Manufacturing method

Abstract

To provide a manufacturing method that can easily mold a molded product having a more complicated internal shape.SOLUTION: A manufacturing method includes: a core molding step in which a core that can be collapsed in a predetermined manner is formed by a three-dimensional molding method; a molded product molding step of placing the core molded in the core molding step together with a molding material inside a mold, and molding a molded product using the mold after the core and the molding material have been placed inside; and a core removing step of disintegrating and removing the core contained in the molded product molded in the molded product molding step by the predetermined method.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This disclosure relates to methods of manufacture. [Background technology]

[0002] Research and development is being conducted into casting using casting cores.

[0003] In this regard, a method for molding a core for casting by inkjet three-dimensional modeling is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-131948 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the method described in Patent Document 1, when casting a molded product having a shape that is difficult to split or has an undercut shape, it can be difficult to remove the core from the molded product. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present disclosure is a manufacturing method including: a core molding step of molding a core that can be disintegrated by a predetermined method by a three-dimensional modeling method; a molded product molding step of placing the core molded by the core molding step together with a molding material inside a mold and molding a molded product using the mold after the core and the molding material have been placed inside; and a core removal step of disintegrating and removing the core contained in the molded product molded by the molded product molding step by the predetermined method. [Brief description of the drawings]

[0007] [Figure 1] 1A to 1C are diagrams illustrating an example of a flow of a manufacturing method according to an embodiment. [Diagram 2] FIG. 13 is a diagram showing an example of a mold formed in a molding step in step S140. [Diagram 3] FIG. 11 is a diagram showing an example of a core formed in a process of forming a core in step S140. [Figure 4] 4 is a diagram showing an example of a state in which the core C1 shown in FIG. 3 is arranged in a space formed between the mold M1 and the mold M2 shown in FIG. 2. FIG. [Diagram 5] FIG. 2 is a diagram showing an example of a molded product MD molded by injection molding using the mold after a core C1 and a molding material are placed inside. [Figure 6] 1 is a diagram showing an example of a molded product MD after a core C1 has been removed. FIG. [Figure 7] FIG. 13 is a diagram showing another example of a core formed in the process of forming a core in step S140. [Figure 8] FIG. 8 is a diagram showing an example of a molded product molded by injection molding using the core C2 shown in FIG. 7. [Figure 9] 9 is a cross-sectional view of the molded product MD2 shown in FIG. 8 cut in half. FIG. [Figure 10] FIG. 13 is a diagram showing still another example of a core molded in the process of molding the core in step S140. [Figure 11] FIG. 11 is a diagram showing an example of a molded product produced by injection molding using the core C3 shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Embodiment> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0009] <Production method overview> First, an overview of the manufacturing method according to the embodiment will be described.

[0010] The manufacturing method according to the embodiment includes a core molding step, a molded product molding step, and a core removal step. The core molding step is a step of molding a core that can be disintegrated by a predetermined method using a three-dimensional modeling method. The molded product molding step is a step of placing the core molded by the core molding step together with a molding material inside a mold, and molding a molded product using the mold after the core and molding material are placed inside. The core removal step is a step of disintegrating and removing the core contained in the molded product molded by the molded product molding step using the predetermined method.

[0011] As a result, the manufacturing method according to the embodiment can easily mold a molded product having a more complicated internal shape.

[0012] The manufacturing method according to the embodiment will be described in detail below.

[0013] <Production process flow> Hereinafter, the flow of the manufacturing method according to the embodiment will be described with reference to FIG.

[0014] 1 is a diagram showing an example of a flow of a manufacturing method according to an embodiment. For convenience of explanation, in the following, a person who manufactures a molded product by the manufacturing method according to an embodiment will be simply referred to as a manufacturer.

[0015] First, the manufacturer selects an object to be manufactured as a molded product (step S110). In the following, as an example, a case where the object is a hollow plastic gear will be described. For this reason, in FIG. 1, the process of step S110 is indicated by "selection of parts." Note that the object may be an everyday item such as an accessory instead of an industrial product such as a plastic gear.

[0016] Next, the manufacturer determines the shape of the molded product (step S120). Specifically, in the process of step S120, the manufacturer derives the three-dimensional shape of the molded product by generative design based on constraint conditions such as a weight reduction target value, an allowable displacement amount, an applicable material, a constraint condition, a loading condition, and a designable area. For example, in step S120, the manufacturer derives the three-dimensional shape of the molded product by generative design by performing the following process. The manufacturer performs topology optimization of the shape of the molded product using the constraint conditions and software for topology optimization among software for performing generative design. After that, the manufacturer performs shape optimization of the shape of the molded product using the constraint conditions and software for shape optimization among software for performing generative design. By performing the above process, the manufacturer derives the three-dimensional shape of the molded product by generative design in step S120. Then, the manufacturer determines the derived three-dimensional shape as the shape of the molded product. In FIG. 1, the process of step S120 is indicated by "determining the shape of the molded product."

[0017] Next, the manufacturer determines the three-dimensional shapes of the mold necessary for molding the molded product having the shape determined in step S120 and the core to be placed inside the mold (step S130). At this time, the manufacturer determines the three-dimensional shapes of the mold and the core so that an opening connecting the outside of the molded product to the core is formed in the molded product.

[0018] Next, the manufacturer molds the mold and the core having the three-dimensional shape determined in step S130 by a predetermined three-dimensional modeling method (step S140). For the sake of convenience, the predetermined three-dimensional modeling method will be referred to as a target three-dimensional modeling method below. Here, the process of step S140 will be described.

[0019] In step S140, the manufacturer uses a target three-dimensional modeling method to mold a core that can be disintegrated by a predetermined method. The predetermined method is, for example, flowing water into the molded product from an opening formed in the molded product. In this case, in step S140, the manufacturer molds the core using a water-soluble binder. If the particles that make up the core are bound together by a water-soluble binder, the bonds will break when exposed to water. Therefore, when water is allowed to flow into the molded product from the opening, the core located inside the molded product will disintegrate.

[0020] The predetermined method may be, for example, applying an external impact to the molded product. In this case, the binder used to bond the particles that make up the core in step S140 may be any binder as long as the binder can be broken by an external impact. In this case, the manufacturer can collapse the core contained in the molded product by applying an external impact to the molded product. For example, the manufacturer can apply an external impact to the molded product by striking, ultrasonic waves, or the like. The manufacturer may apply an external impact to the molded product by other methods.

[0021] Also, in step S140, the manufacturer molds the mold and the core by, for example, a binder jet type three-dimensional modeling method. For example, in step S140, the manufacturer molds the mold and the core using a binder jet type 3D (Dimension) printer. This allows the manufacturer to mold the mold and the core using a desired binder. As a result, the manufacturer can mold a core that can be disintegrated by a predetermined method. This is difficult to achieve with an inkjet type three-dimensional modeling method. Note that the manufacturer may mold the mold and the core by another type of three-dimensional modeling method that can mold a core that can be disintegrated by a predetermined method. The process of molding the core in step S140 may be referred to as a core molding process.

[0022] After the process of step S140 is performed, the manufacturer places the core molded in step S140 together with the molding material inside the mold molded in step S140, and molds a molded product using the mold after the core and molding material are placed inside (step S150). For example, in step S150, the manufacturer molds a molded product by injection molding using the mold after the core and molding material are placed inside. Note that in step S150, the manufacturer may mold a molded product by another method using the mold after the core and molding material are placed inside. The process of step S150 may be referred to as a molded product molding process.

[0023] Next, the manufacturer disintegrates and removes the core contained in the molded product molded in step S150 by the above-mentioned predetermined method (step S160). The process of step S160 may be referred to as a core removal process.

[0024] Next, the manufacturer performs a finishing process on the molded product after the core is removed in step S160 (step S170). The finishing process is, for example, cutting using a machining center or the like, buffing, etc., but is not limited to these. After the process of step S170 is performed, the manufacturer ends the process of the flowchart shown in Fig. 1. Note that in this flowchart, the process of step S170 may be omitted.

[0025] As described above, the manufacturing method according to the embodiment includes a core molding step of molding a core that can be collapsed by a predetermined method by a three-dimensional modeling method, a molded product molding step of placing the core molded by the core molding step together with a molding material inside a mold and molding a molded product using the mold after the core and molding material are placed inside, and a core removal step of collapsing and removing the core contained in the molded product molded by the molded product molding step by a predetermined method. This manufacturing method allows the molding of molded products having more complicated internal shapes to be easily performed.

[0026] Here, FIG. 2 is a diagram showing an example of a mold molded in the process of molding the mold in step S140. However, FIG. 2 shows a cross-sectional view of the mold cut in half in order to clearly show the internal structure of the mold. The mold M1 shown in FIG. 2 is, for example, a mold on the cavity side in injection molding. Moreover, the mold M2 shown in FIG. 2 is a mold on the core side in injection molding. The mold mold molded in step S140 is composed of two molds, the mold M1 and the mold M2. By fitting the mold M1 and the mold M2 together, a space is formed between the mold M1 and the mold M2 in which a core is placed together with the molding material, as shown in FIG. 2.

[0027] The mold M2 has a recess CN formed therein. The recess CN is a recess for forming an opening that connects the outside of the molded product with the core.

[0028] Figure 3 is a diagram showing an example of a core C1 formed in the process of forming a core in step S140. However, in order to clearly show the internal structure of core C1, Figure 3 shows a cross-sectional view of the molding die broken in half. The particles that make up core C1 shown in Figure 3 are bound by a water-soluble binder. For this reason, core C1 disintegrates when exposed to water, as described above.

[0029] A protrusion CV is formed on the core C1. When the core C1 is placed in the space formed between the dies M1 and M2, the protrusion CV is a portion that fits into the recess CN formed in the die M2 shown in Fig. 2, as shown in Fig. 4. Fig. 4 is a diagram showing an example of the state in which the core C1 shown in Fig. 3 is placed in the space formed between the dies M1 and M2 shown in Fig. 2.

[0030] In injection molding, the molding material is filled into the space between each of the metal mold M1 and the metal mold M2 shown in FIG. 4 and the core C1. Therefore, in injection molding, the molding material is placed together with the core C1 inside the mold formed by the metal mold M1 and the metal mold M2. FIG. 5 is a diagram showing an example of a molded product MD molded by injection molding using the mold after the core C1 and the molding material are placed inside. However, the molded product MD shown in FIG. 5 is a molded product before the process of step S160 is performed. Therefore, the core C1 remains inside the molded product MD shown in FIG. 5 without being removed. Note that FIG. 5 shows a cross-sectional view of the mold and the core C1 split in half to clearly show the internal structure of the mold in which the core C1 is placed.

[0031] As shown in Fig. 5, the molded product MD has a convex portion CV penetrating from the inside of the molded product MD to the outside of the molded product MD. Therefore, an opening HL is formed in the molded product MD. The opening HL is an example of an opening that connects the outside of the molded product to the core.

[0032] For example, when the molded product MD shown in FIG. 5 is submerged in water, the core C1 starts to collapse from the convex portion CV. As a result, water flows into the inside of the molded product MD through the opening HL. This allows the manufacturer to collapse the core C1 located inside the molded product MD. The core C1 thus collapsed flows out of the molded product MD through the opening HL. In this way, the manufacturer can remove the core C1 from inside the molded product MD. FIG. 6 is a diagram showing an example of the molded product MD after the core C1 has been removed. However, FIG. 6 shows a cross-sectional view of the molded product MD cut in half in order to clearly show the internal structure of the molded product MD.

[0033] It was difficult to mold a molded product MD having a cavity inside as shown in Figure 6 by injection molding using a conventional core. This is because if the core is given a strength that is not broken during injection molding, it is difficult to collapse the core inside the molded product MD. In the process of the flowchart shown in Figure 1, the core C1 is molded so that it collapses in a predetermined manner. Therefore, this process solves such a problem.

[0034] Fig. 7 is a diagram showing another example of a core molded in the process of molding a core in step S140. Core C2 shown in Fig. 7 has a shape in which six cylindrical protrusions protrude radially from a sphere. Fig. 8 is a diagram showing an example of a molded product molded by injection molding using core C2 shown in Fig. 7. The molded product MD2 shown in Fig. 8 is a molded product having a spherical shell shape with six openings formed therein. Therefore, for example, liquid can be poured into the interior of molded product MD2. The steps in the flow chart shown in Fig. 1 can easily mold a molded product having a shape like the molded product MD2. This is because the core C2 shown in Fig. 7 collapses in a predetermined manner, just like the core C1. Fig. 9 is a cross-sectional view of the molded product MD2 shown in Fig. 8 when it is cut in half.

[0035] FIG. 10 is a diagram showing yet another example of a core molded in the process of molding a core in step S140. The core C3 shown in FIG. 10 has a shape of a cylinder wound in a spiral shape. FIG. 11 is a diagram showing an example of a molded product molded by injection molding using the core C3 shown in FIG. 10. The molded product MD3 shown in FIG. 11 has a shape of a cylinder wound in a spiral shape. Therefore, for example, a liquid can be poured into the molded product MD3. The process of the flowchart shown in FIG. 1 can easily mold a molded product with a shape like the molded product MD3. This is because the core C3 shown in FIG. 10 collapses in a predetermined manner like the core C1.

[0036] As described above, the manufacturing method according to the embodiment can mold a molded product having a complex internal shape that is difficult to split. As a result, the user of the molded product molded by the manufacturing method can, for example, circulate a refrigerant inside the product to improve the heat resistance temperature of the material in a simulated manner. More specifically, for example, the user can resinify parts that had to be metalized in the past, and can perform high-quality design using the properties of resin. The properties include, for example, lubricity, quietness, etc., but are not limited to these. Therefore, the manufacturing method can release shape constraints for improving the functions of resin parts in various fields, not limited to, for example, resin gears such as the molded product MD. Naturally, the manufacturing method can be applied not only to molded products with shapes that are difficult to split, but also to molding of molded products with undercut shapes.

[0037] Furthermore, the molded product produced by the manufacturing method according to the embodiment is less likely to suffer a significant decrease in mechanical properties compared to the molded product produced by additive manufacturing. In other words, the manufacturing method according to the embodiment can also improve the replication efficiency compared to additive manufacturing.

[0038] The above-described contents may be combined in any manner.

[0039] <Additional Notes> [1] A manufacturing method comprising: a core molding step of molding a core that can be disintegrated by a predetermined method using a three-dimensional modeling method; a molded product molding step of placing the core molded by the core molding step together with a molding material inside a mold and molding a molded product using the mold after the core and the molding material have been placed inside; and a core removal step of disintegrating and removing the core contained in the molded product molded by the molded product molding step using the predetermined method. [2] The manufacturing method described in [1], in which the core molding step molds the core using a water-soluble binder. [3] The manufacturing method described in [2], wherein the molded product has an opening connecting the outside of the molded product with the core, the predetermined method is to flow water from the opening into the inside of the molded product, and the core removal step is to disintegrate the core by flowing water from the opening into the inside of the molded product, and to remove the core from the molded product by flowing the disintegrated core out of the opening. [4] The manufacturing method described in [1], wherein the molded product has an opening that connects the outside of the molded product to the core, the predetermined method is to apply an external impact to the molded product, and the core removal step is to collapse the core by applying the external impact to the molded product and release the collapsed core from the opening, thereby removing the core from the molded product. [5] The manufacturing method described in [4], wherein the predetermined method is to apply the impact to the core by striking or ultrasonic waves. [6] The manufacturing method according to any one of [1] to [5], wherein the molded product molding step is performed by injection molding using the mold after the core and the molding material are placed inside. [7] The manufacturing method according to any one of [1] to [6], wherein the core molding step molds the core by a binder jet type three-dimensional modeling method.

[0040] Although an embodiment of the present disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and may be changed, substituted, deleted, etc. without departing from the gist of this disclosure. [Explanation of symbols]

[0041] C1...core, C2...core, C3...core, CN...concave, CV...convex, DL...opening, HL...opening, M1...mold, M2...mold, MD...molded product, MD2...molded product, MD3...molded product

Claims

1. a core molding process for molding a core that can be disintegrated by a predetermined method using a three-dimensional modeling method; a molded product molding step of placing the core molded in the core molding step together with a molding material inside a mold, and molding a molded product using the mold after the core and the molding material have been placed inside; a core removing step of disintegrating and removing the core contained in the molded product molded in the molded product molding step by the predetermined method; The manufacturing method comprising the steps of:

2. The core molding step molds the core using a water-soluble binder. The method of claim 1 .

3. The molded product has an opening that connects the outside of the molded product with the core, the predetermined method is to cause water to flow into the interior of the molded article through the opening; The core removal step includes disintegrating the core by causing water to flow into the molded product from the opening, and removing the core from the molded product by causing the disintegrated core to flow out of the opening. The method according to claim 2 .

4. The molded product has an opening that connects the outside of the molded product with the core, the predetermined method is to apply an external impact to the molded product; The core removal step includes applying an external impact to the molded product to collapse the core, and releasing the collapsed core from the opening to remove the core from the molded product. The method of claim 1 .

5. The predetermined method is to apply the impact to the core by impact or ultrasonic. The method according to claim 4.

6. The molded product molding step molds the molded product by injection molding using the mold after the core and the molding material are placed inside. The method of claim 1 .

7. The core molding step molds the core by the binder jet type three-dimensional modeling method. The method of claim 1 .

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