Mold part and manufacturing method of mold part

Abstract

To provide a molded part and a method for manufacturing a molded part that can easily exhaust air inside a product that cannot come in contact with a mold.SOLUTION: A branch channel 13 is provided in the junction flow channel 15 that connects to the interior space of the product.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a molded part having an internal space and a method for manufacturing the molded part. [Background technology]

[0002] Patent Document 1 describes how, when welding parts using an injection molding machine, air that accumulates in the joining flow path is dealt with by cutting out a part of the molded part and connecting it to a gas vent provided in the mold, thereby discharging the air outside the product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-170534 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method of Patent Document 1, when joining parts by flowing molten resin in the internal space of the parts where the molds cannot come into contact, it is not possible to expel the air that has accumulated in the joining flow path.

[0005] Therefore, an object of the present invention is to provide a molded part and a method for manufacturing a molded part that can easily discharge air from inside a product that cannot come into contact with a mold. [Means for solving the problem]

[0006] Therefore, the molded part of the present invention is a molded part in which a joining flow path and a space are formed inside the molded part by combining a first molded part and a second molded part, and the first molded part and the second molded part are joined together by flowing molten resin into the joining flow path and hardening, and the joining flow path has a branch path that communicates with the space. The branch channel is provided at a position where the molten resin that has flowed through the joining channel joins with another. It is characterized by: [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a molded part and a method for manufacturing a molded part that can easily discharge air from the inside of a product that cannot come into contact with a mold. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a first molded product and a second molded product. [Figure 2] FIG. 3 is a diagram showing molten resin flowing through a joining flow path. [Figure 3] FIG. 2 is a schematic diagram showing the molding and joining steps in order. [Figure 4] FIG. 2 is a diagram showing a first molded product and a second molded product. [Figure 5] FIG. 2 is a diagram showing a first molded product and a second molded product. [Figure 6] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] 1(a) to 1(e) are schematic diagrams showing the state before and after joining of a first molded product 01 and a second molded product 02, which are joined using an injection molding machine in this embodiment, and the joined portion. FIG. 1(a) is a plan view of the first finished product 01 viewed from the second finished product 02 side before the first finished product 01 and the second finished product 02 are combined. FIG. 1(c) is a plan view of the first finished product 01 viewed from the second finished product 02 side after the first finished product 01 and the second finished product 02 are combined. FIG. 1(b) is a cross-sectional view of the first molded product 01 and the second molded product 02 taken along line bb in FIG. 1(a), and FIG. 1(d) is a cross-sectional view of the first molded product 01 and the second molded product 02 taken along line dd in FIG. 1(c). In this embodiment, the first molded product 01 and the second molded product 02 are molded using an injection molding machine. Thereafter, molten resin 05 is poured into a joining flow path 15 formed by combining the first molded product 01 and the second molded product 02, and the first molded product 01 and the second molded product 02 are joined together by hardening the molten resin 05. All of these steps from molding to joining are performed by an injection molding machine.

[0011] A groove 04 is formed on the joining surface of the first molded product 01 with the second molded product, and a joining flow path 15 is formed by combining the second molded product 02 and the first molded product 01. The shape of the joining flow path 15 can be easily changed by changing the shape of the groove 04. Increasing the flow path area of ​​the joining flow path 15 can increase the joining force and simultaneously reduce resistance when pouring the molten resin 05. Joining gates 16, which serve as inlets to the joining flow path 15, are provided at two locations on opposing side surfaces of the first molded product 01, and the molten resin 05 can be poured into the joining flow path 15 from the two joining gates 16. Note that in this embodiment, the groove 04 is formed in the first molded product 01, but this is not limited thereto. It is sufficient that the groove 04 is formed in at least one of the first molded product 01 and the second molded product 02. Similarly, it is sufficient that the joining gate 16 is formed in at least one of the first molded product 01 and the second molded product 02.

[0012] By combining the first molded product 01 and the second molded product 02, multiple spaces 06 are formed inside. In order to form the multiple spaces 06 independently, a joining flow path 15 is formed to surround each space 06, and by pouring molten resin 05 into the joining flow path 15, each space 06 is formed independently.

[0013] 2 is a diagram showing a first molded product 01 and molten resin 05 flowing through a joining flow path 15 formed when the first molded product 01 is combined with a second molded product 02. The molten resin 05 is supplied from a gate 12 provided on the back surface of the first molded product 01, passes through the side of the first molded product 01, and is supplied to the joining flow path 15 from a joining gate 16. The positions of the gate 12 and the joining gate 16 are preferably set appropriately depending on the product.

[0014] 3(a) to 3(d) are schematic diagrams showing the molding and joining process in this embodiment in the order of steps. The molding and joining process will be described below in the order of steps. First, as shown in FIG. 3(a), a first molded product 01 and a second molded product 02 are molded by injection from a fixed mold injection nozzle 09, and the mold is opened. Then, as shown in FIG. 3(b), the movable mold 08 is moved to a position where the first molded product 01 and the second molded product 02 face each other. Then, as shown in FIG. 3(c), the mold is closed and the first molded product 01 and the second molded product 02 are combined. In the combined state, injection is performed from a movable mold injection nozzle 10, and molten resin 05 is poured into a joining flow path 15. Finally, as shown in FIG. 3(d), the mold is opened, and the finished product is removed from the mold, completing the molding and joining process.

[0015] FIG. 4 shows a first molded product 01 and a second molded product 02. FIG. 4(a) is a cross-sectional view taken along line dd in FIG. 1(a), with the molten resin 05 omitted. FIG. 4(b) is a cross-sectional view taken along line dd in FIG. 1(c). In this embodiment, the first molded product 01 is provided with a branch path 13 through which air within the joining flow path 15 is discharged when the molten resin 05 is poured into the joining flow path 15. The branch path 13 is provided to connect the joining flow path 15 to the space 06 so that the air within the joining flow path 15 is discharged into the space 06 inside the product. By providing the branch path 13 in the joining flow path 15, the air within the joining flow path 15 is discharged into the space 06 via the branch path 13. In this way, by discharging the air within the joining flow path 15 into the space 06, air can be easily discharged even when joining parts in an internal space that cannot come into contact with the mold. The position where the branch path 13 is to be provided may be determined by conducting a flow test of the molten resin 05, and the branch path 13 may be provided at a position where the molten resin 05 joins.

[0016] In this embodiment, the space 06 is a closed space, but it may be open to the atmosphere to release the compression pressure caused by the discharged air. Furthermore, if there are multiple locations where the molten resin 05 converges in the joining flow path 15, it is preferable to provide a branch path 13 at each of the confluences. Even if the joining flow path 15 can be in contact with the mold and a gas vent can be installed in the mold, the branch path 13 may be used to discharge air into the space 06 inside the product, as in this embodiment. This prevents gas tar from accumulating in the gas vent and reduces the frequency of mold maintenance. Furthermore, in this embodiment, the joining of two parts, the first molded product 01 and the second molded product 02, has been described. However, the present invention is not limited to this and may be applied to the joining of three or more parts.

[0017] FIG. 5 is a cross-sectional view of the first molded product 01 and the second molded product 02 taken along the line dd in FIG. 1(c). During the joining process, the molten resin 05 flows into the joining channel 15 and into the branch channel 13. Because the branch channel 13 opens into the space 06, the molten resin 05 may infiltrate into the space 06 depending on the conditions (temperature, pressure, etc.) of the molten resin 05. However, if the molten resin 15 infiltrates the space 06 from the branch channel 13, it may impair product functionality. Specifically, in the case of forming a liquid ejection head for an inkjet printer, the ink supply channel corresponds to the space 06. In this case, if the molten resin 05 infiltrates the ink supply channel, the hardened resin may drop off within the ink supply channel after joining, potentially impeding the ink supply. Furthermore, it may clog the ejection nozzle.

[0018] Therefore, in this embodiment, the branch path 13 is configured to have a higher flow resistance of the molten resin 15 than the joint flow path 15. Specifically, the cross-sectional area of ​​the branch path 13 is made as small as possible to reduce the pressure of the molten resin 05. This makes it possible to suppress the intrusion of the molten resin 05 into the space 06. The cross-sectional shape of the branch path 13 can be appropriately selected from a circle, a triangle, a square, or the like. However, by increasing the surface area with which the molten resin 05 comes into contact, such as a star shape, the pressure of the molten resin 05 can be reduced by frictional resistance. Furthermore, making the length of the branch path 13 as long as possible has a pressure reduction effect, making it possible to suppress the intrusion of the molten resin 05 into the space 06.

[0019] The finished product obtained by joining the first molded product 01 and the second molded product 02 formed by the method of this embodiment can be used for a liquid ejection head, a liquid storage container, or the like. (Example) In this embodiment, the first molded product 01 and the second molded product 02 were joined using Zylon (Asahi Kasei Corporation) as the molten resin 05. When the flow pressure of the molten resin 05 at the confluence point was 20 MPa or less, the branch path 13 had a cross section of 150 μm square and a length of 0.5 mm or less, which enabled the outflow of the molten resin 05 into the internal space 06 of the product to be suppressed.

[0020] In this way, a branch path 13 that communicates with the space inside the product is provided in the joining flow path 15. This makes it possible to provide a molded part and a method for manufacturing a molded part that can easily discharge air from the inside of the product, which cannot come into contact with the mold. (Variation) FIG. 6 illustrates a modified example of this embodiment. FIG. 6(a) illustrates a first molded product 01 according to this embodiment, and FIGS. 6(b) and 6(c) are enlarged views of a branch channel 13. If the cross-sectional area of ​​the branch channel 13 is reduced to prevent the molten resin 05 from flowing out, if the joining point of the molten resin 05 is shifted from the position of the branch channel 13, the branch channel 13 may be clogged by the molten resin 05, making it impossible to discharge air (see FIG. 6(c)). Therefore, as shown in FIGS. 6(a) and 6(b), by enlarging the inlet of the branch channel 13 and gradually narrowing it toward the outlet, air can be discharged even if the joining point is shifted. Furthermore, by making the surface roughness of the branch channel 13 rougher than the surface roughness of the joining flow channel 15, frictional resistance within the branch channel 13 increases when the molten resin 05 flows into the branch channel 13, thereby preventing the molten resin 05 from flowing out of the branch channel 13. [Explanation of symbols]

[0021] 01 1st molded product 02 Second molded product 04 Groove 05 Molten resin 06 Space 12 Gates 13 Branching Paths 15 Junction channel 16 Junction Gate

Claims

1. The first molded part and the second molded part are combined to form a joining flow path and a space inside the molded part, A molded part in which the first molded part and the second molded part are joined together by allowing molten resin to flow into the joining flow path and harden, the joining flow path includes a branch path communicating with the space, The molded part is characterized in that the branch channel is provided at a position where the molten resins that have flowed through the joining channel join together.

2. The molded part according to claim 1 , wherein a plurality of said branch paths are provided.

3. The molded part according to claim 1 or 2, wherein the branch passage is provided in at least one of the first molded part and the second molded part.

4. 4. The molded part according to claim 1, wherein the branch channel is configured to have a higher flow resistance for the molten resin than the joining channel.

5. The molded part according to claim 4 , wherein the branch channel gradually narrows from the joining channel to the space.

6. The molded part according to claim 4 or 5, wherein the branch channel has a surface roughness greater than that of the joining channel.

7. 7. The molded part according to claim 1, wherein the space is in communication with the atmosphere.

8. A liquid ejection head comprising the molded part according to claim 1 .

9. A liquid storage container comprising the molded part according to any one of claims 1 to 7.

10. A method for manufacturing a molded part, comprising: a molding step of molding a first molded part and a second molded part; an assembling step in which the first molded part and the second molded part are combined to form a joining flow path and an internal space; a joining step of joining the first molded part and the second molded part by injecting molten resin into the joining flow path and hardening the molten resin, In the molding step, a branch passage communicating with the space is formed in the joining passage of at least one of the first molded part and the second molded part, The method for manufacturing a molded part is characterized in that, in the joining step, the molten resin is flowed into the joining flow path, and air within the joining flow path is discharged from the branch path.

11. 11. The method for manufacturing a molded part according to claim 10, wherein the molding step and the joining step are performed by an injection molding machine.

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