JP2708939B2 - Injection / firing molding method using a multi-material molding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an injection and firing molding method using a multi-material molding machine.

(Prior art) Conventionally, when molding by an injection / sintering molding machine having a core structure, a separately processed or molded article is inserted into a mold by an insert robot or manually, and then injection molding is performed. Molded products are being formed.

For example, when molding a manifold-shaped molded article having a square block as shown in FIG. 8, a core is inserted into a mold to form a "U" -shaped pipe therein, and then the pipe is formed. The end of the road is machined with a drill, then tapped and threaded.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional injection molding machine, an insert robot is required to insert the core, and when inserting manually, the work is cumbersome and requires skill, In any case, the cost is high.

In addition, when using cores of various shapes or making molded products that require complicated processing, molding is not completed just by inserting the core and molding. And

The present invention solves the problems of the injection molding method using the conventional injection molding machine described above, and can easily mold a molded article having a complicated shape without the need for a core insert step or machining. An object of the present invention is to provide a firing molding method.

(Means for Solving the Problems) For the purpose, in the injection and firing molding method using the multi-material molding machine of the present invention, the movable mold and the primary molding fixed mold are brought into contact with each other, and the primary mold formed therebetween is formed. Inject the thermoplastic primary injection resin into the molding cavity to mold the core,
With the core held in the movable mold, the movable mold and the fixed mold for secondary molding are brought into contact with each other, and the thermoplastic resin and the metal powder are mixed in a cavity for secondary molding formed between the two. The secondary molding resin is injected to form a secondary molded product, the secondary molded product is fired, and the primary injection resin constituting the core is gasified.

(Operation) According to the present invention, the movable mold and the primary molding fixed mold are brought into contact with each other, and a thermoplastic primary injection resin is injected into the primary molding cavity formed between the movable mold and the primary molding fixed mold to remove the core. Molding.

Next, while holding the core in a movable mold, the movable mold is inverted or slid to the secondary side, and the movable mold and the secondary molding fixed mold are brought into contact with each other. The secondary molding resin obtained by mixing the thermoplastic resin and the metal powder is injected into the formed secondary molding cavity to form a secondary molded product.

At this time, the core remains inside the secondary molded article.

Subsequently, when the secondary molded article is fired and the primary injection resin constituting the core is gasified, the core portion becomes hollow.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial sectional view of a mold of an injection molding machine for carrying out an injection and firing molding method using a multi-material molding machine according to the present invention.

In the drawing, reference numeral 1 denotes a movable platen which is moved in the left-right direction in the figure by a mold clamping device (not shown), 2 denotes a movable mold attached to the movable platen, 3 denotes a fixed platen disposed to face the movable platen 1, Reference numeral 4 denotes a primary injection fixed mold provided on the fixed platen 3. The primary injection fixed mold 4 includes a sprue portion 6 having a hot sprue 5 therein.
And a slide portion 7 slidably disposed with respect to the sprue portion 6.

The slide portion 7 is composed of two slides 7a and 7b, each of which is disposed on the sprue portion 6 so as to be able to freely move in and out of the direction of the arrow and slide freely. 8 is the above two slides 7
This is a spring for urging a and 7b away from each other.

In this case, in order to form a manifold as shown in FIG. 8, the two slides 7a and 7b each have a concave shape that forms a cavity in a contact state. That is, when the slides 7a and 7b are in contact with each other, a cavity similar to the pipeline shown by the broken line in FIG. 8 is formed.

Also, 12 is an ejector plate for projecting a molded product, and 13 and 14 are attached to the ejector plate 12,
An ejector pin 15 for ejecting a molded product when the ejector plate 12 moves forward is a projecting rod for pushing the ejector plate 12. Reference numeral 16 denotes an injection nozzle that is disposed so as to be able to freely contact and separate from the primary injection fixed mold 4.

In the injection and firing molding method using the multi-material molding machine of the present invention, first, primary injection molding is performed, and the core is molded with the first color thermoplastic primary injection resin.

Thereafter, molding is performed using a secondary injection resin containing metal and ceramics as the second color. In this case, even after molding with the secondary injection resin, the core is present therein.

Then, in the firing step, the molded article is fired, and only the primary injection resin is gasified by firing.

Next, the steps of the injection / firing molding method using the multi-material molding machine of the present invention will be described with reference to FIGS.

FIG. 2 is a diagram showing a primary injection molding process, FIG. 3 is a diagram showing a state after molding with a primary injection resin, FIG. 4 is a diagram showing a state before performing a secondary injection molding, and FIG. Process drawing, 6th
The figure is a state diagram after molding with the secondary injection resin.

In FIG. 2, the movable mold 2 and the fixed primary injection mold 4 are brought into contact with each other, and the injection nozzle 16 is brought into contact with the primary injection fixed mold 4 to perform injection. At this time, the primary injection resin injected from the injection nozzle 16 is a thermoplastic resin which is gasified by firing. Further, the two slides 7a and 7b are brought into contact with each other, and a cavity having a shape similar to that of the core is formed therebetween, and the cavity is filled with the primary injection resin.

In FIG. 3, the movable mold 2 and the primary injection fixed mold 4 are separated from each other, and the two slides 7a and 7b are also separated from each other. Is done.

At this time, since the ejector plate 12 is retracted, a concave portion formed between the ejector pin 14 and the movable mold 2 is formed.
The primary molded article 21 is placed in a state in which a part of the primary molded article 21 has entered. Therefore, the primary molded article 21 is maintained in a state held by the movable mold 2.

In FIG. 4, the movable platen 1, the movable mold 2, and the primary molded product 21 held by the movable mold 2 are moved to the secondary side by the inversion or slide method, and the secondary injection fixed mold 23 is moved. .

Next, in FIG. 5, on the secondary side, a so-called green body is formed by a secondary injection resin obtained by mixing a thermoplastic resin (binder) and a metal powder. Therefore, the movable mold 2 is brought into contact with the secondary injection fixed mold 23,
The secondary injection resin is filled in a cavity 24 formed in the secondary injection fixed mold 23.

Subsequently, in FIG. 6, the movable mold 2 and the secondary injection fixed mold 23 are separated, and a secondary molded product 26 is obtained. At this time, the primary molded article 21 remains in the secondary molded article 26.

The molded article molded as described above is then degreased and fired. This baking oxidizes and gasifies the primary molding resin constituting the primary molded product 21, and the portion becomes a cavity.

FIG. 7 is a diagram showing the shape of a core formed on the primary side, FIG. 7 (A) is a perspective view of a core having a U-shaped cross section, and FIG. FIG. 7 (C) is a perspective view of a core having an expansion portion, and FIG. 7 (D) is a perspective view of a core having an expansion portion.

Even a complicated shape can be molded as a primary molded product as described above, so that there is no need to perform machining after secondary molding.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible based on the gist of the present invention, and they are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the movable mold and the primary molding fixed mold are brought into contact with each other, and the thermoplastic primary mold is formed in the primary molding cavity formed therebetween. Inject the injection resin to form a core, then, while holding the core in a movable mold, flip or slide the movable mold to the secondary side, and Abut the fixed mold for molding,
A secondary molding resin in which a thermoplastic resin and a metal powder are mixed is injected into a secondary molding cavity formed between the two to form a secondary molded product, and subsequently, the secondary molded product is fired. ,
Since the primary injection resin constituting the core is made to be gasified, conventionally, it is possible to easily obtain a molded product having a complicated shape which can be formed by machining or cannot be realized by machining. .

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a mold of an injection molding machine for carrying out an injection and firing molding method using a multi-material molding machine according to the present invention.
FIG. 3 is a diagram showing a primary injection molding process, FIG. 3 is a diagram showing a state after molding with a primary injection resin, FIG. 4 is a diagram showing a state before performing a secondary injection molding, and FIG. FIG. 6, FIG. 6 is a state diagram after molding with the secondary injection resin, FIG. 7 is a diagram showing the shape of the core molded on the primary side, and FIG. FIG. 7 (B) is a perspective view of a core having a screw portion at an end portion, FIG. 7 (C) is a perspective view of a core having a throttle portion, and FIG. FIG. 8 is a perspective view of a manifold-shaped molded product of a square block having an expanded portion. 1 movable platen, 2 movable mold, 3 fixed platen, 4 fixed mold for primary injection, 7a, 7b slide, 9 recess, 12 ejector plate, 13 and 14 …
... Ejector pin, 16 ... Injection nozzle, 21 ... Primary molded product, 23 ... Fixed mold for secondary injection, 26 ... Secondary molded product.

Claims (1)

(57) [Claims] (A) A movable mold and a primary molding fixed mold are brought into contact with each other, and a thermoplastic primary injection resin is injected into a primary molding cavity formed therebetween to form a core. (B) holding the core in a movable mold, bringing the movable mold into contact with a stationary mold for secondary molding, and placing a thermoplastic resin in a secondary molding cavity formed between the two. (C) baking the secondary molded article and gasifying the primary injection resin constituting the core. Injection and firing molding method using a multi-material molding machine.