JP2746616B2 - Low-melting-point alloy core, method of manufacturing the same, and method of forming molded article using the same - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-melting alloy core, a method for producing the same, and a method for molding a molded article using the core, and more particularly, to a low-melting alloy tube having embedded therein a bellows tube. The present invention relates to a melting point alloy core, a method for producing the same, and a method for molding a molded article using the core.

[Prior art and problems to be solved]

In general, when molding a final molded product having a hollow portion, a molding material is filled in a state where a core matching the hollow portion is disposed in a molding cavity, and a primary molded product containing a core is molded. There is a method of obtaining a molded article having a hollow portion by removing only the core from the primary molded article.

As the core used for this purpose, there is known a core made of a low melting point alloy that can melt and remove the core only by heating to a predetermined temperature after molding a primary molded article containing the core.

However, since the core made of the low melting point alloy is entirely made of the low melting point alloy, the core is heavy and inconvenient to handle, and a large amount of heat energy is required when melting the low melting point alloy. In addition to the problem that the core is not economical, and the melting and solidification of the low melting point alloy takes time and the productivity of the core is low, when the core is used to form a final molded article, However, there is a problem that a large amount of melting energy is required to melt and remove the core from the primary molded article containing the, and the melting time is long and the production efficiency of the final molded article is low.

The present invention solves the above-mentioned problems of the conventional one, and reduces the amount of low-melting-point alloy used, reduces the weight of the entire core, and eliminates the inconvenience of handling the core. In addition to saving heat energy and time for melting the low melting point alloy during manufacturing, the time required to solidify the low melting point alloy can be shortened, increasing the productivity of the core itself.Furthermore, the final molding using this core Low-melting alloy cores that can significantly reduce the time required to melt and remove the core from the primary molded product with a built-in core and improve the production efficiency of the final molded product when molding the product. It is an object of the present invention to provide a manufacturing method and a method for molding a molded article using the core.

[Means for solving the problem]

In order to achieve the above object, the low-melting alloy core of the present invention is substantially at the axial center of the core body made of the low-melting alloy,
It has a configuration in which a metal bellows tube is buried, and the method for manufacturing a low melting point alloy core of the present invention is characterized in that both ends of a low-melting point alloy casting mold are formed in a casting cavity formed by a pair of casting molds that are in contact with and separated from each other. A bellows tube made of metal communicating with the outside is provided, and the casting cavity in which the bellows tube is provided is filled with a molten low melting point alloy. After the filling of the low melting point alloy is completed, the inside of the bellows tube is cooled. And a means for forming a core body by cooling the low-melting alloy filled around the hollow bellows tube by flowing the fluid, and a method of forming a molded article using the core of the present invention. A low-melting alloy core in which a metal bellows tube is buried at a substantially axial center of a core body made of a low-melting alloy is arranged in a molding cavity formed by a pair of molding dies that are in contact with and separated from each other. Fluid can be supplied to the inside of the bellows tube by connecting both ends of the bellows tube of the low melting point alloy core to the outside of the molding die After completion of the molding of the primary molded article in which the molding material is filled in the molding cavity in which the low melting point alloy core is provided and the core is built, the core body is placed inside the bellows tube of the low melting point alloy core. And means for flowing a fluid heated to a temperature equal to or higher than the melting point of the low melting point alloy to melt the core body.

[Action]

The present invention adopts the above configuration and means, while reducing the amount of the low melting point alloy used in the hollow low melting point alloy core and reducing the weight of the entire core, when manufacturing the core. The heat energy and time required to melt the low melting point alloy can be saved, and the time required to solidify the low melting point alloy can be significantly reduced by flowing a cooled fluid through the bellows tube embedded in the core. The time required to melt and remove the core from the primary molded article containing the core can be greatly reduced by flowing the heated fluid through the bellows tube embedded in the core.

〔Example〕

 Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIGS. 1 and 2 (a), (b) and (c) show an embodiment of a low melting point alloy core according to the present invention. A metal bellows tube 3 made of stainless steel or the like is embedded at substantially the center in the axial direction of a core body 2 made of a U-shaped low melting point alloy.

The low melting point alloy used for the core body 2 of the low melting point alloy core 1 of the present invention is preferably an alloy having a melting point of 70 to 250 ° C., and includes tin (Sn), bismuth (Bi), lead ( Pb), cadmium (Cd), zinc (Zn), and an alloy containing two to four metal elements selected from the group of antimony (Sb) are preferable. For example, (1) Bi / Pb / Sn / Cd = 5
0 / 26.7 / 13.3 / 10 (melting point 70 ° C), (2) Bi / Pb / Cd = 51.65 /
40.20 / 8.15 (melting point 91.5 ° C), (3) Bi / Sn = 57/43 (melting point
138.5 ° C), (4) Pb / Sn = 38.1 / 61.9 (melting point 183 ° C),
(5) Sn / Zn = 91/9 (melting point 199 ° C.), (6) Pb / Sb = 87.5 /
12.5 (melting point 247 ° C.).

The bellows tube 3 embedded in the low melting point alloy core 1 of the present invention includes:
At one end, a fixture 4 having a hole 4a and a cutout 4b is attached, and at the other end, a fixture 5 having a hole 5a is attached.
A fluid such as oil can flow from the hole 4a of the fitting 4 at one end to the hole 5a of the fitting 5 at the other end via the inside of the bellows tube 3.

The bellows tube 3 is made of a metal material such as stainless steel, for example, welded on the outside diameter side, welded on the inside and outside diameters, and furthermore, any one formed in a bellows shape, such as one integrally formed. May be.

In the low melting point alloy core 1 of the present invention having the above-described structure, the bellows tube 3 made of metal is buried in the core body 2 made of the low melting point alloy. Since the amount of the melting point alloy is reduced, the overall weight of the core 1 can be reduced, and the heat energy and time required to melt the low melting point alloy during the production of the core 1 can be saved, and the low melting point alloy is cooled and solidified. In addition to increasing the productivity of the core 1 itself by shortening the time required for forming the core 1, the core 1 is used to form a final molded product having a hollow portion. The energy and time required for melting and removing the core 1 can be saved, and the production efficiency of the final molded product can be improved.

In order to manufacture the low melting point alloy core 1 of the present invention, first, the fixture 4 having the holes 4a and 5a as shown in FIG.
5 is a metal bellows tube 3 attached to each end,
A first casting mold 11 as shown in FIG. 4 and this first casting mold
As shown in the drawing, a casting cavity 12 is formed by a second casting mold (not shown) which is abutted and separated and is symmetrical with respect to a plane. The casting mold has an inlet 13 for introducing the low melting point alloy 2a into the casting cavity 12, a runner 14, and a flow path 15 communicating with the holes 4a and 5a of the fittings 4 and 5 attached to the bellows tube 3. Are formed respectively.

Next, the molten low melting point alloy 2a is filled into the casting cavity 12 in which the bellows tube 3 is disposed, through the inlet 13 through the runner 14, and further through the notch 4b of the fixture 4.

After the molten low melting point alloy 2a is filled around the bellows tube 3 in the casting cavity 12 as described above, the hole 4a of the fitting 4 provided at one end of the bellows tube 3 via the flow path 15 is provided. Fluid (eg, air, water, oil, etc.) flows from the accordion tube 3
Hole 5a of the fixture 5 provided at the other end, and the flow path 15
Low-melting alloy that flows out of the tube and fills around the bellows tube 3
The core body 2 is formed by cooling the core 2a, and the low melting point alloy core 1 according to the present invention is obtained in which the aerial bellows tube 3 is buried in the axial center of the core body 2 made of a low melting point alloy. .

In the method of manufacturing the low-melting alloy core 1 according to the present invention, which is cast as described above, the amount of the low-melting alloy used in the entire core 1 is small. In addition to saving the heat energy and time for melting, the molten low melting point alloy 2a is filled around the hollow bellows tube 3 and a cooled fluid is flowed into the bellows tube 3 to melt the low melting point alloy 2a. Since cooling can be performed from the inside, the solidification time of the core body 2 formed by cooling the low melting point alloy 2a can be significantly reduced, and the manufacturing time of the core 1 can be significantly reduced, thereby improving productivity. You can do it.

The low-melting-point alloy core 1 according to the present invention manufactured by the above method can form a final molded product having a hollow portion.

Hereinafter, an example of forming a final molded product 30 having a hollow portion as shown in FIG. 6 using the low melting point alloy core of the present invention will be described.

First, the low melting point alloy core 1 according to the present invention, in which a metal bellows tube 3 to which the fittings 4 and 5 are attached, is embedded,
As shown in the drawing, a molding cavity 22 formed by a first molding die 21 as shown in the drawing and a second molding die (not shown) which is in contact with and separated from the first molding die 21 and is plane-symmetrical. After installation,
A molding material is filled into the molding cavity 22 from 23 and molded for a predetermined time, and then the molded product is taken out of the molding die to obtain a primary molded product in which the core 1 is built.

Next, the primary molded article containing the core 1 obtained above is heated to a temperature higher than the melting point of the low melting point alloy constituting the core body 2 and lower than the temperature at which the primary molded article is thermally deformed ( For example, air, oil, water, etc.) flows through the hole 4a of the fitting 4 provided at one end of the bellows tube 3, flows into the inside of the bellows tube 3, and flows out of the hole 5a of the fitting 5 provided at the other end. Then, the low melting point alloy 2a filled around the bellows tube 3 is heated and the core body 2 is heated.
Is melted, and the bellows tube 3 remaining in the hollow portion after the core body 2 is melted is removed to obtain a final molded product 30.

When the final molded article 30 having a hollow portion is formed as described above, a hollow bellows tube 3 is buried at substantially the center of the core 1 in the axial direction, and a core used for the core 1 is used. The total amount of the low melting point alloy constituting the main body 2 is reduced, and the core 1
Can be heated directly from the inside by flowing a heated fluid into the bellows tube 3 embedded in the core 1 of the primary molded article containing the core, so that the melting energy when the core body 2 is melted and removed. As a result, the core 1 can be removed in a short time, and the production efficiency of the final molded product 30 having a hollow portion can be greatly improved.

The low melting point alloy core 1 according to the present invention is injection molded,
The molding material which can be applied to any molding method such as compression molding and transfer molding, and which can be molded using the above-mentioned low melting point alloy core 1 can be any of various materials which do not undergo thermal deterioration or deformation even near the melting point temperature of the low melting point alloy. Resin materials can be used. For example, as the thermoplastic resin, nylon 6, nylon 6,6, nylon 4,6, nylon 11, nylon
Polyamide resin such as 12, polybutylene terephthalate,
Each synthetic resin such as polyphenylene sulfide, polyethylene, polypropylene, polycarbonate, polyacetal and the like, and as the thermosetting resin, phenol,
Examples include synthetic resins such as unsaturated polyester, silicon, epoxy, and urea.

〔The invention's effect〕

The present invention is configured as described above, it is possible to reduce the amount of low-melting alloy used, to reduce the weight of the entire core and to eliminate the inconvenience of handling, and to use the low-melting alloy in the production of the core. In addition to saving heat energy and time for melting, the time required to solidify the low-melting alloy can be significantly reduced by flowing a cooled fluid through the bellows tube embedded in the core, thereby improving the productivity of the core itself. As well as higher
When the final molded article is molded using this core, the melting energy and the time required to melt and remove the core from the primary molded article containing the core are the fluid heated inside the bellows tube embedded in the core. This has an excellent effect, such as saving the flow, and greatly improving the production efficiency of the final molded product.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of a low melting point alloy core according to the present invention, FIGS. 2 (a), 2 (b) and 2 (c) are sectional views of FIG. 1, and FIG. -A sectional view, FIG.
FIG. 2 (c) is a cross-sectional view taken along the line CC, FIG. 3 is a cross-sectional explanatory view of a bellows tube arranged in a casting cavity when manufacturing the low melting point alloy core according to the present invention. FIG. 4 is an explanatory view of a method of manufacturing a low melting point alloy core according to the present invention, and FIG. 5 is an explanatory view of a method of forming a final molded article having a hollow portion using the low melting point alloy core of the present invention. FIG. 6 is a perspective view of a final molded product formed using the low melting point alloy core according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Low melting point alloy core 2 ... Core body 2a ... Low melting point alloy 3 ... Bellows tube 4, 5 ... Fixture 4a, 5a ... Hole 4b ... Notch 11 ... First casting Mold 12 Casting cavity 13 Inlet 14 Runner 15 Flow path 21 First mold 22 Molding cavity 23 Inlet 30 Final molded product

Claims (3)

(57) [Claims] 1. A low melting point alloy core, wherein a metal bellows tube (3) is buried at a substantially axial center of a core body (2) made of a low melting point alloy. 2. A metal bellows pipe (3) having both ends communicating with the outside of the casting mold is disposed in a casting cavity (12) formed by a pair of casting molds which are in contact with and separated from each other. Filling the casting cavity (12) where 3) is disposed with the molten low melting point alloy (2a),
After the completion of the filling of the low melting point alloy (2a), a cooled fluid is allowed to flow through the bellows tube (3) to cool the low melting point alloy filled around the hollow bellows tube (3), and the core body ( 2. A method for producing a low melting point alloy core, comprising forming 2). 3. A bellows tube (3) made of a metal at a substantially axial center of a core body (2) made of a low melting point alloy in a molding cavity (22) formed by a pair of molding dies which are in contact with and separated from each other. ) Is disposed, and both ends of the bellows tube (3) of the low melting point alloy core (1) are communicated with the outside of the molding die to form the bellows tube (3). A molding material (30) is filled in a molding cavity (22) in which the low-melting alloy core (1) is arranged so that a fluid can be supplied to the inside of the core (1). After the molding is completed, a fluid heated to a temperature equal to or higher than the melting point of the low melting point alloy constituting the core body (2) is flowed into the bellows tube (3) of the low melting point alloy core (1). A method for molding a molded article using a core, characterized by melting the core.