JPH0623505A - Collapsible placed core for casting by die casting - Google Patents

Abstract

PURPOSE:To keep high dimensional precision without developing the crack and metal penetration by filling collapsible material into the inner part of an outer shell composed of metal-made or ceramic-made porous material to make a core. CONSTITUTION:By using a method for executing press-working, welding or bonding to a thin porous plate material composed of the metal-made or the ceramic-made sintered body, the outer shell 1 is molded so as to have a cavity 3 in the inner part and the same outer shape as that of the inner part of a product to be cast. The collapsible material 2 is filled into the outer shell 1 to form the collapsible core A so that the outer shell 1 does not deform by casting pressure. By rapid cooling action with the outer shell 1, the casting having fine structure can be cast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core used in die casting, and more particularly to a disintegrating core which can be disintegrated and removed from the inside of the product after the product is cast.

[0002]

2. Description of the Related Art This conventional seed core is silica sand (sand core).
The core body is formed by using sodium chloride or salt (salt core), and the outer surface of the core body is coated with a paint for protecting the molding of the core body. Therefore, with the conventional disintegrating insert core, it is difficult to apply the coating agent evenly to the outer surface of the core body in the first place, and if the coating agent is not applied uniformly, cracks and insertions tend to occur. In addition, it is very fragile, so it is difficult to control the quality of handling at the site, and the dimensional accuracy is poor. In addition, there are also problems that the removal of the core from the core is adversely affected and that the removal of the core from the core requires a large amount of equipment and labor.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and there is no fear of cracking or insertion, and quality control at the site is facilitated. Disclosed is a collapsible insert core for die casting, which has a high dimensional accuracy and does not have a bad influence on the product due to the collapse removal of the core even if its shape is somewhat complicated.

[0004]

The collapsible core for die casting according to the present invention which achieves the above object is obtained by filling a collapsible material inside an outer shell made of a porous material made of metal or ceramics. In addition, a penetration preventing layer is formed on the inner surface of the outer shell, and a collapsible material is filled inside the outer shell.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Disintegratable core A for die casting according to the present invention
Is basically composed of an outer shell 1 made of a porous material made of metal or ceramics and a collapsible material 2 which is filled in the outer shell 1 and collapsed and removed after product casting.

[0006] The outer shell 1 is for molding the inner shape of the cast product that remains inside after the product is cast, and may adversely affect the cast product such as a metal material such as aluminum or its alloy or a ceramic material. Using a porous material such as a sintered body of a material having no crack, the outer shape is molded to have the same shape as the inner shape of the product to be cast and the cavity 3 inside.

That is, the outer shell 1 is made of, for example, a thin porous plate material made of a sintered body made of metal or ceramics, and has a cavity 3 inside by a method such as press working, welding or adhesion, and an outer shape. Is molded to have the same shape as the internal shape of the product to be cast. In the illustrated embodiment, two thin porous plate materials are used to press-form each to a desired shape, and the two constituent members 1a and 1b are integrated by post-processing to form a cavity 3 inside. This is a molding of one outer shell 1 having. (See Figure 2)

The collapsible material 2 is for preventing the outer shell 1 from being deformed by the casting pressure, and is made of a material that can withstand the heat during casting and can be easily collapsed and removed after casting.

That is, as the disintegrating material 2, for example, silica sand for sand core or salt for salt core, which has been conventionally used, may be used. For example, talc is used as a starch-based binder. It is preferable to use a material having excellent water solubility such as a material obtained by mixing or a material which is frozen by adding water.

The use of the water-soluble disintegrating material 2 not only facilitates the removal of the disintegrating material 2 after casting the product, but also makes it possible to remove the sand shot for removing the disintegrating material 2. Not only can it be applied to products, but there is no need to worry about soiling around the machine due to sand falling off or mechanical failure as in the case of using silica sand.

Then, the inside of the outer shell 1 (inside the cavity 3) is filled with the collapsible material 2 to form the collapsible core A, and the collapsible core A is made of gold like the conventional core. When set in a mold and die cast, the molten metal penetrates the outer shell 1 made of a porous material, and the outer shell 1 is integrated with the cast product. Then, after casting the product, if the disintegrating material 2 is disintegrated and removed from the inside of the outer shell 1,
The final product is obtained with a cavity of the required shape inside.

At this time, in order to prevent the inside of the outer shell 1 from being filled with the collapsible material 2 in the process of manufacturing the collapsible core A, as in the embodiment shown in FIG. It is preferable to form the permeation preventive layer 4 on the inner surface of 1.

[0013]

EFFECTS OF THE INVENTION Since the die casting casting core according to the present invention has the collapsible material filled inside the outer shell made of the metal or ceramic porous material, Play.

The core body is several times stronger than the one in which the surface of the core body is coated with a mold-releasing agent, the quality of handling at the site is easily controlled, and there is no fear of cracking or insertion. It is possible to maintain high dimensional accuracy without changing the dimensions even when receiving casting pressure. Due to the rapid cooling effect of the outer shell, it is possible to cast a casting having a finer structure than ever before. When die casting, the molten metal penetrates into the outer shell made of porous material and the outer shell is integrated with the cast product. Only the disintegrating material is disintegrated and removed from the outer shell, so the strength of the cast product can be improved. At the same time, the disintegrating material can be disintegrated and removed relatively easily even if its shape is somewhat complicated. There is no fear of adversely affecting the product due to the removal of the disintegrating material from disintegration. That is, the collapsible material does not remain on the inner surface of the cast product, and the skin inside the cast product can be formed cleanly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a collapsible core according to claim 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of an outer shell according to the present invention.

FIG. 3 is a sectional view showing an embodiment of the collapsible insert core according to claim 2 of the present invention.

[Explanation of symbols]

 A: collapsible core 1: outer shell 2: collapsible material 3: cavity

Claims (2)

[Claims] 1. A collapsible insert core for die casting, comprising a collapsible material filled inside an outer shell made of a porous material made of metal or ceramics. 2. A die-casting casting, characterized in that a permeation preventive layer is formed on the inner surface of an outer shell made of a porous material made of metal or ceramics, and a collapsible material is filled inside the outer shell. Disintegrative Okiko.