Manufacturing method of foam molding die, and foam molding die

Abstract

To provide a manufacturing method that can accurately and efficiently manufacture a foam molding die including a concave-side integral die and a convex-side integral die having a double-structure.SOLUTION: A foam molding die 1 includes a concave-side integral die and a convex-side integral die B having a double-structure. In a manufacturing method of the foam molding die 1, a powder bed fusion bonding method repeats the steps of laying a metal powder MP on a molding platform 2 at a predetermined laminating thickness, and melting and solidifying the metal powder MP with a laser beam L using slice data for each laminating thickness converted from 3D model data of the concave-side integral die or the convex-side integral die B to mold the concave-side integral die or the convex-side integral die B on the molding platform 2.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a mold for molding synthetic resin foams, and to said mold. [Background technology]

[0002] As a mold used for molding synthetic resin foam used in heat-insulating containers, packaging materials, etc., there is a mold using a double-structured concave-side integral mold and a convex-side integral mold (for example, see Patent Document 1). The concave-side integral mold is a mold that is integrated with a concave mold and a concave-side back member of approximately the same shape as the concave mold, which faces the back of the concave mold with a required gap to provide a concave-side back space, and the concave-side back space is a concave-side utility space. The convex-side integral mold is a mold that is integrated with a convex mold and a convex-side back member of approximately the same shape as the convex mold, which faces the back of the convex mold with a required gap to provide a convex-side back space, and the convex-side back space is a convex-side utility space.

[0003] By molding foamed synthetic resin using a double-structured integral concave-side mold and an integral convex-side mold, the volumes of the concave-side utility space and the convex-side utility space can be reduced, thereby improving energy efficiency.

[0004] Aluminum alloys are generally used as the material for foam molding dies from the viewpoints of workability, corrosion resistance, etc. For example, in the concave-side integral die 30A and the convex-side integral die 30B of Patent Document 1, the concave die 31 and the convex die 32 are made of an aluminum alloy having a thickness of 5 to 15 mm (paragraph

[0054] of Patent Document 1), and the concave-side rear member 33 and the convex-side rear member 34 are made of an aluminum alloy having a thickness of 8 to 15 mm (paragraph

[0055] of Patent Document 1).

[0005] In the manufacturing method of a foam molding die in Patent Document 1, a double-structured one-piece concave die 30A and one-piece convex die 30B are manufactured by lost foam casting and machining. For example, when manufacturing the one-piece concave die 30A, the steps include making and assembling a lost foam pattern for casting (FIG. 5), filling with casting sand, hardening (FIG. 6), pouring molten metal, shaping (FIG. 7), removing the casting, and machining the casting (FIG. 8).

[0006] In the production and assembly of the lost form pattern for casting (Fig. 5), a lost form pattern 51 corresponding to the shape of the concave mold 31, and a lost form pattern 52 corresponding to the shape of the concave-side back surface member 33 are produced from polystyrene foam blocks, and these are assembled to produce the assembled lost form pattern 50. In the filling and hardening of the casting sand (Fig. 6), casting sand a is filled into the outside and inside of the assembled lost form pattern 50 placed in a container 55, and the filled casting sand a is hardened.

[0007] In the pouring of molten metal and molding (Fig. 7), molten aluminum alloy b is poured into the part of the assembled lost pattern 50 in the casting sand a (Fig. 6), the lost pattern 50 is decomposed and destroyed by heat, and at the same time, molten metal b is allowed to flow into the lost space to form the concave integrated mold 30A. In the machining of the casting (Fig. 8), the casting immediately after casting, which has a rough and uneven surface due to the casting sand, is machined by an appropriate grinding device 53 to finish it to the specified surface accuracy and to process it to the specified set dimensions.

[0008] On the other hand, there is a method for manufacturing normal shaped concave and convex molds, rather than a method for manufacturing a double-structure one-piece concave and convex molds, which includes a process of forming the mold using a 3D printer with an arc welding method, and stacking convex stripes, which are linear tracks (beads), in multiple stages to increase the surface area of ​​the mold and shorten the time required for cooling (see, for example, Patent Document 2).

[0009] In the manufacturing method of the foam molding die of Patent Document 2, a 3D printer 50 (FIG. 3) using an arc welding method is used to form the foam molding die 30 using aluminum as the metal for molding. As a result, a convex streak 20, which is a linear bead, is formed on the surface of the foam molding die 30. Then, after the foam molding die 30 is formed by the 3D printer 50, the necessary steam holes are drilled in the bottom surface 31 and the peripheral side surface 32. In order to obtain a general foam molding die with a flat molding surface 3a, it is necessary to perform mechanical grinding on the molding surface 3a after the foam molding die 30 is formed by the 3D printer 50. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2010-221535 A [Patent Document 2] JP 2018-176473 A Summary of the Invention [Problem to be solved by the invention]

[0011] When performing lost foam casting consisting of the steps shown in FIGS. 5 to 7 of Patent Document 1, the assembled lost foam pattern made of polystyrene foam, which is lost by the heat of the molten metal, has low rigidity and strength, which makes the lost foam prone to deformation and damage, and generates polystyrene foam combustion gas and leaves combustion residue.

[0012] Therefore, it is difficult to achieve precision in the double-structure concave-side integral die and convex-side integral die that are the casting, and machining is required, which consists of the steps shown in Fig. 8 of Patent Document 1. This requires a lot of time and cost, and even if the required machining is performed, there remains variation in the thickness of the die, which causes variation in the volume of the concave-side utility space and the volume of the convex-side utility space.

[0013] A manufacturing method for a double-structured concave-side integrated die and a convex-side integrated die is not disclosed in Patent Document 2. In order to manufacture a general foam molding die having a flat molding surface by the manufacturing method for a foam molding die in Patent Document 2, it is necessary to perform an operation of drilling the necessary steam holes after forming the foam molding die using a 3D printer by the arc welding method in Figure 3 of Patent Document 2, and to perform mechanical grinding on the molding surface of the foam molding die.

[0014] An object of the present invention is to provide a manufacturing method capable of accurately and efficiently manufacturing a foam molding mold including a double-structure integrated concave mold and integrated convex mold. [Means for solving the problem]

[0015] The manufacturing method of a foam molding mold according to the present invention is a manufacturing method of a mold for molding foamed synthetic resin in a molding space between a concave mold and a convex mold, and the mold includes a double-structure integrated concave mold and integrated convex mold.

[0016] The concave-side integral die includes a concave-side structure formed by integrating the concave mold with a concave-side back member of substantially the same shape as the concave mold, which faces the back of the concave mold with a required interval to provide a concave-side back space, and the concave-side back space is a concave-side utility space. The convex-side integral die includes a convex-side structure formed by integrating the convex mold with a convex-side back member of substantially the same shape as the convex mold, which faces the back of the convex mold with a required interval to provide a convex-side back space, and the convex-side back space is a convex-side utility space. The concave mold and the convex mold have slit-shaped steam holes, and between the concave mold and the concave-side back member there are a plurality of concave-side reinforcing members that connect them, and between the convex mold and the convex-side back member there are a plurality of convex-side reinforcing members that connect them.

[0017] The manufacturing method involves repeating a process of spreading metal powder on a building platform at a predetermined layer thickness, and a process of melting and solidifying the metal powder with a laser beam using slice data for each layer thickness converted from 3D model data of the concave-side one-piece die or the convex-side one-piece die, to build the concave-side one-piece die or the convex-side one-piece die of the above shape on the building platform using a powder bed fusion method.

[0018] Here, the concave-side integral die has a concave-side mounting structure in addition to the concave-side structure, and the concave-side mounting structure is formed with a concave-side steam supply pipe mounting portion for mounting a pipe for supplying steam into the concave-side utility space, a concave-side cooling water supply pipe mounting portion for mounting a pipe for supplying cooling water into the concave-side utility space, a concave-side drain pipe mounting portion for mounting a pipe for discharging drain generated by cooling the steam and the cooling water drain from the concave-side utility space, and a concave-side molding device main body mounting portion for mounting the concave-side integral die to a molding device main body, In a preferred embodiment, the one-piece mold has a convex mounting structure in addition to the convex structure, and the convex mounting structure is formed with a convex steam supply piping mounting portion for mounting a piping for supplying steam into the convex utility space, a convex cooling water supply piping mounting portion for mounting a piping for supplying cooling water into the convex utility space, and a convex drain piping mounting portion for mounting a piping for draining the drain generated by cooling the steam and the cooling water drain from the convex utility space, and a convex molding apparatus main body mounting portion for mounting the convex one-piece mold to the molding apparatus main body.

[0019] According to this manufacturing method for foam molding dies, a double-structure one-piece concave mold and a double-structure one-piece convex mold having complex shapes can be produced with high precision by powder bed fusion bonding using a laser beam as a heat source.

[0020] Furthermore, when the concave-side integral die and the convex-side integral die have complex shapes, the necessary reinforcement can be provided within the concave-side rear space and the convex-side rear space during molding using the powder bed fusion method, and the thickness and shape can be optimized, thereby saving material and reducing weight.

[0021] In addition, in a preferred embodiment, the metal powder is a powder of a stainless steel alloy, a titanium alloy, or a nickel alloy, and the thicknesses of the concave mold and the concave side rear member, and the convex mold and the convex side rear member are 1 mm or more and 3 mm or less.

[0022] According to this manufacturing method of a foam molding mold, the concave-side integral mold and the convex-side integral mold are made of a stainless steel alloy, a titanium alloy, or a nickel alloy, and the thicknesses of the concave mold and the concave-side rear member, and the convex mold and the convex-side rear member are 1 mm or more and 3 mm or less, thereby making it possible to achieve further weight reduction while maintaining the required strength.

[0023] In addition, the volume of the mold made by powder bed fusion using a laser beam as the heat source is small, so the irradiation area of ​​the laser beam is small and the amount of metal powder used is small, so the time to make the mold by powder bed fusion can be shortened and the manufacturing cost of powder bed fusion can be reduced.

[0024] Furthermore, since the concave-side one-piece die and the convex-side one-piece die are made of a stainless steel alloy, a titanium alloy, or a nickel alloy, the thermal conductivity and specific heat are smaller than when the concave-side one-piece die and the convex-side one-piece die are made of an aluminum alloy, which has a high thermal conductivity and specific heat. This means that thermal energy is less likely to be lost when the temperature of the die rises or falls, and energy loss can be significantly reduced.

[0025] The foam molding mold according to the present invention is a mold for molding a foamed synthetic resin in a molding space between a concave mold and a convex mold, and includes a double-structured concave-side integral mold and a convex-side integral mold. The concave-side integral mold includes a concave-side structure formed by integrating the concave mold with a concave-side back member of substantially the same shape as the concave mold, which faces the back of the concave mold with a required interval to provide a concave-side back space, and the concave-side back space is a concave-side utility space. The convex-side integral mold includes a convex-side structure formed by integrating the convex mold with a convex-side back member of substantially the same shape as the convex mold, which faces the back of the convex mold with a required interval to provide a convex-side back space, and the convex-side back space is a convex-side utility space. The concave mold and the convex mold are formed with slit-shaped steam holes, and between the concave mold and the concave-side back member there are a plurality of concave-side reinforcing members connecting them, and between the convex mold and the convex-side back member there are a plurality of convex-side reinforcing members connecting them.

[0026] The concave-side integral mold has, in addition to the concave-side structure, a concave-side mounting structure, which is formed with a concave-side steam supply piping mounting portion for mounting a piping for supplying steam into the concave-side utility space, a concave-side cooling water supply piping mounting portion for mounting a piping for supplying cooling water into the concave-side utility space, a concave-side drain piping mounting portion for mounting a piping for draining the drain generated by cooling the steam and the cooling water drain from the concave-side utility space, and a concave-side molding apparatus main body mounting portion for mounting the concave-side integral mold to a molding apparatus main body. The convex-side integral mold has, in addition to the convex-side structure, a convex-side mounting structure, which is formed with a convex-side steam supply piping mounting portion for mounting a piping for supplying steam into the convex-side utility space, a convex-side cooling water supply piping mounting portion for mounting a piping for supplying cooling water into the convex-side utility space, a convex-side drain piping mounting portion for mounting a piping for draining the drain generated by cooling the steam and the cooling water drain from the convex-side utility space, and a convex-side molding apparatus main body mounting portion for mounting the convex-side integral mold to a molding apparatus main body.

[0027] According to this foam molding mold, the double-structured concave-side integrated mold has the concave-side mounting structure in addition to the concave-side structure, and the double-structured convex-side integrated mold has the convex-side mounting structure in addition to the convex-side structure. Therefore, steam supply piping, cooling water supply piping, and drain piping can be easily attached to the concave-side mounting structure provided integrally with the concave-side integrated mold and the convex-side mounting structure provided integrally with the convex-side integrated mold, and the concave-side mounting structure and the convex-side mounting structure can be easily attached to the molding apparatus main body.

[0028] Here, it is a preferred embodiment that the concave-side integral die and the convex-side integral die are made of a stainless steel alloy, a titanium alloy, or a nickel alloy, and that the thicknesses of the concave mold and the concave-side rear member, as well as the convex mold and the convex-side rear member, are 1 mm or more and 3 mm or less.

[0029] According to such a foam molding mold, the concave-side integral mold and the convex-side integral mold are made of a stainless steel alloy, a titanium alloy, or a nickel alloy, and the thicknesses of the concave mold and the concave-side rear member, and the convex mold and the convex-side rear member are 1 mm or more and 3 mm or less, so that it is possible to achieve weight reduction while ensuring the required strength.

[0030] Furthermore, since the concave-side one-piece die and the convex-side one-piece die are made of a stainless steel alloy, a titanium alloy, or a nickel alloy, the thermal conductivity and specific heat are smaller than when the concave-side one-piece die and the convex-side one-piece die are made of an aluminum alloy, which has a high thermal conductivity and specific heat, and thermal energy is less likely to be lost when the temperature of the die rises or falls, so energy loss can be significantly reduced. Effect of the Invention

[0031] According to the manufacturing method of the foam molding mold of the present invention, a double-structure one-piece concave mold and one-piece convex mold having a complex shape can be manufactured with high precision by powder bed fusion bonding using a laser beam as a heat source.

[0032] Furthermore, when the concave-side integral die and the convex-side integral die have complex shapes, the necessary reinforcement can be provided within the concave-side rear space and the convex-side rear space during molding using the powder bed fusion method, and the thickness and shape can be optimized, thereby saving material and reducing weight.

[0033] According to the foam molding mold of the present invention, steam supply piping, cooling water supply piping, and drain piping can be easily attached to the concave side mounting structure formed integrally with the double-structure concave side integrated mold, and the convex side mounting structure formed integrally with the double-structure convex side integrated mold, and the concave side mounting structure and the convex side mounting structure can be easily attached to the molding apparatus main body. [Brief description of the drawings]

[0034] [Figure 1]1 is a longitudinal sectional view showing a foam molding mold according to an embodiment of the present invention, in which the mold made of stainless steel alloy, titanium alloy, or nickel alloy is shown in a closed state. [Diagram 2] This shows the mold of FIG. 1 in an open state. [Diagram 3] FIG. 2 is a vertical cross-sectional perspective view of a concave-side integrated die as viewed obliquely from above. [Figure 4] FIG. 2 is a perspective view of the concave-side integrated die as viewed obliquely from below. [Diagram 5] FIG. 2 is a cross-sectional plan view of a concave-side integrated die. [Figure 6] FIG. 2 is a vertical cross-sectional perspective view of a protruding-side integrated die as viewed obliquely from above. [Figure 7] FIG. 2 is a perspective view of a protruding-side integrated die as viewed obliquely from below. [Figure 8] FIG. 2 is a cross-sectional plan view of a convex-side integral die. [Figure 9] 1 is a vertical cross-sectional view showing a foam molding mold according to an embodiment of the present invention, in which the mold made of an aluminum alloy is shown in a closed state. [Figure 10] This shows the mold of FIG. 9 in an open state. [Figure 11] FIG. 2 is a schematic diagram showing an example of a method for producing a foam molding mold. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0036] [Materials of foam molding mold] The foam molding mold 1 in Figures 1 to 8 (concave-side integral mold A, convex-side integral mold B) is made of a stainless steel alloy, a titanium alloy, or a nickel alloy, and the foam molding mold 1 in Figures 9 and 10 (concave-side integral mold A, convex-side integral mold B) is made of an aluminum alloy.

[0037] As the stainless steel alloy for the foam molding die 1, for example, SUS316L, which is a stainless steel with high corrosion resistance, or SUS630, which is a stainless steel with high corrosion resistance and high strength, is preferably used. As the titanium alloy for the foam molding die 1, for example, Ti-6Al-4V, which is lightweight, highly corrosion resistant, and high strength, is preferably used. As the nickel alloy for the foam molding die 1, for example, INCONEL (registered trademark) 600 or INCONEL (registered trademark) 718, which is mainly composed of nickel and has improved heat resistance and corrosion resistance by adding alloy components such as chromium, iron, and carbon, is preferably used. As the aluminum alloy for the foam molding die 1, for example, AlSi10Mg, which is a silicon-based aluminum alloy casting material that is lightweight, highly processable, and has good mechanical properties, is preferably used.

[0038] [Thickness of foam molding mold] In a foam molding die 1 made of a stainless steel alloy, a titanium alloy, or a nickel alloy, the thickness T10 of the concave mold 10 and the thickness T11 of the concave side rear member 11, as well as the thickness T20 of the convex mold 20 and the thickness T21 of the convex side rear member 21 shown in FIG. 1, are, for example, 1 mm or more and 3 mm or less.

[0039] In the foam molding die 1 made of an aluminum alloy, the thickness T10 of the concave mold 10 and the thickness T20 of the convex mold 20 shown in FIG. 9 are, for example, 5 mm or more and 15 mm or less, and the thickness T11 of the concave-side back member 11 and the thickness T21 of the convex-side back member 21 are, for example, 8 mm or more and 15 mm or less.

[0040] [Structure of foam molding mold] The foam molding die 1 (concave-side integral die A, convex-side integral die B) described below is attached to the molding machine body when foaming synthetic resin. A steam supply pipe, a cooling water supply pipe, and a drain pipe, as well as a feeder for filling the molding space with foam beads, and a mold release pin for releasing the molded product are attached to the foam molding die 1. The molding machine body, the pipes, the feeder, and the mold release pin are omitted in the drawings of the present application.

[0041] As shown in Figures 1 and 2, as well as Figures 9 and 10, the foam molding mold 1 of the embodiment of the present invention includes a double-structured integrated concave mold A which is the fixed side, and a double-structured integrated convex mold B which is the movable side, and molds foamed synthetic resin in the molding space 30 between the concave mold 10 and the convex mold 20 in Figures 1 and 9 when the mold is closed.

[0042] The foam molding die 1 in Figures 1 and 2 and the foam molding die 1 in Figures 9 and 10 have the same structure except for the material and thickness. Therefore, in the following, the explanation of the die structure and the explanation of the molding method of foamed synthetic resin will be given with respect to the foam molding die 1 in Figures 1 and 2.

[0043] (Concave side integrated mold) 1 to 5, the concave-side integrated mold A includes a concave-side structure C formed by integrating a concave mold 10 with a concave-side back member 11 of substantially the same shape as the concave mold 10, which faces the back of the concave mold 10 with a required gap to provide a concave-side back space 12, and the concave-side back space 12 serves as a concave-side utility space 13. A slit-shaped steam hole 14 is formed in the concave mold 10, and a plurality of concave-side reinforcing members 15 are provided between the concave mold 10 and the concave-side back member 11 to connect them.

[0044] The concave-side reinforcing member 15 is, for example, an octagonal ring or a number of connected octagonal rings, and the ring has a hole in the middle, so that it does not impede the movement of utilities in the concave-side utility space 13. The concave-side reinforcing member 15 is not limited to an octagonal ring as in this embodiment, and any appropriate shape that has the required strength and rigidity as a reinforcing member and does not impede the movement of utilities in the concave-side utility space 13 can be adopted.

[0045] The concave-side integral mold A has a concave-side mounting structure E in addition to the concave-side structure C. The concave-side mounting structure E is formed with a concave-side steam supply pipe mounting portion 16 for mounting a pipe for supplying steam into the concave-side utility space 13, a concave-side cooling water supply pipe mounting portion 17 for mounting a pipe for supplying cooling water into the concave-side utility space 13, a concave-side drain pipe mounting portion 18 for mounting a pipe for discharging the drain generated by cooling the steam and the cooling water drain from the concave-side utility space 13, and a concave-side molding device main body mounting portion 19 for mounting the concave-side integral mold A to the molding device main body.

[0046] The concave side steam supply pipe mounting portion 16 is, for example, a through hole 16A and a screw hole 16B. The concave side cooling water supply pipe mounting portion 17 is, for example, a through hole 17A and a screw hole 17B. The concave side drain pipe mounting portion 18 is, for example, a through hole 18A and a screw hole 18B. The concave side forming device main body mounting portion 19 is, for example, a screw hole.

[0047] A raw material charging port 10A and a mold release pin opening 10B are formed in the concave mold 10. The concave back member 11 has a through hole 11A for inserting a feeder for charging foamed beads into the molding space 30 and a screw hole 11B for attaching the feeder.

[0048] (Convex side integrated mold) 1 and 2, and 6 to 8, the convex-side integrated mold B includes a convex-side structure D formed by integrating a convex mold 20 with a convex-side back member 21 of substantially the same shape as the convex mold 20, which faces the back of the convex mold 20 with a required gap to provide a convex-side back space 22, and the convex-side back space 22 serves as a convex-side utility space 23. A slit-shaped steam hole 24 is formed in the convex mold 20, and a plurality of convex-side reinforcing members 25 are provided between the convex mold 20 and the convex-side back member 21 to connect them.

[0049] The convex-side reinforcing member 25 is, for example, an octagonal ring-shaped body or a plurality of connected octagonal ring-shaped bodies, and the ring-shaped body has a hole in the center, so that it does not hinder the movement of utilities in the convex-side utility space 23. The convex-side reinforcing member 25 is not limited to an octagonal ring-shaped body as in this embodiment, and any appropriate shape that has the required strength and rigidity as a reinforcing member and does not hinder the movement of utilities in the convex-side utility space 23 can be adopted.

[0050] The convex-side integral die B has a convex-side mounting structure F in addition to the convex-side structure D. The convex-side mounting structure F is formed with a convex-side steam supply pipe mounting portion 26 for mounting a pipe for supplying steam into the convex-side utility space 23, a convex-side cooling water supply pipe mounting portion 27 for mounting a pipe for supplying cooling water into the convex-side utility space 23, a convex-side drain pipe mounting portion 28 for mounting a pipe for discharging the drain generated by cooling the steam and the cooling water drain from the convex-side utility space 23, and a convex-side molding device main body mounting portion 29 for mounting the convex-side integral die B to the molding device main body.

[0051] The convex steam supply pipe mounting portion 26 is, for example, a through hole 26A and a screw hole 26B. The convex cooling water supply pipe mounting portion 27 is, for example, a through hole 27A and a screw hole 27B. The convex drain pipe mounting portion 28 is, for example, a through hole 28A and a screw hole 28B. The convex forming device main body mounting portion 29 is, for example, a screw hole.

[0052] [Actions and effects based on the structure of the concave-side integral die and the convex-side integral die] The double-structure concave-side integral die A has a concave-side mounting structure E in addition to the concave-side structure C, and the double-structure convex-side integral die B has a convex-side mounting structure F in addition to the convex-side structure D. Therefore, steam supply piping, cooling water supply piping, and drain piping can be easily attached to the concave-side mounting structure E provided integrally with the concave-side integral die A and the convex-side mounting structure F provided integrally with the convex-side integral die B, and the concave-side mounting structure E and the convex-side mounting structure F can be easily attached to the molding apparatus main body.

[0053] [Method of molding synthetic foam resin] (filling process) With the foam molding die 1 closed as shown in Fig. 1, foamed beads of a thermoplastic resin are supplied by a feeder from the raw material charging port 10A into the molding space 30. The foamed beads are filled into the molding space 30 while air is removed from the slit-shaped steam hole 14 of the concave mold 10 and the slit-shaped steam hole 24 of the convex mold 20, as well as the concave-side drain and the convex-side drain. The term "foamed beads" is a concept that also includes pre-foamed beads obtained by pre-expanding expandable beads.

[0054] (Steam one-way heating process) Steam is introduced into the concave utility space 13, and the steam is passed between the foamed beads, for example through slit-like steam holes 14 formed in the concave mold 10, to expel the air between the foamed beads and let it out through the convex utility space 23 to the convex drain. The heat of the steam is applied to the foamed beads filled in the molding space 30, heating them and causing them to foam and fuse.

[0055] (Double-sided heating process) The concave and convex drains are closed, and steam is introduced into the concave utility space 13 and the convex utility space 23 to slightly melt the surface of the foamed synthetic resin and improve the aesthetic appearance of the surface.

[0056] (Water cooling / drainage process) The drains on the concave side and the convex side are opened, and cooling water is introduced into the concave side utility space 13 and the convex side utility space 23 to cool the concave mold 10 and the convex mold 20, and then the water is discharged from the drains.

[0057] As mentioned above, aluminum alloy is generally used as the material for the foam molding die from the viewpoint of workability and corrosion resistance, and the foam molding die made of aluminum alloy has a large thermal conductivity and specific heat and is thick. Moreover, in a general foam molding die including a normal concave and convex mold, rather than the foam molding die 1 including a double-structured concave integral mold A and a convex integral mold B as in the present invention, the utility space is large, so that only a method of spraying cooling water with a spray nozzle in the "water cooling and drainage process" could be adopted. Therefore, in the molding of foamed synthetic resin using the general foam molding die, it was necessary to perform a "vacuum cooling process" after the "water cooling and drainage process" to evaporate the water in the molding space by making the utility space a vacuum state and lowering the boiling point of water, and to quickly lower the temperature of the normal-shaped die and / or the foamed synthetic resin in the molding space.

[0058] In contrast, in the foam molding die 1 of the present invention, the concave utility space 13 and the convex utility space 23 are extremely narrow, and if they are made of stainless steel alloy, titanium alloy, or nickel alloy, the thermal conductivity and specific heat are small, and the thickness can be reduced to make the die lightweight. Therefore, in the foam molding die 1 of the present invention, the concave utility space 13 and the convex utility space 23 can be filled with cooling water to facilitate heat exchange, so that the "vacuum cooling step" can be omitted. When the "vacuum cooling step" is omitted, the molding cycle can be significantly shortened, and therefore the molding cost can be significantly reduced, and its industrial value is extremely significant.

[0059] (Mold release process) As shown in FIG. 2, the foam molding die 1 is opened, and a release pin is inserted through the release pin opening 10B and pushed out, thereby obtaining a foamed synthetic resin molded product of a desired shape.

[0060] [Manufacturing method of foam molding mold] The concave integral die A and the convex integral die B of the foam molding die 1 are manufactured by selectively melting and solidifying metal powder MP by powder bed fusion (JIS B 9441:2020, 3.2.5) using a laser beam L as a heat source. Fig. 11 is an example of forming the convex integral die B by the powder bed fusion method, and shows the state in which an intermediate object M, which is a part of the convex integral die B, has been formed. The concave integral die A can also be formed in the same manner as the convex integral die B.

[0061] The metal powder MP is a powder of a stainless steel alloy, a titanium alloy, a nickel alloy, or an aluminum alloy.

[0062] The laser beam L is generated by a single-mode Yb (ytterbium) fiber laser with a wavelength of, for example, 1070 nm and an output of, for example, about 200 W to 1 kW, and can efficiently melt metal powder MP made of various materials, including when the metal powder MP is an aluminum alloy.

[0063] (3D model and slice data creation process) A model of the convex-side integrated mold B is created using 3D CAD (3 Dimensional Computer Aided Design) to obtain 3D model data for the convex-side integrated mold B. When molding the concave-side integrated mold A, a model of the concave-side integrated mold A is created using 3D CAD to obtain 3D model data for the concave-side integrated mold A. The 3D model data is converted into an STL (STereo Lithography) file, and then converted into slice data for each specified layer thickness.

[0064] (Metal powder packing process) The metal powder MP contained in the dispenser 3 is swept by, for example, a blade-type recoater 5 moving in the direction of arrow G, and moved onto the modeling platform 2. As a result, a single layer of metal powder MP having a layer thickness of, for example, 20 μm to 50 μm is spread over the modeling platform 2. The remaining metal powder MP is collected by a collector 4.

[0065] (Metal powder melting and solidification process) The excited laser beam L that passes through the condenser lens 6 is reflected by the galvanometer mirror 7, and the direction of the laser beam L is controlled by driving the galvanometer mirror 7 with a galvanometer scanner (not shown) to scan along the cross-sectional shape of the slice data of the convex-side integrated die B. As a result, the metal powder MP in the layer is selectively melted and solidified by the laser beam L irradiated at the position of the cross-sectional shape.

[0066] (Building platform lowering and dispenser raising process) The elevating device 8 lowers the modeling platform 2 by the amount of one layer in the direction of the arrow H, thereby lowering the intermediate model M by the amount of one layer. The elevating device 9 raises the dispenser 3 by a predetermined amount in the direction of the arrow I.

[0067] (Metal powder packing process) The metal powder MP contained in the dispenser 3 is swept by the recoater 5 moving in the direction of the arrow G, and moved onto the modeling platform 2. As a result, the metal powder MP is spread over the space generated above the intermediate model M that has been lowered by the amount of one layer.

[0068] (Metal powder melting and solidification process) As described above, the laser beam L reflected by the galvanometer mirror 7 is scanned along the cross-sectional shape of the slice data for each layer converted from the 3D model data of the convex-side integrated die B. As a result, the metal powder MP in one layer is selectively melted and solidified by the laser beam L irradiated at the position of the cross-sectional shape, and is also bonded to the layer below.

[0069] (Repeat the process) The "build platform lowering and dispenser raising process," "metal powder spreading process," and "metal powder melting and solidifying process" are repeated, and layers of selectively melted and solidified metal powder MP are stacked on the build platform 2 to form a convex-side integrated mold B.

[0070] As described above, the manufacturing method of the foam molding die according to the embodiment of the present invention is a method for manufacturing the concave-side integral die A or the convex-side integral die B on the building platform 2 by a powder bed fusion method that repeats the steps of spreading metal powder MP in a predetermined layer thickness on the building platform 2 and melting and solidifying the metal powder MP with a laser beam L using slice data for each layer thickness converted from the 3D model data of the concave-side integral die A or the convex-side integral die B. As a result, the concave-side integral die A can be directly manufactured from the 3D model data of the concave-side integral die A, and the convex-side integral die B can be directly manufactured from the 3D model data of the convex-side integral die B.

[0071] [Effects] According to the manufacturing method of a foam molding mold of an embodiment of the present invention, a double-structure integral concave mold A and a double-structure integral convex mold B having complex shapes can be formed with high precision by powder bed fusion bonding using a laser beam L as a heat source. Furthermore, for the concave-side integral die A and the convex-side integral die B, which have complex shapes, the necessary reinforcement can be provided within the concave-side rear space 12 and the convex-side rear space 22 during molding using the powder bed fusion method, and the thickness and shape can be optimized, thereby saving material and reducing weight.

[0072] By using the metal powder MP as a powder of a stainless steel alloy, titanium alloy, or nickel alloy, and setting the thickness T10 of the concave mold 10, the thickness T11 of the concave side rear member 11, the thickness T20 of the convex mold 20, and the thickness T21 of the convex side rear member 21 to 1 mm or more and 3 mm or less, it is possible to achieve further weight reduction while maintaining the required strength.

[0073] For example, if the weight of the aluminum alloy concave-side integrated die A in Figures 9 and 10 with the concave die 10 having a thickness T10 = 5 mm and the concave-side rear member 11 having a thickness T11 = 15 mm is taken as 1, then the weight of the stainless steel alloy concave-side integrated die A in Figures 1 and 2 with T10 = T11 = 2 mm is approximately 0.84. Also, if the weight of the aluminum alloy convex-side integrated die B in Figures 9 and 10 with the convex die 20 having a thickness T20 = 5 mm and the convex-side rear member 21 having a thickness T21 = 15 mm is taken as 1, then the weight of the stainless steel alloy convex-side integrated die B in Figures 1 and 2 with T20 = T21 = 2 mm is approximately 0.75.

[0074] Furthermore, by making the concave-side integral die A and the convex-side integral die B from stainless steel alloy, titanium alloy, or nickel alloy and setting T10, T11, T20, and T21 to 1 mm or more and 3 mm or less, the volume of the die formed by powder bed fusion using the laser beam L as the heat source becomes smaller, so that the irradiation area of ​​the laser beam L becomes smaller and the amount of metal powder MP used becomes smaller. Therefore, the time required to form a die by powder bed fusion can be shortened and the manufacturing cost of the powder bed fusion can be reduced.

[0075] Furthermore, by making the concave-side one-piece die A and the convex-side one-piece die B from a stainless steel alloy, a titanium alloy, or a nickel alloy, the thermal conductivity and specific heat are smaller than when the concave-side one-piece die A and the convex-side one-piece die B are made from an aluminum alloy, which has a high thermal conductivity and specific heat. This means that thermal energy is less likely to be lost when the die temperature rises and falls, and energy loss can be significantly reduced.

[0076] The above description of the embodiments is given by way of example only and is not intended to be limiting, and various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of symbols]

[0077] 1 Foam molding mold 2 Modeling Platform 3 Dispenser 4 Collector 5 Recoater 6 Condenser lens 7 Galvano Mirror 8,9 Lifting device 10 Concave 10A Raw material filling port 10B Release pin opening 11 Concave back member 11A through hole 11B Spiral hole 12 Concave rear space 13 Concave utility space 14 Slit-shaped steam vent 15 Concave side reinforcement member 16 Concave steam supply pipe attachment 16A through hole 16B Spiral hole 17 Concave side cooling water supply pipe attachment 17A through hole 17B Spiral hole 18 Concave drain pipe attachment 18A through hole 18B Spiral hole 19 Concave side forming device body mounting part 20 Convex 21 Convex rear member 22 Convex back space 23 Convex side utility space 24 Slit-shaped steam vent 25 Convex side reinforcement member 26 Steam supply pipe attachment on convex side 26A through hole 26B Spiral hole 27 Convex side cooling water supply pipe attachment 27A through hole 27B Spiral hole 28 Convex drain pipe attachment 28A through hole 28B screw hole 29 Convex side forming device body mounting part 30 Molding space A Concave side integral die B Convex side integral mold C concave structure D Convex structure E Concave side mounting structure F Convex side mounting structure L Laser beam M Intermediate object MP metal powder T10 concave thickness T11 Thickness of rear part on concave side T20 Convex thickness T21 Thickness of rear part on convex side

Claims

1. A method for manufacturing a mold for molding a foamed synthetic resin in a molding space between a concave mold and a convex mold, comprising the steps of: The mold includes a double-structured concave integral mold and a convex integral mold, the concave-side integral die includes a concave-side structure formed by integrating the concave mold with a concave-side back surface member having substantially the same shape as the concave mold and facing the back surface of the concave mold with a required gap therebetween to provide a concave-side back surface space, the concave-side back surface space being a concave-side utility space; the convex-side integral die includes a convex-side structure formed by integrating the convex mold with a convex-side rear member having substantially the same shape as the convex mold and facing the rear surface of the convex mold with a required gap therebetween to provide a convex-side rear surface space, the convex-side rear surface space being a convex-side utility space; The concave and convex molds have slit-shaped steam holes formed therein, a plurality of concave-side reinforcing members are provided between the concave mold and the concave-side rear surface member, the concave-side reinforcing members connecting the concave mold and the concave-side rear surface member; Between the convex mold and the convex-side rear member, there are a plurality of convex-side reinforcing members connecting them, Spreading metal powder on a build platform to a predetermined layer thickness; A process of melting and solidifying the metal powder by a laser beam using slice data for each lamination thickness converted from 3D model data of the concave-side integral die or the convex-side integral die; By repeating the powder bed fusion process, forming the concave integral mold or the convex integral mold of the shape on the forming platform; A method for manufacturing a foam molding mold.

2. The concave-side integrated die has a concave-side mounting structure in addition to the concave-side structure, The concave side mounting structure includes: a concave-side steam supply pipe mounting portion for mounting a pipe for supplying steam into the concave-side utility space; a recessed-side cooling water supply pipe mounting portion for mounting a pipe for supplying cooling water into the recessed-side utility space; and a recessed-side drain pipe mounting portion for mounting pipes for discharging the drain generated by cooling the steam and the cooling water drain from the recessed-side utility space; and a concave-side molding device body mounting portion for mounting the concave-side integrated mold to a molding device body; is formed, The convex-side integrated die has a convex-side mounting structure in addition to the convex-side structure, The convex mounting structure includes: a convex-side steam supply pipe mounting portion for mounting a pipe for supplying steam into the convex-side utility space; a convex-side cooling water supply pipe mounting portion for mounting a pipe for supplying cooling water into the convex-side utility space; and a convex-side drain pipe mounting portion for mounting a pipe for discharging the drain generated by cooling the steam and the cooling water drain from the convex-side utility space; and a convex-side molding device body attachment portion for attaching the convex-side integral mold to a molding device body; is formed, A method for producing the foam molding mold according to claim 1.

3. The metal powder is a powder of a stainless steel alloy, a titanium alloy, or a nickel alloy, the thickness of the concave mold and the concave-side rear member, and the thickness of the convex mold and the convex-side rear member are 1 mm or more and 3 mm or less; A method for producing the foam molding mold according to claim 1 or 2.

4. A mold for molding a foamed synthetic resin in a molding space between a concave mold and a convex mold, It includes a double-structure concave integral die and a convex integral die, the concave-side integral die includes a concave-side structure formed by integrating the concave mold with a concave-side back surface member having substantially the same shape as the concave mold and facing the back surface of the concave mold with a required gap therebetween to provide a concave-side back surface space, the concave-side back surface space being a concave-side utility space; the convex-side integral die includes a convex-side structure formed by integrating the convex mold with a convex-side rear member having substantially the same shape as the convex mold and facing the rear surface of the convex mold with a required gap therebetween to provide a convex-side rear surface space, the convex-side rear surface space being a convex-side utility space; The concave and convex molds have slit-shaped steam holes formed therein, a plurality of concave-side reinforcing members are provided between the concave mold and the concave-side rear surface member, the concave-side reinforcing members connecting the concave mold and the concave-side rear surface member; Between the convex mold and the convex-side rear member, there are a plurality of convex-side reinforcing members connecting them, The concave-side integrated die has a concave-side mounting structure in addition to the concave-side structure, The concave side mounting structure includes: a concave-side steam supply pipe mounting portion for mounting a pipe for supplying steam into the concave-side utility space; a recessed-side cooling water supply pipe mounting portion for mounting a pipe for supplying cooling water into the recessed-side utility space; and a recessed-side drain pipe mounting portion for mounting pipes for discharging the drain generated by cooling the steam and the cooling water drain from the recessed-side utility space; and a concave-side molding device body mounting portion for mounting the concave-side integrated mold to a molding device body; is formed, The convex-side integrated die has a convex-side mounting structure in addition to the convex-side structure, The convex mounting structure includes: a convex-side steam supply pipe mounting portion for mounting a pipe for supplying steam into the convex-side utility space; a convex-side cooling water supply pipe mounting portion for mounting a pipe for supplying cooling water into the convex-side utility space; and a convex-side drain pipe mounting portion for mounting a pipe for discharging the drain generated by cooling the steam and the cooling water drain from the convex-side utility space; and a convex-side molding device body attachment portion for attaching the convex-side integral mold to a molding device body; is formed, Foam molding mold.

5. the concave-side integral die and the convex-side integral die are made of a stainless steel alloy, a titanium alloy, or a nickel alloy; the thickness of the concave mold and the concave-side rear member, and the thickness of the convex mold and the convex-side rear member are 1 mm or more and 3 mm or less; The foam molding mold according to claim 4.

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