Molding system and method for manufacturing compression molded articles

Abstract

Provided is a molding system for manufacturing a compression-molded product from a thermosetting resin material, comprising a press machine and at least one portable die. The press machine comprises: a lower plate portion including a lower hot plate; an upper plate portion including an upper hot plate; and at least one lateral wall member which is annular, each being fixed to the lower plate portion or the upper plate portion. When the lower plate portion and the upper plate portion are brought close to each other, a closed space which is surrounded by the lower plate portion, the upper plate portion, and the at least one lateral wall member and that can be decompressed is formed, wherein the portable die can be arranged in the closed space and compressed by the lower plate portion and the upper plate portion.

Description

Technical Field

[0001] The present invention relates to a molding system for manufacturing a compression molded product from a thermosetting resin material and a method for manufacturing a compression molded product. This application claims priority based on Japanese Patent Application No. 2021-059523 filed in Japan on March 31, 2021, the content of which is incorporated herein by reference.

Background Art

[0002] Fiber Reinforced Plastics (FRP) are widely used in a wide range of applications, from sports and leisure to industrial applications such as automobiles and aircraft, because they are lightweight and have excellent mechanical properties.

[0003] Molded products made of fiber reinforced plastics can be manufactured by a compression molding method using a prepreg as a starting material (Patent Document 1).

[0004] In the method described in Patent Document 1, the mold is heated to a temperature at which the prepreg can be sufficiently cured before charging with the prepreg.

[0005] A multi-stage press for manufacturing a large number of molded plates made of a resin composition at one time is known (Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The main objective of the present invention is to provide a molding system and manufacturing method for efficiently producing compression molded articles with few voids using thermosetting resin materials. [Means for solving the problem]

[0008] According to one aspect of the present invention, a molding system for manufacturing a compression molded product from a thermosetting resin material is provided. The molding system comprises a press machine and at least one portable die. The press machine has a lower plate portion including a lower heating plate, an upper plate portion including an upper heating plate, and at least one annular side wall member, each fixed to either the lower plate portion or the upper plate portion, such that when the lower plate portion and the upper plate portion are brought close to each other, a depressurized closed space is formed surrounded by the lower plate portion, the upper plate portion and the at least one side wall member, and the portable die is placed in the closed space so that it can be pressurized by the lower plate portion and the upper plate portion.

[0009] According to another aspect of the present invention, a method for manufacturing a compression molded product is provided, comprising: a first step of charging a portable mold with a thermosetting resin material outside a press machine; a second step of sandwiching the portable mold charged in the first step between a lower heating plate and an upper heating plate of the press machine, which are preheated to the molding temperature, and surrounding it with a space that can be depressurized; a third step of depressurizing the space that can be depressurized and further pressurizing the portable mold between the lower heating plate and the upper heating plate, which are maintained at the molding temperature, to cure the resin material inside the portable mold; a fourth step of removing the portable mold from the press machine; and a fifth step of removing the compression molded product from the portable mold. [Effects of the Invention]

[0010] According to a preferred embodiment of the present invention, a molding system and manufacturing method are provided for efficiently producing compression molded articles with few voids using a thermosetting resin material. [Brief explanation of the drawing]

[0011] [Figure 1]FIG. 1 is a partially cut-away front view of a press machine. [Figure 2] FIG. 2 is a plan view showing the lower plate portion of the press machine. [Figure 3] FIG. 3 is a plan view (seen from below) showing the upper plate portion of the press machine. [Figure 4] FIG. 4 is a partially cut-away front view of a press machine. [Figure 5] FIG. 5 is a partially cut-away front view of a press machine. [Figure 6] FIG. 6 is a partially cut-away front view of a press machine. [Figure 7] FIG. 7 shows a portable mold. [Figure 8] FIG. 8 shows a portable mold. [Figure 9] FIG. 9 shows a portable mold. [Figure 10] FIG. 10 is a partially cut-away front view showing a state where a charged portable mold is pressed by a press machine. [Figure 11] FIG. 11 is a drawing for explaining the manufacturing process included in the manufacturing method according to the embodiment. [Figure 12] FIG. 12 is a drawing for explaining the manufacturing process included in the manufacturing method according to the embodiment. [Figure 13] FIG. 13 is a drawing for explaining the manufacturing process included in the manufacturing method according to the embodiment. [Figure 14] FIG. 14 is a drawing for explaining the manufacturing process included in the manufacturing method according to the embodiment. [Figure 15] FIG. 15 is a drawing showing the relationship between the height of the workbench, the height of the loading platform of the cart, and the height of the upper surface of the lower hot plate of the press machine.

MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described below, and various modifications are possible without departing from the gist of the present invention.

[0013] 1. Forming system One embodiment of the present invention relates to a molding system for manufacturing a compression molded product (hereinafter also simply referred to as "molded product") from a thermosetting resin material. The molding system according to the embodiment includes a press machine and at least one portable mold.

[0014] 1.1. Press Machine FIG. 1 shows an example of a press machine that can constitute the molding system according to the embodiment. Referring to FIG. 1, the press machine 1 includes a lower plate portion 10, an upper plate portion 20 disposed opposite to the lower plate portion 10 above the lower plate portion 10, and a pressing mechanism (only the cylinder 32 of the pressing mechanism is shown in FIG. 1) that moves the lower plate portion 10 and the upper plate portion 20 closer to each other. The lower plate portion 10 includes a horizontally disposed lower substrate 11 and a lower hot plate 12 attached to the upper surface side of the lower substrate 11. The upper plate portion 20 includes a horizontally disposed upper substrate 21 and an upper hot plate 22 attached to the lower surface side of the upper substrate 21. In FIG. 1, the illustration of the frame for fixing the upper plate portion 20 and the like is omitted.

[0015] The pressing mechanism is preferably a hydraulic type because it is easy to control the pressure. The cylinder 32 of the pressing mechanism may be arranged to act on the upper plate portion 20 instead of the lower plate portion 10. Heaters 31 are built into the lower hot plate 12 and the upper hot plate 22, respectively. Examples of the heater 31 include, but are not limited to, a steam heater, an oil heater, an electric heater, and an electromagnetic induction heater.

[0016] An annular lower side wall member 13 is fixed to the upper surface of the lower hot plate 12. As shown in the plan view of FIG. 2, the lower side wall member 13 has a structure in which four vertical walls perpendicular to the upper surface of the lower hot plate 12 are connected to form a rectangular ring, and is disposed slightly inside the peripheral surface of the lower hot plate 12. The lower hot plate 12 and the lower side wall member 13 may be integrally formed without a joint. A groove that goes around the outer peripheral surface is provided in the lower side wall member 13, and a vacuum sealing ring 14 is fitted into the groove.

[0017] An annular upper wall member 23 is fixed to the lower surface of the upper heating plate 22. As shown in the plan view (viewed from below) in Figure 3, the upper wall member 23 has a structure in which four vertical walls, each perpendicular to the lower surface of the upper heating plate 22, are connected to form a rectangular ring, and is arranged along the circumferential surface of the upper heating plate 22. The upper heating plate 22 and the upper wall member 23 may be integrated without any joints. The upper wall member 23 is provided with an exhaust port 24 that penetrates one of the vertical walls. The exhaust port 24 is connected to a vacuum pump 33.

[0018] When the pressurizing mechanism is activated and the lower plate portion 10 is brought closer to the upper plate portion 20, the lower wall member 13 and the upper wall member 23 are fitted together via the vacuum sealing ring 14, as shown in Figure 4, forming a closed space S surrounded by the lower heating plate 12, the lower wall member 13, the upper heating plate 22, and the upper wall member 23. This closed space can be depressurized by activating the vacuum pump 33.

[0019] In a modified example, as shown in Figure 5, the lower wall member 13 may be omitted, and the lower heating plate 12 and the upper wall member 23 may be configured to fit together via a vacuum sealing ring 14. In this case, when the lower plate portion 10 and the upper plate portion 20 are brought close together, a closed space S is formed surrounded by the lower heating plate 12, the upper heating plate 22, and the upper wall member 23.

[0020] In other modifications, as shown in Figure 6, the lower wall member 13 and the upper wall member 23, which interlock with each other via a vacuum sealing ring, may be fixed to the upper surface of the lower substrate 11 and the lower surface of the upper substrate 21, respectively. The lower wall member 13 is positioned to surround the lower heating plate 12, and the upper wall member 23 is positioned to surround the upper heating plate 22. In this case, when the lower plate portion 10 and the upper plate portion 20 are brought close together, a closed space S is formed, surrounded by the lower substrate 11, the lower wall member 13, the upper substrate 21, and the upper wall member 23.

[0021] 1.2. Portable molds Figure 7 shows an example of a portable mold that constitutes the molding system according to the embodiment. Referring to Figure 2, the portable mold 2 consists of a bottom plate 40, an uppermost plate 50, and three intermediate plates 60. The planar shape of each plate is, for example, rectangular. Handles can be attached to the sides of any plate as needed. All plates have the same outer shape and dimensions in plan view, allowing them to be perfectly stacked on top of each other.

[0022] As shown in Figure 8, when three intermediate plates 60 and the top plate 50 are stacked on top of the bottom plate 40 in this order, so that they fit snugly onto each other, molded cavities are formed between the bottom plate 40 and the intermediate plate 60 directly above it, between adjacent intermediate plates 60, and between the top plate 50 and the intermediate plate 60 directly below it. In one example, when the plates are stacked in the correct order, one adjacent plate may have an alignment protrusion and an alignment recess, respectively, so that they interlock only when the two plates are stacked so that they fit together perfectly.

[0023] Each plate has two pin holes. After stacking the plates, to prevent directional misalignment (rotational misalignment) or positional misalignment (horizontal misalignment) between the plates, two pins 3 can be inserted, as shown in Figure 8, from the pin hole 53 of the top plate 50, through the pin hole 63 of the intermediate plate 60, and into the pin hole 43 of the bottom plate 40.

[0024] The number of intermediate plates that a portable mold may have is not limited to three; it may have two or fewer plates, or three or more plates. For example, a portable mold can be constructed using only the bottom plate and the top plate, without using any intermediate plates.

[0025] The lower surface 40b of the bottom plate 40 and the upper surface 50a of the top plate 50 are both completely flat. The upper surface 40a of the bottom plate 40, the lower surface 50b of the top plate 50, and the upper and lower surfaces 60a and 60b of each intermediate plate 60 each have a first region 41a, 51b, 61a, and 61b approximately in the center of each surface, and a second region 42a, 52b, 62a, and 62b around the first region.

[0026] The first region of each surface is the area that becomes the inner surface of the molded cavity when the plates are stacked. Therefore, the first region 41a on the upper surface of the bottom plate and the first region 61a on the upper surface of each intermediate plate have shapes complementary to one side of the molded product being manufactured, and the first region 51b on the lower surface of the top plate and the first region 61b on the lower surface of each intermediate plate have shapes complementary to the other side of the molded product being manufactured.

[0027] The second region of each surface is flat. The second region 42a on the upper surface of the lowest plate is parallel to the lower surface 40b of the lowest plate, and the second region 52b on the lower surface of the uppermost plate is parallel to the upper surface 50a of the uppermost plate. The second region 62a on the upper surface and the second region 62b on the lower surface of each intermediate plate 60 are parallel to each other.

[0028] When plates are stacked, the second regions of adjacent plates come into contact with each other. Therefore, when all plates are stacked, the bottom surface 40b of the bottom plate and the top surface 50a of the top plate are parallel to each other. In each plate, both pin holes are formed to pass through a second region that the plate has on its upper and / or lower surface.

[0029] In the portable mold according to the preferred example, when all the plates are stacked, multiple molding cavities are formed between any adjacent plates. For example, the portable mold 2 shown in Figure 9 has nine first regions on the top surface of the bottom plate 40, the top and bottom surfaces of each of the two intermediate plates 60, and the bottom surface of the top plate 50. When these plates are stacked, nine molding cavities are formed between the bottom plate 40 and the lower intermediate plate 60, between the two intermediate plates 60, and between the upper intermediate plate 60 and the top plate 50. Therefore, using this portable mold, 27 (9 × 3) compression molded products P can be obtained in a single molding process.

[0030] In one example, at least a portion of the plates constituting the portable mold may be divisible into two or more parts. In other words, at least a portion of the plates may have an insert structure and be composed of a master mold and an insert mold. In another example, the portable mold may include a core in addition to the bottom plate, top plate, and intermediate plate. The core is used when manufacturing molded parts with undercuts.

[0031] Figure 10 shows a portable mold 2, charged with a thermosetting resin material M, placed in the closed space S formed in the aforementioned press machine 1, and being pressurized by the lower plate portion 10 and the upper plate portion 20. Since the lower heating plate 12 and upper heating plate 22 are exposed in the lower plate section 10 and upper plate section 20 respectively, the portable mold 2 is in direct contact with the lower heating plate 12 and upper heating plate 22. Since the lower surface (lower surface 40b of the bottom plate) and upper surface (upper surface 50a of the top plate) of the portable mold 2 are flat, the contact with the lower heating plate 12 and upper heating plate 22 is surface-to-surface. On the other hand, the sides of the portable mold 2 are not in contact with either the lower side wall member 13 or the upper side wall member 23. In other words, the sides of the portable mold 2 are surrounded by space.

[0032] The space surrounding the side of the portable mold 2 acts as a trap to prevent the resin material M from entering the vacuum line if it melts inside the molding cavity of the portable mold 2 and some of it leaks out to the outside of the portable mold 2 through the gaps between the plates forming the molding cavity. The presence of clearance between the side of the portable mold 2 and the lower side wall member 13 and the upper side wall member 23 is advantageous because it facilitates the operation of placing the portable mold 2 inside these side wall members.

[0033] Examples of materials used for portable molds include carbon steel and alloy steel (steel with added chromium, molybdenum, tungsten, vanadium, etc.), which have been conventionally used as steel materials for plastic molding.

[0034] Each plate constituting the portable mold 2 typically does not have an internal heat source. The heat sources for heating the resin material M are heaters 31 built into the lower heating plate 12 and the upper heating plate 22, respectively. Therefore, it is desirable to facilitate the transfer of heat from the lower heating plate 12 and the upper heating plate 22 to the resin material M through the portable mold 2 in order to cure the resin material M in a shorter time. From this perspective, in a preferred example, the material of the portable mold 2 may be an aluminum alloy or a copper alloy such as beryllium copper, which have higher thermal conductivity than steel. These alloys have a high thermal conductivity of 100 W / (m·K) or more at 20°C. Aluminum alloys are particularly preferred because they have high thermal conductivity and are lightweight. At 20°C, the specific gravity of steel is around 7.9, and that of beryllium copper exceeds 8, while that of aluminum alloys is typically 2.7 to 2.8.

[0035] Examples of aluminum alloys include, but are not limited to, the 7000 series aluminum alloy (Al-Zn-Mg alloy), which is considered to have the highest strength among aluminum alloys, and the 2000 series aluminum alloy (Al-Cu alloy), which has strength comparable to steel. The thermal conductivity of aluminum alloys varies depending on the heat treatment, but at 20°C, the thermal conductivity is said to be 130-190 W / (m·K) for A2017 (duralumin), 150 W / (m·K) for A7003, and 130 W / (m·K) for A7075 (super duralumin). In contrast, even chromium-molybdenum steel, which has relatively high thermal conductivity, has a thermal conductivity of approximately 60 W / (m·K) at 20°C, and carbon steel has an even lower thermal conductivity.

[0036] The weight of portable mold 2 may be, for example, between 2 kg and 30 kg. Having the weight within this range is convenient for transporting the portable mold. However, the weight of the portable mold is not limited to this range. By introducing a powered transport mechanism, it is possible to use portable molds weighing nearly 200 kg.

[0037] 1.3. Others The components of the molding system according to the embodiment are not limited to a press machine and a portable mold. The molding system according to the embodiment may further include a workbench as components other than the press machine and the portable mold. The workbench can be used for the operation of charging the portable mold 2 with resin material M, and can also be used for the operation of removing the compression molded product P from the portable mold 2. These operations can be performed using the same workbench or different workbenches. The molding system according to this embodiment may further include a trolley for transporting the portable mold 2. Preferred configurations of the workbench and trolley will be described in Section 2 below.

[0038] The molding system according to this embodiment may include at least one of each component. In a preferred example, the molding system according to the embodiment includes at least two portable dies per press machine. The at least two portable dies may include a plurality of portable dies having the same cavity shape, or they may include portable dies with different cavity shapes.

[0039] The number of portable dies per press machine is preferably greater than or equal to the number necessary to prevent the press machine from experiencing downtime due to a shortage of portable dies in continuous production, as described in Section 3 below. By making each plate of a portable mold an insert structure, and by changing the inserts to change the cavity shape, it becomes possible to manufacture molded products of various shapes using a single portable mold, thereby reducing the number of portable molds required.

[0040] 2. Method for manufacturing molded products Another embodiment of the present invention relates to a method for manufacturing a compression-molded article. In the manufacturing method according to the embodiment, the molding system described in Section 1 above may be preferably used. The manufacturing method according to this embodiment typically includes the following steps.

[0041] First step: The portable mold is charged with a thermosetting resin material outside the press machine (Figure 11). Second step: The portable mold charged in the first step is sandwiched between the lower and upper heating plates of the press machine, which are preheated to the molding temperature, and surrounded by a vacuum-reducing space (Figure 12). Third step: The vacuumable space is depressurized, and the portable mold is further pressurized between the lower heating plate and the upper heating plate, which are maintained at the molding temperature, to cure the resin material inside the portable mold. Fourth step: Remove the portable mold from the press machine (Figure 13). Fifth step: Remove the compression molded product from the portable mold (Figure 14).

[0042] The details of each process will be explained below, using the molding system described in Section 1 above as an example.

[0043] 2.1.First step In the first step, the portable mold 2 is charged with a thermosetting resin material (resin composition) M outside the press machine 1. The resin material M may be placed inside the portable mold 2 in layers with a core material such as a honeycomb core or a foam core.

[0044] Examples of thermosetting resins used as base resins in resin materials include epoxy resins, unsaturated polyester resins, acrylic resins, vinyl ester resins, phenolic resins, and benzoxazine resins. In addition to being formulated with a curing agent, the resin material may also contain various additives as needed, such as reactive diluents, release agents, defoaming agents, UV absorbers, and fillers.

[0045] In a preferred example, the resin material may be a prepreg. A prepreg is a thermosetting matrix resin impregnated with fiber reinforcement. The fiber reinforcement material consists of at least one type of fiber, which may be an inorganic fiber, an organic fiber, or a metallic fiber. Examples of inorganic fibers include carbon fibers, silicon carbide fibers, alumina fibers, tungsten carbide fibers, boron fibers, and glass fibers. Inorganic fibers may be coated with metal. Examples of organic fibers include aramid fibers, polyimide fibers, ultra-high molecular weight polyethylene fibers, nylon fibers, and polyester fibers. Examples of metallic fibers include stainless steel fibers and iron fibers. Prepregs, which are fiber reinforced materials made of carbon fibers impregnated with a thermosetting resin composition, particularly an epoxy resin composition, are one of the most preferred resin materials because they provide lightweight and high-strength FRP upon curing.

[0046] Typical examples of prepregs include UD prepregs and woven prepregs. The basis weight of the fiber reinforcement in these prepregs is 50-800 g / m². 2 Preferably, 75-300 g / m² 2 This is preferable. Textile prepregs include, for example, plain weave, twill weave, satin weave, and triaxial weave. Other prepregs include SMC (Sheet Molding Compound).

[0047] Prepregs may be used in single layers or in multiple layers. When using multiple layers, only prepregs of the same type may be laminated, or different types of prepregs may be laminated. When using multiple UD prepregs stacked together, cross-ply lamination or angle-ply lamination is preferable. For example, when laminating multiple prepregs to obtain a molded product with a surface that allows a highly decorative woven fabric to show through, a woven prepreg may be used only for the outermost layer. SMC can also be used in combination with UD prepreg or woven prepreg.

[0048] When charging the portable mold 2, thermal grease may be applied to the contact surfaces between adjacent plates to reduce the thermal resistance between them. In the subsequent second and fourth steps, when the portable mold 2 is sandwiched between the lower heating plate 12 and the upper heating plate 22, thermal conductive grease can be applied to the lower surface 40b of the bottom plate and the upper surface 50a of the top plate of the portable mold 2 in order to reduce the contact thermal resistance between the portable mold 2 and these heating plates.

[0049] The process of charging the portable mold 2 with resin material M can be carried out in a room at a temperature of 17-28°C using a workbench equipped with a top plate on which the plate of the portable mold can be stably placed. The temperature of the portable mold during charging may be the same as room temperature. For example, a portable mold that has been heated for drying purposes after washing may be charged before the temperature drops to room temperature. However, when the resin material is a UD prepreg or a woven prepreg, it is preferable to wait until the temperature of the portable mold falls below 40°C to prevent wrinkles from forming during handling. This is because, in these prepregs, wrinkles disrupt the orientation of the fiber reinforcement, which changes the mechanical properties after curing. If the temperature of the portable mold is below 40°C, the temperature of the prepreg will not rise to the point where the surface tackiness becomes excessively high during the charging process, thus making it less likely for wrinkles to form in the prepreg.

[0050] Maintaining a low temperature during charging, such as 40°C or even 28°C, is advantageous when the shape of the molded product to be manufactured is complex and requires a relatively long charging time. This is because it avoids the problem of the resin material becoming tackier and difficult to handle due to rising temperature during charging. A low temperature in the portable mold during charging is advantageous even when the time required for the first process is long due to the portable mold having numerous molding cavities. This is because there is virtually no difference in physical properties between the molded product obtained from the resin material placed in the portable mold immediately after the start of the first process and the molded product obtained from the resin material placed in the portable mold immediately before the end of the first process, due to differences in the thermal history experienced during the first process.

[0051] It is preferable to preheat the portable mold 2, which has been charged with resin material M, prior to the second step. Preheating can shorten the time required for the subsequent fourth step. Preheating is performed in a manner that does not significantly reduce the viscosity of the resin material. Specifically, the temperature of the portable mold after preheating is preferably between 40°C and 80°C, and more preferably between 60°C and 80°C. If the temperature of the portable mold is 80°C or lower, it can be touched with gloved hands, so there are no problems with transportation, etc.

[0052] The portable molds, charged on the workbench, are transported to a heater for preheating as needed, and then transported to the press for the second process. Transportation may be done manually or using a trolley. A trolley is preferable when the portable molds are heavy or when transporting a large number of portable molds at once.

[0053] When using a trolley, it is preferable to set the height of the trolley's platform to be the same as the height of the workbench. This allows the portable mold to be transferred from the workbench to the trolley simply by sliding it horizontally. Furthermore, providing a roller conveyor on the trolley's platform makes the transfer even easier. In this specification, the height of the trolley platform refers to the height of the underside of the portable mold (the underside of the lowest plate) when the portable mold is properly placed on the platform. In this specification, the height of the workbench refers to the height of the top surface of the workbench. Even if the height of the trolley's platform and the workbench are slightly different, if the difference is less than the thickness of the bottom plate of the portable mold, the two heights can be considered the same.

[0054] 2.2.Second process In the second step, as shown in Figure 12, the portable mold 2 charged in the first step is sandwiched between the lower heating plate 12 and the upper heating plate 22 of the press machine 1, which are preheated to the molding temperature, and surrounded by a closed space S. The reason for preheating the lower heating plate 12 and upper heating plate 22 of the press machine 1 to the molding temperature is to shorten the time required for the subsequent fourth process. The molding temperature may be between 110°C and 130°C, 130°C and 135°C, 135°C and 145°C, 145°C and 150°C, or 150°C and 180°C.

[0055] After the charged portable mold 2 is placed on the lower heating plate 12, the lower plate portion 10 and the upper plate portion 20 are brought closer together until the upper surface of the portable mold (the upper surface 50a of the uppermost plate) contacts the upper heating plate 22. At this time, the annular lower wall member 13 and the upper wall member 23 are fitted together via the vacuum sealing ring 14, and a depressurized closed space S is formed around the portable mold 2. At this stage, the surface pressure on the portable mold 2 is preferably about 1 to 15 mPa.

[0056] In the example shown in Figure 12, the upper end of the lower wall member 13 of the press machine 1 is higher than the upper surface of the lower heating platen 12. Therefore, when transferring the charged portable die 2 from the trolley to the lower heating platen 12, it is necessary to lift it above the upper end of the lower wall member 13. In contrast, by omitting the lower wall member 13 as shown in the example in Figure 5, or by not raising the upper end of the lower wall member 13 higher than the upper surface of the lower heating platen 12 as shown in the example in Figure 6, it becomes easier to transfer the charged portable mold 2 from the trolley to the lower heating platen 12. Furthermore, by matching the height of the trolley's loading platform with the height of the lower heating platen's upper surface, the portable mold can be transferred from the trolley to the lower heating platen simply by sliding it horizontally. Even if the height of the trolley's platform and the height of the top surface of the heating plate differ slightly, if the difference is less than the thickness of the bottom plate of the portable mold, the two heights can be considered the same.

[0057] 2.3.Third step In the third step, the closed space S formed around the portable mold 2 in the second step is depressurized, and the portable mold is further pressurized between the lower heating plate 12 and the upper heating plate 22, which are maintained at the molding temperature, to cure the resin material M inside the portable mold 2. The closed space S is depressurized by operating the vacuum pump 33 so that the pressure after depressurization is preferably 0.1 Pa or less, more preferably 0.01 Pa or less. The portable mold 2 is pressurized so that the surface pressure is preferably in the range of 1 to 15 MPa.

[0058] When the lower heating plate 12 and upper heating plate 22 of the press machine 1 come into close contact with the portable mold 2 due to the pressure, the temperature of the portable mold 2 rises rapidly toward the molding temperature, and eventually the resin material M hardens. The pressurization may begin simultaneously with or after the depressurization of the closed space S. If pressurization is started after the depressurization, the pressurization may begin before or after the closed space S has been sufficiently depressurized.

[0059] The purpose of reducing the pressure in the enclosed space S is to degas the resin material M and obtain a void-free compression molded product P. Therefore, it is desirable that the pressure in the enclosed space S be sufficiently reduced before the resin material M gels. This is because resin material whose viscosity has increased significantly due to gelation is difficult to degass.

[0060] The time for the third step is set to allow sufficient time for the resin material M to harden to the required degree. The specific time can be determined through normal trial and error, taking into account the hardening characteristics of the resin material, the size of the compression molded product to be manufactured, the molding temperature, the material of the portable mold, the number of plates included in the portable mold, etc.

[0061] 2.4.Fourth step In the fourth step, as shown in Figure 13, the portable mold 2 is removed from the press machine 1. The removed portable mold 2 is transported to a workbench. The workbench may be the same as the one used in the first process, or it may be different. The transport may be done by hand or using a trolley.

[0062] In the example shown in Figure 13, the upper end of the lower wall member 13 of the press machine 1 is higher than the upper surface of the lower heating platen 12. Therefore, when transferring the portable die 2 from the lower heating platen 12 to the trolley, it is necessary to lift it above the upper end of the lower wall member 13. As shown in the example in Figure 5, the lower wall member 13 can be omitted, or as shown in the example in Figure 6, the position of the upper end of the lower wall member 13 can be kept lower than the upper surface of the lower heating platen 12, making it easier to transfer the portable mold 2 from the lower heating platen 12 to the trolley. Furthermore, if the height of the trolley's loading platform is matched with the height of the upper surface of the lower heating platen, the portable mold can be transferred from the lower heating platen to the trolley simply by sliding it horizontally. If the height of the trolley's platform is the same as the height of the workbench, then when transferring the portable mold from the trolley to the workbench, it only needs to be slid horizontally.

[0063] 2.5.Fifth step In the fifth step, as shown in Figure 14, the compression molded product P is removed from the portable mold 2. It is preferable to forcibly cool the compression molded product P immediately after removing it from the portable mold 2, taking care not to deform it. It is also preferable that the portable mold be forcibly cooled immediately after the compression molded product is removed, in preparation for use in the next molding cycle. Forced cooling of the portable mold 2 can also be performed before removing the compression molded product P.

[0064] 2.6. Others The method for manufacturing compression molded articles described above with reference to Figures 9 to 14 is illustrative and can be modified as follows, for example. In one embodiment, in the second step, multiple charged portable dies may be arranged in a line between the lower heating plate and the upper heating plate of a single press machine, and in the third step, these multiple portable dies may be pressed simultaneously. In another embodiment, in the second step, multiple charged portable dies may be stacked vertically between the lower and upper heating plates of a single press machine, and in the third step, these multiple portable dies may be pressed simultaneously.

[0065] In one embodiment, a press machine can be used in which the lower plate is fixed and the upper plate is raised and lowered by a pressurizing mechanism. In that case, as shown in Figure 15, it is preferable to set the height of the upper surface of the lower heating plate 12 to the same height as the workbench 71, and further, to match the height of the loading platform of the trolley 72 to these heights. This allows for easy transfer of the portable mold by simply sliding it horizontally between the lower heating plate 12 and the trolley 72, and between the trolley 72 and the workbench 71.

[0066] When using a press that raises and lowers the lower plate, or when using a press that fixes the lower plate and raises and lowers the upper plate, if for some reason the height of the upper surface of the lower heating plate cannot be matched to the height of the workbench, it is preferable to use a lifting trolley to transport the portable mold. When transferring the portable mold between the lower heating plate and the lifting trolley, the height of the lifting trolley's platform can be matched to the upper surface of the lower heating plate, and when transferring the portable mold between the workbench and the lifting trolley, the height of the lifting trolley's platform can be matched to the height of the workbench.

[0067] 3. Continuous production When the first to fifth steps in the manufacturing method described in Section 2 above are considered as one molding cycle, molded products can be continuously produced by repeating this molding cycle. In continuous production, after the fourth step of the Nth molding cycle (where N is an integer of 1 or more) is completed, the production efficiency can be improved by performing the second step of the (N+1)th molding cycle while keeping the lower and upper heating plates of the press machine at the molding temperature without cooling them. In this case, it is preferable to use multiple portable dies and complete the first step of the (N+1)th molding cycle using another portable die before the fourth step of the Nth molding cycle using one portable die is completed.

[0068] For example, different portable molds with different cavity shapes can be used for the Nth molding cycle and the (N+1)th molding cycle. In this case as well, after the fourth step of the Nth molding cycle is completed, the second step of the (N+1)th molding cycle can be performed while the lower and upper substrates of the press are kept at the molding temperature without cooling, thus enabling the production of various molded products in small quantities with high efficiency.

[0069] 4. Summary of Embodiments Embodiments of the present invention include the following:

[0070] [Embodiment 1] A molding system for manufacturing a compression molded product from a thermosetting resin material, wherein the molding system comprises a press machine and one or more portable molds, the press machine having a lower plate portion including a lower heating plate, an upper plate portion including an upper heating plate, and at least one annular side wall member fixed to the lower plate portion or the upper plate portion, and the press machine being configured such that when the lower plate portion and the upper plate portion are brought close to each other, a depressurized closed space is formed surrounded by the lower plate portion, the upper plate portion and the at least one side wall member, and at least one of the portable molds is placed in the closed space so that pressure can be applied between the lower plate portion and the upper plate portion. The enclosed space can be formed by the interlocking of an annular lower wall member fixed to the lower plate and an annular upper wall member fixed to the upper plate, or by the annular lower wall member fixed to the lower plate and the upper heating plate, or by the upper wall member fixed to the upper plate and the lower heating plate, via a vacuum sealing ring. [Embodiment 2] The molding system according to Embodiment 1, wherein at least one of the side wall members of the press machine includes a side wall member fixed to the upper plate portion. [Embodiment 3] A molding system according to Embodiment 1 or 2, wherein at least one side wall member of the press machine includes a side wall member provided with an exhaust port, and the exhaust port is connected to a vacuum pump. [Embodiment 4] A molding system according to any one of Embodiments 1 to 3, wherein the portable mold consists of a plurality of plates including a bottom plate having a flat bottom surface and an top plate having a flat top surface, and when the plurality of plates are stacked with the bottom plate and the top plate at the bottom and top, respectively, the bottom surface of the bottom plate and the top surface of the top plate are parallel to each other, and at least one molding cavity is formed between any adjacent plates. [Embodiment 5] The molding system according to Embodiment 4, wherein the plurality of plates include at least one intermediate plate in addition to the bottom plate and the top plate. [Embodiment 6] A molding system according to any one of Embodiments 1 to 5, wherein the material of the portable mold is an aluminum alloy that may be 2000 series or 7000 series, and further may be A2017, A7003, or A7075. [Embodiment 7] A molding system according to any of Embodiments 1 to 6, wherein the weight of the portable mold is 2 kg or more and 30 kg or less. [Embodiment 8] A molding system according to any one of Embodiments 1 to 7, wherein at least one of the portable molds can be placed in the closed space such that it does not come into contact with any of the at least one side wall members. [Embodiment 9] A molding system according to any one of Embodiments 1 to 8, wherein the lower heating plate and the upper heating plate can each directly and surfacely contact at least one of the portable molds that are pressurized by the lower plate portion and the upper plate portion. [Embodiment 10] A molding system according to any one of Embodiments 1 to 9, comprising two or more portable molds per press machine. [Embodiment 11] A molding system according to any one of Embodiments 1 to 10, further comprising a workbench used for the operation of charging the portable mold with the resin material. [Embodiment 12] A molding system according to any one of Embodiments 1 to 11, further comprising a workbench used for removing the compression molded product from the portable mold. [Embodiment 13] A molding system according to any one of Embodiments 1 to 12, further comprising a trolley for transporting the portable mold. [Embodiment 14] The molding system according to Embodiment 13, wherein the trolley is a lifting trolley. [Embodiment 15] A molding system according to any one of Embodiments 1 to 10, further comprising a first workbench used for the operation of charging the portable mold with the resin material, and a trolley for transporting the portable mold, wherein the height of the first workbench and the height of the trolley's loading platform are the same. [Embodiment 16] The molding system according to Embodiment 15, further comprising a second workbench used for removing the compression molded product from the portable mold, wherein the height of the first workbench and the height of the second workbench are the same. [Embodiment 17] A molding system according to Embodiment 15 or 16, wherein the height of the upper surface of the lower heating plate of the press machine is fixed to the same height as the loading platform of the trolley, and the portable die can be moved between the lower heating plate and the trolley by sliding the portable die horizontally.

[0071] [Embodiment 18] A method for manufacturing a compression molded article, comprising manufacturing a compression molded article from a thermosetting resin material using a molding system according to any of Embodiments 1 to 17. [Embodiment 19] A method for manufacturing a compression molded product, comprising: a first step of charging a portable mold with a thermosetting resin material outside a press machine; a second step of sandwiching one or more of the portable molds charged in the first step between a lower heating plate and an upper heating plate of the press machine, which are preheated to the molding temperature, and surrounding them with a depressurizable space; a third step of depressurizing the depressurizable space and further pressurizing the portable mold between the lower heating plate and the upper heating plate, which are maintained at the molding temperature, to cure the resin material inside the portable mold; a fourth step of removing the portable mold from the press machine; and a fifth step of removing the compression molded product from the portable mold. [Embodiment 20] The manufacturing method according to Embodiment 19, wherein the first step is carried out in a room at a temperature of 17 to 28°C. [Embodiment 21] A manufacturing method according to Embodiment 20, wherein the temperature of the portable mold in the first step is 40°C or less, and may be the same as the temperature of the room. [Embodiment 22] A manufacturing method according to any of Embodiments 19 to 21, wherein the portable mold consists of a plurality of plates including a bottom plate having a flat bottom surface and an top plate having a flat top surface, and when the plurality of plates are stacked with the bottom plate and the top plate at the bottom and top, respectively, the bottom surface of the bottom plate and the top surface of the top plate are parallel to each other, and at least one molding cavity is formed between any adjacent plates. [Embodiment 23] A manufacturing method according to Embodiment 22, wherein the plurality of plates include at least one intermediate plate in addition to the bottom plate and the top plate. [Embodiment 24] A manufacturing method according to Embodiment 22 or 23, wherein the material of the portable mold is an aluminum alloy that may be 2000 series or 7000 series, and further may be A2017, A7003, or A7075. [Embodiment 25] A manufacturing method according to any of Embodiments 22 to 24, wherein the weight of the portable mold is 2 kg or more and 30 kg or less. [Embodiment 26] A manufacturing method according to any of Embodiments 22 to 25, wherein the first step involves applying thermal conductive grease to the contact surfaces between adjacent plates. [Embodiment 27] A manufacturing method according to any of Embodiments 22 to 26, wherein, before the second step, thermal conductive grease is applied to the lower surface of the bottom plate and the upper surface of the top plate. [Embodiment 28] A manufacturing method according to any one of Embodiments 19 to 27, wherein in the third step, the lower heating plate and the upper heating plate each make direct and surface contact with at least one of the portable molds that are pressurized between the lower heating plate and the upper heating plate. [Embodiment 29] A manufacturing method according to any one of Embodiments 19 to 28, wherein in the third step, the depressurizable space is reduced to 0.1 Pa or less, preferably to 0.01 Pa or less, and the portable mold is pressurized with a surface pressure in the range of 1 to 15 MPa. [Embodiment 30] A manufacturing method according to any of Embodiments 19 to 29, wherein the molding temperature is 110°C or more and 130°C or less, 130°C or more and 135°C or less, 135°C or more and 145°C or less, 145°C or more and 150°C or less, or 150°C or more and 180°C or less. [Embodiment 31] A manufacturing method according to any one of Embodiments 19 to 30, wherein the press machine has a lower plate portion including the lower heating plate, an upper plate portion including the upper heating plate, and at least one annular side wall member fixed to the lower plate portion or the upper plate portion, and when the lower plate portion and the upper plate portion are brought close to each other, a depressurizable closed space is formed surrounded by the lower plate portion, the upper plate portion and the at least one side wall member, and at least one portable die is placed in the closed space so that pressure can be applied between the lower plate portion and the upper plate portion. [Embodiment 32] A manufacturing method according to any of Embodiments 19 to 31, wherein when the first to fifth steps constitute one molding cycle, after the fourth step of the Nth molding cycle (where N is an integer of 1 or more) is completed, the lower heating plate and the upper heating plate of the press machine are not cooled and are kept at the molding temperature while the second step of the (N+1)th molding cycle is performed, and the molding cycle is repeated. [Embodiment 33] A manufacturing method according to Embodiment 32, wherein the portable mold used in the N molding cycle is different from the portable mold used in the (N+1) molding cycle. [Embodiment 34] A manufacturing method according to Embodiment 33, wherein the portable mold used in the Nth molding cycle and the portable mold used in the (N+1)th molding cycle have different shaped molding cavities. [Embodiment 35] A manufacturing method according to any one of Embodiments 19 to 34, wherein the resin material is a prepreg.

[0072] Although the present invention has been described above with reference to specific embodiments, each embodiment is presented as an example and does not limit the scope of the present invention. Each embodiment described herein can be modified in various ways within the scope in which the effects of the invention are achieved, and can be combined with features described in other embodiments to the extent that is feasible. [Explanation of Symbols]

[0073] M Resin material P Compression molded product S closed space 1 Press machine 2 Portable molds 3 pins 10 Lower plate part 11 Lower board 12 Lower heating plate 13 Lower wall member 14 Vacuum sealing rings 20 Upper plate section 21 Upper circuit board 22 Top heating plate 23 Upper wall member 24 exhaust holes 31 Heater 32. Cylinder of the pressurizing mechanism 33 Vacuum pump 40 Bottom Plate 41a First area 42a Second area 43 pin holes 50 Top Plate 51b First area 52b Second area 53 pin holes 60 Intermediate Plate 61a First area 61b First area 62a Second area 62b Second area 63 pin holes 71 Workbench 72 bogies

Claims

1. The first step involves charging the portable mold with a thermosetting resin material outside the press machine, The second step involves sandwiching one or more of the portable molds charged in the first step between a lower heating plate and an upper heating plate of a press machine, which are preheated to the molding temperature, and surrounding them with a space that allows for reduced pressure. A third step involves reducing the pressure in the depressurizable space, and further pressurizing the portable mold between the lower heating plate and the upper heating plate, which are maintained at the molding temperature, to cure the resin material inside the portable mold. A fourth step is to remove the portable mold from the press machine, A fifth step involves removing the compression molded product from the aforementioned portable mold, Includes, A method for manufacturing a compression molded product, wherein when the first to fifth steps described above constitute one molding cycle, after the fourth step of the Nth molding cycle (where N is an integer of 1 or more) is completed, the second step of the (N+1)th molding cycle is performed while the lower and upper heating plates of the press machine are kept at the molding temperature without being cooled, and the molding cycle is repeated.

2. The manufacturing method according to claim 1, wherein the first step is carried out in a room at a temperature of 17 to 28°C.

3. The manufacturing method according to claim 2, wherein the temperature of the portable mold in the first step is 40°C or lower.

4. The portable mold consists of a plurality of plates, including a bottom plate having a flat bottom surface and an top plate having a flat top surface. When the multiple plates are stacked with the bottom plate and the top plate at the bottom and top, respectively, the bottom surface of the bottom plate and the top surface of the top plate are parallel to each other, and at least one molding cavity is formed between any adjacent plates. The manufacturing method according to any one of claims 1 to 3.

5. The manufacturing method according to claim 4, wherein the plurality of plates include at least one intermediate plate in addition to the bottom plate and the top plate.

6. The manufacturing method according to claim 4 or 5, wherein the material of the portable mold is an aluminum alloy.

7. The manufacturing method according to any one of claims 4 to 6, wherein the weight of the portable mold is 2 kg or more and 30 kg or less.

8. The manufacturing method according to any one of claims 4 to 7, wherein the first step involves applying thermal conductive grease to the contact surfaces between adjacent plates.

9. The manufacturing method according to any one of claims 4 to 8, wherein, before the second step, thermal conductive grease is applied to the lower surface of the lowest plate and the upper surface of the uppermost plate.

10. The manufacturing method according to any one of claims 1 to 9, wherein in the third step, the lower heating plate and the upper heating plate each make direct and surface contact with at least one of the portable molds that are pressurized between the lower heating plate and the upper heating plate.

11. The manufacturing method according to any one of claims 1 to 10, wherein in the third step, the depressurizable space is reduced to 0.1 Pa or less, and the portable mold is pressurized with a surface pressure in the range of 1 to 15 MPa.

12. The manufacturing method according to any one of claims 1 to 11, wherein the molding temperature is 110°C or higher and 180°C or lower.

13. The manufacturing method according to any one of claims 1 to 12, wherein the press machine has a lower plate portion including the lower heating plate, an upper plate portion including the upper heating plate, and at least one annular side wall member fixed to the lower plate portion or the upper plate portion, and when the lower plate portion and the upper plate portion are brought close to each other, a depressurizable closed space is formed surrounded by the lower plate portion, the upper plate portion and the at least one side wall member, and at least one portable die is placed in the closed space so that pressure can be applied between the lower plate portion and the upper plate portion.

14. The manufacturing method according to any one of claims 1 to 13, wherein the portable mold used in the N molding cycle is different from the portable mold used in the (N+1) molding cycle.

15. The manufacturing method according to any one of claims 1 to 13, wherein the portable mold used in the Nth molding cycle and the portable mold used in the (N+1)th molding cycle have molding cavities of different shapes.

16. The manufacturing method according to any one of claims 1 to 15, wherein the resin material is a prepreg.

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