JPH09253822A - Production method of light alloy die casting using core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a product without any trouble on the quality even if a resin core is used by constituting a part of core print parts and a product corre sponding part of a core with an insert and the rest part with the resin. SOLUTION: The core print parts 6a for the core composed of the iron-made inserts 6 at both ends and the resin core 4 are held and fixed with the dies 1, 2, 3 and molten metal is poured into the cavity between the outer surface of the product corresponding part except the core print part and the inner surface of the die to cast the product. Since the insert 6 is quickly taken out after opening the dies, this insert can simply be taken out without expanding caused by heat. Further, since the insert 6 composed of the core prints 6a at both ends of the resin core 4 and a flange corresponding part 6b of the product, is used, the cooling of the product flange part 5b is quick and solidified in a short time. Further, since the end parts of the resin core 4 is brought into contact with the inserts 6, the end parts is difficult to melt, and even if the resin core 4 is melted during casting, these parts are made in the condition of covering with the inserts 6 and not developed to ooze out or melt down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light alloy die casting manufacturing method using a resin core and a light alloy die casting product.

[0002]

The light alloy die casting method is well known as a method capable of mass-producing inexpensive aluminum castings because of its high mass productivity. The surface shape of the die cast casting can be designed quite freely, although there are restrictions due to the structure of the die. However, hollow thin-walled castings having a complicated internal structure have not been manufactured so far because the sand cores used in other casting methods cannot be used. This is because, compared to other casting methods, the pressure applied to the molten metal and the mold during casting is higher in the die-casting method, so in a normal sand core, the sand core is damaged by the high pressure during casting, and as a core, This is because the purpose could not be achieved.

For casting a light alloy die cast product having a complicated shape, a die cast using a resin core molded of a resin such as polycarbonate as a core material that can withstand high pressure during die casting and is inexpensive and reproducible. Technology is being developed. However, when the resin core comes into contact with a high-temperature molten metal, the surface temperature of the resin core rises and softens, so that there is a problem that the molten resin adheres to a product or a mold. That is, the resin core is set in the die-casting mold, the molten metal of the light alloy is poured, and after the curing is completed, the mold is opened and the cast product is taken out, but the resin core exudes during the curing, or It was found that the resin core melts out when opened.

This phenomenon will be described with reference to FIG. The fixed die 1, the movable die 2 and the sliding die 3 form a die. The resin core 4 is gripped and fixed by the skirting board portion 4a by these molds 1, 2, and 3, and the outer surface of the product corresponding portion 4b corresponding to the inner surface portion of the product other than the skirting board portion 4a of the resin core 4. The product 5 is cast by injecting the molten metal into the cavity formed between the inner surfaces of the molds 1, 2, and 3. First, as a holding time until the poured molten metal solidifies, that is, a problem during curing, as the poured light alloy shrinks as it solidifies, the product 5 and the fixed mold 1, the movable mold 2, or the sliding mold 3 are separated. There is a gap between them. As a result, for example, as shown in FIG. 4, the molds 1, 2, 3 and the resin core 4 are
In the part where the three of the product and the product 5 touch the boundary, the mold 1,
A bleeding 4c of the softened resin is generated in the gap between the products 2 and 3 and the product 5. In the product 5, as the wall thickness nearer to the boundary, that is, the flange portion 5b at the end of the product, becomes larger, the heat capacity of the part becomes larger, and the temperature of the resin on the inner surface does not easily decrease during curing. Or rise. Therefore, the resin bleeding 4c into the gaps between the molds 1, 2, 3 and the product 5 becomes extremely large.

The resin bleeding 4c adheres to the product 5 to impair the quality of the product 5, and also adheres to the molds 1, 2 and 3. The resin attached to the product 5 can be removed when the resin core 4 is removed. However, molds 1, 2, 3
The resin adhered to can not be easily removed, and it is not possible to move to the next shot without removing the work by interrupting the casting cycle or discarding several times. There was a problem that could not be done. In FIG. 4, the shaded portion of the core 4 indicates the skirting board portion 4a.

Further, as a problem at the time of opening the mold after curing and releasing the product, when the movable die 2 and the sliding die 3 are moved to open the die, and the product 5 is released by the extrusion pin,
Since the space that has been closed by the molds 1, 2 and 3 until then is opened, as shown in FIG. 5, the softened resin melts out 4d in this opened space.

As shown in FIG. 6, the cast product immediately after being taken out from the casting machine has resin exudation 4c and melt-out 4d adhered to the portion where the resin core 4 and the product 5 are in contact with each other. There was a risk of causing a problem in the quality of No. 5. The resin attached to the product can be removed to some extent in the subsequent resin core removing step. However, the baseboard portion 4a of the resin core 4
Exuding resin 4 on the molds 1, 2 and 3 that hold the
There was a problem that the c and the melted-out 4d adhered, and these adhered matters had to be removed every time the next shot was started, so that the casting work could not be performed steadily. Therefore, an object of the present invention is to provide a light alloy die-casting manufacturing method using a resin core which can cast a product having no problem in quality and can move to the next shot without any problem in the die. To do.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, that is, the core board of the core is gripped and fixed by a casting mold, and the inner surface of the mold and the core are fixed. In a light alloy die-casting manufacturing method using a core for casting a product by injecting a molten metal into a cavity between the outer surface of the core, a part of the core board and the product corresponding part of the core is constituted by an insert, A light alloy die casting manufacturing method using a core, characterized in that the remaining portion is made of resin. Here, the insert is a part of the normal core is replaced with a material different from the core, in the case of a core using a resin,
For example, it is preferable to use a material having a higher heat transfer coefficient than resin such as iron. If a part of the insert corresponding to the product corresponds to the flange at the end of the product, cooling of the thick flange may be promoted.

[0009]

Embodiments of the present invention will be described.
FIG. 1 shows an embodiment of a die casting method according to the present invention, in which a fixed die 1, a movable die 2 and a sliding die 3 form a die. Iron insert 6 and resin core 4 at both ends
The core insert 6a of the core insert consisting of is held and fixed by these molds 1, 2 and 3, and the outer surface of the product corresponding part other than the core base part and the molds 1, 2, 3 By injecting the molten metal into the cavity between the inner surface of the
Is cast. Since the insert is taken out immediately after opening the mold, it can be taken out easily without expansion due to heat. In this embodiment, as shown in detail in FIG. 2, the baseboard portion 6a and the flange corresponding portion 6b of the product are provided at both ends of the resin core 4.
Since the insert 6 consisting of is used,
The product flange portion 5b is cooled quickly, solidifies in a short time during curing, and the temperature rapidly drops even after solidification.
Further, since the end portion of the resin core 4 is in contact with this insert, melting of the end portion of the resin core is unlikely to occur, and even if the resin core 4 is melted during casting, the insert 6 prevents the resin core 4 from melting. As described above, the exudation and melt-out did not occur.

[0010]

EFFECTS OF THE INVENTION According to the present invention, it is possible to cast a product that does not affect the quality even if a resin core is used, and the die can be moved to the next shot without any problem. The light alloy die casting can be efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

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

FIG. 3 is a sectional view showing a conventional example.

FIG. 4 is a cross-sectional view of essential parts showing exudation of resin according to a conventional example.

FIG. 5 is a cross-sectional view of a main part showing the melt-out of resin according to a conventional example.

FIG. 6 is a schematic plan view showing a cast product immediately after casting according to a conventional example.

[Explanation of symbols]

1 fixed type, 1b eccentricity locking pin, 2 movable type,
3 Sliding type, 1a, 2a, 3a Recessed part, 4 Resin core, 4a Baseboard part, 4b Projected part corresponding part, 4c Product corresponding part, 5 products, 5a Projected part, 6 Insert

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location B22D 17/24 B22D 17/24 A (72) Inventor Katsuhiro Obata 5200 Mikajiri, Kumagaya-shi, Saitama Hitachi Metals Stock company Kumagaya factory

Claims (3)

[Claims] 1. A core for casting a product by holding and fixing a core print of a core by a casting mold and injecting molten metal into a cavity between an inner surface of the mold and an outer surface of the core. In the light alloy die-casting manufacturing method, the light alloy die-casting using the core is characterized in that a part of the baseboard part and the product corresponding part of the core is composed of an insert, and the remaining part is composed of a resin. Law. 2. The method for manufacturing a light alloy die cast using a core according to claim 1, wherein the insert is made of iron. 3. A light alloy die-casting manufacturing method using a core according to claim 1, wherein a part of a product corresponding part of the insert corresponds to a flange part of an end part of the product. Law.