JPH05330902A - Production of two-layered part, compact therefore and two-layered part obtained by the same production method - Google Patents

Abstract

PURPOSE:To provide both a method for producing a two-layered part in which the two-layered part without causing gaps at high temperatures even when materials having different thermal expansion coefficients are combined can readily be prepared by using a technique of composite injection molding and a molding for the two-layered part. CONSTITUTION:(A) The first molding material composed of a kneaded material in which sinterable particles and a removable resin binder are blended so as to have a prescribed shrinkage factor after the sintering and (B) the second molding material which is a blend of sinterable particles different from those of the molding material (A) with a resin binder removable by heating and has the shrinkage factor after the sintering set at a smaller one than that of the first molding material (A) are prepared. The first molding (3) having a fixed fitting recessed part is molded from the first molding material (A). The second molding material (B) is then injection molded so that at least the fixed fitting recessed part can be filled. Thereby, a composite molding (5) in which the first molding (3) and the second molding (4) are fitted and joined is molded and heat-treated to remove the resin binder. The sinterable particles are simultaneously sintered to produce the objective two-layered part fitted in a thermally fitted state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layer component manufacturing method, a two-layer component molded article and a two-layer component manufacturing method.

[0002]

2. Description of the Related Art As a conventional two-layer molding technique, a two-layer molding method which is used for producing a two-layer molded product such as a key top is known. Since this can be manufactured by a plastics molding technique such as injection molding using a different type of thermoplastic resin, it is possible to obtain a minute two-layer molded product. However, since the two-layer molded product obtained by this method is a resin molded product, it is impossible to make one that can be used at high temperature.

Although a two-layer material composed of a combination of dissimilar metals can be processed to produce a two-layer component capable of withstanding high temperatures, in the case of using a molten metal, a minute layer can be formed only by a molding process. Making the final part is difficult.

By the way, recently, a raw material prepared by kneading fine particles such as metal and ceramics and a resin binder is injection-molded, and the obtained molded product is heat-treated to degrease the resin binder in a predetermined portion, thereby forming a complicated shape. A technique for producing a component is known (see Japanese Patent Laid-Open No. 4-70313).

[0005]

DISCLOSURE OF THE INVENTION The present invention is a two-layer component made of different materials selected from hard materials such as metals and ceramics. The two-layer component in which these different materials are firmly bonded is easily manufactured. The present invention provides a method for producing a two-layer component and a molded product for a two-layer component.

[0006]

Thus, according to the invention of "Claim 1", the "sinterable particles and the resin binder which can be removed by heating have a predetermined shrinkage rate after sintering." First molding material consisting of blended kneaded material
A second molding material in which a shrinkage rate after sintering is set to be smaller than that of the first molding material (A) by a mixture of (A), a sinterable particle different from the above, and a resin binder which can be removed by heating. (B)
Is prepared, and a first molded product (3) having a recess (31) is molded from the first molding material (A), and the second molding material (B) is mixed with at least the first molding material (3). Injection molding is performed so that the recess (31) can be filled to form a composite molded product (5) in which the first molded product (3) and the second molded product (4) are fitted and joined, and then the above By heat-treating the composite molded article (5), the composite molded article is obtained.
The resin binder in (5) is removed, each sinterable particle is sintered, and a sintered body of the first molded product (6) and a sintered product of the second molded product.
(7) and a two-layer component manufacturing method comprising manufacturing a two-layer component (8) fitted and welded.

In the molding method of the present invention, the first molding material
As (A), a kneaded product of sinterable particles and a resin binder is used. The composition of the sinterable particles and the resin binder in the kneaded product is adjusted according to the shrinkage ratio between the first molded product (3) and the sintered body (6) obtained by sintering the first molded product (3). .. As the sinterable particles, granular particles that are hard and can be sintered at a predetermined temperature are used, and metal fine particles, ceramic fine particles, and the like are preferably used. The size of the sinterable particles is such that they can smoothly flow through the sprue or runner of the composite molding machine and do not hinder the injection, and can be adapted to the desired size of the two-layer member to be the final product. Is selected.

When the resin binder is kneaded with the sinterable particles, the resin binder maintains fluidity so as not to impair the function of injection molding, and a heating atmosphere until the sinterable particles are sintered. Those that can be completely vaporized and removed below are used. As such a resin binder, those known in the art can be used as they are.

In the molding method of the present invention, the second molding material
As (B), a kneaded product of sinterable particles and a resin binder is used. The sinterable particles and the resin binder are selected from the same as those used for the first molding material (A), but the sinterable particles used for the second molding material (B) are , A kind different from that used for the first molding material (A) is selected. Also, the second molding material
The composition of the sinterable particles and the resin binder in (B) is
The shrinkage rate after sintering is made smaller than that of the first molding material (A).

The first molding material (A) and the second molding material (B)
In each case, a sufficient amount of sinterable particles to secure each intended shape and fluidity to the extent that this amount of sinterable particles can be uniformly dispersed and the function of the injection device is not impaired are provided. It is prepared from a sufficient amount of resin binder. Further, it is preferable that the molding materials (A) and (B) are kneaded so that the sinterable particles are uniformly dispersed in the resin binder.

In the present invention, the first molded product (3) formed from the first molding material (A) is formed to have the concave portion (31). The second molded product (4) formed from the second molding material (B) is formed so as to fit at least the recess (31) of the first molded product (3), and more preferably the recessed part (3). (3
It is molded so as to fit with 1) and to join with the surface having the recess. Further, the concave portion (31) provided in the first molded product (3)
As the above, it is more preferable to form the fitting-recessed concave portion.

In carrying out the molding method of the present invention,
At least two molds having a mold for a molded product and a mold for a composite molded product, and at least 2 for individually melting and injecting the first molding material (A) and the second molding material (B) Two injection devices (2
A composite injection molding machine having 1) and (22) is preferably used. When the concave portion formed in the first molded product is the fit-and-kill concave portion (31), the fit-and-kill concave portion (31) is provided in the first molded product die.
A movable mold or a fixed mold is used as a split mold so that the mold can be formed.

In the above composite injection molding machine, first, the melt of the first molding material (A) is injected into the mold for the first molding and subjected to molding conditions to mold the first molding (3). After this first
By injecting the melt of the second molding material (B) into the molding (3) and subjecting it to molding conditions, the second molding (4) fits into at least the recess (31) of the first molding (3). Combined and bonded composite moldings
(5) is obtained.

The composite molded product (5) obtained above is a molded product for a two-layer component according to the "claim 3" of the present application.

The above-mentioned composite molded product (5) is subjected to heat treatment under the condition that each sinterable particle contained therein can be sintered, but the resin binder is removed in the process leading to this sintering. (Hereinafter referred to as degreasing). It is preferable that degreasing of the resin binder is performed quickly, and from this point, a vacuum sintering furnace is preferably used. An example of the heating conditions when using such a vacuum sintering furnace is 500 ° C. and about 50 hours.

By the above heat treatment, the first molded product (3) and the second molded product (4) are degreased and their volumes are slightly shrunk, and thereafter, the sinterable particles contained in each molded product. It is obtained as a combination of a so-called first porous body and a second porous body, which are bonded to each other while maintaining the shape of each molded product. In this case, the density of the first porous body is lower than the density of the second porous body.
When the combination of the above-mentioned porous bodies is subjected to sintering conditions, particles of each porous body are sintered and welded and contracted,
It is a combination of the sintered body (6) and the second sintered body (7). In the above sintering, the shrinkage ratio of the second sintered body (7) is the same as that of the first sintered body.
Since it is set smaller than the contraction rate in (6),
The shrinkage rate of the recessed portion (61) of the sintered body (6) is larger than that of the fitting body portion (71) of the second sintered body (7) filled in the recessed portion, and can be firmly fitted. Becomes

[0017]

According to the present invention, the first molding material comprises a kneaded product of sinterable particles and a resin binder which can be removed by heating.
After (A) is injection-molded to form the first molded product (3) having the recess (31), at least the recess (3
In 1), a mixture of sinterable particles different from the above and a resin binder that can be removed by heating is prepared so that the shrinkage rate after sintering is smaller than that of the first molding material (A). Two
The molding material (B) is filled and subjected to molding. This allows
Thus, the composite molded article (5) fitted and joined to each other at least in the recess (31) is obtained.

Next, when the composite molded product (5) is heat-treated, the sinterable particles in the composite molded product (5) are sintered and the resin binder is removed, so that the shape and fit of the composite molded product are improved. A so-called porous combination of sinterable particles is maintained while maintaining the combined state, and when this is subjected to sintering conditions, it will be sintered and welded to cause volume contraction.
The volumetric shrinkage when changing from (3) to its sintered body (6) is
Since the volumetric shrinkage ratio when changing from the second molded product (4) to the sintered body (7) is larger, the fitting state becomes a so-called cooling fit and there is no gap in the fitting part and it is very strong. The first sintered body (6) and the second sintered body (7) are fitted and welded while the fitted state is maintained.

[0019]

The present invention will be described in detail below with reference to the illustrated embodiments, but the present invention is not limited thereto. Example 1 FIG. 1 is a schematic view of a main part of an example of a composite injection molding apparatus used in the manufacturing method of the present invention. In the figure,
(1) is a mold device having a rotation mechanism, and (2) is an injection mechanism. The mold device (1) includes two movable molds (12) and (13) provided on the mold rotation mechanism (11) and two movable molds (12) and (13) fixed to face each movable mold (12) (13). It is composed of fixed type (14) and (15). Among the fixed molds, the first fixed mold (14) for molding is a plurality of inner molds (16) forming the sprue (a) and a plurality of concave molds (31) which are in contact with the mold (16) and are killed in the mold cavity. The split mold (17) and the external mold (18) supporting them are configured so that the split mold (17) group slides to the center as the internal mold (16) retracts toward the injection mechanism side. Has been done. Further, the injection mechanism (2) is provided with an injection device (21) in which the first molding material (A) is melted and filled, and an injection device (22) in which the second molding material (B) is melted and filled. Has been.

In this embodiment, the first molding material (A) is
55% iron fine particles and 45% resin binder as sinterable particles
And a mixture that is kneaded to obtain a uniform mixture is used. The second molding material (B) contains ceramic fine particles 6
A mixture is used in which 0% and 40% of the same resin pellets as described above are blended and kneaded to be uniform.

In the above structure, first, in the first injection step, as shown in FIG. 1, the first molding material (A) is melted in the mold cavity composed of the movable mold (12) and the fixed mold (14). The first molded product (3) is molded by injecting the molded product and subjecting it to molding conditions. After molding,
When the internal type (16) of the fixed type (14) is retracted, the split type (17)
The group slides toward the center, then the mold rotation mechanism (1
By moving the movable molds (12) and (13) by 1) and opening the mold,
The first in which the fit-and-kill concave portion (31) is formed in the movable die (12).
A molded product (3) will be obtained.

Next, in the second injection step, first, the mold rotating mechanism (11) is rotationally operated to move the movable mold (12) containing the first molded product (3) into the fixed mold (15). Then, the movable mold (13) is opposed to the fixed mold (14), then the respective molds are closed as shown in FIG. 2, and in this state, the melt of the second molding material (B) is injected and molded. Subject to conditions. In addition, the injection of the second molding material (B) is performed by inserting the fitting-killing concave portion (3) formed in the first molding (3).
1) is fully filled. At this time, the first injection step is performed in parallel in the mold cavity composed of the movable mold (13) and the fixed mold (14).

When the second injection step is completed, the molds are opened as shown in FIG. 3, and the first mold product (3) and the second mold product (4) are separated from the moving mold (12). The composite molded product (5) fitted and joined to each other is discharged.

Composite molded article (5) obtained as described above
Is subjected to heating conditions of, for example, 500 ° C. for about 50 hours in a vacuum incinerator (not shown), and the iron fine particles and ceramic fine particles in the composite molded product (5) are respectively sintered and the resin binder is melted and vaporized and removed. (Degreasing), the composite molded product (5) of the size shown in FIG. 4 is shrunk in its entirety, and the first sintered body (6) and the second sintered product of the size shown in FIG. A two-layer component (8) in which the body (7) is fitted and welded is obtained. In the degreasing process, the first molded product (3)
Since the shrinkage ratio of the second molded product (4) is higher than that of the second molded product (4), the shrinkage ratio of the fitting-killing concave portion (61) of the first sintered body (6) is equal to that of the second sintered body filled in this concave portion. The shrinkage rate is larger than the shrinkage rate of the fitting body portion (71) of the united body (7), the fitting state becomes a so-called cooling swallow, there is no gap in the fitting portion, and there is a very strong fitted state. The sintered body (6) and the second sintered body (7) are fitted and welded. This makes it possible to obtain a two-layer molded product that is firmly adhered at high temperature even if it is formed from sintered bodies having different thermal expansion coefficients.

[0025]

According to the present invention, a two-layer component which cannot be produced by the conventional processing method can be easily produced. Moreover, since it can be manufactured by injection molding, a large amount and inexpensive two-layer component can be provided. Furthermore, since minute parts can be manufactured and the shrinkage ratio of each material can be freely changed, it is possible to manufacture a two-layer part that does not cause a gap at high temperature even from materials having different thermal expansion coefficients.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an example of a composite injection molding machine used in a manufacturing method of the present invention.

FIG. 2 is a schematic view of a main part for explaining an injection / filling state of a molding material in a second injection step.

FIG. 3 is a schematic view of a main part for explaining extraction of a composite molded product.

FIG. 4 is a schematic sectional view of a composite molded article.

FIG. 5 is a schematic sectional view of a two-layer component.

[Explanation of symbols]

(1) ... Mold device (2) ... Injection mechanism (3) ... First molded product (4) ... Second molded product (5) ... Composite molded product (6) ... First sintered body (7) ... No. 2 Sintered body (8) ... Double layer component (11) ... Mold rotating mechanism (12) (13) ... Movable type (14) (15) ... Fixed type (17) ... Split type (21) (22) ... Injection device (A)… Inner molding material (B)… Outer molding material

Claims (5)

[Claims] 1. A first molding material composed of a kneaded material in which sinterable particles and a resin binder which can be removed by heating are blended so as to have a predetermined shrinkage ratio after sintering, and a sinter different from the above. A second molding material having a shrinkage ratio after sintering set to be smaller than that of the first molding material with a mixture of particles and a resin binder that can be removed by heating is prepared, and a recess is formed by the first molding material. A composite in which a first molded product is molded, and the second molded material is injection-molded so as to fill at least a recess of the first molded product, and the first molded product and the second molded product are fitted and joined together. A molded product is molded, and then the composite molded product is heat-treated to remove the resin binder in the composite molded product and sinter each sinterable particle to obtain a sintered body of the first molded product. Manufacture of two-layer parts in which the sintered body of the second molded product is fitted and welded Bilayer component manufacturing process comprising Rukoto. 2. The method for producing a two-layer component according to claim 1, wherein the recess formed in the first molding material is a fitting-and-killing recess. 3. A first molding material comprising a kneaded material in which sinterable particles and a resin binder which can be removed by heating are blended so as to have a predetermined shrinkage ratio after sintering, and a sinter different from the above. A second molding material having a shrinkage ratio after sintering set to be smaller than that of the first molding material by a mixture of particles and a resin binder removable by heating, the first molding material having a recess 1 molded product, 2nd
The molding material is injection-molded so as to fill at least the concave portion of the first molding, and the first molding and the second molding are fitted together.
A molded product for a two-layer component formed in a joined composite molded product. 4. The molded product for a two-layer component according to claim 3, wherein the concave portion formed in the first molding material is a fitting-and-killing concave portion. 5. A two-layer component obtained by the manufacturing method according to claim 1.