JP7808801B2 - Molding apparatus and control method - Google Patents

Description

The present invention relates to a molding device for forming molded articles made by fusing expandable resin particles.

Molded articles made from expandable resin particles (hereinafter referred to as "molded foam articles") are used in a variety of applications, such as packaging materials for industrial products and food, automotive interior materials, and building materials. Various methods have been proposed for forming molded foam articles by heating expandable resin particles (hereinafter referred to as "expandable particles") to fuse them together.

For example, Patent Document 1 discloses a method of forming a foamed molded article by fusing expandable particles with steam heating (so-called bead expansion molding). Specifically, the gap between two opposing molds is filled with expandable resin, and steam heating is supplied into this space to fuse the expandable resin together. However, the technology of Patent Document 1, which fuses expandable resin with steam heating, has the problem that an excess or deficiency of steam can cause poor fusion, making it impossible to obtain a good foamed molded article.

Technologies have therefore been proposed for fusing expandable resins using methods other than steam heating. For example, Patent Document 2 discloses a method for fusing expandable particles by irradiating them with microwaves. Specifically, two molds for forming a foamed molded body are placed in the internal space of a reactor (container) that blocks microwaves, and expandable particles are filled into the gap between the two molds. Microwaves are then generated by a magnetron installed outside the reactor, and the microwaves are irradiated into the interior of the reactor via a waveguide. When the expandable particles are irradiated with microwaves that have passed through the two molds, the particles fuse together.

Japanese Patent Application Laid-Open No. 2003-080545 Special Publication No. 2014-531352

However, the technology described in Patent Document 2 requires a reactor to house the two molds, and a magnetron and introduction pipe must be placed outside the reactor, resulting in a large device for fusing the expandable particles with microwaves. Taking these circumstances into consideration, the present invention aims to miniaturize a molding device for fusing expandable particles with microwaves to form a foamed molded article.

To solve the above problems, the molding device of the present invention is a molding device for forming a molded body by fusing expandable resin particles, and includes a movable unit having a hollow interior and including a movable mold member on its surface; a fixed unit having a hollow interior and including a fixed mold member at a position on its surface facing the movable mold member; a filling device that fills the resin particles into a filling space formed between the fixed mold member and the movable mold member; and a generator that is installed in the internal space of the fixed unit and emits microwaves into the filling space to heat the resin particles, the generator including an oscillator that generates the microwaves and a waveguide that transmits the microwaves to the filling space.

A molding device according to a preferred embodiment of the present invention allows for the miniaturization of a molding device for forming a foamed molded article by fusing expandable particles using microwaves.

FIG. 2 is a cross-sectional view of the molding device according to the first embodiment. FIG. 2 is a cross-sectional view of the molding device according to the first embodiment. FIG. 2 is a plan view of a moving unit according to the first embodiment. FIG. 2 is a plan view of the fixed side unit according to the first embodiment. 1 is a cross-sectional view of a molding device filled with foamed beads according to a first embodiment. FIG. FIG. 1 is a configuration diagram of a generating device according to a first embodiment. FIG. 6 is a cross-sectional view of a molding device according to a second embodiment. FIG. 10 is a schematic diagram for explaining the position at which the stirring mechanism according to the second embodiment is installed. FIG. 10 is a plan view of a passage portion (configuration (1)) according to a second embodiment. FIG. 10 is a plan view of a passing section (configuration (2)) according to the second embodiment. FIG. 10 is a plan view of a passing portion (configuration (3)) according to the second embodiment. FIG. 10 is a plan view of a passing portion (configuration (4)) according to the second embodiment. FIG. 10 is a plan view of a passing portion (structure (5)) according to the second embodiment. FIG. 10 is a plan view of a passing portion (structure (6)) according to the second embodiment. FIG. 10 is a perspective view of a stirring mechanism (configuration (A)) according to a second embodiment. FIG. 10 is a perspective view of the stirring mechanism (configuration (B)) according to the second embodiment. FIG. 10 is a perspective view of the stirring mechanism (configuration (C)) according to the second embodiment. FIG. 10 is a perspective view of the stirring mechanism (configuration (D)) according to the second embodiment. FIG. 10 is a perspective view of the stirring mechanism (configuration (E)) according to the second embodiment. FIG. 10 is a perspective view of the stirring mechanism (configuration (F)) according to the second embodiment. FIG. 10 is a perspective view of the stirring mechanism (structure (G)) according to the second embodiment. FIG. 10 is a configuration diagram illustrating functions of a control unit according to a second embodiment. 10 is a flowchart (method (a)) of a process executed by a control unit according to the second embodiment. 10 is a flowchart (method (b)) of a process executed by a control unit according to the second embodiment. 10 is a flowchart (method (b)) of a process executed by a control unit according to the second embodiment. FIG. 11 is a configuration diagram illustrating functions of a control unit according to a third embodiment. FIG. 10 is a schematic view of a mold member according to a fourth embodiment. 10A and 10B are schematic views illustrating the configuration of a slit according to a fourth embodiment.

[First embodiment]
1 is a cross-sectional view of a molding apparatus 100 according to a first embodiment of the present invention. The molding apparatus 100 is an apparatus for forming a molded article (hereinafter referred to as a "molded foam article") made of expandable resin particles (hereinafter referred to as "expandable particles"). The molded foam article is used for various purposes, such as automotive interior materials, building materials, and packaging materials.

Generally speaking, a foam molded article is formed by filling the internal space (hereinafter referred to as the "filling space") of a molding die with expandable particles and then fusing the expandable particles. The molding die of the first embodiment is composed of a movable mold member 211 and a fixed mold member 311 that correspond to each other, as described below. The molding apparatus 100 of the present invention is an apparatus that includes a molding die. In the first embodiment, it is assumed that a box-shaped foam molded article is formed.

Specifically, the molding device 100 comprises a movable unit 20 (the portion where the movable mold member 211 is provided), a fixed unit 30 (the portion where the fixed mold member 311 is provided), a filling device 40, and a generating device 50. As illustrated in FIG. 1, the movable unit 20 and the fixed unit 30 are provided in positions facing each other. In the following description, the direction in which the movable unit 20 and the fixed unit 30 are arranged is referred to as the X direction, the direction perpendicular to the X direction is referred to as the Y direction, and the direction perpendicular to the X-Y plane is referred to as the Z direction.

The movable unit 20 is movable toward the fixed unit 30 (negative side of the X direction) and away from the fixed unit 30 (positive side of the X direction). Figure 2 is a cross-sectional view of the molding device 100 when the movable unit 20 is closest to the fixed unit 30. As illustrated in Figure 2, when the movable unit 20 approaches the fixed unit 30, a filling space U is formed between the movable mold member 211 and the fixed mold member 311.

Figure 3 is a plan view of the mobile unit 20 (as viewed from the negative side in the X direction). Figure 4 is a plan view of the fixed unit 30 (as viewed from the positive side in the X direction). Note that Figures 1 and 2 are cross-sectional views of the mobile unit 20 taken along line a-a in Figure 3, and cross-sectional views of the fixed unit 30 taken along line b-b in Figure 4.

Specifically, the movable unit 20 is a hollow structure. As illustrated in Figures 1 and 3, for example, the movable unit 20 comprises a movable mold member 211, a support plate 213, a frame portion 215, and a back plate portion 217. The back plate portion 217 is a flat member parallel to the Y-Z plane. For example, the back plate portion 217 is formed in an elongated shape when viewed from above in the X direction.

The frame portion 215 is a member that protrudes along the periphery of the back plate portion 217 to the negative side in the X direction (towards the fixed unit 30). The frame portion 215 is formed around the entire periphery of the back plate portion 217. In other words, the frame portion 215 is formed in a ring shape when viewed in a plan view. The method of connecting the frame portion 215 to the back plate portion 217 is arbitrary. For example, the back plate portion 217 and the frame portion 215 can be connected by fasteners (e.g., bolts) or welding.

The movable mold member 211 is one of two members that make up the molding die. In the first embodiment, as shown in Figure 3, the movable unit 20 is configured to include four movable mold members 211. The movable mold member 211 is formed into a shape that corresponds to the molded body. The planar shape of the movable mold member 211 is typically rectangular.

As illustrated in Figures 1 and 3, each movable mold member 211 has a recess G recessed from the surface. Specifically, an annular recess G is formed according to the planar shape of the movable mold member 211. The movable mold member 211 is supported by the frame portion 215 via a support plate 213.

As illustrated in FIG. 1, the frame portion 215 includes a protrusion N1 at the end opposite the back plate portion 217. The protrusion N1 is a portion of the frame portion 215 that protrudes in the Y direction toward the space enclosed by the frame portion 215. For example, the protrusion N1 is formed around the entire periphery of the frame portion 215.

The support plate 213 is a plate-shaped member parallel to the back plate portion 217 and is connected to the frame portion 215. Specifically, the support plate 213 is connected to the side of the frame portion 215 opposite the back plate portion 217. That is, the back plate portion 217 is located on the positive side of the frame portion 215 in the X direction, and the support plate 213 is located on the negative side of the X direction. The support plate 213 is connected to the frame portion 215 around its entire periphery. Specifically, the protrusion N1 of the frame portion 215 is connected to the periphery of the support plate 213. The method for connecting the support plate 213 to the frame portion 215 is arbitrary. For example, the frame portion 215 and the support plate 213 can be connected by fasteners (e.g., bolts) or welding.

As shown in Figure 1, the support plate 213 has through holes H formed therein that correspond to each movable mold member 211. The periphery of the movable mold member 211 is connected to the support plate 213 with the recess G of the movable mold member 211 inserted into the through hole H. The movable mold member 211 is positioned so that it is spaced apart from the back plate portion 217.

The movable unit 20 has an internal space R1 formed by the movable mold member 211, support plate 213, frame portion 215, and back plate portion 217. As can be understood from the above explanation, the movable unit 20 is an element that is hollow inside and includes the movable mold member 211 on its surface. In addition, a support member K1 is provided on the back plate portion 217 to support the movable mold member 211 and support plate 213 in the internal space R1.

A plurality of spacers S are provided on the surface of the movable unit 20 opposite the back plate portion 217. As illustrated in FIG. 2, the spacers S are portions that come into contact with the surface of the fixed unit 30 when the movable unit 20 approaches the fixed unit 30. For example, spacers S are provided on the surface of the movable mold member 211 (the surface opposite the internal space R1) or the surface of the support plate 213 (the surface opposite the internal space R1). Spacers S are provided in areas of each movable mold member 211 other than the portion that forms the filling space U, and in areas of the support plate 213 that do not overlap with the movable mold member 211. However, the location, number, and shape of the spacers S are optional.

The moving unit 20 is supported by the moving plate 23. The moving plate 23 is connected to the surface of the back plate 217 opposite the frame 215.

The fixed side unit 30 is a hollow structure. As illustrated in Figures 1 and 4, for example, the fixed side unit 30 comprises a fixed side mold member 311, a support plate 313, a frame portion 315, and a back plate portion 317. The back plate portion 317 is a flat member parallel to the Y-Z plane. For example, the back plate portion 317 is formed in an elongated shape when viewed from above in the X direction.

The frame portion 315 is a member that protrudes in the positive X-direction (toward the moving unit 20) along the periphery of the back plate portion 317. The frame portion 315 is formed around the entire periphery of the back plate portion 317. In other words, the frame portion 315 is formed in a ring shape when viewed in a plan view. The method of connecting the frame portion 315 to the back plate portion 317 is arbitrary. For example, the back plate portion 317 and the frame portion 315 can be connected by fasteners (e.g., bolts) or welding.

As illustrated in FIG. 1, the frame portion 315 includes a protrusion N2 at the end opposite the back plate portion 317. The protrusion N2 is a portion of the frame portion 315 that protrudes in the Y direction toward the space enclosed by the frame portion 315. For example, the protrusion N2 is formed around the entire periphery of the frame portion 315.

The support plate 313 is a plate-shaped member parallel to the back plate portion 317 and is connected to the frame portion 315. Specifically, the support plate 313 is connected to the side of the frame portion 315 opposite the back plate portion 317. That is, the back plate portion 317 is located on the negative side of the frame portion 315 in the X direction, and the support plate 313 is located on the positive side of the X direction. The support plate 313 is connected to the frame portion 315 around its entire periphery. Specifically, the protrusion N2 of the frame portion 315 is connected to the periphery of the support plate 313. The method for connecting the support plate 313 to the frame portion 315 is arbitrary. For example, the frame portion 315 and the support plate 313 can be connected using fasteners (e.g., bolts) or welding.

The fixed-side mold member 311 is a member of the molding die that corresponds to the movable-side mold member 211. The same number (four) of fixed-side mold members 311 as the movable-side mold members 211 are provided in the fixed-side unit 30. A single foam molded body is formed in a molding die configured as a pair of a movable-side mold member 211 and a fixed-side mold member 311. In other words, four foam molded bodies are formed in the molding device 100 of the first embodiment. The number of molding dies is optional.

Specifically, the fixed-side mold member 311 is formed in a shape corresponding to the movable-side mold member 211. In the first embodiment, the fixed-side mold member 311 is formed in a shape corresponding to the inner area of the outer periphery of the recess G of the movable-side mold member 211 in a plan view. For example, the fixed-side mold member 311 is formed in a rectangular shape in a plan view. Each fixed-side mold member 311 is provided at a position facing the movable-side mold member 211 on the surface of the support plate 313.

The fixed side unit 30 has an internal space R2 formed by the fixed side mold member 311, support plate 313, frame portion 315, and back plate portion 317. As can be understood from the above explanation, the fixed side unit 30 is an element that is hollow inside and includes the fixed side mold member 311 on its surface. In addition, a support member K2 is provided on the back plate portion 317 to support the fixed side mold member 311 and support plate 313 in the internal space R2.

The fixed unit 30 is supported by the fixed plate 33. The fixed plate 33 is connected to the surface of the back plate 317 opposite the frame portion 315.

As illustrated in Figure 2, when the movable unit 20 approaches the fixed unit 30 until the spacer S of the movable unit 20 abuts against the support plate 313 of the fixed unit 30, a filling space U is formed between the movable mold member 211 and the fixed mold member 311. The movable mold member 211 and the fixed mold member 311 are made of various metals, such as aluminum.

The filling device 40 is an injector for filling the filling space U with expandable particles. In the first embodiment, the filling device 40 is provided in the fixed side unit 30. A filling device 40 is provided for each fixed side mold member 311 (filling space U). The filling device 40 is provided so as to penetrate the back plate portion 317, the support plate 313, and the fixed side mold member 311. The filling device 40 ejects expandable particles toward the positive side in the X direction.

Figure 5 is a cross-sectional view of the molding device 100 with the filling space U filled with expandable particles. The molding device 100 fills the filling space U with expandable particles. The filling device 40 is a so-called injector. The filling device 40 is connected to a raw material tank (not shown) that contains expandable particles. In practice, when filling the filling space U with expandable particles, the filling port (the end on the positive side in the X direction) of the filling device 40 moves toward the fixed unit 30. The number of filling devices 40 for each filling space U and the locations at which the filling devices 40 are installed are arbitrary.

Expandable particles are formed by impregnating particles made of a thermoplastic resin, such as polystyrene resin, polyolefin resin, polyolefin, polyamide resin, or polyester resin, with a foaming agent. Expandable particles may also be formed by mixing two or more of these resins. Expandable particles whose surfaces are coated with various flame retardants may also be used. In addition to expandable particles, the filling space U may also be filled with various other materials (e.g., closed-cell foam particles, copolymers such as polypropylene or polyethylene). Furthermore, salt water or the like may be filled to improve the conductivity of the filling space U.

Any known method can be used to fill the filling space U with the expandable particles. For example, a method in which the expandable particles are pressurized with pressurized gas to apply a predetermined internal pressure to the expandable particles before filling the filling space U (pressure filling method), a method in which the expandable particles are compressed with pressurized gas and filled into the pressurized filling space U, and then the pressure within the filling space U is released (compression filling method), or a method in which the expandable particles are filled into the filling space U while leaving a small gap between the movable mold member 211 and the fixed mold member 311, and then the movable mold member 211 and the fixed mold member 311 are completely closed to mechanically compress the expandable particles (cracking filling method), etc. can be used.

The generator 50 is a device for heating the expandable particles by emitting microwaves E of a predetermined frequency band into the filling space U. The generator 50 of the first embodiment is provided in the internal space R2 of the fixed side unit 30. The generator 50 of the present invention is used to fuse the expandable particles filled in the filling space U. The microwaves E generated by the generator 50 are irradiated onto the expandable particles filled in the filling space U, heating them, and the surfaces of the softened expandable particles fuse together. The fused expandable particles are then cooled to form a foamed molded article.

In addition, in order to promote the fusion of the expandable particles, the molding device 100 according to the first embodiment also employs a configuration in which copper pipes through which a liquid at a constant temperature flows are brought into close contact with the movable mold member 211 and the fixed mold member 311, thereby controlling the heat of the movable mold member 211 and the fixed mold member 311.

The frequency band of the microwaves E generated by the generator 50 is, for example, the 2450 MHz band, which is the "frequency band designated for use as an ISM fundamental frequency" defined by J Standard: J55011 (H27). However, the microwave frequency band is not limited to the above examples. It can be changed as appropriate depending on, for example, the material of the expandable particles and the size of the foamed molded body. Furthermore, the microwaves are irradiated so that the temperature reaches, for example, 80°C to 180°C (but is not limited to this temperature).

Figure 6 is a structural diagram (schematic diagram) showing an example of a generator 50. The generator 50 includes, for example, an oscillator 51, a waveguide 53, an isolator 55, a power monitor 57, and a tuner 59. The oscillator 51 (magnetron: output 300 W to 10 kW) is a device that generates microwaves E. The waveguide 53 is connected to the oscillator 51 and is a component that transmits the microwaves E generated by the oscillator 51 to the filled space.

An isolator 55, a power monitor 57, and a tuner 59 are provided in the waveguide 53. Microwaves E are irradiated into the filled space U via the waveguide 53. The isolator 55 is a device that absorbs reflected waves from the filled space U. The power monitor 57 is a device that detects the power of the forward wave and the reflected wave of microwaves E propagating within the waveguide 53. Note that the power monitor 57 can detect not only the power of the reflected wave, but also the amplitude and phase of the reflected wave. The tuner 59 is a device that adjusts the power of the reflected wave.

In the first embodiment, for example, the portion of the waveguide 53 beyond the tuner 59 branches toward each fixed-side mold member 311. Specifically, as illustrated in FIG. 6, the waveguide 53 includes the same number of branch sections 531 as the number of fixed-side mold members 311 at the end opposite the oscillator 51. That is, in the first embodiment, it includes four branch sections 531. Note that, for convenience, only the cross section of the branch section 531 is shown in the generator 50 of FIG. 1.

The following explanation focuses on one fixed side mold member 311, but the other three fixed side mold members 311 have the same configuration.

The branch portion 531 is connected to the fixed-side mold member 311. As illustrated in Figures 1, 4, and 6, a through hole T for connecting the branch portion 531 is formed in each fixed-side mold member 311. Specifically, the end (opening portion) of the waveguide 53 opposite the oscillator 51 is connected to the through hole T from the opposite side to the movable-side mold member 211. In the first embodiment, the end of the branch portion 531 of the waveguide 53 is connected to the through hole T.

In addition, insertion holes through which the branch portions 531 are inserted are formed in the support plate 313 at positions corresponding to the through holes T. That is, each branch portion 531 of the waveguide 53 is connected to the through hole T while inserted through the support plate 313. The positions at which the through holes T are formed in the fixed-side mold member 311 are arbitrary. The branch portions 531 are connected to the through holes T so that their tips do not protrude from the surface of the fixed-side mold member 311.

The opening of the through-hole T on the movable mold member 211 side (the filling space U side) is closed by a lid member 532. The lid member 532 is formed in a thin plate shape from a material that transmits microwaves E. Examples of materials that transmit microwaves E include resins such as polypropylene, polyethylene, polyetherimide, and polytetrafluoroethylene, and ceramics such as alumina, mullite, and pyrophyllite. However, microwave-transmitting materials are not limited to the above examples. The microwaves E transmitted from the branching portion 531 pass through the lid member 532 and are irradiated onto the expandable particles in the filling space U. A tuner 59 may be provided for each branching portion 531. Furthermore, if the through-hole T is large enough to allow microwaves to pass through and not allow the expandable particles to enter, the lid member 532 is not required.

In the first embodiment, it is preferable that the elements of the movable unit 20 and the fixed unit 30 are configured to prevent microwave E from leaking outside the molding device 100. For example, the elements of the movable unit 20 and the fixed unit 30 are formed from a material that blocks microwaves. For example, the movable mold member 211 and the fixed mold member 311 are formed from various metals such as aluminum, copper, or iron. However, it is not necessary to form all elements of the movable unit 20 and the fixed unit 30 from a material that blocks microwaves. The configuration of the generator 50 is not limited to the example shown in Figure 6, as long as it is capable of generating microwaves in a specified frequency band.

In order to prevent sparks from being generated by the microwaves E within the filling space U, it is preferable to provide a safety device (earth) within the filling space U to allow the microwaves E to escape.

Comparative Example 1 (e.g., Patent Document 1), which fuses the foamable resin with heated steam, has the problem of failing to produce a good foamed molded article because poor fusion occurs due to an excess or deficiency of heated steam. In contrast, the molding device 100 of the present invention fuses the foamable resin using microwaves, which has the advantage of being less likely to result in poor fusion than the configuration of Comparative Example 1.

Furthermore, in Comparative Example 2 (e.g., Patent Document 2), in which microwaves are supplied from a generator located outside a housing that houses the entire movable unit and fixed unit, there is a problem in that the molding device becomes larger. In contrast, with the molding device 100 of the first embodiment, in which a generator 50 is built into the internal space R2 of the fixed unit 30 and microwaves are irradiated onto the expandable resin from the internal space R2, it is possible to reduce the size of the molding device 100 for fusing the expandable particles with microwaves compared to Comparative Example 2.

Furthermore, in Comparative Example 2, in order to irradiate microwaves onto the foamable resin, the majority of the mobile unit and fixed unit must be made of a material that transmits microwaves. In other words, it is difficult to form the mobile unit and fixed unit from metal, which blocks microwaves. Therefore, in Comparative Example 2, the materials from which the mobile unit and fixed unit can be formed are limited, resulting in low design freedom. In contrast, in the first embodiment, microwaves E are transmitted to the filling space U via the waveguide 53 of the generator 50 installed inside the internal space R2, so it is possible to form each element of the mobile unit 20 and fixed unit 30 from metal. Ultimately, compared to Comparative Example 2, this has the advantage of providing greater design freedom for the mobile unit 20 and fixed unit 30.

In addition, in Comparative Example 2, microwaves are generated outside the moving unit and the fixed unit, making it difficult to predict the direction in which the microwaves will travel. This makes it difficult to properly irradiate the expandable granules filled in the filling space with microwaves. This ultimately leads to problems such as uneven fusion, which can lead to errors in the quality of the molded product. In contrast, the first embodiment has the advantage of being able to properly irradiate the expandable granules with microwaves E via the waveguide 53 of the generator 50 installed in the internal space R2.

Second Embodiment
A second embodiment will be described. In the following examples, elements that have the same functions as those in the first embodiment will be designated by the same reference numerals as those in the first embodiment, and detailed descriptions thereof will be omitted as appropriate.

Figure 7 is a cross-sectional view of a molding apparatus 100 according to the second embodiment. The molding apparatus 100 according to the second embodiment is configured by adding a stirring mechanism 60 to the molding apparatus 100 according to the first embodiment. The stirring mechanism 60 is a mechanism for stirring the microwaves in the filling space U, thereby irradiating the microwaves over the entire expandable granules in the filling space U. A stirring mechanism 60 is provided for each filling space U.

Figure 8 is a schematic diagram illustrating the location where the stirring mechanism 60 is installed. As illustrated in Figure 8, it is installed on the surface of at least one of the fixed-side mold member 311 and the movable-side mold member 211 (the surface opposite the filling space U). Note that Figure 7 illustrates a case where the stirring mechanism 60 is installed on the surface of the movable-side mold member 211. However, a configuration in which the stirring mechanism 60 is installed on the surface of the fixed-side mold member 311 or on the surfaces of both the fixed-side mold member 311 and the movable-side mold member 211 can also be used.

In the following description, the surface of the fixed-side mold member 311 and the movable-side mold member 211 on which the stirring mechanism 60 is provided will be referred to as the installation surface F. Furthermore, when there is no need to distinguish between the fixed-side mold member 311 and the movable-side mold member 211, they will simply be referred to as mold members.

As illustrated in Figure 8, the installation surface F is provided with a passage D through which microwaves within the filling space U can pass. The stirring mechanism 60 changes the amplitude and phase of microwaves that have passed through the passage D from the filling space U, and emits the microwaves with the changed amplitude and phase from the passage D into the filling space U, thereby stirring the microwaves (electromagnetic field distribution) within the filling space U.

Specifically, the stirring mechanism 60 includes a housing 601. The housing 601 is, for example, a structure having an opening O and is made of a metal that does not allow microwaves to pass through. In the second embodiment, a cylindrical housing 601 with a square bottom is exemplified. That is, the opening O is on the side of the housing 601 opposite the bottom. The housing 601 is provided on the installation surface F so that the passage D is located inside the opening O of the housing 601. In other words, the housing 601 is provided on the installation surface F so as to cover the passage D. Microwaves enter the internal space R3 of the housing 601 from the filling space U via the passage D.

The shape of the housing 601 is arbitrary as long as microwaves can pass between the internal space R3 of the housing 601 and the filling space U via the passage D and can block microwaves. For example, the housing 601 may be formed so as to cover the entire surface of the mold member on which the stirring mechanism 60 is provided. The specific configuration of the stirring mechanism 60 other than the housing 601 will be described later.

A variety of configurations can be used for the passage section D, as long as microwaves can pass through without the expandable particles in the filling space U leaking to the outside. For example, the following configurations (1)-(6) can be used as the passage section D. Figures 9-14 are diagrams of the passage section D relating to configurations (1)-(6) when viewed from the W direction in Figure 8 (a direction perpendicular to the installation surface F).

<Configuration (1)>
As illustrated in Fig. 9, the passage D of the configuration (1) includes a long slit D1 (an example of a first slit). The slit D1 penetrates the installation surface F. That is, the filling space U and the internal space R3 of the housing 601 communicate with each other via the slit D1. The direction in which the slit D1 extends is a direction intersecting the direction of vibration of the electric field of the microwaves emitted by the generator 50. Fig. 9 illustrates a case in which the slit D1 extends in a direction perpendicular to the direction of vibration of the electric field of the microwaves emitted by the generator 50.

The length L of the slit D1 is, for example, at least half the wavelength of the microwaves emitted by the generator 50, from the viewpoint of allowing the microwaves to pass through appropriately. The width W of the slit D1 is set to, for example, smaller than the diameter of the expandable particles, from the viewpoint of preventing the expandable particles in the filling space U from leaking into the internal space R3 through the slit D1.

<Configuration (2)>
10 , the passage portion D of the configuration (2) includes two or more slits D1 arranged at a distance T from each other. The distance T is set to, for example, ¼ or more of the wavelength of the microwave in order to suppress electromagnetic coupling between the slits D1 and reduce heat loss in the slits D1. The configuration (2) allows microwaves to pass through more efficiently than the configuration (1).

<Configuration (3)>
11 , the passing portion D of the configuration (3) is a slit D2 (an example of a first slit). However, the slit D2 of the configuration (3) extends in a direction different from that of the slit D1. Specifically, the slit D2 of the configuration (3) extends in a direction inclined at an angle other than 90 degrees (for example, about 45 degrees) with respect to the direction of oscillation of the electric field of the microwaves emitted by the generator 50.

By adopting configuration (3), it is possible to change the direction of oscillation (polarization) of the magnetic field of microwaves entering and leaving through the passage D. In other words, the passage D (slit D2) of configuration (3) functions as a polarizer. Therefore, compared to configuration (1), it is possible to generate microwaves polarized on multiple axes within the filled space U. This has the remarkable effect of being able to irradiate microwaves throughout the entire filled space U. The angle at which slit D2 is inclined can be any angle as long as it can function as a polarizer.

<Configuration (4)>
12 , the passage portion D of the configuration (4) includes two or more slits D arranged at a distance T from each other. As in the case of the configuration (2), the distance T is set to, for example, ¼ or more of the wavelength of the microwave from the viewpoint of suppressing electromagnetic coupling between the slits D and reducing heat loss in the slits D. The configuration (4) allows microwaves to pass through more efficiently than the configuration (3).

<Configuration (5)>
As illustrated in Fig. 13, the passing portion D of the configuration (5) is a transmitting member D3 that transmits microwaves. The material of the transmitting member D3 is arbitrary, but examples of suitable materials include glass, quartz, ceramic, and Teflon (registered trademark), which have a low degree of microwave loss (low dielectric tangent). A through-hole is formed in the installation surface F, and the transmitting member is provided to close the through-hole. The size of the transmitting member D3 is arbitrary.

Configuration (5) allows microwaves to pass through more efficiently than configurations (1)-(4). On the other hand, configurations (1)-(4) do not require the transparent member D3, so the configuration of the passing section D can be simplified compared to configuration (5).

<Configuration (6)>
As illustrated in FIG. 14 , the passing section D of the configuration (6) includes a polarizer B in addition to the transmitting member D3 of the configuration (5). The polarizer B is a long member formed of a metal that reflects microwaves. For example, the polarizer B is installed on the surface of the transmitting member D3 (the surface on the filling space U side or the surface on the stirring mechanism 60 side). Specifically, the polarizer B is formed so as to extend in a direction inclined at an angle other than 90 degrees (e.g., approximately 45 degrees) with respect to the direction of vibration of the electric field of the microwaves emitted by the generator 50. The angle at which the polarizer B is inclined may be any angle as long as it can function as a polarizer.

By adopting configuration (6), it is possible to change the direction of oscillation (polarization) of the electric field of microwaves entering and exiting through the passage section D (transparent member D3). Therefore, compared to configuration (5), it is possible to generate microwaves polarized on multiple axes within the filled space U. This has the remarkable effect of being able to irradiate microwaves throughout the entire filled space U.

However, the configuration of the passage section D is not limited to configurations (1)-(6) as long as microwaves can pass between the internal space R3 of the housing section 601 and the filling space U via the passage section D and the expandable particles in the filling space U do not leak.

A variety of configurations can be used for the stirring mechanism 60, as long as they are capable of changing the amplitude and phase of the microwaves that have passed through the passage D. For example, the following configurations (A)-(G) are exemplified. Figures 15-21 are schematic perspective views of configurations (A)-(G). The stirring of the microwaves by the stirring mechanism 60 is controlled by the control unit, which will be described later.

<Configuration (A)>
15 , the stirring mechanism 60 of configuration (A) has a screw unit 602 including a plurality of blades that rotate around a rotation axis, in an internal space R3 of a housing unit 601. The amplitude and phase of the microwaves change due to the rotating screw unit 602. The specific configuration of the screw unit 602 (e.g., the shape of the blades, the position of the rotation axis, etc.) is set appropriately so that the amplitude and phase of the microwaves change.

<Configuration (B)>
As illustrated in FIG. 16 , the stirring mechanism 60 of configuration (B) has a configuration in which the housing 601 itself is extendable and retractable. The configuration for extending and retracting the housing 601 is arbitrary. For example, the housing 601 is composed of a cylindrical first member 611 that is open at both ends and a cylindrical second member 612 that is open at only one end and has a bottom. One open side of the first member 611 is placed on the installation surface F so that the passing section D is located inside, and the other open side of the first member 611 is inserted inside the second member 612. With the first member 611 inserted inside, the second member 612 can move both toward and away from the passing section D. The extension and retraction of the housing 601 changes the amplitude and phase of the microwaves.

<Configuration (C)>
As illustrated in FIG. 17 , the stirring mechanism 60 of configuration (C) includes a metal shaft member 603 that can move within the internal space R3 of the housing 601. The number of shaft members 603 can be any number, but FIG. 17 illustrates a case in which there are two shaft members 603. One of the shaft members 603 is, for example, arranged in the internal space R3 along the same direction as the vibration of the electric field of the microwaves emitted from the generator 50, and is movable along the same direction as the vibration of the electric field. The other shaft member 603 is, for example, arranged in the internal space R3 along the same direction as the vibration of the magnetic field of the microwaves emitted from the generator 50, and is movable along the same direction as the vibration of the magnetic field. The movement of the shaft member 603 changes the amplitude and phase of the microwaves. However, the number and orientation of the shaft members 603 are not limited to the above example.

<Configuration (D)>
As illustrated in Fig. 18, the stirring mechanism 60 of configuration (D) has a configuration in which the housing 601 is rotatable. Specifically, the housing 601 rotates around an axis passing through the center of the opening O of the housing 601. Any specific configuration can be used to rotate the housing 601. The stirring mechanism 60 of configuration (D) also functions as a polarizer. The rotation of the housing 601 changes the amplitude and phase of the microwave.

<Configuration (E)>
As illustrated in FIG. 19 , the stirring mechanism 60 of configuration (E) is configured to be able to open and close an opening O in a housing 601. The stirring mechanism 60 includes, for example, a plate-shaped shielding portion 604 for opening and closing the opening O. The shielding portion 604 is made of, for example, metal and is provided so as to be positioned between the end of the housing 601 on the opening O side and the installation surface F. For example, two shielding portions 604A are provided that are movable along the same direction as the oscillation direction of the magnetic field of the microwaves emitted from the generator 50, and two shielding portions 604B are provided that are movable along the same direction as the oscillation direction of the electric field of the microwaves emitted from the generator 50. The two shielding portions 604A are located on opposite sides of the opening O, and the two shielding portions 604B are similarly located on opposite sides of the opening O. Each shielding portion 604A and each shielding portion 604B is movable in a direction to open and close the opening O, respectively. It is to be noted that only one of the shielding portion 604A and the shielding portion 604B may be provided. The amplitude and phase of the microwave change when the opening portion O of the housing portion 601 is opened or closed. However, the configuration of the shielding portion 604 is not limited to the above example.

<Configuration (F)>
As illustrated in Fig. 20, the stirring mechanism 60 of configuration (F) includes a probe 605 installed in the internal space R3 of the housing 601. In configuration (F), the impedance of the load connected to the probe 605 is changed. By changing the impedance of the load connected to the probe 605, the length of the probe 605 functions to expand and contract. As a result, the amplitude and phase of the microwave change.

The configuration for changing the impedance of the load connected to the probe 605 is arbitrary, but for example, the following configurations (F1)-(F3) are adopted.

Configuration (F1) is a configuration in which one of multiple loads with different impedances is selectively connected to the probe 605. The load is switched using a switch.

Configuration (F2) is a configuration in which impedance is changed by phase control using a phase shifter (e.g., a line stretcher). The impedance of the load is changed by changing the phase of the microwaves transmitted through the line stretcher through expansion and contraction of the line stretcher. Note that a digital phase shifter may be used as the phase shifter, and the method of phase change is not important.

The configuration (F3) is a configuration using an element whose impedance changes by voltage control.
Specifically, the impedance of the load connected to the probe 605 is changed by changing the voltage applied to the element. Examples of elements whose impedance changes under voltage control include a variable capacitor and a PIN diode.

<Configuration (G)>
As shown in Figure 21, the stirring mechanism 60 of configuration (G) includes a coil 606 (helical antenna) made of a linear conductor wound into a spiral. The coil 606 is installed in the internal space R3 of the housing 601. By rotating the coil 606 with a motor 607, it becomes possible to equivalently control the phase of the microwaves entering and emitting from the coil 606. The rotation of the coil 606 changes the amplitude and phase of the microwaves.

It is also possible to adopt a configuration in which the coil 606 has circular polarization characteristics (the property that the vibration direction of the input and output microwaves rotates over time). For example, by designing the coil 606 as described in "Balanis, Constantine A. Antenna theory: analysis and design. John Wiley & Sons, 2015.", it is possible for the coil 606 to have circular polarization characteristics. Therefore, the microwaves input and output to the coil 606 will have circular polarization characteristics. This makes it possible to excite microwaves with polarization on multiple axes even within the filled space U. As described above, the stirring mechanism 60 of configuration (G) also functions as a polarizer.

In configuration (F), changing the impedance requires switching the switch an enormous number of times, which makes the switch prone to wear. This is expected to shorten the lifespan of the stirring mechanism 60. In contrast, configuration (G) is easier to implement than configuration (F), and is also expected to extend the lifespan of the stirring mechanism 60.

The microwaves whose amplitude and phase have been changed by the stirring mechanism 60 are emitted into the filling space U through the passage D. Note that the configuration of the stirring mechanism 60 is not limited to configurations (A)-(G), as long as it is possible to change the amplitude and phase of the microwaves incident from the passage D. A drive device (not shown) for driving the stirring mechanism 60 is appropriately installed in the molding machine.

The molding apparatus 100 of the second embodiment is equipped with a control unit 70 for controlling the stirring mechanism 60. The control unit 70 is a computer system including one or more processing circuits, such as a CPU (Central Processing Unit), and provides overall control of the stirring mechanism 60.

Here, microwave loss decreases in areas of the filling space U where heating of the expandable particles progresses and moisture content decreases. As microwave loss decreases, reflected waves naturally decrease as well. In other words, if the stirring mechanism 60 is controlled so as to reduce reflected waves, it can be assumed that heating is progressing appropriately throughout the expandable particles in the filling space U.

Taking the above into consideration, the control unit 70 controls the stirring mechanism 60 to reduce reflection. Specifically, the control unit 70 changes the stirring state (hereinafter referred to as the "stirring state") of the stirring mechanism 60 so as to reduce reflection (i.e., reduce the power of the reflected wave). The stirring state can also be described as the state of the amplitude and phase of the microwaves.

Figure 22 is a configuration diagram explaining the function of the control unit 70. As illustrated in Figure 22, the control unit 70 controls the stirring mechanism 60 in accordance with reflected wave information P detected by the power monitor 57 (hereinafter referred to as "reflected wave information").

The manner in which the stirring state is changed differs depending on which of configurations (A) to (F) is adopted. For example, in configuration (A), the stirring state can be changed by changing the rotation speed of the screw portion 602 or the position of the blades of the screw portion 602; in configuration (B), the degree and speed of expansion and contraction can be changed; in configuration (C), the movement speed and position of the shaft member 603 can be changed; in configuration (D), the angular velocity and rotation angle can be changed; in configuration (E), the degree and speed of opening can be changed; in configuration (F), the impedance of the load can be changed; and in configuration (E), the angular velocity and rotation angle of the coil can be changed to change the stirring state.

Below, methods (a) and (b) for the control unit 70 to control the stirring mechanism 60 are illustrated.

<Method (a)>
In the method (a), the reflected wave information P detected by the power monitor 57 is exemplified by the power of the reflected wave.

Figure 23 is a flowchart showing an example of the processing executed by the control unit 70 relating to method (a). The processing in Figure 23 is initiated, for example, when the generator 50 starts operating (heating starts). When the processing in Figure 23 starts, the control unit 70 first acquires the power of the reflected wave (reflected wave information P) from the power monitor 57 (Sa1). Note that the power of the reflected wave is repeatedly acquired at predetermined intervals.

Next, the control unit 70 determines whether the power of the reflected wave has decreased (Sa2). For example, the control unit 70 compares the power of the reflected wave acquired in step Sa1 with the power of the reflected wave acquired previously. Note that the power of the reflected wave acquired previously may be, for example, the power of the reflected wave acquired immediately before step Sa1 (the previous point in time), or the power of the reflected wave acquired at a point in time over a predetermined period of time (for example, a few seconds to a few minutes ago).

If it is determined that the power of the reflected waves has not decreased (i.e., the power of the reflected waves is maintained or increasing) (Sa2; NO), it can be assumed that heating is not proceeding properly. In other words, it can be assumed that the current stirring state of the stirring mechanism 60 is not appropriate. Therefore, the control unit 70 changes the stirring state (Sa4). Then, after changing the stirring state, the process returns to step Sa1.

On the other hand, if it is determined that the power of the reflected wave is decreasing (Sa2; YES), it can be assumed that heating is proceeding appropriately. In other words, it can be assumed that the stirring state of the stirring mechanism 60 is appropriate. In this case, the control unit 70 determines whether a predetermined time has elapsed since the start of heating (for example, the time at which it can be assumed that heating has been completed throughout the entire filling space U) (Sa3).

If the predetermined time has elapsed since the start of heating (Sa3; YES), the processing in Figure 23 ends. On the other hand, if the predetermined time has not elapsed since the start of heating (Sa3; NO), the processing returns to step Sa1.

In step Sa2, it may be possible to determine whether the power of the reflected waves is decreasing by, for example, determining whether the rate of decrease (rate of change) in the power of the reflected waves exceeds a predetermined threshold, or by determining whether the value of the power of the reflected waves is below a predetermined threshold. Furthermore, the specific process for determining whether heating has completed throughout the entire filling space U in step Sa3 is not limited to the above example. As can be understood from the above explanation, the method by which the control unit 70 controls the stirring mechanism 60 in method (a) is not limited to the above example. Method (a) can be employed in any of configurations (A)-(F).

<Method (b)>
In the method (b), the control unit 70 uses the power and phase of the reflected wave as the reflected wave information P acquired from the power monitor 57. The method (b) is employed in, for example, the configuration (F).

Figure 24 is a flowchart showing an example of processing executed by the control unit 70 in method (b). Note that in configuration (F), the load is set to an arbitrary impedance in advance. The processing in Figure 24 is initiated, for example, when the generator 50 starts operating (heating starts).

When the processing in Figure 24 begins, the control unit 70 sets the load impedance (Sb1). Specifically, the control unit 70 sets the load impedance to an impedance that reduces reflection. Figure 25 is a detailed flowchart of the processing in Sb1.

First, the control unit 70 acquires the power and phase of the reflected wave (an example of reflected wave information P) from the power monitor 57 (Sb11). Note that in step Sb1, the amplitude of the reflected wave may be used instead of the power of the reflected wave. The control unit 70 repeats step Sb11 until the power and phase of the reflected wave are acquired for multiple different impedances (e.g., three) (Sb12; NO).

Once the power and phase of the reflected wave for multiple impedances have been acquired (Sb12; YES), the control unit 70 determines the relationship between the reflection level and the load impedance (hereinafter referred to as "reflection characteristics") from the power and phase of the reflected wave determined for the multiple impedances (Sb13). Note that any known technology (e.g., "Receiver-Feedback-Free Cavity Resonant Wireless Power Transfer Based on In Situ S-Parameter Estimation Using a Parasitic Antenna," IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 20, NO. 10, OCTOBER 2021) can be used to estimate the reflection characteristics.

Then, the control unit 70 identifies the load impedance at which reflection is reduced from the reflection characteristics identified in step Sb13 (Sb14). For example, the control unit 70 identifies the impedance at which the reflection level is minimized in the reflection characteristics. The load impedance is then set to the identified impedance. In other words, the stirring state changes.

Once step Sb1 is completed, steps Sa1-Sa3 are executed, similar to method (a). However, if it is determined that the power of the reflected wave has not decreased (Sa2; NO), the process returns to step Sb1. In other words, the load impedance is set again.

Method (b) can also be applied to configurations other than (F). For example, with configuration (G), it is possible to obtain the power and phase of the reflected wave when the coil is fixed at multiple different rotation angles, and estimate the reflection characteristics.

As can be understood from the above explanation, the stirring mechanism 60 and tuner 59 are controlled in accordance with the reflected wave information P. Examples of the reflected wave information P include at least one of the power, amplitude, and phase of the reflected wave. However, the method for controlling the stirring mechanism 60 is not limited to method (a) and method (b).

In the second embodiment, the stirring mechanism 60 is controlled in accordance with the reflected wave information P, making it possible to reduce reflected waves while sufficiently irradiating the expandable particles filled in the filling space U with microwaves.

[Third embodiment]
FIG. 26 is a configuration diagram showing the functions of the control unit 70 according to the third embodiment.

The reflected waves are not consumed within the filling space U, but are lost as wasted heat energy in the isolator 55. Therefore, the control unit 70 of the third embodiment further reduces the reflected waves by controlling the tuner 59 to remove any reflected waves remaining after controlling the stirring mechanism 60. In other words, in addition to controlling the stirring mechanism 60, the control unit 70 also controls the tuner 59 in accordance with the reflected wave information P detected by the power monitor 57.

Specifically, the control unit 70 sets the impedance in the tuner 59 to an impedance that reduces reflection. The control unit 70 can specify the impedance by any method. For example, the control unit 70 may specify (search for) an impedance that reduces reflection based on a sweep or probabilistic method in accordance with the power of the reflected wave detected by the power monitor 57 (an example of reflected wave information P), or may specify (search for) a unique impedance that reduces reflection in accordance with the power and phase of the reflected wave detected by the power monitor 57 (an example of reflected wave information P). The specified impedance is then set in the tuner 59.

The method for uniquely identifying the impedance that reduces reflection involves determining in advance, through experiments, simulations, etc., the impedance at which the tuner 59 can reduce reflection for any "power and phase of the reflected wave," thereby identifying the relationship between the impedance and reflection characteristics. Then, the impedance that corresponds to the "power and phase of the reflected wave" detected by the power monitor 57 in the relationship between the impedance and reflection characteristics is uniquely identified as the impedance that reduces reflection.

In the third embodiment, the tuner 59 is controlled in addition to the stirring mechanism 60, making it possible to further reduce reflected waves. It is also possible to adopt a configuration in which only the tuner 59 is controlled, without assuming control of the stirring mechanism 60.

[Fourth embodiment]
The mold member of the fourth embodiment has a slit (an example of a second slit). The configuration of the fourth embodiment may be provided in any of the molding apparatuses 100 of the first to third embodiments.

Figure 27 is a schematic diagram of a mold member (211, 311) according to the fourth embodiment. A slit (through hole) is provided at any corner J (corner) of the mold member. Corner J is a portion where different surfaces of the mold member (211, 311) intersect and connect.

Here, electromagnetically, only an electric field perpendicular to the surface of a conductor is excited. Therefore, an electric field is unlikely to be generated at the corner J of the mold member. This means that microwaves are unlikely to be stirred at the corner J.

In the fourth embodiment, an electric field is excited at corner J by trapping the electric field in a slit provided at corner J (bringing the electric field close to the slit without leaking out of the slit). This makes it possible to sufficiently stir the microwaves even at corner J.

Various configurations are used for the slit. Figure 28 is a schematic diagram illustrating slit configurations. Figure 28 shows slits (elongated white portions) related to configurations (I)-(VI). Figure 28 also shows a corner J where two intersecting (orthogonal) surfaces F1 and F2 are connected.

The length I (longitudinal length) of the slit in Figure 28 is set to, for example, 1/4 or less (preferably 1/8 or less) of the wavelength of the microwaves emitted by the generator 50 in order to prevent the microwaves from leaking through the slit. The width (transverse length) of the slit is set to be smaller than the diameter of the expandable particles in order to prevent the expandable particles from leaking through the slit.

Configuration (I) includes a slit 71 provided along the edge of corner J (i.e., the boundary line where two faces connect).

Configuration (II) includes a slit 72 arranged perpendicular to the side at corner J.

Configuration (III) includes slits 71 and 72 arranged perpendicular to each other.

Configuration (IV) includes a slit 73 that is provided at a predetermined angle (less than 90 degrees) relative to the side of corner J. For example, the slit 73 is provided at an angle of approximately 45 degrees relative to the side of corner J. Furthermore, two slits 73 may be provided that intersect with each other and form a predetermined angle relative to the side of corner J.

Configuration (V) includes slits 74 and 75 in addition to slits 71 and 72. Slits 71 and 72 are located at different positions (i.e., not perpendicular to each other). Slit 74 is located at the end of slit 72 so as to be perpendicular to slit 72. Slit 75 is located at the end of slit 71 so as to be perpendicular to slit 71.

Like configuration (V), configuration (IV) includes slits 71, 72, 74, and 75. However, in configuration (IV), slits 71 and 72 are positioned perpendicular to each other, and slits 74 and 75 are also provided.

Note that, as shown in Figure 28, it is preferable that the slits provided in structures (I)-(VI) be provided on surfaces F1 and F2 symmetrically about the side at corner J. In particular, at corners where three surfaces intersect within corner J (for example, corner Jz shown in Figure 27), it is preferable that the slits be provided with corner Jz at the center, as shown in Figure 28. However, the slits provided at the corners are not limited to structures (I)-(VI).

The configuration of the fourth embodiment makes it possible to sufficiently agitate microwaves even at corners J.

<Modification>
The above-described embodiments can be modified in various ways. Specific examples of the modifications are shown below. Two or more embodiments selected from the following examples can be combined as appropriate.

(1) In each of the above-described embodiments, the specific configuration of the movable unit 20 is arbitrary, as long as it has an internal space R1 formed therein and includes a movable mold member 211 on its surface. Similarly, the specific configuration of the fixed unit 30 is arbitrary, as long as it has an internal space R2 formed therein and includes a movable mold member 211 on its surface.

(2) In the above-described embodiments, a configuration in which the generator 50 is disposed in the internal space R2 of the fixed unit 30 has been exemplified, but the generator 50 may also be disposed in the internal space R1 of the mobile unit 20. Furthermore, a generator 50 may also be provided in both the internal space R1 of the mobile unit 20 and the internal space R2 of the fixed unit 30.

(3) In each of the above-described embodiments, the shapes of the movable-side mold member 211 and the fixed-side mold member 311 are arbitrary. For example, a movable-side mold member 211 having a convex portion that protrudes toward the fixed-side unit 30 and a fixed-side mold member 31 having a concave portion that corresponds to the convex portion of the movable-side mold member 211 may be used. In addition, the filling device 40 may be provided in the fixed-side unit 30.

(4) In each of the above-described embodiments, a configuration was adopted in which the waveguide 53 of one generator 50 was branched and connected to each fixed-side mold member 31, but the configuration for irradiating microwaves E to the expandable particles in the filling space U is not limited to the above example. For example, a generator 50 may be provided for each fixed-side mold member 31. The molding device 100 may have any configuration as long as it is possible to irradiate microwaves E to the expandable particles via the waveguide 53 of the generator 50 provided in the internal space R2 (or internal space R1).

(5) In each of the above-described embodiments, a configuration in which fine irregularities are formed (microfabrication) on the surfaces of both the movable-side mold member 211 and the fixed-side mold member 31 facing the filling space U is preferable in order to diffusely reflect the microwaves E transmitted into the filling space U. The diffused reflection of the microwaves E within the filling space U makes it possible to effectively fuse the expandable particles.

(6) The stirring mechanism according to the second embodiment can be considered an independent feature, regardless of the specific configuration of the molding device. Specifically, it can be considered a molding device for forming a molded body by fusing expandable resin particles, comprising a mold member (mold) having a filling space into which the resin particles are filled, a generator that emits microwaves into the filling space to heat the resin particles, and a stirring mechanism for stirring the microwaves in the filling space, wherein the mold member has a passage through which the microwaves can pass, and the stirring mechanism is connected to the passage, changes the amplitude and phase of microwaves that pass through the passage from the filling space, and emits the microwaves, after the amplitude and phase have been changed, from the passage to the filling space. In the above molding device, the position of the generator and the specific configuration of the mold member are arbitrary.

The above molding device solves the problem of agitating microwaves within the filling space. Therefore, microwaves can be properly irradiated throughout the resin particles within the filling space.

(7) The control method for the stirring device according to the second embodiment can be considered an independent feature, regardless of the specific configuration of the molding device. Specifically, the control method can be considered as a control method for a molding device for forming a molded body by fusing expandable resin particles, the molding device comprising: a mold member having a filling space into which the resin particles are filled; a generator that emits microwaves into the filling space to heat the resin particles; and a stirring mechanism for stirring the microwaves in the filling space, the generator including a power monitor that detects reflected wave information (reflected wave information), in which the stirring mechanism is controlled in accordance with reflected wave information detected by the power monitor. In the above control methods, the presence or absence of a passage and the specific configuration of the stirring mechanism are optional.

The above control method solves the problem of appropriately controlling the stirring mechanism based on information from reflected waves. Ultimately, it becomes possible to appropriately irradiate microwaves over the entire resin particles filled in the filling space.

(8) The molding device with a slit according to the fourth embodiment can be considered an independent feature, regardless of the specific configuration of the molding device other than the slit or the presence or absence of a stirring mechanism. Specifically, it is a device for forming a molded body by fusing foamable resin particles, and includes a mold member having a filling space into which the resin particles are filled, a generator that heats the resin particles by emitting microwaves into the filling space, and a slit (second slit) provided at a corner of the mold member.

The above molding device solves the problem of being able to properly irradiate microwaves even at the corners of the mold members.

20: moving side unit 23: moving side plate 30: fixed side unit 31: fixed side mold member 33: fixed side plate 40: filling device 50: generator 51: oscillator 53: waveguide 55: isolator 57: power monitor 59: tuner 60: stirring mechanism 70: control unit 71: slit 72: slit 73: slit 74: slit 75: slit 100: molding device 211: moving side mold member 213: support plate 215: frame portion 217: back plate portion 311: fixed side mold member 313: support plate 315: frame portion 317: back plate portion 531: branch portion 532: cover member 601: housing portion 602: screw portion 603: shaft member 604: shielding portion 605: probe 606: coil 607 : Motor 611 : First member 612 : Second member D : Passing section E : Microwave F : Installation surface G : Recess H : Through hole J : Corner K1 : Support member K2 : Support member N1 : Protrusion N2 : Protrusion P : Reflected wave information R1 : Internal space R2 : Internal space R3 : Internal space S : Spacer T : Through hole U : Filled space

Claims (15)

A molding apparatus for forming a molded body in which expandable resin particles are fused together,
a movable unit having a hollow interior and including a movable mold member on its surface;
a fixed-side unit having a hollow interior and including a fixed-side mold member at a position on the surface facing the movable-side mold member;
a filling device that fills the resin particles into a filling space formed between the fixed-side mold member and the movable-side mold member;
a microwave generator provided in the internal space of the fixed unit for emitting microwaves into the filling space to heat the resin particles;
The generating device includes an oscillator that generates the microwaves and a waveguide that transmits the microwaves to the filling space. a through hole is formed in the fixed-side mold member;
an opening of the through hole on the movable mold member side is closed by a cover member made of a material that transmits microwaves;
The molding apparatus according to claim 1 , wherein an end of the waveguide opposite to the oscillator is connected to the through-hole from an end opposite to the movable mold member. the fixed-side mold member includes a plurality of fixed-side mold members,
the movable-side mold member includes a plurality of movable-side mold members provided at positions facing the plurality of fixed-side mold members, respectively;
The molding apparatus according to claim 2 , wherein the waveguide branches out so as to connect to the through-holes in the fixed mold members. A molding apparatus for forming a molded body in which expandable resin particles are fused together,
a movable unit having a hollow interior and including a movable mold member on its surface;
a fixed-side unit having a hollow interior and including a fixed-side mold member at a position on the surface facing the movable-side mold member;
a filling device that fills the resin particles into a filling space formed between the fixed-side mold member and the movable-side mold member;
a microwave generating device provided in the internal space of the moving unit for heating the resin particles in the filling space by microwaves;
The generating device includes an oscillator that generates the microwaves and a waveguide that transmits the microwaves to the filling space. a passage portion provided on at least one of the movable mold member and the fixed mold member, through which the microwaves can pass;
the molding apparatus according to any one of claims 1 to 4, further comprising: a stirring mechanism connected to the passing portion, which changes the amplitude and phase of microwaves that have passed through the passing portion from the filling space, and emits the microwaves , after having had the amplitude and phase changed, from the passing portion to the filling space. the passage portion includes one or more first slits,
the width of the first slit is smaller than the diameter of the resin particle;
The molding apparatus according to claim 5 , wherein the first slit extends in a direction that intersects with a direction of oscillation of an electric field in the microwaves emitted by the generating device. The molding apparatus according to claim 6 , wherein the direction intersecting the direction of vibration of the electric field is a direction intersecting the direction of vibration of the electric field at an angle other than 90 degrees. the passage portion includes a plurality of first slits,
The molding apparatus according to claim 6 or 7, wherein the plurality of first slits are arranged at intervals of at least ¼ of the wavelength of the microwaves emitted by the generator. The molding apparatus according to any one of claims 6 to 8, wherein the length of the first slit is equal to or greater than half the wavelength of the microwave emitted by the generator. The molding apparatus according to claim 5 , wherein the passage portion includes a transmitting member that transmits the microwaves. A control unit for controlling the stirring mechanism is provided.
the generator includes a power monitor that detects information about the reflected wave;
The molding apparatus according to any one of claims 5 to 10, wherein the control unit controls the stirring mechanism in accordance with information on the reflected wave detected by the power monitor. The molding apparatus of claim 11 , wherein the information about the reflected wave includes one or more of the power of the reflected wave, the amplitude of the reflected wave, and the phase of the reflected wave. The molding apparatus according to claim 11 or 12, wherein the control unit controls the stirring mechanism so as to reduce reflected waves. a second slit provided at a corner of at least one of the movable mold member and the fixed mold member;
the width of the second slit is smaller than the diameter of the resin particle;
The molding apparatus according to any one of claims 1 to 13, wherein the length of the second slit is equal to or less than ¼ of the wavelength of the microwave emitted by the generator. A method for controlling a stirring mechanism in a molding apparatus according to claim 5, comprising:
A control method for controlling the stirring mechanism in accordance with information on the reflected wave.