectional view taken along line C-C in Fig. 5(a), Fig. 6(a) is a sectional view of a mold with a conventional insert piece placed, and Fig. 6(b) is a sectional view of the mold in Fig. 6(a). The front view of the stationary mold, and FIGS. 7(a) and 7(b) show cross-sectional views of the mold equipped with a conventional pressure bottle. In the figure, l...Metal foil 2...Cavity 3, 3
", 3"...Cast pin 4...Fixed type
5...Movable type 6...Sleeve 7...
・Guihesu tusk 1 figure 3 ■zemukan・ 4 figure (a) (D) 6 figure (a) (b) Off figure

Claims (1)

[Claims] (1) Place metal foil in the part of the mold cavity where the pressure leakage occurs in the cast product, or wrap the inner surface of the mold in the part where the pressure leakage occurs, and then pour the molten metal into the mold. A casting defect prevention method characterized by injection and solidification.