JP6624574B2 - Mold and mold manufacturing method - Google Patents

Description

  The present disclosure relates to a mold and a method for manufacturing the mold. Specifically, the present disclosure relates to an injection mold and a method of manufacturing the injection mold.

  One of the technologies that has supported the Japanese “manufacturing” industry is molding technology using dies. Examples of the molding technique include a pressure molding method, an injection molding method, an extrusion molding method, and a casting method. Among these molding methods, the injection molding method is mainly a method of obtaining a molded product by injecting a resin melted by heating into a mold, cooling, and solidifying the molded product. Suitable for producing. The steps of this injection molding method are roughly divided into a mold clamping step, an injection step, a cooling step, and a mold opening step. By repeating these steps, a molded product can be continuously produced.

WO2008 / 038694 WO2010 / 082331

  The injection mold includes a movable mold, a fixed mold, and a sprue bush formed in the fixed mold. The sprue bush has a sprue portion for injecting the molten resin into the cavity. The volume per unit area of the sprue may be larger than the cavity. Therefore, the time required for the molten resin in the sprue portion to be solidified is longer than the time required for the molten resin in the cavity to be solidified. Therefore, even if the molten resin in the cavity is solidified, the mold cannot be opened until the molten resin in the sprue portion is solidified. If the timing of opening the mold is too early, problems arise in stringing the molten resin and taking out the molded product. Therefore, it is necessary to delay the opening timing of the mold until the molten resin in the sprue portion is completely solidified. Therefore, the molding time becomes longer.

  In order to shorten the time for solidifying the molten resin in the sprue portion, sprue bushes having a coolant flow path for passing a coolant have been disclosed (Patent Documents 1 and 2). In the mold including the sprue bush, an inlet and an outlet of the coolant flow path of the sprue bush, and a water pipe path for passing the coolant formed by using a gun drill or the like on the side surface of the fixed mold are O-rings. (See FIG. 7). However, it is not easy to form a water pipe path using a special tool such as a gun drill on the side surface of the fixed side mold of the mold. Also, it is not easy to form a water pipe path even when a hole is formed in a mold base. In particular, since the mold may have an interference portion of a mold base such as a pin, it may be difficult to form a water tube path inside the mold while avoiding the interference portion. When a high-temperature refrigerant is used as the cooling liquid, the O-ring is easily damaged. Further, when the water pipe path is formed by using a special tool such as a gun drill, maintenance in the water pipe path is difficult. In addition, since the cooling pipe is not directly connected to the inlet and outlet of the cooling liquid flow path, it is not easy to accurately control the temperature.

Accordingly, in order to solve the above-mentioned problems, the present invention provides a mold and a mold that efficiently cools a molten resin passing through a sprue portion, shortens a molding cycle, and facilitates formation and maintenance of a water pipe path. It is an object of the present invention to provide a method for producing the same.

To achieve the above object, in one embodiment of the present invention,
A movable mold, a fixed mold, and a sprue bush provided with a coolant passage provided in the fixed mold, a mold including:
Each of the inlet portion and the outlet portion of the cooling liquid flow path is directly connected to a cooling pipe arranged along a space region formed in the fixed mold,
The space region has a form in which at least one surface of the fixed mold is open, and includes a portion that extends in a non-linear manner,
At least one of the cooling pipes directly connected to the inlet and the outlet has flexibility, and the flexible cooling pipe extends in the non-linear manner in the space region. A mold is provided, characterized in that it is arranged along the part.

In order to achieve the above object, in one embodiment of the present invention,
A movable mold, a fixed mold, and a sprue bush provided with a coolant passage provided in the fixed mold, a method for manufacturing a mold comprising:
Opening at least one surface of the fixed mold, thereby forming a space region including a portion extending non-linearly in the fixed mold; and forming the space formed in the fixed mold. Arranging a cooling pipe along the region and directly connecting the cooling pipe to an inlet and an outlet of the cooling liquid flow path,
The flexible cooling pipe is used for at least one of the cooling pipes directly connected to the inlet section and the outlet section, and the flexible cooling pipe is formed in the non-linear shape of the space region. A manufacturing method is provided, wherein the method is arranged along an extending part.

  In one embodiment of the present invention, at least one surface of the fixed mold has an open shape, so that the cooling pipe can be directly connected to the inlet and outlet of the coolant flow path. it can. Therefore, the temperature of the coolant can be controlled accurately, and the molten resin passing through the sprue portion can be cooled efficiently. Therefore, there is an advantage that the molding cycle can be shortened. Further, in one embodiment of the present invention, since at least one surface of the fixed mold has an opening, the surface of the fixed mold can be easily cut, and the degree of freedom of cutting can be increased. Therefore, in order to avoid an interference part of the mold base such as a pin, it is easy to form and maintain a non-linearly extending portion in a space region having a form in which at least one surface of the fixed mold is open. Becomes possible. In particular, in one embodiment of the present invention, a flexible cooling pipe is used for at least one of the cooling pipes directly connected to the inlet and the outlet of the coolant flow path, and the flexible cooling pipe is used. A tube is positioned along the non-linearly extending portion. That is, in one embodiment of the present invention, the non-linearly extending portion is provided so as to avoid the interference portion, and the cooling pipe arranged along the non-linearly extending portion is flexible. Has the property. Therefore, it is possible to provide the cooling pipe so as to avoid the interference part as a whole.

FIG. 1A is a partial schematic sectional view of an injection mold according to one embodiment of the present invention. FIG. 1B is a photograph of a sprue bush of a component of the injection mold according to one embodiment of the present invention. FIG. 1C is a schematic perspective view of a sprue bush having a coolant flow path therein. FIG. 2A is a partial schematic perspective view of an injection mold according to one embodiment of the present invention. FIG. 2B is a partial schematic perspective view of the components of the mold for injection molding according to one embodiment of the present invention when the fixed-side mounting plate and the fixed-side template are schematically separated. FIG. 3A is a partial schematic cross-sectional view of the injection mold of the present invention when a space region is formed in a lower portion of the fixed-side mounting plate. FIG. 3B is a partial schematic cross-sectional view of an injection mold according to one embodiment of the present invention in a case where a space region is formed in an upper portion of a fixed mold plate. FIG. 3C is a partial schematic cross-sectional view of the injection mold according to one embodiment of the present invention when the space region is formed in the lower side of the fixed mold plate. FIG. 3D is a partial schematic cross-sectional view in a case where a space region is formed between a part of a lower part of the fixed-side mounting plate and a part of an upper part of the fixed-side template. FIG. 3E shows a case where a space area where the cooling pipe on the suction side is provided is formed in the upper part of the fixed-side mounting plate, and a space area where the cooling pipe on the discharge side is provided is formed in the lower part of the fixed-side mold plate. It is a partial schematic sectional view of the metallic mold for injection molding concerning one embodiment of the present invention. FIG. 4A is a part of an injection molding die according to an embodiment of the present invention when a cooling pipe is directly connected to an inlet and an outlet of a coolant flow path exposed on a main surface of a flange portion. It is a schematic sectional drawing. FIG. 4B is a view for use in injection molding according to an embodiment of the present invention when the cooling pipe is directly connected to the inlet and outlet of the coolant flow path exposed on the surface facing the main surface of the flange portion. It is a partial schematic sectional view of a metallic mold. FIG. 4C shows a cooling liquid flow path in which the cooling pipe on the suction side is directly connected to the inlet of the cooling liquid flow path exposed on the main surface of the flange portion, and the cooling pipe on the discharge side is exposed on the side face of the sprue bush base. FIG. 4 is a partial schematic cross-sectional view of an injection mold according to an embodiment of the present invention when directly connected to an outlet of the injection molding apparatus. FIG. 4D shows that the cooling pipe on the suction side is directly connected to the inlet of the coolant flow path exposed on the main surface of the flange portion, and the cooling pipe on the discharge side is exposed on the surface facing the main surface of the flange portion. FIG. 3 is a partial schematic cross-sectional view of an injection mold according to one embodiment of the present invention when directly connected to an outlet of a cooling liquid flow path. FIG. 4E shows a cooling pipe in which the cooling pipe on the suction side is directly connected to the inlet of the cooling liquid flow path exposed on the side surface of the flange portion, and the cooling pipe on the discharge side is exposed on the surface facing the main surface of the flange portion. FIG. 2 is a partial schematic cross-sectional view of an injection molding die according to an embodiment of the present invention when directly connected to an outlet of a liquid flow path. FIG. 5A is a schematic plan view of an injection mold according to an embodiment of the present invention in a case where an inlet portion and an outlet portion of a coolant flow path are provided on both side surfaces of a sprue bush so as to face each other. It is. FIG. 5B is a schematic plan view of the injection mold according to one embodiment of the present invention when both the inlet and outlet of the coolant flow path are provided on one side surface of the sprue bush. FIG. 5C is a schematic plan view of an injection molding die according to an embodiment of the present invention in a case where a flexible hose is used for a suction-side or discharge-side cooling pipe provided along a space area. FIG. 6A is a schematic perspective view showing a form in which a part of the surface of the fixed mold is opened. FIG. 6B is a schematic perspective view showing a form in which the fixed mold is continuously opened from one surface to the other surface. FIG. 6C is a schematic perspective view when the space region has a form of a gap formed between two sub-molds constituting the fixed mold. FIG. 6D is a schematic perspective view when the space region has a form of a gap formed between three sub-molds constituting the fixed-side mold. FIG. 7 is a partial schematic sectional view of a conventional injection mold. FIG. 8A is a molding cycle diagram for obtaining a molded product using the injection mold according to one embodiment of the present invention. FIG. 8B is a molding cycle diagram for obtaining a molded product using a conventional injection mold. FIG. 8C is a photograph of a sprue runner obtained by the injection mold according to one embodiment of the present invention. FIG. 8D is a photograph of a sprue runner obtained by a conventional injection mold. FIG. 9A is a molding cycle diagram for obtaining a molded product using the injection mold according to one embodiment of the present invention. FIG. 9B is a molding cycle diagram for obtaining a molded product using a conventional injection molding die. FIG. 9C is a schematic perspective view showing a temperature distribution region of the sprue bush. FIG. 10 is an exploded perspective view of an injection mold according to one embodiment of the present invention.

  Hereinafter, an embodiment of an injection mold 1 according to an embodiment of the present invention will be described.

  FIG. 1A is a partial schematic cross-sectional view of an injection mold 1 according to one embodiment of the present invention. An injection mold 1 according to one embodiment of the present invention includes a fixed mold 2 and a sprue bush 3 formed in the fixed mold 2. As shown in FIG. 1B, the sprue bush 3 includes a sprue bush base 4 and a flange 5 integrated with the sprue bush base 4. The sprue bush 3 has a sprue portion 6 for injecting a molten resin into a cavity formed by the movable mold and the fixed mold 2 therein, and a coolant flow path. In addition, as shown in FIG. 1C, the coolant flow path 7 is provided so as to surround the periphery of the sprue portion 6. In addition, the fixed mold 2 includes a fixed mounting plate 8 and a fixed mold plate 9. In addition, in the injection mold 1 according to one embodiment of the present invention, as shown in FIG. 1A, a cooling pipe 10 that allows cooling water to pass through a side surface of the flange portion 5 of the sprue bush 3 includes a joining member 15, specifically, Typically, they are directly connected via a female screw. In addition, the joining member 15 is not limited to a female screw, and may be a male screw or a cooling joint 16. Specifically, the cooling pipe 10 is directly connected to the inlet portion 11 and the outlet portion 12 of the coolant flow passage exposed on both side surfaces of the flange portion 5. That is, the inlet portion 11 and the outlet portion 12 of the coolant flow path are provided on both side surfaces of the sprue bush 3 so as to face each other. Further, as shown in FIG. 1A, it is preferable that the space region 14 is perpendicular to the extending direction of the sprue portion 6 which is a component of the sprue bush 3. Further, as shown in FIG. 2A, the cooling pipe 10 is provided along a groove 13 formed in the upper part of the fixed-side mounting plate 8. In the present specification, the sprue bushing outlet side is the fixed side mounting plate 8, that is, “the lower side” of the fixed side mold 2, and the side facing the sprue bushing outlet is the fixed side mounting plate 8, ie, the fixed side metal. Defined as "upper" of mold 2. That is, the cooling pipe 10 is provided along the space region 14 in which a part of the upper surface of the fixed-side mounting plate 8 is open. In addition, as shown in FIG. 2B, after the cooling pipe 10 is provided along the groove 13 formed in the upper part of the fixed-side mounting plate 8, the fixed-side mounting plate 8 and the fixed-side mold plate 9 are joined. . As shown in FIG. 10, first, cooling pipes 10 connected to both side surfaces of the sprue bush 3 and the flange 5 of the sprue bush 3 are provided along the groove 13 formed in the upper part of the fixed-side mounting plate 8. . Next, the sprue bush 3 provided along the groove 13 and the cooling pipes 10 connected to both side surfaces of the flange 5 of the sprue bush 3 are fixed by a locating ring 22. Thereby, the injection mold 1 according to one embodiment of the present invention is obtained.

  Since the cooling pipe 10 is directly connected to the inlet portion 11 and the outlet portion 12 of the coolant flow path, the temperature of the coolant can be more accurately controlled. Therefore, the molten resin passing through the sprue portion 6 can be efficiently cooled, and the molding cycle can be shortened. Thereby, the production efficiency of the obtained molded article can be improved. Further, since the cooling pipe 10 is provided along the space region 14 formed in the upper part of the fixed-side mounting plate 8, the cooling pipe 10 can be visually confirmed from the outside. Therefore, the fixed-side mounting plate 8, that is, the surface of the fixed-side mold 2 is easily cut, and the degree of freedom in cutting can be increased. That is, access to the cooling pipe 10 is easy. Thereby, there is an advantage that maintenance in the space region 14 becomes easy.

  The cooling pipe 10 described above is (1) directly connected to the inlet part 11 and the outlet part 12 of the coolant flow path, and (2) the space formed in the upper part of the fixed side mounting plate 8. It is characterized by being provided along the region 14. However, the injection molding die 1 of the present invention is not limited to the above-described embodiment, and as shown by a dashed line in FIG. 1A, the cooling pipe 10 is formed by the upper part or the lower part of the fixed-side mounting plate 8 or the fixed-side mold. It may be provided on the upper side or the lower side of the plate 9.

  Therefore, hereinafter, another embodiment of the injection mold 1 of the present invention will be described.

  First, the space region 14 may be formed in the lower portion of the fixed-side mounting plate 8 as shown in FIG. 3A. Further, the space region 14 may be formed in the upper part of the fixed mold plate 9 as shown in FIG. 3B. Further, the space region 14 may be formed in the lower portion of the fixed mold plate 9 as shown in FIG. 3C. The space region 14 may be formed between a part of the lower part of the fixed-side mounting plate 8 and a part of the upper part of the fixed-side template 9 as shown in FIG. 3D. That is, the space region 14 does not necessarily need to be formed in a part of one member, and may be formed in at least two members. Further, the space area 14 where the cooling pipe 10 on the suction side is provided and the space area 14 where the cooling pipe 10 on the discharge side are provided need not be flush. For example, as shown in FIG. 3E, the space area 14 where the cooling pipe 10 on the suction side is provided is formed in the upper part of the fixed side mounting plate 8, and the space area 14 where the cooling pipe 10 on the discharge side is provided is the fixed side plate 9. May be formed in the lower portion. Alternatively, the reverse may be applied.

  Further, since the space region 14 can be freely defined by milling, the space region 14 can be formed to extend in a non-linear manner. Therefore, a flexible member, for example, a flexible hose can be used as the cooling pipe 10 provided along the space region 14. Thereby, the interference part of the mold base can be avoided. In addition, since a flexible member can be used as the cooling pipe 10, the degree of freedom in arrangement can be increased.

  Therefore, hereinafter, still another embodiment of the injection mold 1 of the present invention will be described.

  First, as shown in FIG. 4A, the cooling pipe 10 may be directly connected to the inlet and outlet of the coolant flow path exposed on the main surface of the flange 5. That is, the cooling pipe 10 has a non-linear shape but a non-linear shape. Further, as shown in FIG. 4B, the cooling pipe 10 may be directly connected to the inlet and the outlet of the coolant flow path exposed on the surface facing the main surface of the flange portion 5. 4C, the cooling pipe 10 on the suction side is directly connected to the inlet 11 of the coolant flow path exposed on the main surface of the flange 5, and the cooling pipe 10 on the discharge side is connected to a sprue bush. It may be directly connected to the outlet portion 12 of the coolant flow passage exposed on the side surface of the base portion 4. Alternatively, the reverse is also possible. The cooling pipe 10 on the suction side is directly connected to the inlet 11 of the coolant flow path exposed on the main surface of the flange 5 as shown in FIG. 5 may be directly connected to the outlet portion 12 of the cooling liquid flow path exposed on the surface facing the main surface of the cooling liquid flow path 5. Alternatively, the reverse is also possible. The cooling pipe 10 on the suction side is directly connected to the inlet 11 of the coolant flow path exposed on the side surface of the flange 5 as shown in FIG. May be directly connected to the outlet portion 12 of the cooling liquid flow path exposed on the surface facing the main surface of the cooling liquid. Alternatively, the reverse is also possible.

  Preferably, the space region 14 is formed so as to reach near the exit of the sprue bush 3. As a result, the molten resin in the vicinity of the injection port of the sprue bush 3 can be quickly solidified, so that the timing for opening the mold can be further increased. Therefore, the molding time can be shortened, and the production efficiency of the obtained molded article can be further improved.

  Further, as shown in FIG. 5A, the inlet portion 11 and the outlet portion 12 of the coolant flow path need not necessarily be provided on both side surfaces of the sprue bush 3 so as to face each other. That is, the inlet portion 11 and the outlet portion 12 of the coolant flow path may be provided at arbitrary positions on the side surface of the sprue bush 3. For example, as shown in FIG. 5B, both the inlet portion 11 and the outlet portion 12 of the coolant flow path may be provided on one side surface of the sprue bush 3. Thereby, downsizing of the injection mold 1 of the present invention can be realized. Further, as described above, since the space region 14 can be freely defined by milling, the space region 14 can be formed to extend in a non-linear manner. Therefore, as shown in FIG. 5C, the flexible hose 17 can be used for the suction-side or discharge-side cooling pipe 10 provided along the space region 14. Thereby, the interference part 18 of the mold base such as a pin can be avoided. Note that the flexible hose 17 may be used for both the suction side and the discharge side cooling pipes 10 provided along the space region 14.

  As shown in FIG. 6A, the space region 14 described above has a form in which a part of the surface of the fixed-side mounting plate 8 or the fixed-side mold plate 9, that is, a part of the surface of the fixed-side mold 2 is opened. ing. However, the space region 14 is not limited to this, and may have a form in which the space is continuously opened from one surface to the other surface of the fixed mold 2 as shown in FIG. 6B, for example. As shown in FIG. 6C, the space region 14 may have a form of a gap formed between two sub-molds 21 constituting the fixed mold 2. Further, as shown in FIG. 6D, the space region 14 may have a form of a gap formed between three sub-molds 21 constituting the fixed mold 2. As a matter of course, the space region 14 may have a form of a gap formed between four or more sub-molds 21 constituting the fixed mold 2.

<Example 1>
A molded article was obtained under the following conditions.
Resin material: PPWW567w3952
Die: (dimensions) 300 mm x 500 mm x 345 mm / (mass) 403 kg
Molding machine: Nissei ES2000

  As shown in FIGS. 8A and 8B, in the injection mold 1 according to one embodiment of the present invention, the cooling time of the molten resin can be reduced from 13 s to 8 s as compared with the conventional mass production mold, As a result, the molding cycle could be reduced to 25.7% (35s → 26s) as a whole.

  When the injection mold 1 according to one embodiment of the present invention is used, as shown in the photograph of FIG. 8C, the cooling temperature of the molten resin can be appropriately controlled to sufficiently cool the molten resin. As a result, the sprue runner was in good condition. On the other hand, when using the conventional mass-production mold, as shown in FIG. 8D, the cooling temperature of the molten resin could not be appropriately controlled, and the cooling of the molten resin was insufficient, so that the sprue runner broke. It could not be continuously molded.

<Example 2>
As shown in FIGS. 9A and 9B, in the injection mold 1 according to one embodiment of the present invention, the cooling time of the molten resin can be reduced from 39 s to 25 s as compared with the conventional mass production mold, As a result, the molding cycle could be reduced to 30.8% (65s → 45s) as a whole.

  When the injection mold 1 according to one embodiment of the present invention is used, the cooling temperature of the molten resin can be appropriately controlled to sufficiently cool the molten resin. Did not. In addition, when the temperature analysis of the sprue bush 3 during the cooling process was performed, as shown in FIG. 9C, the temperature near the injection port of the sprue bush was more sufficiently cooled than the other parts of the sprue bush. I understood. On the other hand, when the conventional mass production mold was used, the cooling temperature of the molten resin could not be appropriately controlled, and the cooling of the molten resin was insufficient. Therefore, continuous molding could not be performed because the product was caught when the mold was opened.

  The mold according to one embodiment of the present invention can be used as an injection mold.

REFERENCE SIGNS LIST 1 injection molding die 2 fixed die 3 sprue bush 4 sprue bush base 5 flange 6 sprue 7 coolant flow path 8 fixed side mounting plate 9 fixed side mold plate 10 cooling pipe 11 inlet of coolant flow path 12 Coolant flow path outlet 13 Groove 14 Space area 15 Joining member 16 Cooling joint 17 Flexible hose 18 Mold base interference part 19 O-ring 20 Water pipe path 21 Sub-mold 22 Locating ring

Claims (17)

A movable mold, a fixed mold, and a sprue bush provided with a coolant passage provided in the fixed mold, a mold including:
Each of the inlet portion and the outlet portion of the cooling liquid flow path is directly connected to a cooling pipe arranged along a space region formed in the fixed mold,
The space region has a form in which at least one surface of the fixed mold is open, and includes a portion that extends in a non-linear manner,
At least one of the cooling pipes directly connected to the inlet and the outlet has flexibility, and the flexible cooling pipe extends in the non-linear manner in the space region. A mold characterized by being arranged along a part.   The mold according to claim 1, wherein the space region has a shape of a groove provided on a surface of the fixed mold.   2. The mold according to claim 1, wherein the space region has a form that is continuously opened from the one surface to the other surface of the fixed mold. 3. The mold comprises at least two sub-molds,
The mold according to claim 3, wherein the space region has a form of a gap formed between the at least two sub molds. The fixed mold includes a fixed mounting plate and a fixed mold plate,
The space region is configured on at least one of an upper surface and a lower surface of the fixed-side mounting plate, and / or at least one of an upper surface and a lower surface of the fixed-side template. The mold according to claim 1.   The mold according to any one of claims 1 to 5, wherein the inlet part and the outlet part of the coolant flow path are provided on a side surface of the sprue bush.   The mold according to claim 6, wherein the inlet and the outlet of the coolant flow path are provided so as to face each other on both side surfaces of the sprue bush.   The mold according to claim 6, wherein both the inlet and the outlet of the coolant flow path are provided on one side surface of the sprue bush.   The mold according to any one of claims 1 to 8, wherein a flexible hose is used as the flexible cooling pipe.   The flexible cooling pipe is arranged along the non-linearly extending portion formed so as to avoid an interference portion provided in the mold. The mold according to any one of claims 1 to 9. The sprue bush has a sprue portion,
The mold according to claim 1, wherein the space region extends in a direction orthogonal to an extending direction of the sprue portion.   The mold according to any one of claims 1 to 11, wherein the space region is provided so as to reach near the sprue bush outlet.   The cooling liquid passage is configured such that the inlet portion and the outlet portion are directly connected to the cooling pipe via at least one joining member selected from a group including a male screw, a female screw, and a cooling joint. The mold according to any one of claims 1 to 12, which is characterized in that: A movable mold, a fixed mold, and a sprue bush provided with a coolant passage provided in the fixed mold, a method for manufacturing a mold comprising:
Opening at least one surface of the fixed mold, thereby forming a space region including a portion extending non-linearly in the fixed mold; and forming the space formed in the fixed mold. Arranging a cooling pipe along the region and directly connecting the cooling pipe to an inlet and an outlet of the cooling liquid flow path,
The flexible cooling pipe is used for at least one of the cooling pipes directly connected to the inlet section and the outlet section, and the flexible cooling pipe is formed in the non-linear shape of the space region. A manufacturing method characterized by being arranged along an extending part.   The method according to claim 14, wherein a flexible hose is used as the flexible cooling pipe.   The non-linearly extending portion is formed so as to avoid an interference portion provided in the mold, and the movable portion is formed along the non-linearly extending portion formed to avoid the interference portion. The method according to claim 14, wherein the cooling pipe having flexibility is arranged.   17. The method according to claim 14, wherein the space region is formed to have a groove shape.

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