Method of manufacturing resin molding, and apparatus of manufacturing resin molding

Abstract

To provide a method of manufacturing a resin molding and an apparatus of manufacturing the resin molding that can accommodate a plurality of shapes.SOLUTION: A method of manufacturing a resin molding having a front surface and a back surface comprises the steps of: mold-closing a first mold for forming the back surface and a second mold for forming the front surface; protruding a columnar pin from either one mold of the first mold and the second mold toward the other mold; injecting a resin material into a cavity formed by mold-closing the first mold and the second mold in a state in which the pin is extruded, to form the resin molding and a through-hole penetrating from the back surface toward the front surface; pulling the pin toward the one side; and mold-opening the first mold and the second mold to take out the resin molding.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a resin molded body and an apparatus for manufacturing a resin molded body. [Background technology]

[0002] Conventionally, there are known manufacturing methods for manufacturing resin molded articles used as exterior components for automobiles. Patent Document 1 discloses a manufacturing method for manufacturing a resin molded article having through holes. In the manufacturing method for resin molded articles of Patent Document 1, a resin molded article is manufactured by an injection molding method in which a resin material is injected into a cavity, and then the through holes are formed by processing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-121420 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the number of components such as sensors and headlamp washers installed in automobiles has increased to improve their functionality. Therefore, resin molded articles used in automobile exterior components are required to have through holes depending on whether or not the components are installed in the automobile. As a result, multiple shapes of resin molded articles are required depending on whether or not they have through holes.

[0005] In order to accommodate this increase in shapes, conventional methods for manufacturing resin molded products require processing of the resin molded product removed from the injection molding process. This increases manufacturing costs. Therefore, it is preferable that the injection molding method be able to accommodate a variety of resin molded product shapes.

[0006] An object of the present disclosure is to provide a method and an apparatus for manufacturing a resin molded body that can accommodate a variety of shapes. [Means for solving the problem]

[0007] A method for manufacturing a resin molded body according to the present disclosure is a method for manufacturing a resin molded body having a front surface and a back surface, comprising the steps of: closing a first mold that forms the back surface and a second mold that forms the front surface; protruding a columnar pin from one of the first mold or the second mold toward the other mold; injecting a resin material into a cavity formed by closing the first mold and the second mold with the pin protruded, to form the resin molded body and a through hole that penetrates from the back surface to the front surface; retracting the pin toward one of the first mold and the second mold; and opening the first mold and the second mold and removing the resin molded body.

[0008] According to this method for manufacturing a resin molded body, a through hole is formed in the resin molded body by injecting a resin material while the pin is extruded. On the other hand, since the extruded pin is retracted by the injected resin material, the next time injection molding is performed, a resin molded body without a through hole can be manufactured.

[0009] In addition, the manufacturing apparatus for resin molded bodies according to the present disclosure includes a first mold that forms the back surface, a second mold that forms the front surface, and a columnar pin that protrudes from either the first mold or the second mold toward the other mold and forms a through hole that penetrates from the front surface to the back surface.

[0010] Such a resin molding manufacturing apparatus can realize the above-described method for manufacturing a resin molding. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a method and an apparatus for manufacturing a resin molded body that can accommodate a variety of shapes. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 10 is a diagram showing an example of a state in which the resin molded body is attached to an automobile. [Figure 2] FIG. 2 is a diagram showing an example of a first resin molding body. [Figure 3] Cross section AA of Figure 2. [Figure 4] FIG. 4 is a diagram showing an example of a second resin molded body. [Figure 5] FIG. 3 is a cross-sectional view showing a manufacturing apparatus for a resin molded body. [Figure 6] An enlarged view of the area around the pin during through-hole formation. [Figure 7] FIG. 3 is a schematic diagram showing the flow of a resin material. [Figure 8] 4 is a flowchart showing a method for manufacturing a resin molded body. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0014] As shown in FIG. 1, the resin molded body 1 of this embodiment is an exterior member used in a portion such as a bumper C1 or a front grille C2 provided at the front of an automobile C. Parts such as a sensor for detecting obstacles outside the automobile C and a headlamp washer for spraying cleaning fluid onto the headlamps are attached to such portions. When the above-mentioned parts are to be attached to such portions, the resin molded body 1 requires a first resin molded body 1a (see FIG. 2) having through holes 6 (see FIG. 2) corresponding to the positions of the parts.

[0015] 2 and 3, the resin molded body 1 used in such a portion has a front surface 2 and a back surface 4. Such a resin molded body 1 used in an automobile C is manufactured by injection molding a thermoplastic resin such as polypropylene, polyethylene, ABS resin, or polycarbonate resin. However, the resin molded body 1 may be made of any resin material that can be injection molded.

[0016] The surface 2 may be disposed facing the outside of the automobile C and function as a design surface. Furthermore, the through-hole 6 must be designed not to obstruct detection waves such as laser waves emitted from a sensor. Therefore, when forming the through-hole 6 in the first resin molding 1a, it is necessary to prevent burrs from being generated on the surface 2 side and on the inner peripheral surface 6a of the through-hole 6.

[0017] On the other hand, the above-mentioned parts may not be necessary depending on the specifications of the automobile C. In such cases where the above-mentioned parts are not necessary, it is preferable to use a second resin molded body 1b that has the same outer peripheral shape as the first resin molded body 1a but does not have through holes 6, as shown in Fig. 4. This makes it possible to avoid, for example, the work of filling the through holes 6.

[0018] Next, a manufacturing apparatus 20 for manufacturing the first resin mold body 1a and the second resin mold body 1b will be described with reference to FIG.

[0019] 5, the manufacturing apparatus 20 includes a fixed mold (an example of a second mold) 22 that forms the front surface 2, a movable mold (an example of a first mold) 24 that forms the back surface 4, and a columnar pin 26 that protrudes from either the fixed mold 22 or the movable mold 24 toward the other mold and forms a through hole 6 that penetrates from the front surface 2 to the back surface 4. In this embodiment, two pins 26 are provided. However, the number of pins 26 can be changed as appropriate depending on the number of the above-mentioned parts.

[0020] The fixed mold 22 has a gate 22a for injecting a resin material into a cavity 28, which will be described later. In this embodiment, the gate 22a is provided in approximately the center of the cavity 28.

[0021] The movable die 24 is disposed opposite the fixed die 22. The movable die 24 can move in a direction away from the fixed die 22 from a state in which the fixed die 22 and the movable die 24 are closed (clamped). The movable die 24 is positioned in a closed state when the resin molded body 1 is injection molded, and moves away from the fixed die 22 to a mold-open position when the resin molded body 1 is removed.

[0022] The movable mold 24 has a cavity 28 recessed in the shape of the resin molded body 1. A bottom surface 28a of the cavity 28 is formed in the shape of the back surface 4. Two insertion holes 28b through which the two pins 26 pass are provided in the bottom surface 28a. A cylindrical cylinder 24a through which the pins 26 move is provided at a position opposite the cavity 28 from the insertion holes 28b.

[0023] The pin 26 is a columnar member that is pushed out from the insertion hole 28b toward the cavity 28. In this embodiment, the pin 26 is formed in a cylindrical shape. The pin 26 includes a flange 26a that is provided on the bottom side of the pin 26 and is movable along the cylinder 24a. The flange 26a is connected to a rod 26b. The rod 26b is linked to a slider 26c. The slider 26c is formed by a cam member in which two members with right-angled triangular cross sections are arranged with their hypotenuses overlapping. One member of the slider 26c slides due to an actuator such as a motor, pushing the other member. As a result, the other member pushes the rod 26b toward the cavity 28. When the rod 26b is pushed out, the flange 26a moves along the cylinder 24a, and the pin 26 is pushed out toward the cavity 28. The actuator may be controlled, for example, by a control device (not shown), and may move the pin 26 when producing the first resin molding body 1a, while maintaining the pin 26 in a position where it does not protrude into the cavity 28 and is housed in the fixed mold 22 when producing the second resin molding body 1b.

[0024] Next, a method for manufacturing the resin molded body 1 will be described with reference to FIGS.

[0025] 8, in the process of step S1, a selection is made as to whether to manufacture a first resin molded body 1a having through holes 6 or a second resin molded body 1b not having through holes 6. Such a selection may be performed, for example, by the above-mentioned control device. If a first resin molded body 1a having through holes 6 is to be manufactured (YES in step S1), the process proceeds to step S2.

[0026] In step S2, the movable mold 24 is moved toward the fixed mold 22 and the mold is closed. Once the mold is closed, the process proceeds to step S3, where the pin 26 is pushed toward the cavity 28. As shown in FIG. 6, the pin 26 is stopped at a position where there is a gap from the forming surface 22b (the surface facing the cavity 28) that forms the surface 2 of the fixed mold 22. According to the inventors' findings, it is desirable that the distance D from the top surface 26d of the pin 26 to the forming surface 22b be between 5% and 20% of the thickness of the first resin molding body 1a. Once the pin 26 has been stopped, the process proceeds to step S4.

[0027] In step S4, the resin material is injected from the gate 22a. As shown in FIG. 7, the resin material injected from the gate 22a flows along the cavity 28, around the pin 26, and then flows. As shown in FIG. 6, the resin material flows without entering the gap between the top surface 26d of the pin 26 and the molding surface 22b. That is, the resin material flowing from the gate 22a (see FIG. 7) flows along the bottom surface 28a of the cavity 28. Meanwhile, because a gap is formed between the top surface 26d of the pin 26 and the bottom surface 28a, the flow rate of the resin material decreases before it reaches the molding surface 22b. This makes it difficult for the resin material to enter the gap. As a result, burrs are less likely to occur in the through-hole 6. That is, it is preferable that the injection direction of the resin material and the extrusion direction of the pin 26 are opposite. Furthermore, it is preferable that the pin 26 be provided on the opposite side of the mold from where the gate 22a is provided. After the resin material is injected, the process proceeds to step S5.

[0028] In the process of step S5, the stopped pin 26 is moved toward the movable die 24, and the pin 26 is retracted into the movable die 24 and stored in the movable die 24. Once the pin 26 is stored, the process proceeds to the process of step S6.

[0029] In the process of step S6, the movable mold 24 is moved in a direction away from the fixed mold 22, the mold is opened, and the process proceeds to the process of step S7. In the process of step S7, the first resin molding body 1a is taken out.

[0030] On the other hand, if it is selected in step S1 to manufacture a second resin molding body 1b that does not have through holes 6 (step S1 NO), the process proceeds to step S8, where the mold is closed and the resin material is injected with the pins 26 housed in the movable mold 24 (step S9), and the process proceeds to step S6. In this way, the second resin molding body 1b is manufactured and removed.

[0031] In the first resin molding body 1a manufactured in this manner, the pins 26 are pushed out from the side of the movable mold 24 that forms the back surface 4, and the pins 26 are stopped with a gap between them and the molding surface 22b that forms the front surface 2, thereby suppressing the generation of burrs on the side of the front surface 2. This also makes it possible to omit processes such as deburring, reducing manufacturing costs.

[0032] Furthermore, with the manufacturing apparatus 20, the first resin molded body 1a and the second resin molded body 1b can be manufactured using the same mold, eliminating the need for mold setup. Furthermore, since the through holes 6 are formed simultaneously with the injection molding, there is no need to process the through holes 6. This further reduces manufacturing costs.

[0033] Furthermore, according to the manufacturing method of the resin molded product 1 of the present disclosure, the resin material is injected while the pin 26 is extruded, which reduces wear on the pin 26 compared to when the pin 26 is extruded during or after injection. This reduces the frequency with which the pin 26 needs to be replaced. As a result, manufacturing costs are further reduced.

[0034] Furthermore, since the pins 26 are housed in the fixed mold 22 before the mold is opened, no load is applied to the pins 26 when the resin molded body 1 is removed. This further reduces wear on the pins 26.

[0035] As described above, according to the present disclosure, it is possible to provide a method for manufacturing a resin molded body 1 and an apparatus 20 for manufacturing a resin molded body 1 that can accommodate a variety of shapes.

[0036] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0037] (a) In the above embodiment, an electric device is used to move the pin 26 using an actuator such as a motor, but the present disclosure is not limited to this. The pin 26 may also be moved by a hydraulic device that hydraulically moves the flange 26a, for example.

[0038] (b) In the above embodiment, the pin 26 is pushed out from the movable mold 24 , but the pin 26 may be pushed out from the fixed mold 22 .

[0039] (c) In the above embodiment, the resin molded body 1 is used as an exterior component of the automobile C, but the present disclosure is not limited to this. The resin molded body 1 may be used as an interior component of the automobile C or as a component other than the automobile C. [Explanation of symbols]

[0040] 1: Resin molded body 1a: First resin molded body 1b: Second resin molded body 2: Surface 4: Back side 6:Through hole 20: Manufacturing equipment 22: Fixed type 22a: Cylinder 24: Mobile type 26: Pin 28: Cavity

Claims

1. A method for manufacturing a resin molded article having a front surface and a back surface, comprising: a step of closing a first mold forming the back surface and a second mold forming the front surface; a step of protruding a columnar pin from one of the first die and the second die toward the other die; a step of injecting a resin material into a cavity formed by closing the first mold and the second mold with the pin pushed out, to form the resin molded body and a through hole penetrating from the back surface to the front surface; retracting the pin toward the one side; a step of opening the first mold and the second mold and removing the resin molded body; A method for manufacturing a resin molded body comprising:

2. The pin stops with a gap between it and the other die. A method for producing the resin molded article according to claim 1.

3. the pin protrudes from a surface of the first mold that forms the back surface and stops with a gap between the surface of the second mold that forms the front surface. A method for producing the resin molded article according to claim 1.

4. the resin molded body includes a first resin molded body having the through hole and a second resin molded body not having the through hole, When the first resin molded body is manufactured, the pin is protruded, When the second resin molding body is produced, the pin is positioned in a state where it is accommodated in the one mold. The method for producing the resin molded article according to any one of claims 1 to 3.

5. a first mold forming a back surface; a second mold for forming a surface; a columnar pin protruding from one of the first die and the second die toward the other die and forming a through hole penetrating from the front surface to the back surface; An apparatus for manufacturing a resin molded body, comprising:

6. The pin protrudes from the first die toward the second die. The resin material forming the resin molded body is injected from the second mold. The apparatus for producing a resin molded article according to claim 5 .

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