JP4124111B2 - Insert molding method - Google Patents

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 porous body having a thin plate shape having a three-dimensional network structure made of metal, and the surface of the porous body from the outer peripheral edge of the porous body. There is a desire to manufacture a composite porous body in which a resin portion extending in a direction is 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

By the way, in this type of mold apparatus for insert molding, when the porous body is disposed on the mold surface, the porous body is manually positioned in the direction along the surface of the mold surface using a scale. Therefore, there is a problem that it is impossible to avoid an increase in the number of manufacturing steps and manufacturing cost of the composite porous body.
Further, since the porous body as an insert part has a rough surface due to its structure, the mold surface does not uniformly contact the surface of the porous body when clamping, so the mold surface Thus, there is a problem that in the process of compressing and fixing the surface of the porous body, positional displacement of the porous body is likely to occur, and it is difficult to manufacture a highly accurate composite porous body.

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

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 using an insert molding die apparatus for manufacturing a composite porous body in which a porous body and a resin portion are integrally formed, wherein the insert molding mold apparatus is A positioning means for positioning the porous body in a direction along the mold surface in contact with an edge of the porous body disposed on the mold surface; After positioning in the direction along the mold surface, the positioning means is clamped in a state of being in contact with the edge of the porous body, and the porous body is compressed in the mold opening and closing direction by the mold surface. Fix Both, after forming the cavity, in a state where the positioning means is in contact with the edge of the porous body, the molten resin is injected into the cavity so as to continue to the porous body, and then the molten resin is Before or simultaneously with the entire area in the cavity, the contact of the edge of the porous body by the positioning means is released.

The invention according to claim 2 is the insert molding method according to claim 1 , wherein the positioning means gradually releases the contact of the edge of the porous body by the injection pressure of the molten resin in the cavity. Features.

According to the insert molding methods according to these inventions, the porous body as the insert part can be easily and reliably positioned in the direction along the surface of the mold surface by the positioning means.
Further, in the clamping process in which the mold surface compresses and fixes the porous body in the mold opening and closing direction, the positioning means can be kept in contact with the edge of the porous body. It is possible to suppress the occurrence of positional deviation in the direction along the mold surface of the porous body.
Furthermore, when the molten resin is injected into the cavity, the positioning means is kept in contact with the edge of the porous body, so that the displacement of the porous body due to the injection pressure of the molten resin in the cavity can be suppressed. it can.
As described above, a highly accurate composite porous body can be manufactured with low man-hours and low cost.

  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 at low cost.

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 method, will be described with reference to FIG.
The composite porous body 10 includes, for example, a thin plate-like porous body 11 having a three-dimensional network structure made of metal, and a resin extending in the surface direction of the porous body 11 from each outer peripheral edge of the porous body 11. The portion 12 is integrally formed, and has a rectangular thin plate shape as a whole.

The porous body 11 is in the shape of a rectangular thin plate, and has pores opened in the side portions in each direction, thereby providing air permeability and water absorption, light weight and large surface area.
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.
The composite porous body 10 having the shape of a rectangular thin plate in which the porous body 11 and the resin portion 12 are integrated as described above is attached to various apparatuses by fixing or sandwiching the resin portion 12. For example, it is used for a filter, a gas diffusion member, a heat dissipation member, a water absorption member, 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. 5 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 a frame-shaped positioning member 8a having an opening on the inside, and a drive (not shown) including, for example, a hydraulic or pneumatic cylinder that supports the positioning member 8a so that it can protrude and retract with respect to the movable mold surface 4a. And an elastic member 8b made of, for example, a spring or rubber, disposed between the positioning member 8a and the drive unit. In the present embodiment, a spring is illustrated as the elastic member 8b.

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 positioning member 8a 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 positioning member 8a. Thereby, the outer peripheral edge of the porous body 11 is in contact with at least a part of the inner surface of the positioning member 8a, so that the porous body 11 is oriented along the surfaces of the mold surfaces 3a and 4a as shown in FIG. Is positioned.
Second, after the porous body 11 is disposed on the movable mold surface 4a, the positioning member 8a is moved forward to the movable mold surface 4a by the drive unit. At this time, at least a part of the inner surface of the positioning member 8 a comes into 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. 6 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). As described above, with the positioning member 8a in contact with the outer peripheral edge of the porous body 11, the movable mold 4 is moved forward toward the fixed mold 3 and clamped, and the mold surfaces 3a and 4a are clamped. Thus, the porous body 11 is compressed and fixed in the mold opening / closing direction, and the cavity 2 is formed. At this time, in this embodiment, as shown in FIG. 2, a gap 2a is formed between the fixed mold surface 3a and the distal end surface of the positioning member 8a.

  Thereafter, the molten resin 7 is injected from the runner 5 into the cavity 2 and the gap 2 a through the gate 6 while the positioning member 8 a is in contact with the outer peripheral edge of the porous body 11. Then, in the process in which the molten resin 7 spreads into the cavity 2 and the gap 2a, the positioning member 8a is gradually moved by the elastic member 8b due to the injection pressure of the molten resin 7 in the cavity 2 or the like, thereby gradually moving the movable mold surface 4a. Retreats from the surface of the surface, and the protruding length from the surface becomes shorter. When the molten resin 7 spreads over the entire space 2a and the cavity 2, the distal end surface of the positioning member 8a and the movable mold surface 4a are flush with each other, and the outer peripheral edge of the porous body 11 is contacted by the positioning member 8a. Is released. Thereby, the composite porous body 10 which is an insert-molded product in which the porous body 11 and the resin portion 12 are continuous and integrated with no step is formed.

  Thereafter, the movable mold 4 is moved backward so as to be separated from the fixed mold 3, and the positioning member 8a is moved forward again by the drive unit so as to protrude from the movable mold surface 4a. Thereby, the composite porous body 10 is satisfactorily separated from the surface of the movable mold 4a and removed from the insert molding mold apparatus 1.

In the composite porous body 10 formed as described above, when the molten resin 7 is injected into the cavity 2 or the like, 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. Thus, 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 .

  The thickness of the cavity 2 during mold clamping (size in the mold opening / closing direction) is set slightly smaller than that of the porous body 11, and the porous body 11 is interposed between the mold surfaces 3a and 4a during mold clamping. By compressing 3 to 90%, the porous body 11 is securely fixed to the cavity 2 and the flatness of the porous body 11 is improved.

As described above, according to the insert molding method according to the present embodiment, the porous body 11 as the insert part is easily and reliably positioned in the direction along the surfaces of the mold surfaces 3a and 4a by the positioning means 8. Can do.
Further, in the mold clamping process in which the mold surfaces 3a and 4a compress and fix the porous body 11 in the mold opening / closing direction, the positioning members 8a are brought into contact with the outer peripheral edge of the porous body 11, so this process The occurrence of misalignment in the direction along the mold surfaces 3a and 4a of the porous body 11 can be suppressed.
Further, when the molten resin 7 is injected into the cavity 2 or the like, the positioning member 8a is brought into contact with the outer peripheral edge of the porous body 11, so that the porous body 11 is caused by the injection pressure of the molten resin 7 in the cavity 2 or the like. Misalignment can also be suppressed.
As described above, the highly accurate composite porous body 10 can be manufactured with low man-hour and low cost.

As described above, the porous body 11 is appropriately selected according to the characteristics required for the composite porous body 10 produced using the porous body 11. If the rate is too small, the molten resin 7 will not enter the pores properly, the anchor effect will be insufficient, and the bonding strength with the resin part 12 may not be sufficiently obtained.
On the other hand, even if the pore size or porosity of the porous body 11 is too large, the strength of the porous body 11 itself is insufficient, and the resin molding pressure and the compression at the time of resin curing cannot be endured. The molten resin 7 may permeate too deep into the pores of the porous body 11, and the desired shape may not be maintained.
Therefore, it is preferable that the porous body 11 has a pore diameter of about 10 μm to 2 mm and a porosity of about 40 to 98%.

On the other hand, the resin portion 12 is also appropriately selected in consideration of heat-resistant temperature, hardness, and the like according to characteristics required for the composite porous body 10 produced using the resin portion 12. Any material that can be injection-molded, such as rubber).
Further, the resin portion 12 may be flat as shown in FIG. 6B, but a screw insertion hole, a groove shape for fitting to the apparatus, a rib shape for improving strength, a boss Etc. may be provided during resin molding.

Further, in the above embodiment, as shown in FIG. 6B, the composite porous body 10 has the resin portion 12 having a thickness 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 approximately 0.01 mm thinner than the thickness of the porous body 11, and may be connected to the outer peripheral edge portion of the porous body 11 with a step.
Furthermore, as shown in FIG. 6A, the resin portion 12 does not need to be continuous with the entire outer peripheral edge portion 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 connected to at least one side of the porous body 12 in a lattice shape, for example.

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 positioning member 8a disposed on the fixed mold 3 contacts 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 / closing direction by the mold surfaces 3a and 4a. become. Thereafter, the contact of the porous body 11 by the positioning member 8a is released before or at the same time as the molten resin 7 spreads over the entire area such as the cavity 2.
Further, 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 positioning member 8a is advanced and moved again onto the fixed mold surface 3a. 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.

  Moreover, in the said embodiment, the structure which retracts the positioning member 8a from the movable mold surface 4a was shown by the elastic member 8b of the positioning means 8 being gradually reduced by the injection pressure of the molten resin 7 in the cavity 2 etc. However, the present invention is not limited to this, and the positioning member 8a may be retracted by driving the drive unit of the positioning means 8. In this case, after injecting the molten resin into the cavity 2 or the like, the timing at which the positioning member 8 releases the contact with the outer peripheral edge of the porous body 11 is the same as when the molten resin 7 spreads over the entire area of the cavity 2 or the like. Not limited to certain cases, it can be set arbitrarily.

Furthermore, in the said embodiment, although the frame-shaped structure by which the inner side was made into the opening part was shown as the positioning member 8a, it is not restricted to this, For example, as shown in FIG. One or more pin members having a circular cross-sectional view supported so as to be able to appear and retract may be used. In addition, the cross-sectional view of this pin member may be rectangular or elliptical, for example.
Further, the elastic member 8b of the positioning means 8 is not limited to the case where the elastic member 8b is used for retreating by the injection pressure of the molten resin 7 in the cavity 2 or the like as in the above-described embodiment. It can also be used as a buffer member when colliding with the mold surface 3a or 4a. In this case, the positioning member 8a may not be moved backward only by the injection pressure of the molten resin 7 as in the above embodiment. In this case, the positioning unit 8 may be moved backward by the driving unit.

  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 of the insert molding method shown as 1st embodiment of this invention. It is a figure which shows the 3rd process of the insert molding method shown as 1st embodiment of this invention. It is a cross-sectional top view which shows a part of mold apparatus for insert molding used for the insert method shown as 2nd 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert mold apparatus 2 Cavity 3 Fixed mold 4 Movable mold 3a Fixed mold surface 4a Movable mold surface 7 Molten resin 8 Positioning means 8a Positioning member 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 insert molding in which a molten resin is injected so as to be continuous with the porous body, the porous body and the resin An insert molding method using a mold apparatus for insert molding for producing a composite porous body formed integrally with a part,
The insert molding die device includes positioning means for contacting the edge of the porous body disposed on the mold surface and positioning the porous body in a direction along the mold surface,
After positioning the porous body in the direction along the mold surface by the positioning means,
Clamping the positioning means in contact with the edge of the porous body, compressing and fixing the porous body in the mold opening and closing direction by the mold surface, and after forming a cavity,
In a state where the positioning means is in contact with the edge of the porous body, the molten resin is injected into the cavity so as to be continuous with the porous body,
Thereafter, before or at the same time as the molten resin has spread over the entire area of the cavity, the contact of the edge of the porous body by the positioning means is released. In the insert molding method according to claim 1 ,
The insert molding method according to claim 1, wherein the positioning means gradually releases the contact of the edge of the porous body by the injection pressure of the molten resin in the cavity.

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