JPH02112850A - Low melting point alloy core and its manufacture - Google Patents

Abstract

PURPOSE:To make compressing strength of a low m.p. alloy core highly by packing bundle and wire-like materials of heat resistant fibers in a bag-like coating body knitted with yarn made of heat resistant fibers to form a core material, embedding the core material into the low m.p. alloy and also filling up the low m.p. alloy in the core material. CONSTITUTION:An upper and lower casting molds 11, 12 are opened and after arranging the core material 3 in the casting cavity 13, both molds 11, 12 are clamped. Successively, the molten low m.p. alloy 2 is filled up into the casting cavity 13 arranging the core material 3 from an introducing hole 14. Then, after filling up the low m.p. alloy 2 into the inner part of the core material 3 and in the casting core 13, the casting molds 11, 12 are cooled to obtain the low m.p. alloy core 1. Therefore, the compressing strength of the core 1 can be made to high and even if the forming pressure is acted at the time of forming a primary forming product including the core, the core has the compressing strength without any deformation and also after forming the primary forming product, by heating, only the core can be removed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a low melting point alloy core and a method for manufacturing the same, and in particular, a low melting point alloy core in which a core material is embedded to increase compressive strength and a method for manufacturing the same. It is related to.

[Prior art and problems to be solved]-IIIQ, when molding a final molded product with a hollow part, a molding material is filled with a core that matches the hollow part placed in the molding cavity. , after molding the primary molded product with a built-in core, this −
There is a method of obtaining a molded product with a hollow portion by removing only the core from the next molded product.

As the core used for this, it is known that the core is made of a low melting point alloy, and the core can be melted and removed by heating to a predetermined temperature after forming a primary molded product containing the core.

However, the core made of the above-mentioned low melting point alloy has a compressive strength of 300 to 800 K at room temperature, depending on the material.
g/cd, and has the property that near the melting point temperature, the compressive strength decreases to about 1/3 of the compressive strength at room temperature.For example, in the case of injection molding, the molding material during injection molding Pressure (J normal 800-1200 Kg/cj
), the core is easily deformed and does not function as a core, resulting in a problem that a final molded product having a precise hollow shape cannot be molded.

To deal with this, it is possible to increase the compressive strength by incorporating fibers into the core made of the low melting point alloy, but this would result in poor wetting between the fibers and the low melting point alloy and the specific gravity of the low melting point alloy relative to the fibers. It is difficult to incorporate fibers into the low melting point alloy because the fibers are so large that even if an attempt is made to simply incorporate them, the fibers will separate into the upper layer of the low melting point alloy.

The present invention solves the above-mentioned problems of the conventional products by embedding a core material that does not separate from the low melting point alloy in the low melting point alloy, and forming it during molding of the primary molded product containing the core. A low melting point alloy that has a compressive strength that does not deform even when pressure is applied, can be removed by a simple heating operation after forming the next molded product, and can be molded into a final molded product with a precise hollow part shape. The purpose of this invention is to provide a product and a method for producing the same.

[Means to solve the problem]

In order to achieve the above object, the low melting point alloy core of the present invention has a bundle of heat resistant fibers inside a bag-shaped covering made by knitting threads of heat resistant fibers into a bag-like shape that allows fluid to flow in. and/or a core material is filled with cotton-like material, this core material is embedded in a low melting point alloy, and the core material is filled with a low melting point alloy, and the present invention The manufacturing method for low melting point alloy cores involves knitting heat-resistant fiber threads into a bag-like shape in a casting cavity formed by an upper casting mold and a lower casting mold that are in contact with each other in a space that allows fluid to flow in. A core material formed by filling bundles of heat-resistant fibers and/or cotton-like material is disposed inside the formed coating, and a low melting point alloy melted by pressure penetrating into the core material is poured into the casting cavity. After filling the mold, the lower casting mold is cooled to a temperature below the melting point of the low melting point alloy.

[Effect]

By employing the above configuration and means, the present invention has the following features:
This means that the primary molded product containing the core will not be deformed by the molding pressure during molding, and the core that has these properties can be manufactured easily and reliably.

[Example] Embodiments of the present invention shown in the drawings will be described below.

FIG. 1+at fbl shows an embodiment of a low melting point alloy core according to the present invention, and this low melting point alloy core l is
A core material 3 is formed by filling bundles 3b of heat resistant fibers inside a covering 3a formed into a bag by knitting threads of heat resistant fibers into a coarse mesh that allows fluid to flow in. The core material 3 is embedded in the melting point alloy 2, and the core material 3 is filled with the low melting point alloy 2 to form a core having a substantially U-shaped cross section.

The core material 3 embedded in the low melting point alloy core 1 according to the present invention is formed into a shape that is slightly smaller than the core shape as a whole, as shown in FIG. As shown in Fig. 2+bl, bundles 3b of heat-resistant wind fibers are placed on the shaft of the core, as shown in Fig. 2 (C1), inside a covering 3a formed into a bag by knitting to a coarse mesh through which fluid flows. It is formed by arranging and packing in the direction.

Further, another example of the core material 3 embedded in the low melting point alloy core 1 according to the present invention is as shown in FIG. 3, as shown in FIG. The core material 3 used in the low melting point alloy core l of the present invention is formed by arranging the core materials 3b in the axial direction of the core and filling the center with a cotton-like material 3c of heat-resistant fibers. The bag-like covering 3a is formed by stuffing bundles 3b of heat-resistant fibers and/or cotton-like material 3c, and any material may be used as long as it is the same.

The heat-resistant fibers used in the heat-resistant fiber threads used in the covering body 3a of the core material 3, the heat-resistant fiber bundles 3b and the heat-resistant fiber flocs 3c filled inside the covering body 3a are as follows: , those that do not deteriorate even when exposed to temperatures 80° C. or more higher than the melting point of the low melting point alloy 2 are preferable, such as carbon fibers, E-glass fibers, alumina fibers, inorganic fibers such as silicon carbide whiskers, aramid fibers, nylon fibers, etc. Metal fibers that do not form an alloy with the low melting point alloy 2, such as organic fibers, stainless steel fibers, and copper fibers, can be mentioned.

The low melting point alloy 2 used in the low melting point alloy core 1 according to 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 (Z n) and antimony (S
An alloy containing 2 to 4 metal elements selected from the group b) is preferable, for example, (1) B i /P
b/Sn/Cd=50/26,
7 /13.3/10 (melting point 70℃), +2) B
i/Pb/Cd=51. 65/40. 20
/8. 15 (melting point 91.5°C), (31B i
/ S n = 57 /43 (melting point 138.5°C)
, +41 Pb/Sn -38,1/61.9
(Melting point 183°C), +51 S n/Zn = 9
1/9 (melting point 199°C), +6) Pb/Sb=
87.5/12.5 (melting point 247°C) and the like.

Low melting point alloy core 1 according to the present invention configured as described above
In this case, a core material 3 formed by stuffing a bundle of heat-resistant fibers 3b and/or a cotton material 3c inside a bag-like covering 3a is embedded in a low melting point alloy 2, and the inside of the core material 3 is Since the core is also filled with the low melting point alloy 2, the low melting point alloy core l according to the present invention
showed more than twice the compressive strength, and even near the melting point of the alloy, the compressive strength decreased by about 1/2 compared to room temperature, which was a significant improvement over that of the alloy alone.

As shown in FIGS. 4 and 5, the casting mold used in the method for manufacturing the low melting point alloy core 1 of the present invention is moved so as to come into contact with and away from the upper casting mold 11. The upper casting mold 11 has an inlet for introducing the molten low melting point alloy 2 into the casting cavity 13. 14 is formed, and an air vent hole 15 connected to the casting cavity 13 is formed in the dividing surface of both molds 11 and 12.

In order to manufacture the low melting point alloy core l according to the present invention using the casting mold configured as described above, first, with the upper and lower casting molds 11 and 12 open, the inside of the casting cavity 13 is After disposing the core material 3 in
The low melting point alloy 2 melted at a temperature 0° C. higher is filled into the casting cavity 13 in which the core material 3 is disposed.

The filling pressure of the low melting point alloy 2 at this time is such that the molten low melting point alloy 2 can penetrate into the inside of the core material 3, and the low melting point alloy 2 is filled into the casting cavity 13 including the inside of the core material 3. After filling, the first and second casting molds 11 and 12 are cooled to below the melting point temperature of the low melting point alloy 2. After the final casting, the molds 11 and 12 are separated, the cast product low melting point alloy core is taken out from the casting cavity 13, and the edges are cut to obtain the low melting point alloy core l according to the present invention.

Further, it is preferable that the upper and lower casting molds 11 and 12 are heated in advance to a temperature 5 to 50°C lower than the melting point of the low melting point alloy 2 before casting, and furthermore, both molds 11 and 12 after casting are
The cooling temperature of 1.12 is preferably 3°C or more lower than the melting point of low melting point alloy 2.

In the method for producing the low melting point C hit element 1 of the present invention, which is cast as described above, the bundle 3b of heat-resistant fibers and/or the cotton material 3c are stuffed inside the bag-like covering 3a. The core material 3 can be embedded in the low melting point alloy 2 without separating the core material 3 from the low melting point alloy 2, and the core material 3 is filled with the low melting point alloy 2.

Low melting point alloy core 1 according to the present invention manufactured by the above method
is used as the core of a mold for compression molding, injection molding, transfer molding, etc., and can form a final molded product with a precise hollow part.

Hereinafter, an example of molding a final molded product having a hollow portion using the low melting point alloy core of the present invention will be described.

First, the low melting point alloy core l according to the present invention is placed at a predetermined position in the molding cavity of a mold for molding a primary molded product with a built-in core, and then a molding material such as a resin is filled into the molding cavity. ,
After molding for a predetermined period of time, the molded product is removed from the mold to obtain a primary molded product containing the low melting point alloy core 1.

Next, the primary molded product containing the low melting point alloy core 1 obtained above is heated in an air bath or a liquid bath at a temperature higher than the melting point temperature of the low melting point alloy 2 and lower than the temperature at which the next molded product is thermally deformed. The low melting point alloy 2 of the low melting point alloy core 1 is heated by means such as high frequency induction heating, and then the low melting point alloy 2 of the low melting point alloy core 1 is melted and removed, and the core material 3 remaining in the hollow part after the low melting point alloy 2 is melted is removed, resulting in a final molded product. get.

The above low melting point alloy core 1 according to the present invention can be applied to any molding method such as injection molding, compression molding, transfer molding, etc. As a molding material that can be molded using the above low melting point alloy core 1, Various resin materials that do not undergo thermal deterioration or thermal deformation even near the melting point temperature of Melting Point Alloy 2 can be used. For example, thermoplastic resins include nylon 6, nylon 6.6, nylon 4,6, nylon 11,
Examples include polyamide resins such as nylon 12, polybutylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, polycarbonate, polyacetal, and other synthetic resins, and thermosetting resins include phenol, unsaturated polyester, silicone, epoxy,
Examples include various synthetic resins such as urea.

〔Effect of the invention〕

By configuring the present invention as described above, the core material that is not separated from the low melting point alloy is embedded in the low melting point alloy, and
By filling the inside of the core material with a low melting point alloy, the compressive strength of the low melting point alloy core can be increased, and it will not deform even when the molding pressure is applied during molding of the primary molded product containing the core. In addition to having high compressive strength, it has the advantage of being able to remove only the core with a simple heating operation after molding the next molded product, making it possible to mold molded products with precise hollow parts. It is something that you have.

[Brief explanation of drawings]

Figure 1 (al [bl] shows one embodiment of the low melting point alloy core according to the present invention, Figure 1 fal is a perspective view, Figure 1 fbl
Figure 1 (l-1yA cross-sectional explanatory diagram of al, Figure 2 (a)
('b) tc+ shows the first embodiment of the core material embedded in the low melting point alloy core according to the present invention, and FIG. 2 (al is a front view,
FIG. 2+b) is an enlarged surface explanatory diagram, FIG. 4 and 5 (δ) (b) are explanatory views of a casting mold for producing a low melting point alloy core according to the present invention, and FIG. Figure 5 (al is a perspective view of the upper casting mold, 5th
Figure (bl is an explanatory view of the cross section on line ■V in Figure 5 (al). 1...Low melting point alloy core 2...Low melting point alloy 3...Core material 3a...Coating 3b...Bundle of fibers 3c...Fib-like material 11...1 Casting mold 12...Top casting Mold 13... Casting cavity 14... Inlet 15... Air vent hole Figure (b) Figure Figure 2 (G) (b) ■ (C) Figure (b) 13 brocade u'FPrT

Claims (2)

[Claims] (1) A bundle of heat-resistant fibers (3b) and/or a cotton-like substance (3c) is placed inside a bag-shaped covering (3a) formed by knitting threads of heat-resistant fibers into a coarse mesh that allows fluid to flow in. This core material (3) is embedded in the low melting point alloy (2), and the low melting point alloy (2) is filled inside the core material (3).
) A low melting point alloy core characterized by being filled with. (2) Upper casting mold (11) and lower casting mold (12) that come into contact and separate
A bundle of heat-resistant fibers ( ) is placed inside a bag-shaped covering (3a) formed by knitting threads of heat-resistant fibers into a bag-like shape that allows fluid to flow into the casting cavity (13). A core material (3) formed by filling 3b) and/or a cotton material (3c) is disposed, and the low melting point alloy (2) melted by pressure penetrating into the core material (3) is cast. After filling the void (13),
A method for producing a low melting point alloy core, characterized in that the upper and lower casting molds (11) and (12) are cooled to a temperature below the melting point of the low melting point alloy (2).