Manufacturing method for molding dies and molded products
The molding die with a separable intermediate piece addresses complex molding issues by allowing integral molding and demolding with minimal deformation, enhancing design freedom and material versatility for molded bodies with narrow openings and hollow sections.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KK MATSUZAKI SEISAKUSHO
- Filing Date
- 2024-12-20
- Publication Date
- 2026-07-02
AI Technical Summary
Existing molding techniques for molded bodies with narrow openings and hollow portions are complex, require multiple steps, and often result in material deterioration due to adhesion and joining issues, limiting design flexibility and material choice.
A molding die with a separable intermediate piece made of low-melting-point material is used, allowing for integral molding and demolding with minimal deformation by melting and removing the intermediate piece after molding, eliminating the need for draft tapers and expanding the design freedom.
Enables high-quality, versatile molded articles with narrow openings and hollow sections, reducing material deformation and increasing design flexibility without the need for draft tapers.
Smart Images
Figure 2026110408000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a mold for molding and a method for manufacturing a molded body.
Background Art
[0002] In manufacturing a molded body having a narrow opening and a hollow portion, conventionally, a plurality of parts cut out from a sheet-like material are bonded together by adhesion for molding, or a plurality of molds are used, and the filling and solidification of the molded body raw material are divided into multiple times and molded while being joined. However, the operation steps related to molding are numerous and complicated. In particular, when introducing a fluid (liquid or gas) into the hollow portion through the narrow opening of the molded body, it is difficult to maintain the strength at the adhesion and joining surfaces, which accelerates the deterioration of the molded body and leads to breakage.
[0003] Therefore, for a molded body having a narrow opening and a hollow portion, a molding technique for integrally molding (forming) is required so that no adhesion and joining surfaces are formed. Hereinafter, the molding technique for integrally molding (forming) using a mold is referred to as "one-piece molding". For example, Patent Document 1 discloses a molding method for molding a resin product in which a hollow spherical main body with an opening at one side and a cylindrical neck continuous with the opening of the main body are integrally provided. A core (insert) of a mold in which a spherical portion for molding the main body and a cylindrical column portion for molding the neck are integrally formed is used, and an air passage penetrating through the spherical portion and the column portion is provided. After filling and solidifying the resin material, air injection is performed through the air passage provided in the core (insert), and while elastically deforming the solidified resin material (resin product), it is脱模させることが記載されている。
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] According to Patent Document 1, after integral molding, when demolding the molded body (removing the inner insert), it is necessary to temporarily expand the narrow opening by the width (diameter) of the main body. Therefore, the materials that can be used as molded bodies are limited to those that can undergo elastic deformation, and the range of designs that can be used as molded bodies (especially the diameter of the narrow opening) is restricted.
[0006] Furthermore, to facilitate the smooth release of the molded product, a draft taper (draft angle) is sometimes incorporated into the molding die. In this case as well, however, the shape and dimensions of the molded product are limited.
[0007] Therefore, the object of the present invention is to provide a molding die and a method for manufacturing a molded article that can perform integral molding and release the molded article with minimal deformation, relating to the manufacture of a molded article having a narrow opening and a hollow section. [Means for solving the problem]
[0008] As a result of diligent research into the above-mentioned problems, the inventors of the present invention have found that, in the manufacture of a molded body having a narrow opening and a hollow section, by using an intermediate piece with a separable structure, and after integral molding of the molded body, the intermediate piece can be separated and removed from inside the molded body, thereby enabling integral molding of the molded body and allowing for demolding with minimal deformation of the molded body, thus completing the present invention. In other words, the present invention relates to the following molding die and method for manufacturing a molded article.
[0009] The present invention, which solves the above problems, is a mold for molding a molded body having a narrow opening and a hollow portion, and includes an intermediate piece that forms a space for filling the raw material of the molded body between itself and a mold body having a shape corresponding to the outer shape of the molded body, the intermediate piece having a divisible structure using a low melting point material and a plurality of intermediate piece members, and the melting point of the low melting point material is lower than the melting point of the intermediate piece members and the molded body. According to this feature, the molding die for integrally molding a molded body having a narrow opening and a hollow section is equipped with a divisible inner piece, and this inner piece consists of multiple inner piece components. By using a low-melting-point material with a melting point lower than the melting points of the inner piece components and the molded body, after integral molding, only the low-melting-point material can be melted and removed, and then the inner piece components can be removed from the outside of the molded body through the narrow opening. In other words, instead of demolding the molded body by significantly deforming it, the molded body can be demolded by removing the divided inner piece from inside the molded body, making it possible to obtain a molded body having a narrow opening and a hollow section by integral molding, regardless of the material. Furthermore, there is no need to provide a draft taper in the structure of the molding die, which increases the degree of freedom regarding the shape and dimensions of the molded body.
[0010] Furthermore, in one embodiment of the molding die of the present invention, the intermediate die is characterized by having a structure that has a shape corresponding to the internal shape of the molded body and a hollow portion, achieved by combining a plurality of intermediate die members and fixing them with a low melting point material. This feature allows the intermediate piece itself to have a hollow section, which reduces the number of parts required for the intermediate piece and makes the intermediate piece lighter.
[0011] Furthermore, one embodiment of the molding die of the present invention is characterized in that the molded body is made of a polymer material. This characteristic makes it possible to obtain molded articles with narrow openings and hollow sections that are highly versatile as materials and applicable to various technical fields. In particular, even when using elastically deformable polymer materials, elastic deformation is less likely to occur during demolding, making it possible to provide high-quality molded articles (products).
[0012] Furthermore, in one embodiment of the molding die of the present invention, the intermediate insert member is characterized by comprising an insert member used for removing the molded body from the narrow opening. This feature makes it possible to quickly and easily remove the inner insert (component for the inner insert) from the narrow opening of the molded body after integral molding.
[0013] The present invention, which solves the above problems, is a method for manufacturing a molded body using the above-mentioned molding die, and is characterized by comprising: a middle piece procurement step of procuring a middle piece; a raw material filling step of filling the mold body with raw materials for the molded body between the mold body and the middle piece; a molding step of forming the molded body by solidifying the raw materials for the molded body after the raw material filling step; a low-melting-point material removal step of heating at a temperature that melts only the low-melting-point material after the molding step and removing it from the molded body; and a middle piece removal step of removing the middle piece member from the narrow opening of the molded body after the low-melting-point material removal step. According to this feature, by integrally molding a molded body having a narrow opening and a hollow section using the above-mentioned molding die, it becomes possible to melt and remove only the low-melting-point material after integral molding, and then to remove the inner component through the narrow opening to the outside of the molded body. In other words, instead of demolding the molded body by significantly deforming it, the molded body can be demolded by removing the inner component in a divided state from inside the molded body, making it possible to manufacture molded bodies having a narrow opening and a hollow section by integral molding, regardless of the material, and with a high degree of freedom regarding the shape and dimensions of the molded body. [Effects of the Invention]
[0014] According to the present invention, it is possible to provide a molding die and a method for manufacturing a molded article having a narrow opening and a hollow section, which enable integral molding and allow demolding with minimal deformation of the molded article. [Brief explanation of the drawing]
[0015] [Figure 1] This is a schematic diagram illustrating the structure of a molded article in a first embodiment of the present invention. [Figure 2] This is a schematic diagram showing the overall structure of a molding die in a first embodiment of the present invention. [Figure 3] This is a schematic diagram illustrating the structure of the middle piece in a molding die according to the first embodiment of the present invention. [Figure 4] This is a schematic diagram showing a partial structure of the middle piece of a molding die in the first embodiment of the present invention. [Figure 5]It is an explanatory view showing a part of a process related to a method for manufacturing a molded body using a molding die in a first embodiment of the present invention. [Figure 6] It is a schematic explanatory view showing the structure of a molded body in a second embodiment of the present invention. [Figure 7] It is a schematic explanatory view showing the structure of a core in a molding die in a second embodiment of the present invention.
Embodiments for Carrying Out the Invention
[0016] Hereinafter, embodiments of a molding die and a method for manufacturing a molded body according to the present invention will be described in detail while referring to the drawings. Note that the molding die and the method for manufacturing a molded body described in the embodiments are merely examples for explaining the molding die and the method for manufacturing a molded body according to the present invention, and are not limited thereto.
[0017] 〔First Embodiment〕 [Molded Body] First, the molded body 100A manufactured using the molding die 1A of the present embodiment will be described. As shown in FIG. 1, the molded body 100A of the present embodiment includes a main body 110A having a hollow portion 200A and a narrow mouth portion 120A communicating with the main body 110A. More specifically, examples of the molded body 100A of the present embodiment include those provided with a bag-shaped (balloon-shaped) main body 110A having a substantially spherical shape and a substantially cylindrical narrow mouth portion 120A having a diameter d1 smaller than the maximum width (diameter) of the main body 110A.
[0018] The molded body 100A of the present embodiment preferably has a structure that allows introduction and discharge of a fluid (liquid or gas) to and from the hollow portion 200A via the narrow mouth portion 120A, but is not limited thereto. Furthermore, as an example of the molded body 100A of the present embodiment, those that accompany a volume change of the hollow portion 200A (a shape change of the main body 110A) with the introduction and discharge of a fluid to and from the hollow portion 200A are preferable.
[0019] An example of a molded body 100A is one in which the main body 110A expands overall upon the introduction of fluid into the hollow section 200A. A specific example of such a molded body 100A is a water-stopping ball used to block the water flow inside a water pipe by introducing fluid after insertion into the pipe. In particular, the molded body 100A of this embodiment is manufactured using a molding die 1A described later, which allows for the integral molding of the main body 110A and the narrow opening section 120A, while also allowing for the free setting of the dimensions (diameter d1) of the narrow opening section 120A. This makes it possible to obtain a molded body 100A that maintains sufficient strength during fluid introduction and has a shape that facilitates insertion and installation in a predetermined location (for example, inside a water pipe).
[0020] Another example of a molded body 100A is one that utilizes the fact that applying external pressure to the main body 110A causes the fluid in the hollow section 200A to be discharged as the main body 110A deforms, temporarily reducing the volume of the hollow section 200A. In this case, it is preferable to transfer the fluid temporarily held in the hollow section 200A or to utilize the fluid discharged from the hollow section 200A to act on other structures or mechanisms. Specific examples of such a molded body 100A include droppers and valves in valve syringes that are formed by integral molding.
[0021] The shapes of the main body 110A and the narrow opening 120A in this embodiment are not limited to the shapes shown in Figure 1, but are acceptable as long as they have an integrated structure connected by a hollow section 200A, and the diameter d1 of the narrow opening 120A is smaller than the maximum width (diameter) of the main body 110A. For example, in addition to the approximately spherical shape shown in Figure 1, the main body 110A may be a bag-like (balloon-like) shape with an elliptical or polygonal cross-section, or a shape consisting of complex uneven parts (including curved surfaces). Also, in addition to the approximately cylindrical shape shown in Figure 1, the narrow opening 120A may be a conical or polygonal cylindrical shape.
[0022] The material of the molded body 100A can be any material formed by filling the molding die 1A (described later) with the raw material M for the molded body and then allowing it to solidify. Examples include materials used in the industrial field or materials used in the food industry. The molded body 100A in this embodiment is preferably made of a polymer material, more specifically, a resin or rubber. This makes it possible to obtain a molded body 100A having a narrow opening and a hollow portion that is highly versatile and applicable to various technical fields. Furthermore, a particularly preferred example of the molded body 100A in this embodiment is that it is made of a polymer material (rubber, etc.) that is elastic and flexible and elastically deformable after molding (solidification). As will be described later, when manufacturing the molded body 100A using the molding die 1A of this embodiment, elastic deformation occurs less during demolding, making it possible to provide a high-quality molded body (product).
[0023] The raw material M for the molded body is selected according to the material of the molded body 100A described above. The form of the raw material M for the molded body may be a liquid (including highly viscous liquids) or a solid.
[0024] [Forming mold] The molding die 1A of this embodiment will be described with reference to Figures 2 to 4. Figure 2 is a cross-sectional view showing the overall structure of the molding die 1A in this embodiment, and Figures 3 and 4 are cross-sectional views showing the structure related to the middle insert 10 of the molding die 1A in this embodiment.
[0025] First, we will explain the entire molding die 1A of this embodiment based on Figure 2. As shown in Figure 2, the molding die 1A comprises a mold body 11 having a shape corresponding to the outer shape of the molded body 100A, and an intermediate insert 10 that forms a space S for filling the molded body material M between the mold body 11.
[0026] <Mold body> The mold body 11 only needs to have a surface that corresponds to the outer shape of the molded body 100A and an area inside in which the intermediate insert 10 can be placed. As shown in Figure 2, a suitable example is a structure that is divided into two halves, left and right. Furthermore, if the raw material M for the molded body is fluid, like a liquid, and can move through the space S at room temperature and pressure, it is preferable, but not limited to, that the mold body 11 be provided with at least one raw material inlet 11a for filling the space S with the raw material M for the molded body, as shown in Figure 2. For example, if the raw material M for the molded body is a solid and molding is performed with this solid placed in the space S, the raw material inlet 11a can be omitted.
[0027] Furthermore, it is preferable that the mold body 11 be provided with means to maintain the fitted state during molding. For example, this could include providing a fitting portion on each of the divided mold bodies 11, or providing means to apply pressure from outside the mold body 11.
[0028] The mold body 11 then applies or maintains the temperature necessary for molding to the raw material M of the molded body filled in the space S by means of temperature control (heating up, cooling).
[0029] <Middle piece> As shown in Figure 2, the middle piece 10 has an outer circumference that corresponds to the inner shape of the molded body 100A, and is placed inside the mold body 11 to form a space S into which the raw material M of the molded body is filled. Furthermore, the intermediate piece 10 has a separable structure formed by combining a plurality of intermediate piece members 20 and a low-melting-point material 30. Furthermore, in this embodiment, it is preferable that the intermediate piece 10 has a structure having a hollow portion 40, as shown in Figure 3. In this embodiment, the intermediate piece 10 is formed by combining a plurality of intermediate piece members 20 with a low-melting-point material 30, so that the plurality of intermediate piece members 20 are fixed by the low-melting-point material 30. Therefore, even if the structure of the intermediate piece 10 has a hollow portion 40, the shape of the intermediate piece 10 is maintained without collapsing during molding. As a result, it is not necessary to form an intermediate piece 10 that fills the entire hollow portion 200A of the molded body 100A (fills the entire hollow portion 200A), which makes it possible to reduce the number of parts of the intermediate piece members 20 and to lighten the intermediate piece 10.
[0030] (Component for the central piece) A specific example of the central component member 20 in this embodiment is one consisting of a combination of a small piece 20a and a core rod 20b, as shown in Figure 3. The material of the small pieces 20a and the core rod 20b is not particularly limited, but it is preferable that they be made of a material that deforms little due to temperature changes during molding, has sufficient strength resistance to pressure during molding, and does not deteriorate or deform much due to contact with the raw material M of the molded body.
[0031] The small piece 20a is a component (part) that forms a shape corresponding to the inner shape of the main body 110A (a substantially spherical shape in this embodiment) within the molded body 100A of this embodiment. The small pieces 20a in this embodiment can be any pieces that can form the inner shape of the main body 110A by combining multiple small pieces 20a, and as shown in Figure 3, they can be any structure that has a contact surface 21 that contacts the raw material M of the molded body and a predetermined thickness. Hereinafter, the side with the contact surface 21 will be referred to as the "outside (of the middle insert member 20)". The structure (shape) of the contact surface 21 of the small piece 20a is sufficient as long as it can form the internal shape of the main body 110A when assembled. For example, as shown in Figure 3, it can consist of various polygons such as triangles, trapezoids, and squares, or it can have a recess or a protrusion on one side, and the internal shape of the main body 110A can be formed by the fitting of these recesses and protrusions, like a jigsaw puzzle. Furthermore, from the viewpoint of maintaining stability (strength resistance) when assembled, it is preferable that the small piece 20a is a structure with a predetermined thickness rather than a thin plate. This makes it possible to increase the strength of the middle piece 10 and also makes it possible to suppress the flow of the low-melting-point material 30, which will be described later, to the contact surface 21 side.
[0032] The core rod 20b is a component that forms a shape corresponding to the inner shape of the narrow opening portion 120A (a substantially cylindrical shape in this embodiment) of the molded body 100A in this embodiment. The core rod 20b in this embodiment can be any shape that can form the inner shape of the narrow opening 120A, but it is preferable to have a shape that can support the structure formed by the small pieces 20a. More specifically, as shown in Figure 3, a cylindrical structure is used as the core rod 20b, which is inserted into the structure formed by the small pieces 20a, and is positioned so that a part of it protrudes to correspond to the narrow opening 120A. In this case, the overall structure of the central piece 10 formed by the small piece 20a and the core rod 20b will have a hollow section 40 on the inside.
[0033] As will be described later, the intermediate insert component 20 (small piece 20a and core rod 20b) will be separated and removed from inside the molded body 100A after molding. Therefore, the small piece 20a and core rod 20b will be designed to pass through the diameter d1 of the narrow opening 120A of the molded body 100A. More specifically, in the case of the small piece 20a, the longest side or diagonal of the contact surface 21, or the thickness of the small piece 20a, whichever is longer, is designed to be shorter than the diameter d1. In addition, the core rod 20b is designed so that the width (diameter) of the core rod 20b does not exceed the diameter d1 along the entire length of the cylindrical shape. This makes it possible to remove the middle insert member 20 after molding the molded body 100A without forcibly widening the narrow opening 120A.
[0034] (Low melting point material) The low-melting-point material 30 is used to fix the structure formed by multiple intermediate component members 20. In this embodiment, the low-melting-point material 30 refers to a material whose melting point is lower than that of the intermediate insert member 20 and the molded body 100A, and which is a solid under the molding conditions (temperature and pressure). More specifically, if the molded body 100A is made of a polymer material, a substance (compound / composition) that is in a solid state under the molding temperature and pressure (heating and high pressure) conditions, but has a melting point lower than that of the polymer material and the intermediate insert member 20 after molding (solidification), can be used as the low-melting-point material 30 in this embodiment. Examples of such low-melting-point materials 30 include those made of organic materials such as waxes and waxes, and those made of inorganic materials (metals) such as alloys. In particular, materials referred to as low-melting-point alloys are preferred.
[0035] The low-melting-point material 30 is used to fix the structure formed by the intermediate component member 20 (a structure corresponding to the internal shape of the molded body 100A). For example, as shown in Figure 4A, it can be used to fill the gaps between the assembled small pieces 20a, or as shown in Figure 4B, it can be used to coat the inside of the assembled small pieces 20a. Alternatively, the steps shown in Figures 4A and 4B may be performed in parallel, with the low-melting-point material 30 used to fill the gaps between the assembled small pieces 20a and to coat the inside of the small pieces 20a. More specifically, this can involve applying (coating) molten low-melting-point material 30 to the thickness of small pieces 20a, assembling the small pieces 20a into a predetermined shape and cooling them to solidify the low-melting-point material 30, thereby filling the gaps between the small pieces 20a, or pouring molten low-melting-point material 30 into the interior of the structure of small pieces 20a assembled into a predetermined shape, removing any excess low-melting-point material 30 if necessary, and then cooling it to solidify the low-melting-point material 30, thereby coating the inside of the small pieces 20a.
[0036] In this case, it is preferable that the low-melting-point material 30 does not flow out (leak) to the outside of the central insert member 20 (the side of the contact surface 21 of the small piece 20a). This suppresses contact between the components contained in the low-melting-point material 30 and the molded body 100A (the raw material M of the molded body), and prevents the low-melting-point material 30 from being mixed into the molded body 100A as an impurity. In particular, when an alloy is used as the low-melting-point material 30, it is possible to suppress the effects of metal components adhering to the molded body 100A (such as molding defects in the molded body 100A or a decrease in quality when the molded body 100A is provided as a product).
[0037] In this embodiment, the low-melting-point material 30 is used to fix the structure assembled by the intermediate component member 20, and the intermediate component 10 is not formed solely of the low-melting-point material 30. Therefore, the amount of low-melting-point material 30 used can be significantly reduced compared to the case where the intermediate component 10 is formed solely of the low-melting-point material 30, thereby reducing the impact on the molded body 100A and lowering costs.
[0038] [Method for manufacturing molded products] Next, the steps related to the manufacturing method of a molded body using the molding die 1A described above will be explained in order with reference to Figure 5. First, as part of the preparation process for the molding die 1A described above, the intermediate insert 10 is procured according to the molding of the molded body 100A (molding of the internal shape of the molded body 100A) (intermediate insert procurement process). Here, "procurement" includes not only designing and assembling the intermediate insert 10, but also separately acquiring (purchasing) already assembled intermediate insert 10. At the same time, the mold body 11 corresponding to the molding of the molded body 100A (molding the outer shape of the molded body 100A) is procured (designed, manufactured, or acquired separately), and the mold body 11 is fitted with the intermediate insert 10 in the predetermined position, thereby completing the preparation of the molding die 1A.
[0039] Next, a raw material filling step is performed in which the raw material M of the molded body is filled into the space S formed between the mold body 11 and the intermediate insert 10. The raw material filling step can be carried out using a standard method in molding technology using a mold. For example, as described above, if the mold body 11 is equipped with a raw material inlet 11a, one example of a raw material filling process is to introduce the raw material M for the molded body, which has fluidity that allows it to move through the space S, into the raw material inlet 11a while the mold body 11 is in a fitted state, thereby filling the space S with raw material, as shown in Figure 5A. Furthermore, if the raw material M for the molded body is a solid, one example of the raw material filling process is to place the raw material M (solid) for the molded body in the space S after the intermediate insert procurement process and before fitting the mold body 11, as part of the preparation process for the molding die 1A described above. In this state, the mold body 11 is fitted, and the raw material M for the molded body is melted by heating and pressurizing, thereby filling the space S with raw material.
[0040] After the raw material filling process, a molding process is performed to solidify the raw material M of the molded body, thereby forming the molded body 100A. In this case, as a means of solidifying the raw material M of the molded body, a conventional method can be used depending on the material of the molded body 100A (the type of raw material M of the molded body). For example, if the material of the molded body 100A is a polymer material and consists of components (compounds, compositions) that solidify due to temperature changes (heating up or cooling), the molding process may include an operation to adjust the temperature of the molding die 1A. Furthermore, if the material of the molded body 100A is a polymer material, particularly rubber, the molding process includes operations to promote the crosslinking reaction (operations related to vulcanization). In vulcanization, heating and pressurizing of the raw material M of the molded body are required. As described above, the molding die 1A of this embodiment is structurally capable of maintaining high strength, and because it has a hollow section 40, the inside of the central insert 10 becomes closer to a positive pressure state when the molding die 1A is heated and pressurized. This makes it easy to maintain the pressure state necessary for vulcanization for a predetermined time for the entire molding die 1A. As a result, the shape (volume) of the space S for forming the molded body 100A is also maintained, so there is less unevenness in the raw material M of the molded body during molding, and it is easy to obtain a molded body 100A with a substantially uniform thickness throughout.
[0041] Here, the operation related to demolding the mold body 11 and the molded body 100A can be performed at any time after the molding process. As shown in Figure 5B, it is preferable to perform it before the low-melting-point material removal process, but this is not the only option.
[0042] After the molding process (and the demolding operation of the mold body 11 and the molded body 100A), a low-melting-point material removal process is performed, in which the material is heated at a temperature at which only the low-melting-point material 30 melts, that is, at a temperature above the melting point of the low-melting-point material 30 and below the melting points of the molded body 100A and the intermediate insert member 20 after molding (solidification), and removed from the molded body 100A. As described above, the low-melting-point material 30 is in a solid state during the molding process. However, in order to remove the intermediate piece 10 from the molded body 100A, only the low-melting-point material 30 that fixes the intermediate piece member 20 is melted, and it is removed (taken out) from the molded body 100A before the intermediate piece member 20. As a result, in the low-melting-point material removal process, the low-melting-point material 30 is removed from the molded body 100A in a molten state, as shown in Figure 5B. The removed low-melting-point material 30 can also be reused in the formation of the inner piece 10.
[0043] After the low-melting-point material removal process, an intermediate insert removal process (intermediate insert component removal process) is performed to remove the intermediate insert component 20 from the narrow opening 120A of the molded body 100A. Since the low-melting-point material 30 that fixed the structure formed by the intermediate insert member 20 has been removed, the intermediate insert member 20 is in a state where it can be divided inside the molded body 100A. Therefore, by sequentially removing the divisible intermediate insert member 20 from the narrow opening 120A, the molded body 100A and the intermediate insert 10 can be separated with almost no change in the shape of the narrow opening 120A. In this embodiment, it is preferable to first remove the core rod 20b, and then remove the small pieces 20a that form the inner shape of the main body 110A of the molded body 100A. At this time, it is preferable that the structure formed by the central component member 20 becomes easily separable (easily crumbled) after removing the core rod 20b and some of the small pieces 20a, or that multiple small pieces 20a can be removed together. This makes it possible to shorten the time required for the central component removal process.
[0044] In this case, the specific operations and means for removing the intermediate component member 20 in the intermediate component removal process are not particularly limited. For example, the intermediate component member 20 can be removed using a jig such as tweezers. Alternatively, the intermediate component member 20 can be made of a material that reacts with magnets, and removed using magnetic force (magnets). In this case, an auxiliary tool may be used to stabilize the shape of the narrow opening 120A (width of the narrow opening 120A) in order to smoothly remove the intermediate component member 20.
[0045] Furthermore, the intermediate insert member 20 may be provided with an extraction member used for removing it from the narrow opening 120A of the molded body 100A. Such an extraction member may consist of a string-like member attached to the small pieces 20a or the core rod 20b, and the small pieces 20a or the core rod 20b can be removed from inside the molded body 100A by pulling out the string-like member from the narrow opening 120A. In this case, the string-like member may be provided for each individual small piece 20a, or multiple or all of the small pieces 20a may be connected with the string-like member so that they can be pulled out in a connected state. This makes it possible to perform the intermediate insert extraction process quickly and easily.
[0046] As described above, the molding die of this embodiment, as a molding die for integrally molding a molded body having a narrow opening and a hollow section, is equipped with a divisible inner piece, and this inner piece consists of multiple inner piece members, and by using a low-melting-point material having a melting point lower than the melting point of the inner piece members and the molded body, after integral molding, only the low-melting-point material can be melted and removed, and furthermore, the inner piece members can then be removed from the outside of the molded body through the narrow opening. In other words, instead of demolding the molded body by greatly deforming it, the molded body can be demolded by removing the divided inner piece from inside the molded body, and a molded body having a narrow opening and a hollow section can be obtained by integral molding regardless of the material. In addition, there is no need to provide a draft taper in the structure of the molding die, and the degree of freedom regarding the shape and dimensions of the molded body can be increased.
[0047] Furthermore, the manufacturing method of the molded body in this embodiment involves integrally molding a molded body having a narrow opening and a hollow section using the above-mentioned molding die. After integral molding, only the low-melting-point material is melted and removed, and then the inner component can be removed to the outside through the narrow opening. In other words, instead of demolding the molded body by significantly deforming it, the molded body can be demolded by removing the inner component in a divided state from inside the molded body. This makes it possible to manufacture a molded body having a narrow opening and a hollow section by integral molding, regardless of the material, and with a high degree of freedom regarding the shape and dimensions of the molded body.
[0048] [Second Embodiment] [Molded body] Referring to Figure 6, the molded body 100B according to the second embodiment will be described. Note that components with the same function and structure as those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.
[0049] The molded body 100B according to the second embodiment is a molded body having a narrow opening and a hollow section, and is equipped with a nozzle structure having a partially curved shape. As shown in Figure 6, it comprises a main body 110B having a hollow section 200B and an opening 111, and a narrow opening section 120B communicating with the main body 110B. More specifically, the molded body 100B of this embodiment is equipped with a conical main body 110B, and a substantially conical narrow opening section 120B is provided that curves from the middle of the main body 110B and has a diameter d2 smaller than the maximum width of the main body 110B (diameter d3 of the opening 111). In other words, the molded body 100B of this embodiment differs in structure from the molded body 100A of the first embodiment in that it is equipped with an open section (opening 111) other than the narrow opening section 120B in relation to the main body 110B.
[0050] [Forming mold] Next, the molding die 1B of this embodiment will be described. The molding die 1B of this embodiment, like the molding die 1A described above, comprises a mold body (not shown) having a shape corresponding to the outer shape of the molded body 100B, and an intermediate piece 12 that forms a space S for filling the raw material M of the molded body between the mold body. The description of the mold body in molding die 1B is the same as the description of the mold body 11 shown in molding die 1A above, and therefore the details are omitted.
[0051] Figure 7 is a cross-sectional view showing the structure of the middle insert 12 in the molding die 1B of this embodiment. In this embodiment, the central insert 12, like the central insert 10 in the molding die 1A described above, has an outer circumference that corresponds to the inner shape of the molded body 100B, and is placed inside the mold body to form a space S into which the raw material M of the molded body is filled. Furthermore, the intermediate piece 12 has a separable structure formed by combining a plurality of intermediate piece members 20 and a low-melting-point material 30.
[0052] As the intermediate member 12 of the present embodiment, as shown in FIG. 7, there is an example formed to fill the entire region of the hollow portion 200B of the molded body 100B. In a molded body (product) having a nozzle structure like the molded body 100B, the dimensions of the entire molded body tend to be relatively small. Therefore, when the structure formed by the intermediate member 12 maintains sufficient strength and has a hollow portion inside, there is a possibility that high-precision work may be required for the design and manufacture of the intermediate member member 20 (particularly the small piece 20a). Therefore, as the intermediate member 12 of the present embodiment, the mandrel 20b is omitted, and by forming a structure that fills the entire hollow portion 200B using only the small piece 20a, it becomes possible to reduce the cost related to the procurement of the intermediate member 12.
[0053] As the intermediate member member 20 used for the intermediate member 12 of the present embodiment, a frustum-shaped structure body further divided into two parts according to the shape of the hollow portion 200B of the molded body 100B can be used as the small piece 20a. At this time, for the small piece 20a arranged at the location corresponding to the hollow portion 200B on the narrow mouth portion 120B side, in addition to having a width smaller than the diameter d2 of the narrow mouth portion 120B (for the width L1 of the small piece 20a in FIG. 7, L1 < d2 holds), for the small piece 20a arranged at the location corresponding to the hollow portion 200B on the main body 110B side, it may have a width larger than the diameter d2 of the narrow mouth portion 120B and smaller than the diameter d3 of the opening 111 of the main body 110B (for the width L2 of the small piece 20a in FIG. 7, d2 < L2 < d3 holds). That is, when taking out the intermediate member member 20, a part of the intermediate member member 20 may be performed through the narrow mouth portion 120B, and the other intermediate member member 20 may be performed through the opening 111.
[0054] Further, the low melting point material 30 is used to fix the structure formed by the intermediate member member 20 (the structure corresponding to the inner shape of the molded body 100B) in the same manner as the above-described molding die 1A. For example, as shown in FIG. 7, using the low melting point material 30 to fill the gap between the small pieces 20a can be mentioned.
[0055] [Manufacturing method of molded body] Next, we will explain in order each step of the manufacturing process for a molded body using the molding die 1B described above. First, as part of the preparation process for the molding die 1B described above, the intermediate insert 12 is procured according to the molding of the molded body 100B (molding of the internal shape of the molded body 100B) (intermediate insert procurement process). At the same time, the mold body corresponding to the molding of the molded body 100B (molding the outer shape of the molded body 100B) is procured (designed, manufactured, or acquired separately), and the mold body is fitted with the intermediate insert 12 in the predetermined position, thereby completing the preparation of the molding mold 1B.
[0056] Next, a raw material filling step is performed in which the raw material M of the molded body is filled into the space S formed between the mold body and the intermediate insert 12. As described above in the first embodiment, the raw material filling step can be carried out by a conventional method in molding technology using a mold, and details are omitted.
[0057] After the raw material filling process, a molding process is performed to solidify the raw material M of the molded body, thereby forming the molded body 100B. In this case, as a means of solidifying the raw material M of the molded body, as described above in the first embodiment, a conventional method can be used depending on the material of the molded body 100B (type of raw material M of the molded body), and details will be omitted.
[0058] Here, the operation related to demolding the mold body and the molded body 100B may be performed at any time after the molding process, and it is preferable to perform it before the low-melting-point material removal process, but this is not the only option.
[0059] After the molding process (and the release operation of the mold body and the molded body 100B), a low-melting-point material removal process is performed, in which the material is heated at a temperature at which only the low-melting-point material 30 melts, that is, at a temperature above the melting point of the low-melting-point material 30 and below the melting points of the molded body 100B and the intermediate insert member 20 after molding (solidification), and removed from the molded body 100B. The low-melting-point material removal process is as described above in the first embodiment, and details will be omitted here.
[0060] After the low-melting-point material removal process, an intermediate insert removal process (intermediate insert component removal process) is performed to remove the intermediate insert component 20 from the narrow opening 120B of the molded body 100B. Since the low-melting-point material 30 that fixed the structure formed by the intermediate insert member 20 has been removed, the intermediate insert member 20 is in a state where it can be divided inside the molded body 100B. Therefore, by sequentially removing the divisible intermediate insert member 20 from the narrow opening 120B, the molded body 100B and the intermediate insert 12 can be separated with almost no change in the shape of the narrow opening 120B. In this embodiment, as described above, it is preferable to remove small pieces 20a having a width L1 less than or equal to the diameter d2 of the narrow opening 120B through the narrow opening 120B, while removing small pieces 20a having a width L2 greater than or equal to the diameter d2 of the narrow opening 120B and less than or equal to the diameter d3 of the opening 111 through the opening 111. In this case, it is preferable that the structure formed by the intermediate piece member 20 becomes easily separable (easily crumbled) after removing some of the small pieces 20a, or that multiple small pieces 20a can be removed together. This makes it possible to shorten the time required for the intermediate piece removal process.
[0061] The embodiments described above are merely examples of methods for manufacturing molding dies and molded articles. The methods for manufacturing molding dies and molded articles according to the present invention are not limited to the embodiments described above, and the methods for manufacturing molding dies and molded articles according to the embodiments described above may be modified without changing the gist of the claims. [Industrial applicability]
[0062] The molding die and method for manufacturing a molded article of the present invention can be suitably used for manufacturing molded articles, particularly for manufacturing molded articles having a narrow opening and a hollow portion. [Explanation of symbols]
[0063] 1A, 1B…Molding die, 10, 12…Intermediate piece, 11…Mold body, 11a…Raw material input port, 20…Component for intermediate piece, 20a…Small piece, 20b…Core rod, 21…Contact surface, 30…Low melting point material, 40…Hollow part (of intermediate piece), 100A, 100B…Molded body, 110A, 110B…Main body, 111…Opening, 120A, 120B…Narrow opening, 200A, 200B…Hollow part (of molded body), d1~d3…Diameter, L1, L2…Width (of small piece), M…Raw material for molded body, S…Space
Claims
1. A mold for molding a molded body having a narrow opening and a hollow section, A middle piece is provided between the mold body, which has a shape corresponding to the outer shape of the molded body, and the mold body, which forms a space for filling the raw material of the molded body. The molding die is characterized in that the intermediate piece has a separable structure using a low-melting-point material and a plurality of intermediate piece members, and the melting point of the low-melting-point material is lower than the melting points of the intermediate piece members and the molded body.
2. The molding die according to claim 1, characterized in that the intermediate piece has a structure having a shape corresponding to the internal shape of the molded body and a hollow portion, achieved by combining a plurality of the intermediate piece members and fixing them with the low-melting-point material.
3. The molding die according to claim 1, characterized in that the molded article is made of a polymer material.
4. The molding die according to claim 1, characterized in that the intermediate insert member is provided with an extraction member used for removing the molded body from the narrow opening.
5. A method for manufacturing a molded article using a molding die according to any one of claims 1 to 4, The intermediate component procurement process involves procuring the aforementioned intermediate components, A raw material filling step in which the raw material for the molded body is filled between the mold body and the intermediate insert, After the raw material filling step, a molding step is performed to solidify the raw material of the molded body and form the molded body, After the molding process, a low-melting-point material removal step is performed, in which the low-melting-point material is heated to a temperature that melts only the low-melting-point material and removed from the molded body. A method for manufacturing a molded body, comprising: a step of removing the intermediate insert member from the narrow opening of the molded body after the step of removing the low-melting-point material.