JP2005161541A - Insert molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert molding method capable of manufacturing a composite porous body as an insert molded product with high precision at a low cost. <P>SOLUTION: This insert molding method for manufacturing the composite porous body wherein a porous body 11 and a resin part are integrally formed comprises a mold clamping process for compressing the porous body 11 arranged to mold surfaces 3a and 4a in a mold on-off direction by mold clamping using the mold surfaces 3a and 4a to fix the same and an injection process for injecting a molten resin in a cavity after the mold clamping process. In the mold clamping process, the whole surface opposed to the mold surfaces 3a and 4a of the outer surface of the porous body 11 is uniformly brought into close contact with the mold surfaces 3a and 4a before the injection process. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an insert molding method, and more particularly to an insert molding method suitable for insert molding using a porous body as an insert part.

In general, an injection mold apparatus in which a cavity is formed between mold surfaces in a clamped state is used for producing an injection molded product having a predetermined shape by injecting a molten resin into a cavity. In recent years, using such an injection mold apparatus, for example, a thin plate-like porous body made of metal, and a resin portion extending from the outer peripheral edge of the porous body in the surface direction of the porous body, There is a desire to manufacture a composite porous body in which the two are integrated.
That is, a request to manufacture an insert molded product that is a composite porous body by inserting a porous body as an insert part into a cavity and performing insert molding in which a molten resin is injected so as to be continuous with the porous body. (See, for example, Patent Document 1).
JP 2003-127190 A

  However, in the conventional insert molding method, the porous body arranged on the mold surface can be simply fixed in the mold opening / closing direction or adsorbed by air at the time of mold clamping. Therefore, due to the injection pressure of the molten resin in the cavity, the outer surface of the porous body enters the surface facing the mold surface, or the porous body is displaced in the direction along the surface of the mold surface. There was a case. That is, the entire outer surface of the porous body may be coated with a molten resin, and the above-described composite porous body may not be manufactured, or the porous body may be disposed at a desired position in the composite porous body. There was a case that could not be.

  This invention is made | formed in view of such a subject, and it aims at providing the insert molding method which can manufacture the composite porous body as an insert molded product with high precision and certainty.

In order to solve the above-described problems and achieve such an object, the present invention proposes the following means.
The invention according to claim 1 performs insert molding in which a porous body as an insert part is inserted into a cavity formed between mold surfaces in a mold-clamped state, and a molten resin is injected so as to be continuous with the porous body. Thus, an insert molding method for producing a composite porous body in which a porous body and a resin portion are integrally formed, wherein the porous body disposed on the mold surface is clamped to clamp these porous bodies. The mold clamping includes: a mold clamping step for compressing and fixing in a mold opening / closing direction by a mold surface; and a mold clamping step for forming the cavity; and an injection step for injecting molten resin into the cavity after the mold clamping step. The step fixes the porous body by bringing the entire surface of the outer surface of the porous body facing the mold surface uniformly into close contact with the mold surface, and in this state, Injection process Characterized in that it go through.

According to the insert molding method of the present invention, the entire surface of the outer surface of the porous body that faces the mold surface is in close contact with the mold surface at the time of injection molding. Regardless of the high injection pressure of the resin, it is possible to prevent the molten resin from entering between the porous body and the mold surface. Furthermore, regardless of the injection pressure of the molten resin, the porous body can be prevented from being displaced in the direction along the surface of the mold surface.
As described above, a composite porous body in which the porous body and the resin portion extending in the surface direction of the porous body from the outer peripheral edge of the porous body can be reliably manufactured, and the porous body Can be disposed at a desired position in the composite porous body, and the composite porous body can be manufactured with high accuracy.

  According to a second aspect of the present invention, in the insert molding method according to the first aspect, in the mold clamping step, when the porous body is uniformly brought into close contact with the mold surface, the porous body is clamped in the mold clamping direction. The porosity is adjusted by plastic deformation.

  According to the insert molding method according to the present invention, it is possible to more reliably suppress the occurrence of the above-described intrusion of the molten resin and the occurrence of the displacement of the porous body. In addition, when the porous body has a three-dimensional network structure, even if the porous body is plastically deformed in the mold clamping direction, the porous body does not spread in the plane direction and is substantially in the thickness direction. Therefore, the composite porous body can be manufactured with high accuracy. Furthermore, the porosity of the porous body constituting the composite porous body to be manufactured is not set in advance at the time of manufacturing the porous body itself, but is set at the time of mold clamping. It is possible to realize a manufacturing method in which a large number of porous bodies are manufactured in advance and the porosity is adjusted appropriately according to the specifications required by the customer regarding the composite porous body, resulting in a reduction in manufacturing costs. Can be achieved. Further, the flatness of the composite porous body 10 is also improved by the plastic deformation in the mold clamping direction.

  According to the insert molding method of the present invention, a composite porous body as an insert molded product can be manufactured with high accuracy and reliability.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a composite porous body, which is an insert molded product manufactured by this insert molding die apparatus, will be described with reference to FIG. .
In this composite porous body 10, for example, a porous body 11 in the form of a thin plate made of metal and a resin portion 12 extending in the surface direction of the porous body 11 from each outer peripheral edge of the porous body 11 are integrated. It is formed and has a rectangular thin plate shape as a whole.

  The porous body 11 has a rectangular thin plate shape having a three-dimensional network structure, and has air permeability, water absorption, light weight, and a large surface area because pores opened in the side portions communicate with each direction. have.

On the other hand, the resin portion 12 has a frame-like thin plate shape having substantially the same thickness as the porous body 11, and is connected to the outer peripheral edge portion of the porous body 11 without a step as shown in FIG. ing.
In addition, the composite porous body 10 having a rectangular thin plate shape in which the porous body 11 and the resin portion 12 are integrated is attached to various devices by fixing or sandwiching the resin portion 12. For example, it is used for filters, gas diffusion members, heat radiating members, water absorbing members, and the like. Further, the porous body 11 is appropriately selected according to the characteristics required for the composite porous body 10 produced using the porous body 11, and may be a metal nonwoven fabric, not limited to metal. The carbonaceous material may include crystalline graphite or amorphous carbon that is not crystalline.

Here, as a method for producing the metal porous body 11, there is a method in which a green sheet is obtained by thinly forming and drying a slurry containing metal powder and then firing the green sheet.
FIG. 4 shows a green sheet manufacturing apparatus for thinly forming a slurry by the doctor blade method.

The slurry S is, for example, a mixture of metal powder such as SUS316L, an organic binder (methylcellulose), and a solvent (water). If necessary, a foaming agent (hexane) or an antifoaming agent (ethanol) that is vaporized by heat treatment is used. Etc. are added.
In the green sheet manufacturing apparatus 30, first, when the slurry S is supplied from the hopper 31 in which the slurry S is stored onto the carrier sheet 33 conveyed by the roller 32, the slurry S on the carrier sheet 33 moves. It extends between the sheet 33 and the doctor blade 34 and is formed to a predetermined thickness.

The formed slurry S is further conveyed by the carrier sheet 33, passes through the heating furnace 35, and is dried in the heating furnace 35, whereby the green sheet G in a state where the SUS316L powder is bonded by the organic binder is formed. It is formed. In addition, when a foaming agent is contained in the slurry S, the slurry S in a state of being extended on the carrier sheet 33 is heat-treated in a high humidity atmosphere before drying to foam the foaming agent to obtain a foamed slurry. The green sheet G is formed by performing a drying process.
Finally, the green sheet G is removed from the carrier sheet 33 and then degreased and fired in a vacuum furnace (not shown) to remove the organic binder, and the porous body 11 in which the metal powders are sintered together. Become.

  The porous body 11 thus obtained is inserted into the cavity 2 as an insert part in the insert molding using the insert molding die apparatus 1 as shown in FIG. 1 to FIG. Is injected to produce a composite porous body 10 as shown in FIG.

  As shown in FIGS. 1 to 3, the insert molding mold apparatus 1 includes a fixed mold 3 and a movable mold 4, and is disposed so that the mold surfaces 3a and 4a face each other. A pair of molds configured such that the movable mold 4 is supported so as to be movable back and forth toward the fixed mold 3 and positioning means 8 for positioning the porous body 11 in a direction along the surfaces of the mold surfaces 3a and 4a. It is set as the schematic structure provided with these. Then, as shown in FIGS. 2 and 3, when the movable mold 4 advances toward the fixed mold 3 and is in a clamped state, the composite porous body 10 is insert-molded between the mold surfaces 3a and 4a. For this purpose, a cavity 2 is formed.

  The positioning means 8 includes four pin members, a drive unit (not shown) composed of, for example, a hydraulic or pneumatic cylinder that supports these pin members so as to be movable in and out of the movable mold surface 4a, and these four pin members. And an elastic member (not shown) made of, for example, a spring or rubber, disposed between the motor and the drive unit.

With the positioning means 8 configured as described above, the porous body 11 is positioned in the direction along the surfaces of the mold surfaces 3a and 4a by the following two methods.
First, after the pin member is advanced and moved to the movable mold surface 4a by the drive unit, the porous body 11 is disposed on the movable mold surface 4a located inside the pin member. As a result, the outer peripheral edge of the porous body 11 contacts at least one of the four pin members, so that the porous body 11 extends along the surfaces of the mold surfaces 3a and 4a as shown in FIG. Positioned in the direction.
Second, after the porous body 11 is disposed on the movable mold surface 4a, the drive member moves the pin member to the movable mold surface 4a. At this time, at least one of the four pin members is in contact with the outer peripheral edge of the porous body 11, thereby positioning the porous body 11 as shown in FIG. 1.

A method of manufacturing the composite porous body 10 shown in FIG. 5 using the insert molding die apparatus 1 configured as described above will be described.
First, the porous body 11 is arranged in a positioned state on the movable mold surface 4a as described above (see FIG. 1).

  In this positioning state, that is, in a state where at least one of the pin members is in contact with the outer peripheral edge portion of the porous body 11, the movable mold 4 is moved forward toward the fixed mold 3 and clamped. The porous body 11 is compressed and fixed in the mold opening / closing direction by the mold surfaces 3a and 4a, and the cavity 2 is formed. Here, in the process of clamping, after the tip surface of the pin member of the positioning means 8 comes into contact with the fixed mold surface 3a, the elastic member is gradually reduced as the movable mold 4 moves forward. Thus, the protruding length of the pin member from the movable mold surface 4a is shortened.

  The thickness of the porous body 11 arranged on the movable mold surface 4a (size in the mold opening / closing direction) is set larger than the thickness of the cavity 2 at the time of mold clamping, and the mold surface at the time of mold clamping The mold surfaces 3a, 4a are plastically deformed in the mold clamping direction with the entire surfaces of the outer surfaces of the porous body 11 facing the mold surfaces 3a, 4a being in close contact with each other. Fixed between. At this time, the porous body 11 is adjusted to the porosity of the porous body 11 constituting the composite porous body 10 to be manufactured by being compressed by 3 to 90%.

  Thereafter, the four pin members of the positioning means 8 are moved back until the tip surfaces of these pin members are flush with the movable mold surface 4a, and then the porous body 11 between the mold surfaces 3a and 4a is moved. In the state where the above-described fixed state is maintained, as shown in FIG. 3, by filling the cavity 2 with the molten resin 7 injected from the runner 5 through the gate 6, the porous body 11 and the resin part 12 can be stepped without any step. The composite porous body 10 which is an insert molded product that is continuous and integrated is formed.

  Then, the movable mold 4 is moved backward so as to be separated from the fixed mold 3, and the pin member of the positioning means 8 is moved forward again by the drive unit so as to protrude from the movable mold surface 4a. Thereby, the porous body 10 is satisfactorily separated from the movable mold surface 4a.

In the composite porous body 10 formed as described above, when the molten resin 7 is injected into the cavity 2, the molten resin 7 is impregnated to a depth of about 5 μm to 1000 μm in the pores opened in the side portion of the porous body 11. As a result, the porous body 11 and the resin portion 12 are firmly bonded by the anchor effect. For example, when polypropylene is used as the material of the resin part 12, such a composite porous body 10 is obtained by clamping at a molding temperature of 180 ° C. and 80 kN and injection molding at a molding pressure of 250 kg / cm ² .

  As described above, according to the insert molding method according to the present embodiment, the entire surface of the outer surface of the porous body 11 that faces the mold surfaces 3a and 4a during the injection molding is the mold surfaces 3a and 4a. Therefore, it is possible to prevent the molten resin 7 from entering between the porous body 11 and the mold surfaces 3a and 4a regardless of the high injection pressure of the molten resin 7 in the cavity 2. it can. Furthermore, regardless of the high injection pressure of the molten resin 7, it is possible to suppress the displacement of the porous body 11 in the direction along the surfaces of the mold surfaces 3a and 4a.

  As described above, the composite porous body 10 in which the porous body 11 and the resin portion 12 extending in the surface direction of the porous body 11 from the outer peripheral edge of the porous body 11 are integrated can be reliably manufactured. At the same time, the porous body 11 can be disposed at a desired position in the composite porous body 10, and the composite porous body 10 can be manufactured with high accuracy.

  Further, as described above, even if the porous body 11 is plastically deformed in the mold clamping direction in order to fix the porous body 11 in a state of being in close contact between the mold surfaces 3a and 4a, the porous body 11 is in a tertiary state. Since it has the original mesh structure, it does not spread in the surface direction and deforms only in the substantially thickness direction, so that the composite porous body 10 can be manufactured with high accuracy. Furthermore, the porosity of the porous body 11 constituting the composite porous body 10 to be manufactured is not set in advance when the porous body 11 itself is manufactured, but is set at the time of mold clamping. As a result, it is possible to manufacture a large amount of the porous body 11 having a reduced rate and adjust the porosity as appropriate according to the required specifications from the customer regarding the composite porous body 10. The manufacturing cost can be reduced. Moreover, the flatness of the composite porous body 10 is also improved by the plastic deformation in the mold clamping direction described above.

The resin portion 12 is appropriately selected in consideration of heat-resistant temperature, hardness, and the like according to the characteristics required for the composite porous body 10 produced using the resin portion 12, and includes a thermoplastic resin, an elastomer ( Any material that can be injection-molded, such as rubber).
The resin portion 12 may be flat as shown in FIG. 5 (b). However, a hole for screw insertion holes, a groove shape for fitting to the device, a rib shape for improving strength, a boss Etc. may be provided during resin molding.

Furthermore, in the embodiment, as the composite porous body 10, as shown in FIG. 5B, the thickness of the resin portion 12 is made substantially the same as the thickness of the porous body 11, and the resin portion 12 is made porous. Although a configuration in which the outer peripheral edge portion of the body 11 is connected without a step is shown, a configuration having this step may be used. For example, the resin portion 12 may have a thickness that is about 0.01 mm thinner than the thickness of the porous body 11, and is connected to the outer peripheral edge portion of the porous body 11 with a step.
Furthermore, as shown in FIG. 5A, the resin portion 12 does not need to be continuous with all the outer peripheral edge portions of the porous body 11, and may be partially continuous as necessary. The resin part 12 may be connected not only in the outer peripheral edge part of the porous body 11 but also in the middle by providing a hole in 11 in advance and injecting it so that the molten resin 7 is filled therein. In addition, for example, the porous body 12 may be continuous with at least one side of the porous body 12 in a lattice shape.

  Moreover, in the said embodiment, although the pin member was employ | adopted as a structure which contacts the edge part of the porous body 11 among the positioning means 8, it is not restricted to this, For example, at least one part of an inner surface is the outer periphery of the porous body 11 The frame may be in contact with the part. Furthermore, as shown in FIG. 1B, the pin member has a circular configuration in cross-sectional view, but is not limited thereto, and may be, for example, rectangular or elliptical.

Further, in the above-described embodiment, the configuration in which the positioning means 8 is arranged in the movable mold 4 is shown, but it may be arranged in the fixed mold 3. Even in such a configuration, the same effects as those of the above-described embodiment are obtained.
That is, with this configuration, the following manufacturing method is realized. In the process in which the movable mold 4 moves forward and clamps, the pin member disposed in the fixed mold 3 comes into contact with the outer peripheral edge of the porous body 11, so that the porous body 11 gradually becomes the mold. When positioning is completed in the direction along the surfaces 3a and 4a and the mold clamping is completed, the positioning is completed and the porous body 11 is compressed and fixed in the mold opening and closing direction by the mold surfaces 3a and 4a. become. Thereafter, in the same manner as in the above-described embodiment, the pin members of the positioning means 8 are moved backward until the tip surfaces of these pin members are flush with the fixed mold surface 3a, and then between the mold surfaces 3a and 4a. The molten resin 7 injected from the runner 5 through the gate 6 is filled into the cavity 2 while maintaining the fixed state of the porous body 11.
Furthermore, in this configuration, after the composite porous body 10 is formed, the movable mold 4 is moved backward so as to be separated from the fixed mold 3, and then the pin member is moved forward onto the fixed mold surface 3a again. When the movable mold 4 moves backward from the fixed mold 3, the occurrence of a problem that the composite porous body 10 is taken on the fixed mold surface 3 a, so-called “cavity removal”, is suppressed.

  In the above embodiment, the movable mold 4 is fixed as a method of plastically deforming the porous body 11 in the mold clamping direction in order to fix the porous body 11 in a state of being in close contact with the mold surfaces 3a and 4a. Although the means for moving forward toward the mold 3 is shown, the present invention is not limited to this. For example, the mold surface 3a or 4a supported by a driving means different from the driving means for moving the movable mold 4 forward is used. You may make it pass through the mold-clamping process mentioned above by moving the compression metal mold | die which has it forward toward the other metal mold | die 4 or 3. FIG.

That is, for example, as shown in FIG. 6, the movable mold 4 includes a movable mold body 4c and a compression mold 4b having a movable mold surface 4a, and the movable mold body 4c and the compression mold 4b are integrated. As shown in FIG. 6, after the forward movement toward the fixed mold 3, only the compression mold 4b is moved forward toward the fixed mold 3, and the mold surface 4a of the compression mold 4b in FIG. By moving from the position to the position of the solid line, the porous body 11 is plastically deformed in the compression direction and fixed in a state of being in close contact between the mold surfaces 3a and 4a, and between the mold surfaces 3a and 4a. A cavity 2 is formed, thereby completing the mold clamping. Thereafter, similarly to the above embodiment, after the pin member is moved backward, the molten resin 7 is injected in a state where the above-described fixed state of the porous body 11 between the mold surfaces 3a and 4a is maintained.
This method can have the same effects as those of the above embodiment.

  Provided is an insert molding method capable of manufacturing a composite porous body as an insert molded product with high accuracy and at low cost.

(A) is a figure which shows the 1st process of the insert molding method shown as 1st embodiment of this invention, (b) is a cross-sectional top view which shows a part of mold apparatus for insert molding shown to (a). It is. It is a figure which shows the 2nd process (clamping process) of the insert molding method shown as 1st embodiment of this invention. It is a figure which shows the 3rd process (injection process) of the insert molding method shown as 1st embodiment of this invention. It is a schematic diagram which shows an example of the method of manufacturing a porous body. (A) is a top view of a composite porous body, (b) is a cross-sectional side view of a composite porous body. It is a figure which shows the clamping process of the insert molding method shown as 2nd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert mold apparatus 2 Cavity 3 Fixed mold 3a Fixed mold surface 4 Movable mold 4a Movable mold surface 7 Molten resin 10 Composite porous body 11 Porous body 12 Resin part

Claims (2)

By inserting a porous body as an insert part into a cavity formed between mold surfaces in a mold-clamped state, and performing injection molding to inject a molten resin so as to be continuous with the porous body, the porous body and the resin An insert molding method for producing a composite porous body formed integrally with a part,
By clamping the mold, the porous body disposed on the mold surface is compressed and fixed in the mold opening and closing direction by these mold surfaces, and the mold clamping step for forming the cavity, and after the mold clamping step An injection step of injecting molten resin into the cavity,
In the mold clamping step, the porous body is fixed by bringing the entire surface of the outer surface of the porous body facing the mold surface uniformly into close contact with the mold surface. In the insert molding method, the injection process is performed. The insert molding method according to claim 1,
The mold-clamping step adjusts the porosity by plastically deforming the porous body in the mold-clamping direction when the porous body is uniformly brought into close contact with the mold surface. .

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