WO2016093265A1

WO2016093265A1 - Molding method

Info

Publication number: WO2016093265A1
Application number: PCT/JP2015/084491
Authority: WO
Inventors: 健次青木; 豊竹渕; 健太郎坂本; 学寺川
Original assignee: エア・ウォーター・マッハ株式会社
Priority date: 2014-12-12
Filing date: 2015-12-09
Publication date: 2016-06-16
Also published as: CN107000289A; JP6353930B2; JPWO2016093265A1; CN107000289B

Abstract

In order to prevent a molding material 11 from being pushed out from a molding material supply port (311) even when a molding material (11) is heated between a first mold (31) and a second mold (32), a convex portion (326) is provided at a position that overlaps a sprue (312) in plan view in the second mold (32), and a concave portion (316) into which the convex portion (326) enters is provided in the first mold. During molding, the molding material (11) is supplied from a nozzle (40) through the molding material supply port (311) and sprue (312) to a space between the first mold (31) and second mold (32) in a state in which the first mold (31) and second mold (32) are separated, and the molding material (11) is then compressed by superposing the first mold (31) and second mold (32). As a result, the molding material (11) fills a cavity (30) through a runner (33) and a gap (36) between the convex portion (326 and the inner surface of the concave portion (316).

Description

Molding method

The present invention relates to a molding method suitable for manufacturing a thermosetting rubber product or the like.

The production of O-rings and the like is generally compression molding, but a method by injection molding has also been proposed (see Patent Document 1). In the case of injection molding, for example, as shown in FIGS. 5A and 5B, a first mold 31 in which a molding material supply port 311 and a sprue 312 communicating with the molding material supply port 311 are formed; A runner 33 and a second mold 32 constituting the cavity 30 are used between the mold 31 and the first mold 31 when they are superposed on the mold 31. Here, the connection portion between the sprue 312 and the runner 33 is a cavity 39 wider than the gap between the runners 33. In order to perform injection molding of a thermosetting material such as a thermosetting resin or a rubber material using the first mold 31 and the second mold 32, the thermosetting molding material 11 supplied from the nozzle 40 is molded. After filling the cavity 30 through the material supply port 311, the sprue 312, the cavity 39, and the runner 33, the molding material 11 is heated through the first mold 31 and the second mold 32 to cure the molding material 11. Let

JP 2005-279949 A

However, when the molding material is heated via the first mold 31 and the second mold 32, as shown in FIG. 5C, if the nozzle 40 is separated from the molding material supply port 311, the molding material Since the supply port 311 is in an open state, the molding material 11 expanded during thermosetting is largely pushed out from the molding material supply port 311 through the cavity 39 and the sprue 312. For this reason, since the pressure in the cavity 30 cannot be maintained high, there is a problem that the molding accuracy is lowered, for example, a cavity is generated in the cavity 30.

On the other hand, as shown in FIG. 5B, if the heating process (curing process) is performed with the nozzle 40 connected to the molding material supply port 311, the molding material 11 that has expanded at the time of thermosetting becomes the molding material supply port. It can be prevented from being greatly pushed out from 311. However, since the pressure due to the expansion of the molding material 11 tends to escape to the inside of the nozzle 40, the pressure is applied to the molding material in the nozzle 40 and the first mold 31 and the second mold 32 from the nozzle 40 side. It is necessary to apply a pressure to the molding material 11 between them and maintain the pressure in the cavity 30 high. As a result, the configuration on the nozzle 40 side becomes complicated.

In view of the above problems, an object of the present invention is to suppress the molding material from being extruded from the molding material supply port even when the molding material is heated between the first mold and the second mold. An object of the present invention is to provide a molding method that can be used.

In order to solve the above-described problems, a molding method according to the present invention includes a first mold in which a molding material supply port and a sprue communicating with the molding material supply port are formed, and the first mold is overlapped. In performing molding using a second mold that constitutes a runner and a cavity between the first mold and the first mold, thermosetting is performed in a state in which the first mold and the second mold are separated from each other. After the molding material is supplied between the first mold and the second mold from the nozzle through the molding material supply port and the sprue, the first mold and the second mold are stacked. And a filling step of filling the cavity with the molding material, a curing step of curing the molding material by heating the molding material in a state where the first mold and the second mold are overlapped, On one side of the first mold and the second mold A convex portion protruding toward the other side of the first mold and the second mold is provided at a position overlapping with the sprue in plan view, and the other side is provided with a plan view with respect to the sprue. When the first mold and the second mold are overlapped with each other, the convex part enters inside and the sprue passes through the gap with the convex part. And a recess for communicating with the runner. The “cavity” in the present invention means a hollow portion filled with resin, and the “runner” in the present invention means a resin passage connecting the sprue and the cavity.

In the present invention, after the first mold and the second mold are separated from each other, the molding material is supplied from the nozzle to the first mold and the second mold via the molding material supply port and the sprue. The molding material is compressed by superimposing the first mold and the second mold, and the cavity is filled through the runner. For this reason, even when the pressure with respect to the molding material supplied from a nozzle is low, the pressure similar to compression molding can be applied to a molding material. Further, it is suitable for molding a molding material having a high viscosity, such as a thermosetting rubber material, as compared with ordinary injection molding. In the present invention, a convex portion is formed on one side of the first mold and the second mold, and a concave portion is formed on the other side, and the first mold and the second mold are overlapped. In this case, the protrusion enters the inside of the recess, and the sprue and the runner communicate with each other through the gap between the inner surface of the recess and the protrusion. Therefore, when the molding material is heated through the first mold and the second mold in the curing step, the molding material is blocked by the gap between the inner surface of the concave portion and the convex portion even if the molding material is thermally expanded. . Moreover, since the molding material located in the clearance gap between the inner surface of a recessed part and a convex part is thin, it hardens | cures in a short time in a hardening process. For this reason, even if the molding material is thermally expanded, the molding material is blocked by the gap between the inner surface of the concave portion and the convex portion. Therefore, it is difficult for the molding material to flow back through the sprue and be pushed out of the molding material supply port. Therefore, since the pressure in the cavity can be kept high, appearance defects such as insufficient filling of the cavity, scratches on the surface of the molded product, and poor fusion in the molded product can be reduced.

In the present invention, in the curing step, it is possible to employ a mode in which the molding material is heated in a state where the nozzle is separated from the molding material supply port. In the present invention, even when the molding material is thermally expanded, it is difficult for the molding material to flow back through the sprue and be pushed out from the molding material supply port. Therefore, when performing the curing step, the pressure in the cavity can be kept high even if the molding material supply port is not blocked by the nozzle.

In the present invention, the curing step may employ a mode in which the molding material is heated while the nozzle is connected to the molding material supply port. In the present invention, even when the molding material is thermally expanded, it is difficult for the molding material to flow back through the sprue and be pushed out from the molding material supply port. Therefore, when performing the curing process, pressure is applied to the resin in the nozzle, and pressure is applied to the molding material between the first mold and the second mold from the nozzle side to keep the pressure in the cavity high. There is no need to do. Therefore, a simple configuration may be used on the nozzle side.

In the present invention, a configuration in which a plurality of the cavities are arranged around the sprue can be employed.

In the present invention, the runner is a gap sandwiched between a flat surface facing the second mold in the first mold and a flat surface facing the first mold in the second mold. It is preferable. According to such a configuration, since it is not necessary to form a groove for forming the runner in the first mold and the second mold, the configuration of the first mold and the second mold can be simplified.

In the present invention, it is possible to adopt a configuration in which the concave portion is formed in the first mold and the convex portion is formed in the second mold. In the present invention, the gate that connects the runner and the cavity when the first mold and the second mold are overlapped is the first mold and the second mold in the runner. A first portion having a larger interval than the interval, and a space between the first portion and the cavity that is narrower than the interval between the first mold and the second mold in the first portion and the cavity. The second portion may be adopted.

The present invention provides a gate for forming a thin portion for cutting along an edge of the molded product between the runner and the cavity when the first mold and the second mold are overlapped with each other. It may be applied when is configured.

In the present invention, the molding material is, for example, a rubber material before vulcanization. In the present invention, the rubber material includes, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluorine rubber (FKM, FEPM, FFKM), silicone rubber (VMQ), fluorosilicone rubber (FVMQ), ethylene propylene One of rubber (EPDM, EPT), chloroprene rubber (CR), acrylic rubber (ACM), and butyl rubber (IIR).

In the present invention, a configuration in which an O-ring is formed can be employed in the cavity.

It is explanatory drawing which shows the specific example of the molded article to which this invention is applied. It is explanatory drawing of the 1st example of the metal mold | die apparatus, the shaping | molding apparatus, and shaping | molding method to which this invention is applied. It is explanatory drawing of the 2nd example of the metal mold | die apparatus to which this invention is applied, a shaping | molding apparatus, and a shaping | molding method. It is explanatory drawing of the 3rd example of the metal mold | die apparatus to which this invention is applied, a shaping | molding apparatus, and a shaping | molding method. It is explanatory drawing of the metal mold | die apparatus which concerns on the reference example of this invention, a shaping | molding apparatus, and a shaping | molding method.

Embodiments of the present invention will be described with reference to the drawings. In the following description, portions corresponding to the configuration shown in FIG. 5 are denoted by the same reference numerals so that the correspondence with the configuration described with reference to FIG. 5 can be easily understood.

[Embodiment 1]
(Specific examples of molded products)
FIG. 1 is an explanatory view showing a specific example of a molded product to which the present invention is applied. FIGS. 1 (a) and 1 (b) are explanatory views of a rubber sheet formed in an O-ring manufacturing process, and rubber. It is sectional drawing of a sheet | seat.

Molded product 1 shown in FIG. 1 includes nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluorine rubber (FKM, FEPM, FFKM), silicone rubber (VMQ), fluorosilicone rubber (FVMQ), ethylene propylene rubber ( EPDM, EPT), chloroprene rubber (CR), acrylic rubber (ACM), butyl rubber (IIR) and other rubber molded products.

In this embodiment, the molded product 1 is an O-ring 1a. In manufacturing the molded product 1 (O-ring 1a), after the rubber sheet 10 is molded in a molding process described later with reference to FIG. 2, the rubber sheet 10 is cut to obtain a plurality of O-rings 1a. The rubber sheet 10 includes a first rod-shaped convex portion 12 having a round bar shape and a sheet portion 18 that spreads around the first rod-shaped convex portion 12. The sheet portion 18 includes a plurality of annular projections 13, a thin connecting portion 14 that connects the annular projections 13 on the outside of the plurality of annular projections 13, and a thin portion 15 formed on the inside of the annular projection 13. The annular convex portion 13 constitutes the O-ring 1a.

In this embodiment, the rubber sheet 10 further includes a round bar-shaped second bar-shaped convex part 16 projecting opposite to the first bar-shaped convex part 12, a root portion of the first bar-shaped convex part 12, and the sheet part 18. And a thin step portion 17 that is bent in the protruding direction of the first rod-like convex portion 12.

(Configuration of molding apparatus 2 and mold apparatus 3)
FIG. 2 is an explanatory diagram of a first example of a mold apparatus 3, a molding apparatus 2, and a molding method to which the present invention is applied. FIGS. 2 (a), (b), (c), and (d) It is explanatory drawing which shows the principal part of the shaping | molding apparatus 2, explanatory drawing of the 1st process in a filling process, explanatory drawing of the 2nd process in a filling process, and explanatory drawing of a hardening process.

As shown in FIGS. 2A and 2B, the molding apparatus 2 according to the present embodiment includes a mold apparatus 3 and an injection provided with a nozzle 40 for supplying a thermosetting molding material into the mold apparatus 3. Machine 4. Although not shown, the injector 4 includes an injection pot connected to the nozzle, a plunger that can slide in the injection pot, and the like. The tip of the nozzle 40 located on the mold device 3 side has a convex curved surface.

The mold apparatus 3 includes a plate-shaped first mold 31 located on the nozzle 40 side, and a second mold that faces the first mold 31 on the side opposite to the nozzle 40 with respect to the first mold 31. 32. One of the first mold 31 and the second mold 32 is a fixed mold, and the other is a movable mold. In this embodiment, the first mold 31 is a fixed mold and the second mold 32 is a movable mold. The first mold 31 and the second mold 32 are formed with flow paths (not shown) through which a heat medium for heating the molding material 11 is passed.

The first mold 31 includes a molding material supply port 311 that opens toward the opposite side of the second mold 32, and a sprue that extends from the molding material supply port 311 toward the side where the second mold 32 is located. 312, and a plurality of annular first grooves 310 are formed around the sprue 312 on the first end surface 313 that is a flat surface facing the second mold 32. In the first mold 31, the periphery of the molding material supply port 311 is a concave curved surface.

The second mold 32 has a plurality of annular second grooves 320 formed in positions overlapping with the first grooves 310 on the second end surface 323 formed of a flat surface facing the first mold 31.

In this embodiment, as shown in FIGS. 2C and 2D, when the first mold 31 and the second mold 32 are stacked, the first annular groove 310 and the second annular groove are formed. The cavity 30 is formed by overlapping with 320. Further, when the first mold 31 and the second mold 32 are overlapped, the first end face 313 and the second end face 323 face each other through a gap, and the gap between the first end face 313 and the second end face 323 is A runner 33 is configured.

Here, at a position overlapping the sprue 312 in a plan view, a convex portion protruding toward the other side is formed on one side of the first mold 31 and the second mold 32, and one side is formed on the other side. A recess is formed on the side opposite to the side. In the present embodiment, at the position overlapping the sprue 312 in plan view, a convex portion 326 protruding toward the first mold 31 is formed on the second mold 32 side, and on the first mold 31 side, A recess 316 is formed on the side opposite to the second mold 32. When the first mold 31 and the second mold 32 are stacked, the convex portion 326 formed in the second mold 32 enters the concave portion 316 formed in the first mold 31. As a result, a gap 36 that allows the sprue 312 and the runner 33 to communicate with each other is formed between the inner surface 316 a of the recess 316 and the convex portion 326, and the sprue 312 and the runner 33 communicate with each other via the gap 36. In the second mold 32, a concave reservoir portion 322 is formed at a position overlapping the sprue 312 on the tip surface of the convex portion 326.

(First example of molding method)
In order to manufacture the O-ring 1a and the like using the molding apparatus 2 of this embodiment, first, in the filling process, the thermosetting molding material 11 supplied from the nozzle 40 is used as the molding material supply port 311, the sprue 312 and the runner 33. The cavity 30 is filled via

In this embodiment, in the filling step, first, in the first step shown in FIG. 2B, molding made of a rubber material before vulcanization in a state where the first mold 31 and the second mold 32 are separated from each other. The material 11 is supplied between the first mold 31 and the second mold 32 from the nozzle 40 via the molding material supply port 311 and the sprue 312. At that time, the molding material 11 is heated to a temperature of, for example, 70 ° C. to 120 ° C. to impart fluidity. The first mold 31 and the second mold 32 were also brought into contact with the heat medium passing through the first mold 31 and the second mold 32 and the first mold 31 and the second mold 32. Heat with a hot plate.

Next, in the second step shown in FIG. 2C, the first mold 31 is pressed against the second mold 32, and the first mold 31 and the second mold 32 are overlapped. As a result, the molding material 11 is compressed between the first mold 31 and the second mold 32 and filled into the cavity 30 via the runner 33. Further, the sprue 312 forms the first rod-like convex portion 12 shown in FIG. 1, and the pool portion 322 forms the second rod-like convex portion 16 shown in FIG. Here, the molding material 11 which is not vulcanized or insufficiently vulcanized accumulates in the reservoir portion 322. Further, the step portion 17 shown in FIG. 1 is formed by the gap 36 between the inner surface 316 a of the concave portion 316 of the first mold 31 and the convex portion 326 of the second mold 32.

Next, in the curing step shown in FIG. 2D, the molding material 11 is, for example, 160 ° through the first mold 31 and the second mold 32 in a state where the nozzle 40 is separated from the molding material supply port 311. By heating to a temperature of ˜190 °, the molding material 11 is vulcanized and cured. At that time, since the molding material located in the gap 36 between the inner surface 316a of the recess 316 and the projection 326 is thin between the first mold 31 and the second mold 32, the molding material located in the gap 36 is It hardens faster than the molding material filled in the cavity 30.

Next, the first mold 31 is separated from the second mold 32 to obtain the rubber sheet 10 shown in FIG. After that, the annular protrusion 13 is separated from the rubber sheet 10 to obtain the O-ring 1a.

(Main effects of this form)
As described above, in this embodiment, the convex portion 326 is formed on one side (second mold 32) of the first mold 31 and the second mold 32, and the other side (first mold 31). ) Is formed with a recess 316, and when the first mold 31 and the second mold 32 are overlapped, the protrusion 326 enters the inner side of the recess 316, and the inner surface 316 a and the protrusion 326 of the recess 316 The sprue 312 and the runner 33 communicate with each other through the gap 36. Therefore, when the molding material 11 is heated through the first mold 31 and the second mold 32 in the curing step, the molding material 11 is not affected by the expansion of the inner surface 316a of the concave portion 316 and the convex portion even if the molding material 11 is thermally expanded. It is dammed up by a gap 36 with 326. Further, since the molding material located in the gap 36 between the inner surface 316a of the concave portion 316 and the convex portion 326 is thin, it is cured in a short time in the curing step. For this reason, even if the molding material 11 is thermally expanded, the molding material 11 is blocked by the gap 36 between the inner surface 316a of the recess 316 and the projection 326. For this reason, the situation where the molding material 11 flows backward through the sprue 312 and is pushed out from the molding material supply port 311 hardly occurs. Therefore, even when the molding material supply port 311 is not blocked by the nozzle 40 during the curing process, the pressure in the cavity 30 is unlikely to decrease. Therefore, since a cavity or the like is hardly generated in the cavity 30, the molding accuracy of the molded product 1 (O-ring 1a) is high.

Further, in the filling step, the first mold 31 and the second mold 32 are separated from the first mold 31 and the second mold 32 from the nozzle 40 via the molding material supply port 311 and the sprue 312. After being supplied between the molds 32, the first mold 31 and the second mold 32 are overlapped to compress the molding material 11, and the gap 36 between the inner surface 316a of the recess 316 and the projection 326, and The cavity 30 is filled through the runner 33. For this reason, even when the pressure with respect to the molding material 11 supplied from the nozzle 40 is low, the pressure similar to compression molding can be applied to the molding material 11. Therefore, it is suitable for molding a molding material 11 having a high viscosity, such as a thermosetting rubber material.

The runner 33 has a first end surface 313 (flat surface) facing the second mold 32 in the first mold 31 and a second end surface 323 (flat surface) facing the first mold 31 in the second mold 32. The gap between the two surfaces. For this reason, since it is not necessary to form the groove | channel for forming the runner 33 in the 1st metal mold | die 31 and the 2nd metal mold | die 32, the structure of the 1st metal mold | die 31 and the 2nd metal mold | die 32 can be simplified. it can.

[Embodiment 2]
FIG. 3 is an explanatory diagram of a second example of the mold apparatus 3, the molding apparatus 2, and the molding method to which the present invention is applied. FIGS. 3 (a), (b), (c), and (d) It is explanatory drawing which shows the principal part of the shaping | molding apparatus 2, explanatory drawing of the 1st process in a filling process, explanatory drawing of the 2nd process in a filling process, and explanatory drawing of a hardening process. Since the basic configuration of this embodiment is the same as that of Embodiment 1, common portions are denoted by the same reference numerals and description thereof is omitted.

Also in this embodiment, the O-ring (molded product) described with reference to FIG. Further, as shown in FIGS. 3A and 3B, the molding apparatus 2 of the present embodiment is similar to the first embodiment in the mold apparatus 3 and the thermosetting molding material inside the mold apparatus 3. And an injection machine 4 provided with a nozzle 40 for supplying the same. The mold apparatus 3 includes a plate-shaped first mold 31 located on the nozzle 40 side, and a second mold that faces the first mold 31 on the side opposite to the nozzle 40 with respect to the first mold 31. 32. The first mold 31 includes a molding material supply port 311 that opens toward the opposite side of the second mold 32, and a sprue that extends from the molding material supply port 311 toward the side where the second mold 32 is located. 312 are formed. In the mold apparatus 3, when the first mold 31 and the second mold 32 are overlapped, the annular first groove 310 and the annular second groove 320 overlap to form the cavity 30. Further, when the first mold 31 and the second mold 32 are overlapped, the first end face 313 and the second end face 323 face each other through a gap, and the gap between the first end face 313 and the second end face 323 is A runner 33 is configured. Further, at a position overlapping the sprue 312 in a plan view, a convex portion 326 protruding toward the first mold 31 is formed on the second mold 32 side, and the second mold is disposed on the first mold 31 side. A recess 316 is formed on the opposite side to the mold 32. When the first mold 31 and the second mold 32 are stacked, the convex portion 326 formed in the second mold 32 enters the concave portion 316 formed in the first mold 31. As a result, a gap 36 that allows the sprue 312 and the runner 33 to communicate with each other is formed between the inner surface 316 a of the recess 316 and the convex portion 326, and the sprue 312 and the runner 33 communicate with each other via the gap 36.

When manufacturing the O-ring 1a and the like using the molding apparatus 2 of this embodiment, in the filling process, first, in the first process shown in FIG. 3B, the first mold 31 and the second mold 32 are separated from each other. In this state, the molding material 11 made of a rubber material before vulcanization is supplied from the nozzle 40 between the first mold 31 and the second mold 32 through the molding material supply port 311 and the sprue 312. Next, in the second step shown in FIG. 3C, the first mold 31 is pressed against the second mold 32, and the first mold 31 and the second mold 32 are overlapped. As a result, the molding material 11 is compressed between the first mold 31 and the second mold 32, and the cavity 30 via the gap 36 between the inner surface 316 a of the recess 316 and the protrusion 326 and the runner 33. Filled.

Next, in the curing step shown in FIG. 3D, with the nozzle 40 connected to the molding material supply port 311, the molding material 11 is moved through the first mold 31 and the second mold 32, for example, 160 ° to The molding material 11 is vulcanized and cured by heating to a temperature of 190 °. At that time, since the molding material located in the gap 36 between the inner surface 316a of the recess 316 and the projection 326 is thin between the first mold 31 and the second mold 32, the molding material located in the gap 36 is It hardens faster than the molding material filled in the cavity 30.

As described above, in this embodiment as well as in the first embodiment, in the filling step, the molding material 11 is fed from the nozzle 40 to the molding material supply port while the first mold 31 and the second mold 32 are separated from each other. After being supplied between the first mold 31 and the second mold 32 via the 311 and the sprue 312, the first mold 31 and the second mold 32 are overlapped to compress the molding material 11 and runners. The cavity 30 is filled via 33. For this reason, even when the pressure with respect to the molding material 11 supplied from the nozzle 40 is low, the pressure similar to compression molding can be applied to the molding material 11. Therefore, the same effects as those of the first embodiment can be obtained, such as being suitable for molding a molding material 11 having a high viscosity like a thermosetting rubber material.

Also in this embodiment, as in the first embodiment, when the first mold 31 and the second mold 32 are overlapped, the protrusion 326 enters the inside of the recess 316 and the inner surface 316a of the recess 316 and the protrusion The sprue 312 and the runner 33 communicate with each other through the gap 36 with the H.326. Therefore, when the molding material 11 is heated through the first mold 31 and the second mold 32 in the curing step, the molding material 11 is not affected by the expansion of the inner surface 316a of the concave portion 316 and the convex portion even if the molding material 11 is thermally expanded. It is dammed up by a gap 36 with 326. Further, since the molding material located in the gap 36 between the inner surface 316a of the concave portion 316 and the convex portion 326 is thin, it is cured in a short time in the curing step. For this reason, the situation where the molding material 11 flows backward through the sprue 312 and is pushed out from the molding material supply port 311 hardly occurs. Therefore, when performing the curing process, the nozzle 40 is connected to the molding material supply port 311 and pressure is not applied to the molding material 11 between the first mold 31 and the second mold 32 from the nozzle 40 side. The pressure in the cavity 30 can be kept high. Therefore, a simple configuration may be used for the nozzle 40 side.

[Embodiment 3]
FIG. 4 is an explanatory diagram of a third example of the mold apparatus 3, the molding apparatus 2, and the molding method to which the present invention is applied, and an enlarged explanation of the periphery of the cavity 13 described with reference to FIGS. FIG. In the present invention, as shown in FIG. 4, when the first mold 31 and the second mold 32 are overlapped, the gate 38 that connects the runner 33 and the cavity 30 is the first mold 31 in the runner 33. Between the first portion 38a and the cavity 30 between the first portion 38a and the cavity 30. The first portion 38a and the cavity 30 between the first portion 38a and the cavity 30 are wider. This may be applied to the case where the second portion 38b formed at a narrower interval than the first interval 38b is provided. According to such a configuration, since the molding material 11 uniformly reaches each of the plurality of cavities 30 via the first portion 38a, each of the plurality of cavities 30 can be appropriately filled with the molding material 11. . Further, since the thin portion is formed by the second portion 38b, the molded product 1 (O-ring 1a) can be appropriately separated from the seat portion 18.

(Other embodiments)
In the above embodiment, the convex portion 326 is formed on the second mold 32 side and the concave portion 316 is formed on the first mold 31 side. However, the convex portion is formed on the first mold 31 side. Alternatively, a configuration in which a recess is formed on the second mold 32 side may be employed.

In the above embodiment, the first end face 313 (flat surface) facing the second mold 32 in the first mold 31 and the second end face 323 (flat face) facing the first mold 31 in the second mold 32 are described. However, the runner 33 may be configured by grooves formed in the first mold 31 and the second mold 32.

In the above embodiment, an O-ring is exemplified as the molded product 1, but the present invention may be applied to manufacture other molded products 1.

In the present invention, after the first mold and the second mold are separated from each other, the molding material is supplied from the nozzle to the first mold and the second mold via the molding material supply port and the sprue. The first mold and the second mold are overlapped to compress the molding material and fill the cavity. For this reason, even when the pressure with respect to the molding material supplied from a nozzle is low, the pressure similar to compression molding can be applied to a molding material. Further, it is suitable for molding a molding material having a high viscosity, such as a thermosetting rubber material, as compared with ordinary injection molding. In the present invention, a convex portion is formed on one side of the first mold and the second mold, and a concave portion is formed on the other side, and the first mold and the second mold are overlapped. In this case, the protrusion enters the inside of the recess, and the sprue and the runner communicate with each other through the gap between the inner surface of the recess and the protrusion. Therefore, when the molding material is heated through the first mold and the second mold in the curing step, the molding material is blocked by the gap between the inner surface of the concave portion and the convex portion even if the molding material is thermally expanded. . Moreover, since the molding material located in the clearance gap between the inner surface of a recessed part and a convex part is thin, it hardens | cures in a short time in a hardening process. For this reason, even if the molding material is thermally expanded, the molding material is blocked by the gap between the inner surface of the concave portion and the convex portion. Therefore, it is difficult for the molding material to flow back through the sprue and be pushed out of the molding material supply port. Therefore, since the pressure in the cavity can be kept high, appearance defects such as insufficient filling of the cavity, scratches on the surface of the molded product, and poor fusion in the molded product can be reduced.

Claims

A runner and a cavity are formed between the first mold in which the molding material supply port and the sprue communicating with the molding material supply port are formed, and the first mold when they are overlapped with each other. In performing molding using the second mold,
In a state where the first mold and the second mold are separated from each other, the thermosetting molding material is transferred from the nozzle to the first mold and the second mold through the molding material supply port and the sprue. A filling step of superposing the first mold and the second mold and filling the cavity with the molding material,
A curing step of curing the molding material by heating the molding material in a state where the first mold and the second mold are overlapped;
Have
On one side of the first mold and the second mold, there is a protrusion protruding toward the other side of the first mold and the second mold at a position overlapping the sprue in plan view. Provided,
The other side is recessed on the opposite side to the one side at a position overlapping the sprue in plan view, and the convex portion is located on the inner side when the first mold and the second mold are overlapped with each other. A forming method is provided, wherein a recess is provided to allow the sprue and the runner to communicate with each other through a gap with the protrusion.
The molding method according to claim 1, wherein, in the curing step, the molding material is heated in a state where the nozzle is separated from the molding material supply port.
The molding method according to claim 1, wherein, in the curing step, the molding material is heated in a state where the nozzle is connected to the molding material supply port.
The molding method according to claim 1, wherein a plurality of the cavities are arranged around the sprue.
The runner is a gap sandwiched between a surface facing the second mold in the first mold and a surface facing the first mold in the second mold. Item 2. The molding method according to Item 1.
The recess is formed in the first mold;
The molding method according to claim 1, wherein the convex portion is formed in the second mold.
When the first mold and the second mold are overlapped, the gate connecting the runner and the cavity is wider than the distance between the first mold and the second mold in the runner. And a second part formed between the first part and the cavity at a distance narrower than a distance between the first part and the second mold in the cavity. The molding method according to claim 1, comprising:
The molding method according to any one of claims 1 to 7, wherein the molding material is a rubber material before vulcanization.
The rubber material is any one of nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, silicone rubber, fluorosilicone rubber, ethylene propylene rubber, chloroprene rubber, acrylic rubber, and butyl rubber. Molding method.
The molding method according to claim 8, wherein an O-ring is molded in the cavity.