Apparatus and method for manufacturing fiber-reinforced resin molded product

Abstract

To provide an apparatus and method for manufacturing a thermoplastic fiber-reinforced resin molded product with reduced costs and increased yields.SOLUTION: A manufacturing apparatus for manufacturing a box-shaped fiber-reinforced resin molded product composed of a bottom surface and three or more flat side surfaces includes: a lower mold with a convex part; and an upper mold with a recess. The convex part has first heating means for heating a convex corner part corresponding to a corner part formed by the bottom surface of the fiber-reinforced resin molded product and two adjacent flat surfaces, and the recess has second heating means for heating a recess corner part corresponding to the corner part formed by the bottom surface of the fiber-reinforced resin molded product and two adjacent flat surfaces.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a manufacturing apparatus and a manufacturing method for producing a thermoplastic fiber-reinforced resin molded product by pressing a prepreg.

Background Art

[0002] In recent years, due to environmental problems, efforts have been made to improve fuel efficiency in the automotive and aviation industries. Among them, for the purpose of reducing the weight of vehicle bodies and aircraft bodies, substitution from metals to fiber-reinforced resins is expected and is attracting great attention. The resins used in fiber-reinforced resins are thermoplastic resins and thermosetting resins, and fiber-reinforced resins are those in which fibers are reinforced with these resins. Fiber-reinforced resins can be molded and shaped by heating, have high productivity, are easy for secondary processing such as welding, have electrical insulation properties, and do not corrode and are excellent in recyclability, so they are widely used in various fields. In addition, carbon fiber-reinforced resins using carbon fibers as fibers are lightweight, high-strength, and high-rigidity, so application research has been carried out and they are already used in a wide range of fields including the aforementioned automotive and aviation industries, the shipbuilding industry, the space field, wind power generation, and sports goods.

[0003] As manufacturing methods for fiber-reinforced resin molded products, there are autoclave molding, oven molding, press molding, RTM / VaRTM method, pultrusion molding, filament winding, sheet winding, etc. Among them, from the viewpoint of high productivity and obtaining high-quality fiber-reinforced resin molded products, press molding is considered desirable.

[0004] The molding of fiber-reinforced resin molded products is preferably carried out using a prepreg that is obtained by impregnating a fibrous reinforcing material such as a glass cloth or carbon fiber with a resin mixed with additives such as a curing agent and an adhesive, and heating or drying it to a semi-cured state as a material.

[0005] However, fiber-reinforced resin prepregs have less ductility than metals, and when press-molded at the same speed as metals such as iron, they may tear or wrinkle. Also, if too much heat is applied to the prepreg for molding, the resin viscosity drops too much, the resin melts, and a clean molded product cannot be formed. Moreover, if no heat is applied, the viscosity does not decrease, resulting in molding defects.

[0006] For example, Patent Document 1 describes a method for manufacturing a fiber-reinforced resin molded product from a fiber-reinforced resin prepreg by setting appropriate conditions.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] In recent years, fiber-reinforced resin molded products have been used in various fields, and their applications, shapes, sizes, and required costs vary. Therefore, press molding that can meet the increasing needs is required. The matrix resin of resin-based composite materials has mainly been thermosetting resins such as epoxy resins for reasons such as prepreg manufacturability and moldability. However, thermoplastic resin composite materials that have features such as high toughness, recyclability, mass productivity, and that are developing technologies to improve prepreg manufacturability and moldability, which were conventional technical issues, are attracting attention. Patent Document 1 is about prepregs of thermosetting resins and does not mention thermoplastic resin prepregs. The molding temperature of thermoplastic resin prepregs is higher than that of thermosetting resin prepregs. Therefore, it is desirable to perform molding using a mold that can withstand a higher temperature than the mold used for thermosetting resin prepregs. However, when using a mold corresponding to the molding temperature of thermosetting resin prepregs with thermosetting resin prepregs being the mainstream, there are standard parts for steel materials, heating devices, and mold mounting parts. When using a mold corresponding to a higher temperature, since there are no standard parts, the cost increases. Also, a method of heating a thermoplastic resin prepreg to the molding temperature and molding it with a mold for thermosetting resin prepregs has become widespread. However, when heating a thermoplastic resin prepreg to the temperature required for molding the resin using an infrared heater or the like and then moving it to the molding equipment, the temperature drops within several tens of seconds until it is transferred to the mold. To further heat it to the temperature required for molding the thermoplastic resin, it is necessary to heat the entire mold. This not only incurs an electric cost but also requires a heating time. Also, when it is not heated sufficiently, when pressed, a whitening phenomenon occurs on the surface of the fiber-reinforced resin molded product, or the fibers get caught and a fiber cutting phenomenon occurs at the corner portions of the fiber-reinforced resin molded product, resulting in a poor yield. Therefore, an object of the present invention is to provide a manufacturing apparatus and a manufacturing method for a thermoplastic fiber-reinforced resin molded product that can suppress costs and increase the yield.

Means for Solving the Problems

[0009] As a result of intensive research, the inventors have found a manufacturing apparatus and a manufacturing method for a reinforced resin molded product that can reduce costs and increase yield by providing a cartridge heater for locally heating a portion corresponding to a corner portion formed on three or more surfaces of a box-shaped fiber-reinforced resin molded product in a mold. That is, the present invention includes the following. [1] A manufacturing apparatus for manufacturing a fiber-reinforced resin molded product having a box shape composed of a bottom surface and side surfaces composed of three or more flat surfaces, a lower mold having a convex portion, an upper mold having a concave portion, wherein the convex portion has first heating means for heating a convex corner portion corresponding to a corner portion formed by two of the flat surfaces adjacent to the bottom surface of the fiber-reinforced resin molded product, and the concave portion has second heating means for heating a concave corner portion corresponding to a corner portion formed by two of the flat surfaces adjacent to the bottom surface of the fiber-reinforced resin molded product. [2] The manufacturing apparatus according to [1], wherein the fiber-reinforced resin molded product contains a thermoplastic resin. [3] The manufacturing apparatus according to [1], wherein at the time of press molding, the difference between the temperature of the center of gravity portion of the top surface of the convex portion corresponding to the center of gravity of the bottom surface and the temperature of the convex corner portion is 30°C or more. [4] A method for manufacturing a fiber-reinforced resin molded product by the manufacturing apparatus according to [1], a step of heating a convex corner portion corresponding to a corner portion formed by two of the flat surfaces adjacent to the bottom surface of the fiber-reinforced resin molded product by the first heating means, a step of heating a concave corner portion corresponding to a corner portion formed by two of the flat surfaces adjacent to the bottom surface of the fiber-reinforced resin molded product by the second heating means, a step of disposing a fiber-reinforced resin prepreg on the lower mold, a step of sandwiching and pressing the fiber-reinforced prepreg between the upper mold and the lower mold, and a step of separating the upper mold and the lower mold and taking out the fiber-reinforced resin molded product. [5] The manufacturing method according to [4], wherein the temperature of the convex corner portion heated by the first heating means and the temperature of the concave corner portion heated by the second heating means are higher than the mold temperature other than the convex corner portion and the concave corner portion.

Advantages of the Invention

[0010] By manufacturing using a manufacturing apparatus including a mold for a thermosetting resin prepreg having a cartridge heater that heats portions corresponding to corner portions formed on three or more surfaces of a fiber-reinforced resin molded article, costs can be suppressed and a reinforced resin molded article can be manufactured with a high yield.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0012] Modes for carrying out the present invention will be described in detail based on the drawings of the examples. It should be noted that the present invention is not limited to the examples, and design changes and the like can be appropriately made within the range well known to those skilled in the art.

[0013] In this specification, a fiber-reinforced resin molded article is a molded article obtained by curing a prepreg in which a fiber bundle, for example, a fiber bundle such as carbon fiber or glass fiber is impregnated and dried with a thermoplastic resin or a thermosetting resin by heating and cooling. A thermoplastic fiber-reinforced resin molded article refers to one of the above fiber-reinforced resin molded articles in which the resin is composed of a thermoplastic resin. In addition, in the present invention, the thermoplastic fiber-reinforced resin molded article is composed of a thermoplastic resin and a resin composition containing one of them. Examples of the thermoplastic resin include polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, Teflon (registered trademark), acrylic, polyamide, polyacetal, polycarbonate, polyphenylene sulfide (PPS), polyethers (such as polyether ether ketone, polyether ketone, polyether sulfone), polyester, or combinations thereof. These may be used alone or in combination of two or more. In this example, a prepreg containing a thermoplastic resin is used for explanation. However, the manufacturing method and manufacturing apparatus described in this specification are applicable not only to the molding of thermoplastic resin prepregs but also to prepregs of thermosetting resins.

[0014] FIG. 1 is a schematic cross-sectional view for explaining press molding using a mold. 1 is an upper mold having a concave portion. 2 is a lower mold having a convex portion. 3 is a prepreg. 4 is a fiber-reinforced resin molded article. As shown in FIG. 1, in press molding using a mold, a prepreg 3 is disposed between the upper mold 1 and the lower mold 2, the prepreg 3 is sandwiched between the upper mold 1 and the lower mold 2, and a load is applied by the upper mold 1 and the lower mold 2 to deform the prepreg 3 to obtain a fiber-reinforced resin molded article 4. In FIG. 1, the portion surrounded by a line and labeled A is the corner formed by the bottom surface and the side surface of the fiber resin-reinforced molded article 4. The portion surrounded by a line and labeled B is the convex corner portion of the lower mold 2 corresponding to the corner formed by the bottom surface and the side surface of the fiber resin-reinforced molded article 4. The portion surrounded by a line and labeled C is the concave corner portion of the upper mold 1 corresponding to the corner formed by the bottom surface and the side surface of the fiber resin-reinforced molded article 4.

[0015] FIG. 2 is a perspective view of the fiber-reinforced resin molded product 4 formed by press molding. The portion surrounded by a line and labeled A is the corner formed by two adjacent planes, the bottom surface and the side surface. In the perspective views of the molds of Examples 1 and 2 shown in FIGS. 3 and 4, the portion surrounded by a line and labeled B is a convex corner corresponding to the corner formed by two planes adjacent to the bottom surface of the fiber-reinforced resin molded product 4. The portion surrounded by a line and labeled C is a concave corner corresponding to the corner formed by two planes adjacent to the bottom surface of the fiber-reinforced resin molded product 4.

Example

[0016] Example 1 (Configuration) The manufacturing apparatus of the fiber-reinforced resin molded product 4 of the present invention includes a lower mold 2 having a convex portion and an upper mold 1 having a concave portion. As shown in FIG. 3b, the lower mold 2 has a cartridge heater 5 as a heating means for heating the convex corner B corresponding to the corner formed by two planes adjacent to the bottom surface of the fiber resin-reinforced molded product 4. For example, along the intersection line of the top surface and the side surface of the convex portion of the convex corner B, there is a cartridge heater 5 perpendicularly below the top surface. Here, the cartridge heater 5 is composed of 521 arranged parallel to the top surface of the convex portion and 522 arranged perpendicular to the top surface of the convex portion. Note that the heating means may be composed only of the cartridge heater 521 arranged parallel to the top surface of the convex portion, or only of the cartridge heater 522 arranged perpendicular to the top surface of the convex portion, or both the cartridge heaters 521 and 522. In the present invention, the first heating means for heating the convex corner is the cartridge heater 521 or the cartridge heater 522, and if necessary, it can include both the cartridge heater 521 and the cartridge heater 522. As shown in Fig. 3a, the upper mold 1 has a cartridge heater 5 as a heating means for heating a concave corner C corresponding to a corner formed by two planes adjacent to the bottom surface of the fiber resin reinforced molded product 4 in the concave portion. For example, along the intersection line of the bottom surface of the concave portion of the concave corner and the side surface of the concave portion, there is a cartridge heater 5 perpendicularly below the bottom surface. Here, the cartridge heater 5 is composed of 511 arranged parallel to the top surface of the concave portion and 512 arranged perpendicular to the top surface of the concave portion. Note that the heating means may be composed only of the cartridge heater 511 arranged parallel to the top surface of the concave portion, or may be composed only of the cartridge heater 512 arranged perpendicular to the top surface of the concave portion, or may be composed of both the cartridge heaters 511 and 512. In the present invention, as the second heating means for heating the concave corner, it is the cartridge heater 511 or the cartridge heater 512, and if necessary, it can include both the cartridge heater 511 and the cartridge heater 512. Although not shown in the figure, the upper mold 1 and the lower mold 2 can also be provided with heaters that can raise the entire mold to a predetermined temperature so as to be able to mold the fiber reinforced resin prepreg, or heaters can be arranged around the mold to raise the temperature of the entire mold.

[0017] (Mold) The upper mold 1 and the lower mold 2 are not particularly limited as long as they are molds corresponding to the molding temperature of the resin. For example, a mold corresponding to 160 °C can be used.

[0018] (Cartridge heater) The cartridge heater 5 is not particularly limited as long as it can heat the concave corner C of the upper mold 1 and the convex corner B of the lower mold 2 to the molding temperature of the thermoplastic resin prepreg 3. If the concave corner C of the upper mold 1 and the convex corner B of the lower mold 2 are maintained at the molding temperature (e.g., 220°C) of the thermoplastic resin prepreg 3 by the cartridge heater 5 while applying a load with the upper mold 1 and the lower mold 2 to deform the prepreg 3, the prepreg 3 softens and is drawn into the upper mold 1 and the lower mold 2 while forming the corner A. As a result, fiber breakage is less likely to occur without the fibers being caught on the convex corner B and the concave corner C of the mold corresponding to the corner A of the fiber-reinforced resin molded product of the mold. Also, the whitening phenomenon generally occurs most frequently at the corner portions formed on three or more surfaces of the fiber-reinforced resin molded product, but such a whitening phenomenon can also be prevented. Further, when the whitening phenomenon occurs in other portions, the cartridge heater 5 may be added to and heated on the corresponding portions of the mold. The number of the cartridge heaters 5 is not particularly limited as long as it can heat the concave corner of the upper mold 1 and the convex corner B of the lower mold 2 to the molding temperature of the thermoplastic resin prepreg 3. In this embodiment, a rod-shaped cartridge heater is used as the heating means, but it is not limited as long as it can heat the corner portion.

[0019] During press molding, the difference between the temperature of the center of gravity of the top surface of the convex portion corresponding to the center of gravity of the bottom surface of the fiber-reinforced resin molded product and the temperature of the convex corner B is 30°C or more. If it is less than 30°C, the temperature is low, and there is a risk that the prepreg will not deform. Also, a whitening phenomenon may occur on the surface of the fiber-reinforced resin molded product, or the fibers may be caught and a fiber cutting phenomenon may occur at the corner portion of the fiber-reinforced resin molded product. Here, the center of gravity is, for example, when the plane is a quadrilateral, the midpoint of the line segment connecting the midpoints of the two line segments formed from each pair of two vertices out of the four vertices.

[0020] (Method for manufacturing a fiber-reinforced resin molded product) A method for manufacturing a fiber-reinforced resin molded product 4 having a box shape composed of a bottom surface and side surfaces composed of three or more planes includes a step of heating a convex corner corresponding to a corner formed by two planes adjacent to the bottom surface of the fiber-reinforced resin molded product by first heating means, a step of heating a concave corner corresponding to a corner formed by two planes adjacent to the bottom surface of the fiber-reinforced resin molded product by second heating means, a step of disposing a fiber-reinforced resin prepreg on a lower mold, a step of sandwiching and pressing the fiber-reinforced prepreg between an upper mold and the lower mold, and a step of separating the upper mold and the lower mold and taking out the fiber-reinforced resin molded product.

[0021] First, the upper mold 1 and the lower mold 2 are heated to a first temperature. Here, the first temperature is not particularly limited as long as it is a temperature that a general mold material can withstand (for example, a temperature at which a thermosetting resin prepreg can be molded), but for example, it is 140 to 180°. The upper mold 1 and the lower mold 2 may be heated to the first temperature by a heater capable of raising the entire mold provided in the mold to a predetermined temperature, or a heater may be disposed around the mold and heated to the first temperature.

[0022] Next, a convex corner B corresponding to a corner A formed by two planes adjacent to the bottom surface of the fiber-reinforced resin molded product 4 of the lower mold 2 having a convex portion is heated to a second temperature by a cartridge heater 5. The second temperature is not particularly limited as long as it is higher than the first temperature, but for example, it is a temperature at which a thermoplastic resin prepreg can be molded, for example, 200 to 250°C. Further, the concave corner C may be heated to the second temperature by the cartridge heater 5 together with the convex corner B of the lower mold 2. By heating both the convex corner B and the concave corner C, the accuracy of the corner A can be further improved and the product yield can be increased. Note that there is no boundary between the first temperature and the second temperature, and the temperature changes gradually. Therefore, the temperatures of the convex corner B and the concave corner C are higher than the temperatures at other positions in the mold.

[0023] In this example, although the prepreg 3 uses a thermoplastic fiber-reinforced resin prepreg composed of carbon fiber and polypropylene, it is not particularly limited. In this embodiment, the prepreg manufactured by Mitsubishi Chemical (twill weave, 0.23 mm per sheet) was used, and multiple sheets were laminated so that the thickness of the completed thermoplastic fiber reinforced resin molded product was 1.6 mm. The technology disclosed in this specification can be used for a thermoplastic fiber reinforced resin molded product with a thickness of 0.2 to 5.0 mm, and the thickness of the finished product can be adjusted by the number of prepregs laminated. Furthermore, when laminating the prepregs, an adhesive and / or an adhesive resin sheet can be placed between the prepregs to increase the lamination strength of the prepregs (to make the prepregs less likely to peel off from each other). For example, an acrylic adhesive or an acrylic adhesive resin sheet can be used as the adhesive resin sheet, and it may be placed between all the prepregs to be laminated, or an adhesive resin sheet may be placed only at the necessary places between the prepregs.

[0024] The temperature required to mold the thermoplastic fiber reinforced resin prepreg used in this embodiment is 220°C. The second temperature is a temperature close to the temperature for molding the material, and is a temperature at which the resin of the prepreg 3 to be placed later can be sufficiently softened and shaped between the concave corner of the upper mold 1 and the convex corner of the lower mold 2. The molding temperature and the holding temperature are, for example, in the range from the thermoplastic resin melting point of the prepreg 3 to the thermoplastic resin melting point + 100°C, and in one example, from the thermoplastic resin melting point to the thermoplastic resin melting point + 60°C. If the molding temperature or holding temperature is too high, it may cause burning or poor gloss of the thermoplastic fiber reinforced resin molded product, and if the holding temperature is too low, the fluidity of the resin may be poor, causing distortion or whitening.

[0025] A fiber reinforced resin prepreg 3 is placed in the lower mold 2. It is preferable that the fiber reinforced resin prepreg 3 is preliminarily heated to a molding temperature of the thermoplastic resin prepreg.

[0026] A fiber reinforced resin prepreg 3 is sandwiched between an upper mold 1 and a lower mold 2 and pressed. After placing the prepreg 3, while maintaining the temperatures of the upper mold 1, the lower mold 2, and the convex corner portions or the convex and concave corner portions, the upper mold 1 and / or the lower mold 2 is moved to sandwich the fiber-reinforced resin prepreg 3. Taking the case where the upper mold 1 descends as an example, the upper mold 1 contacts the prepreg 3 and further descends until the upper mold 1 reaches the bottom dead center. When the upper mold 1 reaches the bottom dead center, the load reaches its maximum value.

[0027] After the upper mold 1 reaches the bottom dead center, the load and temperature are held in that state for a predetermined time. The holding time at the bottom dead center is mainly adjusted according to the thickness of the prepreg 3. Usually, the holding time is between 0.3 and 2 minutes per 1 mm of the thickness of the prepreg 3. In this embodiment, in order to manufacture a thermoplastic fiber-reinforced resin molded product with a thickness of 1.6 mm, it is held for about 2 minutes. If the holding time is short, heat will not be transferred to the entire material, so it is difficult to obtain the desired shape. In particular, the molding of the corners is insufficient. Also, if the holding time is too long, the fluidity and color tone of the resin will change.

[0028] The load of the upper mold 1 at the bottom dead center is not particularly limited, and 800 to 1500 KN is preferable, and 900 to 1400 KN is more preferable.

[0029] The upper mold 1 and the lower mold 2 are separated, and the fiber-reinforced resin molded product 4 is taken out. When the upper mold 1 is at the position of the bottom dead center and after holding the temperature and load, when the temperatures of the upper mold 1 and the lower mold 2 are decreased and reach the temperature at which the thermoplastic resin solidifies, the pressurization of the upper mold 1 is stopped, the upper mold 1 is raised to its original position, the fiber-reinforced resin molded product 4 is demolded from the upper mold 1, and the press molding is completed.

[0030] When performing continuous pressing, it is not necessary to return the temperature of the entire mold to room temperature. For example, it may be 60 to 90 °C. If it is at a certain high temperature, the time for reheating can be shortened and the required energy can be reduced.

[0031] In the manufacturing apparatus of the fiber-reinforced resin molded product 4 of the present invention, since a mold corresponding to the molding temperature of a thermosetting resin prepreg in which standard parts exist as a mold is used, the cost is suppressed, and when molding a thermoplastic resin prepreg heated to the molding temperature, the temperature of the prepreg drops and the corners of the molded product where the influence of curing due to the temperature drop is large are increased. By heating the convex corner portions of the mold corresponding to the molding temperature of the thermoplastic resin prepreg, the yield can be increased. Since the thermoplastic resin prepreg requires less time for molding than the thermosetting resin prepreg, it is durable without softening or deterioration of the convex corner portions of the mold.

[0032] Example 2 The manufacturing apparatus of the fiber-reinforced resin molded product 4 of Example 2 is particularly effective when the molding depth is deep. As shown in FIG. 4b, the lower mold 2 of Example 2 has a cartridge heater 5 as a heating means for heating the convex corner portions corresponding to the corners formed by two adjacent planes of the bottom surface and the side surface of the fiber resin-reinforced molded product 4. For example, similar to Example 1, along the intersection line of the convex top surface and the convex side surface of the convex corner portion, there is a cartridge heater 5 under the top surface, and in addition, along the parallel lines of the intersection line of the convex top surface and the convex side surface of the convex corner portion in the middle and lower parts in the height direction of the side surface, there is a cartridge heater 5. As shown in FIG. 4a, the upper mold 1 has a cartridge heater 5 as a heating means for heating the concave corner portions corresponding to the corners formed by two adjacent planes of the bottom surface and the side surface of the fiber resin-reinforced molded product 4. For example, similar to Example 1, along the intersection line of the concave bottom surface and the concave side surface of the concave corner portion, there is a cartridge heater 5 under the bottom surface, and in addition, along the intersection line of the concave bottom surface and the concave side surface of the concave corner portion under the side surface, there is a cartridge heater 5. Thereby, not only the corner portion A but also the portion constituted by the two planes of the side surface can be heated. In Example 2, a plurality of cartridge heaters 5 parallel to the convex top surface or the concave bottom surface are provided, but the cartridge heaters 512 or 522 arranged in the vertical direction on the convex top surface or the concave bottom surface of Example 1 may be provided.

Explanation of reference numerals

[0033] 1: Upper mold 2: Lower mold 3: Prepreg 4: Fiber-reinforced resin molded product 5: Cartridge heater A: Corner B: Convex corner C: Concave corner

Claims

1. A manufacturing apparatus for manufacturing a fiber-reinforced resin molded product having a box shape composed of a bottom surface and a side surface composed of a plurality of three or more planes, a lower mold having a convex portion, and an upper mold having a concave portion, wherein the convex portion has first heating means for heating a convex corner portion corresponding to a corner portion formed by two of the planes adjacent to the bottom surface of the fiber-reinforced resin molded product, and the concave portion has second heating means for heating a concave corner portion corresponding to a corner portion formed by two of the planes adjacent to the bottom surface of the fiber-reinforced resin molded product. The manufacturing apparatus.

2. The manufacturing apparatus according to claim 1, wherein the fiber-reinforced resin molded product contains a thermoplastic resin.

3. The manufacturing apparatus according to claim 1, wherein, during press molding, the difference between the temperature of the center of gravity portion of the top surface of the convex portion corresponding to the center of gravity of the bottom surface and the temperature of the convex corner portion is 30°C or more.

4. A method for manufacturing a fiber-reinforced resin molded product by the manufacturing apparatus according to claim 1, a step of heating a convex corner portion corresponding to a corner portion formed by two of the planes adjacent to the bottom surface of the fiber-reinforced resin molded product by the first heating means, a step of heating a concave corner portion corresponding to a corner portion formed by two of the planes adjacent to the bottom surface of the fiber-reinforced resin molded product by the second heating means, a step of disposing a fiber-reinforced resin prepreg on the lower mold, a step of sandwiching and pressing the fiber-reinforced prepreg with the upper mold and the lower mold, and a step of separating the upper mold and the lower mold and taking out the fiber-reinforced resin molded product. The manufacturing method.

5. The manufacturing method according to claim 4, wherein the temperature of the convex corner portion heated by the first heating means and the temperature of the concave corner portion heated by the second heating means are higher than the mold temperature other than the convex corner portion and the concave corner portion.

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