JP2018176473A - Foam formation molding die and method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam formation apparatus including a foam formation molding die, the apparatus being capable of shortening a period of time necessary to cool down the foam formation molding die in a foam formation cycle.SOLUTION: In a foam formation molding die 30 used in a foam formation apparatus of this invention, a rear face side 3b of a forming face 3a that forms at least a formation cavity is made a face on which protruded strips 20 are arranged consecutively. Because of the protruded strips 20, a surface area increases, which increases cooling effect. By molding the foam formation molding die by using a 3D printer 50 of an arc-welding method type, it is possible to produce the foam formation molding die 30 of this shape easily and at low cost.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foam mold and a method of manufacturing the same.

  It has been practiced to foam prefoamed particles (beads) in a foam molding cavity to form a foam. As described in Patent Document 1 and Patent Document 2 etc., for such foam molding, a foam molding apparatus 1 as schematically shown in FIG. 5 is generally used. The foam molding apparatus 1 has a pair of foam molding molds 2 and 3, and the foam molding molds 2 and 3 are fixed to the machine frames 4 and 5 so as to face each other. . A large number of steam holes 6, 7 are formed in each of the foam molding molds 2, 3.

  As shown in FIG. 5, when the foam molding molds 2 and 3 are in a closed state, a molding cavity 10 which is a space for foam molding is formed therebetween. Then, prefoamed particles are filled from the raw material feeder 11 into the molding cavity 10.

  In the foam molding molds 2 and 3, the molding surfaces 2a and 3a forming the molding cavity 10 and the back surfaces 2b and 3b on the back surface side are both flat surfaces. Further, steam chambers 8 and 9 are provided between the back surfaces 2 b and 3 b and the machine frames 4 and 5. Then, the heated steam is supplied to the steam chambers 8 and 9 from the steam supply port 12 or 13. The supplied heated steam enters the molding cavity 10 from the steam chamber 8 or 9 to foam and partially melt the pre-expanded particles filled in the molding cavity 10. As a result, a foam molded body in which foam particles are fused to each other is formed in the cavity 10.

  Thereafter, cooling water is supplied into the steam chambers 8 and 9 from water pipes 14 and 15 etc. disposed in the steam chambers 8 and 9, and the molds 2 and 3 for foam molding are cooled by the cooling water. In addition, if necessary, the pressure in the steam chambers 8 and 9 is reduced to evaporate the attached water of the foam molding molds 2 and 3 and the moisture in the cavity 10, and the heat of vaporization at that time causes the foam molding mold. 2 and 3 are further cooled together with the foam in the cavity 10. After cooling, the pair of foam molding molds 2 and 3 are opened, and the foam molded body is taken out. This completes one cycle of foam molding.

  On the other hand, as described in Non-Patent Document 1, development of a 3D printer by an arc welding method has progressed as a technique for manufacturing an appropriate three-dimensional model, and has reached a practical application area.

Japanese Patent Application Laid-Open No. 11-953 Unexamined-Japanese-Patent No. 11-309734

Hidekazu Murata "Development of High-Speed, High-Strength, Low-Cost Metal 3D Printer" Value Arc MA5000-S1 "Using Arc Welding" Nikkan Kogyo Shimbun "New Technology" Feb. 2016

  In the above-described normal foam molding cycle, the time required for cooling the foam mold is the time required for filling the pre-foamed particles, and the time required for heating the filled pre-foamed particles to cause foaming and mutual fusion. Generally longer than. Although it is required to reduce the time required for one foam molding cycle, the current situation is that the long mold cooling time is a bottleneck and the request for time reduction has not been adequately answered.

  The present invention has been made in view of the above-mentioned situation, and in a foam molding apparatus provided with a foam molding mold, the foam which can shorten the time required for cooling the foam molding mold in the foam molding cycle. It is an object of the present invention to provide a molding die and a foam molding apparatus provided with the foam molding die. Another object of the present invention is to provide a method for producing such a foam molding die.

  The mold for foam molding according to the present invention is a mold for foam molding used in a foam molding apparatus, and at least the back surface side of the molding surface forming the molding cavity is a surface on which the ridges are continuous. It features.

  In the foam molding die according to the present invention, the width of the ridges is not particularly limited, but preferably the width of one ridge is 1 mm to 10 mm.

  The foam molding apparatus according to the present invention is characterized by comprising at least the above-described foam mold.

  In addition, the method of manufacturing a foam molding die according to the present invention is characterized in that the manufacturing process includes a step of forming using a 3D printer by an arc welding method.

  In the foam molding die according to the present invention, at least the back surface side of the molding surface forming the molding cavity is a surface on which the convex streaks are continuous. For this reason, the area in contact with the coolant, which is, for example, cooling water, is increased as compared with the foam molding mold in which the back surface is simply a flat surface. As a result, the time required for cooling can be shortened as compared with the conventional mold for foam molding in which the back surface is simply a flat surface, and as a result, the foam molding provided with the foam mold according to the present invention The device allows the time required for a single foam molding cycle to be reduced compared to conventional devices.

  In general, when forming a three-dimensional model with a 3D printer by the arc welding method, the formed three-dimensional model has a shape in which convex streaks (beads) having a convex cross section as a whole are stacked in multiple rows. Therefore, by using the arc welding method 3D printer as a means for producing the foam molding die according to the present invention, it is possible to easily and inexpensively produce the foam molding die having a surface in which the ridges are continuous. It becomes.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view for explaining an embodiment of a foam mold according to the present invention. FIG. 7 is a perspective view for explaining another embodiment of the foam mold according to the present invention. The figure for demonstrating the working principle of 3D printer by an arc welding system. A figure explaining an example of a process of manufacturing a foaming mold. The schematic sectional drawing which shows the foam molding apparatus provided with the conventional foam mold.

  Hereinafter, an embodiment of a foam molding die, a foam molding apparatus and a method of manufacturing the foam molding according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a foam mold according to the invention in a perspective view with a cross section. The foam molding mold 30 corresponds to one of the foam molding molds 3 of the foam molding molds 2 and 3 described based on FIG. 5, and is a thin metal product as a whole. is there. Although the description is omitted, the technical matters of the present invention can be applied to the other pair of foam molding molds 2 as in the case of the foam molding mold 30.

  In this example, the foam molding mold 30 has a recess that forms one side of the molding cavity 10 described above, and the recess is configured of a flat bottom surface 31 and a circumferential side wall 32 rising from its four turns Be done. A mounting flange 33 extends outward from the upper end of the circumferential side wall 32.

  The bottom surface 31 forming the concave portion and the molding surface 3a which is the inner surface of the circumferential side wall 32 and the rear surface 3b which is the outer surface are not flat surfaces, but many have a lateral width of about 1 mm to 3 mm. Projected ridges 20 are formed in a row. The front and back surfaces of the mounting flange 33 are flat. Further, appropriate numbers of through holes are formed as steam holes 7 in the bottom surface 31 and the circumferential side wall 32.

  The above-described foam molding mold 30 is attached to the foam molding mold 3 of the usual foam molding apparatus 1 described with reference to FIG. Further, although not shown, a foam molding mold 30A (not shown) in which a large number of ridges 20 are formed in the same manner on the molding surface 2a and the back surface 2b of the other foam molding mold 2 is shown. Change to the mold 2 and attach. In that state, foam molding is performed in the same manner as in the conventional method.

  In the foam molding apparatus provided with the above-described foam molding molds 30 and 30A, the steps of filling the pre-foamed particles and heating the foamed pre-foamed particles to foam and mutually fuse them are the conventional foam molding devices. It can be done in the same way. The time it takes them is the same. In the foam molding apparatus provided with the foam molds 30, 30A according to the present invention, the time required for the process of cooling the next mold is shortened.

  That is, the surface that comes in contact with a coolant such as cooling water in the cooling cycle, that is, the surface area of the back surface 3b of the foam molding die 30 and the back surface of the foam molding die 30A is the conventional foam molding in which the back surface is flat. The difference between the surface area of the curved surface portion of the ridge 20 and the bottom area is larger than the surface area of the back surface of the molds 2 and 3. As a result, it is possible to shorten the time required for cooling the foam molds 30, 30A and the foam. By this time reduction, it is possible to shorten the foam molding cycle. In some cases, one of the molding dies, for example, only the molding die 3 in FIG. 5 is used as a foam molding die 30 having a shape provided with the convex streaks 20 shown in FIG. The mold 2 can also be subjected to foam molding as a mold having a conventional shape, that is, a foam molding mold 2 having a shape without the ridges 20.

  In the foam mold, the width of the ridge 20 is not particularly limited, but it is practical to be 1 mm to 10 mm. A ridge less than 1 mm wide is difficult to manufacture, and a ridge exceeding 10 mm wide does not provide an increase in surface area to affect the cooling effect. Note that all the ridges may have the same width, or may have different widths. According to the type of resin used for the foam molding, the shape of the foam molded article, etc., an experimentally optimum one may be set. The cross-sectional shape of the ridges 20 is preferably a smooth curve such as a part of a circle or a part of an ellipse. The height of the ridges 20 is preferably about 2 mm to 3 mm.

  In the case of using the foam molding mold 30 shown in FIG. 1, the surface of the molded foam molded article has the concave streaks to which the convex streaks 20 are transferred. When a foam molded article having a flat surface is desired, as shown in FIG. 2, a foam molding die 30 is used in which the inner side surface 3 a to be a molding surface of the molding cavity 10 is a flat surface. .

  The foam molding mold 30 shown in FIGS. 1 and 2 can be manufactured by an appropriate method. Even if conventional molding molds 2 and 3 for foam molding having flat front and back surfaces are subjected to post processing such as cutting at necessary places to form convex streaks 20. Good. Another suitable manufacturing method is a manufacturing method using a 3D printer by arc welding.

  FIG. 3 illustrates the operating principle of the arc welding type 3D printer 50. As illustrated, a metal wire 51 having a diameter of about 1 mm continuously supplied from a feeder is fed into a welding torch 52 to which shield gas is fed. A welding power source 53 applies a positive potential to the metal wire 51 to generate an arc discharge with the underlying substrate 54. The heat from the discharge melts the metal wire 51 and drops it on the substrate 54. By appropriately moving the welding torch 52 by NC control, the molten dripped metal draws a linear locus (bead) on the substrate 54. A three-dimensional model is formed by laminating the beads in multiple stages.

  By using the 3D printer 50 by the above arc welding method and creating a control program according to the shape to be shaped, and appropriately moving the welding torch 52 by NC control, the foam molding mold is three-dimensionally shaped be able to. Then, since the shaped article is a layered product of linear beads as described above, the surface and the back surface of the shaped article are a continuous surface in which a large number of convex streaks form a row. The ridges formed by the beads can be used as the ridges 20 on the molding surface 3a and the back surface 3b of the foam molding die 30 described above and shown in FIG.

  If the mounting flange 33 can not be simultaneously molded due to molding technology, the mounting flange 33 is post-applied by welding or the like to the planar bottom surface 31 and the peripheral side wall 32 rising from its four circumferences. It can also be done. Further, in the case of using the foam molding mold in which the inner side surface 3a as the molding surface of the molding cavity 10 shown in FIG. 2 is a flat surface, after molding by the 3D printer 50, the inner side surface 3a is formed. Mechanical grinding may be applied to form a flat surface.

  FIG. 4 shows another example in which the foam molding mold 30 shown in FIG. 1 is manufactured (shaped) using the 3D printer 50 by the arc welding method. Here, first, a flat plate-like member is formed on the substrate 54 in the longitudinal direction. This flat member is a member corresponding to the bottom surface 31 of the foam molding die 30. Next, a flat plate-like member is arranged horizontally, and this is used as a substrate 54, and a bead by arc welding is continuously laminated around it. The layered product of the beads is a member corresponding to the circumferential side surface 32 of the foam molding die 30.

  In any of the manufacturing methods, after forming, by performing the drilling operation of the steam holes necessary for the bottom surface 31 and the circumferential side surface 32, the mold 30 for foam molding is obtained.

  In the 3D printer by the arc welding method, mild steel, stainless steel, inconel, SKD61, titanium, aluminum, magnesium, nickel alloy, etc. are generally used as a forming metal which is the metal wire 51, but for forming a foam molding die Are preferably metals such as aluminum.

  In fact, using a 3D printer by an arc welding method and using aluminum as a forming metal, a mold having a 300 mm × 200 mm × 200 mm rectangular parallelepiped cavity was produced. In addition, the back surface side of the molding surface which forms the cavity for shaping | molding was made into the surface (The width | variety of one convex strip is 2 mm) which made the convex line continuous, and made the molding surface the grinding | polishing surface.

  A pre-expanded polystyrene resin particle (60 times) is filled in the cavity of an automatic foam bead molding machine (manufactured by Sekisui Koki Mfg. Co., Ltd., trade name "Ace 3 type") equipped with the produced mold, and the gauge pressure is 0.040 MPa. The heat molding was carried out with steam of 1. for one second heating, 4 seconds for opposite heating, and 3 seconds for double-sided heating (total heating time 11 seconds). Next, after the foam in the cavity of the mold was water-cooled for 10 seconds, it was allowed to cool for 40 seconds under reduced pressure (cooling step) to obtain a foam molded body (molding cycle 90 seconds).

  On the other hand, in order to obtain a foamed molded product of the same quality (appearance) as the foamed molded product using a general casting mold, one-sided heating 4 seconds, opposite one-sided heating 4 seconds, double-sided heating 12 seconds (total heating time The heat molding was performed for 20 seconds, the foam in the cavity of the mold was water-cooled for 10 seconds, and then 60 seconds of cooling (cooling step) under reduced pressure was required (molding cycle: 120 seconds).

  From the above, it was confirmed that the molding cycle can be improved by using the foam molding die of the present invention.

1 ... foam molding device,
2, 3 ... Mold for foam molding,
8, 9 ... steam room,
10 ... molding cavity,
11 ... Raw material feeder,
30. Mold for foam molding according to the present invention,
3a ... molding surface which is the inner side,
3b ... back side of molding surface,
31 ... bottom 31,
32 ... peripheral side wall,
33 ... Mounting flange,
20 ... a ridge formed on the back side of the molding surface forming at least the molding cavity,
50 ... 3D printer by arc welding method,
51 ... metal wire,
52: Welding torch,
53 ... welding power supply,
54 ... substrate.

Claims (4)

  1. A foam molding mold for use in a foam molding apparatus, wherein at least the back surface side of the molding surface forming the molding cavity is a surface on which the convex streaks are continuous.   A mold for foam molding characterized in that the width of one ridge is 1 mm to 10 mm.   A foam molding apparatus comprising at least the foam mold according to claim 1 or 2.   A method for producing a foam molding die, wherein a part of the production process includes a step of forming using a 3D printer by an arc welding method.

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