Core and molding method using core

Abstract

To provide a core that can be used repeatedly.SOLUTION: A core 3 includes: a soft core 5 that comes into contact with a raw material; and a hard core 4 that is arranged inside the soft core 5 and reinforces the soft core 5. The soft core 5 and the hard core 4 are provided with a soft resin and a hard resin. At the time of demolding, the hard core 4 is removed from the soft core 5, and the soft core 5 is deformed to remove it from a molded body 6. The hard core 4 and the soft core 5 are reused.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a core and a molding method using the core. [Background technology]

[0002] When manufacturing refractory precast blocks, ceramic products, precast concrete, etc., a green body is formed. The green body is formed by pouring raw materials into a mold, releasing the mold after the raw materials have hardened, and then drying or firing the green body as necessary.

[0003] Conventionally, the main types of molds used are metal molds, wooden molds, and foam molds. Sometimes a combination of these is used, with the outer frame being a metal mold and the core being a foam mold. Molds have the advantage of being permanent and reusable, but they also have the disadvantage of requiring storage space and being heavy and difficult to handle. Wooden patterns have the advantage of being semi-permanent and can be reused multiple times, and are lighter than metal molds, but have the disadvantage of requiring storage space. The foam mold has the disadvantage that it is a mold that can only be used once because it is melted and released, but it has the advantage that it does not require storage space and is lightweight. In recent years, with the spread of 3D printers, the use of 3D printers to produce resin molds has been considered. Resin molds produced by 3D printers are promising for use in producing molds with complex shapes, similar to foam molds.

[0004] When a precast block or the like is cylindrical with a bottom (i.e., crucible-shaped) or tubular, a mold called a core is placed inside the outer frame. Patent Document 1 discloses a molding method using a core in slip casting (i.e., slip casting), in which a hard core and a flexible, stretchable resin core are placed inside an outer frame made of a metal mold and a plaster mold, slurry as a raw material is poured into the outer frame, and after the slurry has hardened, the hard core is pulled out from the molded body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-77222 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the molding method described in Patent Document 1, the molded body is dried while the flexible and stretchable resin core is still attached, and the resin core is softened, melted, and removed, which presents a problem in that the resin core cannot be reused.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to provide a core that can be used repeatedly and a molding method using the core. [Means for solving the problem]

[0008] In order to solve the above problems, one aspect of the present invention is a core comprising a soft core that comes into contact with the raw material, and a hard core that is placed inside the soft core and reinforces the soft core, the soft core and the hard core comprising a soft resin and a hard resin, or a resin and a metal, and at the time of demolding, the hard core is removed from the soft core and deformed to remove it from the molded body, allowing the soft core and the hard core to be reused.

[0009] In one aspect of the present invention, the soft core and the hard core may comprise a soft resin and a hard resin, or the soft core and the hard core may comprise a resin and a metal.

[0010] Another aspect of the present invention is a molding method using a core, in which raw material is poured into an outer frame provided with the core, and after the raw material hardens, the hard core is removed from the soft core, and the soft core is deformed to remove it from the molded body. [Effects of the Invention]

[0011] According to the present invention, the hard core and the soft core can be used repeatedly. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1(a) is a cross-sectional view of a core according to a first embodiment of the present invention, and FIG. 1(b) is a cross-sectional view showing the process of pouring monolithic refractories into an outer frame. [Figure 2] FIG. 10 is a cross-sectional view showing a step in which the outer frame is released from the mold. [Figure 3] FIG. 10 is a cross-sectional view showing the step of releasing the hard core. [Figure 4] FIG. 10 is a cross-sectional view showing the step of releasing the soft core. [Figure 5] FIG. 4 is a cross-sectional view of a core according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view of a core according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a core and a molding method using a core according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the core and the molding method using a core according to the present invention can be embodied in various forms and are not limited to the embodiments described herein. The present embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by providing sufficient disclosure in the specification.

[0014] (First embodiment) 1 to 4 show process diagrams of a molding method using a core according to a first embodiment of the present invention. The core 3 of the first embodiment is used to mold a compact 6 in the shape of a crucible.

[0015] As shown in FIG. 1(a), an outer frame 2 is placed on a table 1, and a core 3 having a hard core 4 and a soft core 5 is placed inside the outer frame 2. The outer frame 2 may be a metal mold, a wooden mold, a foam mold, or a resin mold produced with a 3D printer.

[0016] The soft core 5 is used in the part that comes into contact with the monolithic refractory. The soft core 5 is cylindrical with a bottom and forms the inner peripheral surface and bottom surface (the ceiling surface in Figure 1(a)) of the crucible-shaped precast block. Only the soft core 5 comes into contact with the monolithic refractory, and the hard core 4 does not. The soft core 5 comprises a soft resin such as TPU (thermoplastic polyurethane elastomer) that has rubber-like elasticity. The soft core 5 may be made of a single type of resin, or may comprise two or more types of resin.

[0017] The soft core 5 is preferably manufactured using a 3D printer, as this is possible with complex shapes and can be manufactured in a short period of time. 3D printing, also known as additive manufacturing, is a process of creating an object from a numerical representation of a three-dimensional shape by attaching material. The additive manufacturing method used in 3D printers is not particularly limited, but the FDM method, for example, can be used. In the FDM method, reel-shaped plastic is melted with heat and then stacked in a single stroke like ice cream to create the desired shape.

[0018] The hard core 4 is placed inside the soft core 5 to reinforce the soft core 5. A hole 5a having substantially the same shape as the hard core 4 is formed in the soft core 5. The hard core 4 is fitted into the hole 5a of the soft core 5. Since deformation and fixation are difficult with the soft core 5 alone, the soft core 5 is reinforced by the hard core 4. The hard core 4 may be solid (for example, cylindrical) or hollow (for example, tubular) as long as it can reinforce the soft core 5. When manufacturing the hard core 4 using a 3D printer, the hard core 4 may have a honeycomb structure covered with walls.

[0019] The hard core 4 comprises a hard resin that is harder than the soft core 5. The hard resin is PLA resin (polylactic acid), ABS resin (acrylonitrile butadiene styrene resin), etc. The hard core 4 may be made of a single type of resin, or may comprise two or more types of resin. It is desirable that the hard core 4 is also manufactured using a 3D printer. The hard core 4 may also be made of metal such as steel.

[0020] Next, as shown in FIG. 1(b), a monolithic refractory 6 is poured into the outer frame 2 as a raw material. The monolithic refractory 6 contains refractory raw materials and a binder. The monolithic refractory 6 is then hardened. The monolithic refractory 6 may be pressurized by hydrostatic pressure or the like. Alternatively, the monolithic refractory 6 may be heat-treated and dried while the core 3 and / or the outer frame 2 are still attached to the monolithic refractory 6. After the monolithic refractory 6 has hardened, the outer frame 2 is released from the mold as shown in FIG.

[0021] Next, the core 3 is demolded as shown in Figures 3 and 4. When demolding the core 3, first, the hard core 4 is removed from the soft core 5 as shown in Figure 3. Then, as shown in Figure 4, the soft core 5 with the hard core 4 removed is deformed to remove it from the monolithic refractory molded body 6. Because the soft core 5 is formed thin and comprises a soft resin, it can be easily deformed. For this reason, the soft core 5 can be removed from the molded body 6 even without a draft taper. After the core 3 is demolded, the outer frame 2 may also be demolded. The released hard core 4 and soft core 5 are reused, and the steps of FIGS. 1 to 4 are repeated.

[0022] Next, the released molded body 6 is heat treated as needed to dry and / or sinter. Because the hard core 4 and the soft core 5 are removed from the molded body 6, it is possible to prevent the molded body 6 from cracking due to thermal expansion of the hard core 4 and the soft core 5 during drying and / or sintering. In this way, a crucible-shaped precast block is manufactured.

[0023] (Second embodiment) 5 shows a core 3 according to a second embodiment of the present invention. Reference numeral 1 denotes a table, reference numeral 2 denotes an outer frame, reference numeral 4 denotes a hard core, reference numeral 5 denotes a soft core, and reference numeral 6 denotes a monolithic refractory.

[0024] The core 3 of the second embodiment is used to mold a cylindrical molded body 6. The soft core 5 is formed in a hollow cylindrical shape. A substantially cylindrical solid hard core 4 is fitted into the through hole 5a of the soft core 5. A cylindrical precast block can be manufactured using the core 3 of the second embodiment through the same steps as those shown in Figures 2 to 4.

[0025] (Third embodiment) 6 shows a core 3 according to a third embodiment of the present invention. Reference numeral 1 denotes a table, reference numeral 2 denotes an outer frame, reference numeral 4 denotes a hard core, reference numeral 5 denotes a soft core, and reference numeral 6 denotes a monolithic refractory.

[0026] The core 3 of the third embodiment is used to mold a cylindrical molded body 6 having a step on the inner surface. The hard core 4 and soft core 5 are formed into a hollow cylindrical shape. A step is formed on the outer peripheral surface of the soft core 5. A draft taper 5b is formed on the inner peripheral surface of the soft core 5.

[0027] A draft taper 4b is formed on the outer peripheral surface of the hard core 4. The inner peripheral surface of the hard core 4 is formed into a cylindrical shape. Using the core 3 of the third embodiment and going through the same steps as those shown in Figures 2 to 4, a cylindrical precast block with a step on the inner surface can be manufactured.

[0028] In the case of a cylindrical molded body 6 with steps on the inner surface, it is difficult to release the core 3 from the mold, but if the core 3 is made up of a hard core 4 and a soft core 5, and the hard core 4 is removed first, then the soft core 5 is removed, the core 3 can be easily released from the mold. In addition, by forming the hard core 4 and the soft core 5 hollow, the amount of resin used can be reduced.

[0029] In the above embodiment, an example of forming a precast block molded body has been described, but the molded body may be a ceramic product molded body or a precast concrete molded body. [Explanation of symbols]

[0030] 2...Outer frame 3…Middle child 4…Hard core 5… Soft neutron 6…Irregular refractory materials (shaped bodies)

Claims

1. A soft core that comes into contact with the raw material, a hard core disposed inside the soft core to reinforce the soft core, The soft core and the hard core comprise a soft resin and a hard resin, or a resin and a metal, At the time of demolding, the hard core is removed from the soft core, and the soft core is deformed to remove the soft core from the molded body; A core that reuses the soft core and the hard core.

2. 2. The core according to claim 1, wherein the raw material is a monolithic refractory.

3. The core according to claim 1 or 2, wherein the soft core and the hard core are manufactured using a 3D printer.

4. 3. The core according to claim 1, wherein the soft core and the hard core are hollow.

5. Pour raw materials into an outer frame provided with the core according to claim 1 or 2, A molding method using a core, in which, after the raw material has hardened, the hard core is removed from the soft core, and the soft core is deformed to remove it from the molded body.

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