JP2013095124A - Injection mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection mold configured to prevent a defect due to a history of a flow of a molten resin material in multiple molded articles.SOLUTION: The injection mold 10 includes a hot sprue 13 to which an injection nozzle for injecting the molten resin material is connected, a hot runner 15 through which the molten resin material injected to the hot sprue 13 passes, and a cavity 16 which is connected to the hot runner 15, and supplies the molten resin material to a plurality of cavities by branching off the hot runner 15 halfway to form a plurality of moldings at a time. The hot sprue 13 includes a sprue bush 18 for forming an opening part 17 as a connection part for the injection nozzle, a branch port formed at the opening part 17 and distributing the molten resin material injected from the injection nozzle to as many as branches of the hot runner 15, and a branch passage 20c for supplying molten resin materials distributed by the branch port to a plurality of corresponding hot runners 15 respectively.

Description

  The present invention relates to an injection mold, and more particularly to an injection mold that branches a molten resin material injected from an injection nozzle and supplies it simultaneously to a plurality of cavities.

  Conventionally, in the molding industry using a molten resin as a material, in order to improve production efficiency, so-called high cycle and enhancement of production capacity by taking a large number of pieces have been studied.

  In general, the high cycle has a great influence on the quality of the molded product, except for the simultaneous operation of some processes in one molding cycle. .

On the other hand, in the case of multi-cavity that increases the number of molded products, since a substantial improvement in production efficiency is proportional to the number of molded products in one molding cycle, a significant improvement in production efficiency can be expected. In addition, it is necessary to devise the setting of the gate balance and the flow path shape for uniformly supplying the molten resin material.
For example, in a multi-cavity injection mold, one that supplies a molten resin material from a common flow path before branching to a branch flow path (hot runner) via a branching section is known (for example, a patent) Reference 1).

Japanese Utility Model Publication No. 07-037617

  However, in the above-described injection mold, when the molten resin material is branched from the common flow path, the flow of the molten resin material is likely to stagnate or oriented at the branch portion, and the molten resin material at this time The flow history remains as a straight defect in the molded product as it is, resulting in a problem that the appearance of the product is impaired and the mechanical strength is impaired.

  In addition, when a large number of molded products are preforms for blow molding, the molded product may be easily ruptured at the blow molding stage of the next process, or may not be ruptured. There has been a problem of producing a single line-like appearance defect.

  Therefore, for example, a molded product molded with an injection mold having a multi-cavity structure must be applied to a product that is free from defects caused by the flow history of the molten resin material with respect to appearance and strength. The problem of inferior versatility has arisen. In addition, in the case of products that are severe in appearance and strength and preforms for blow molding, it is still necessary to adopt a one-piece structure, which is a limiting factor for improving production efficiency including high cycle. It was.

  Further, when a plurality of injection devices are used for multi-cavity picking, the entire device becomes large and the cost increases, which causes a problem in terms of cost effectiveness.

  Therefore, an object of the present invention is to provide an injection mold that can suppress the occurrence of defects due to the history of the flow of molten resin material in a molded product that has been obtained in large numbers.

  In order to solve the above problems, an injection mold according to the present invention includes a hot spur to which an injection nozzle for injecting a molten resin material is connected, a hot runner through which the molten resin material injected into the hot sprue passes, and the hot mold An injection mold for simultaneously molding a plurality of molded products by branching a middle part of the hot runner and supplying a molten resin material to the plurality of cavities. A sprue bush that forms an opening as a connecting portion of the injection nozzle, and a branch port that divides the molten resin material formed in the opening and injected from the injection nozzle into the same number as the number of branches of the hot runner And a branch passage for supplying the molten resin material diverted at the branch port in association with each of the plurality of hot runners. And wherein the Rukoto.

  According to such a configuration, the molten resin material can be branched and supplied in association with a plurality of hot runners, and the flow of the molten resin material can be supplied to a molded product including a preform for blow molding. It is possible to make it difficult to generate a single-line defect due to the history, to improve the appearance and strength of the molded product, and to contribute to the improvement of the production efficiency by taking a large number of pieces. Moreover, when applied to a preform for blow molding as a molded product, the occurrence of rupture during blow molding can be suppressed, which can contribute to improvement in production efficiency.

  In the injection mold according to the present invention, the branch port and the branch passage are formed by inserting a branch member formed separately from the hot sprue into the hot sprue. To do.

  According to such a structure, a branch port and a branch channel | path can be formed by inserting a branch member in the existing hot sprue.

  Furthermore, the injection mold according to the present invention is characterized in that a molded product formed in each of the plurality of cavities is a preform for blow molding.

  According to such a structure, the preform for blow molding can be molded as a molded product by the molten resin material branched by the branch port and the branch passage.

  The injection mold according to the present invention can suppress the occurrence of defects due to the history of the flow of the molten resin material in a large number of molded products.

It is sectional drawing of the principal part of the metal mold | die for injection molding which concerns on one Embodiment of this invention. It is a disassembled perspective view of the principal part of the injection mold of one Embodiment of this invention. The principal part of the injection mold of one Embodiment of this invention is shown, (A) is a perspective view of the principal part, (B) is sectional drawing of the branch bush before inserting a branch member, (C) is a branch. It is sectional drawing of the branch bush of the state which inserted the member. It is a disassembled perspective view of the principal part in Example 2 applied to the injection mold of one Embodiment of this invention. It is sectional drawing of the principal part in Example 2 applied to the metal mold | die for injection molding of one Embodiment of this invention. It is a perspective view of the principal part in Example 3 applied to the metal mold | die for injection molding of one Embodiment of this invention. It is a disassembled perspective view of the principal part in Example 4 applied to the injection mold of one Embodiment of this invention. It is a rear view of the principal part in Example 4 applied to the metal mold | die for injection molding of one Embodiment of this invention.

  Next, an injection mold according to an embodiment of the present invention will be described with reference to the drawings. In addition, although the Example shown below is a suitable specific example in the injection die of this invention, and there may be various technically preferable restrictions, the technical scope of this invention is especially this. Unless stated to limit the invention, it is not limited to these embodiments. In addition, the constituent elements in the embodiments shown below can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the embodiment described below does not limit the contents of the invention described in the claims.

  FIG. 1 is a cross-sectional view of an essential part of an injection mold according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a branch member applied to the injection mold according to an embodiment of the present invention. 3 is a perspective view of a branch member in Example 2 applied to an injection mold according to an embodiment of the present invention, and FIG. 4 is Example 3 applied to an injection mold according to an embodiment of the present invention. It is a perspective view of the branch member in.

  In FIG. 1, an injection mold 10 includes a locating ring 11 for axial alignment (positioning) between an injection nozzle of an injection molding apparatus (injection apparatus for molten resin material) (not shown) and an injection mold 10. A hot sprue 13 disposed on the downstream side in the supply direction of the molten resin material with respect to the locating ring 11 and held by the mold mounting plate 12, and a hot runner for guiding the molten resin material via the hot sprue 13 to the gate 14 on the most downstream side in the supply direction 15 and a cavity 16 for forming a molded product such as a preform from the molten resin material supplied from the gate 14.

  The hot sprue 13 includes a sprue bush 18 that forms an opening 17 as a connection portion of an injection nozzle, and a heater 19 that is provided on the outer periphery of the sprue bush 18 and that constitutes a temperature adjusting means for maintaining the temperature of the molten resin material. And a branching member 20 disposed inside the sprue bush 18.

  The hot runner 15 has its midway portion branched as a branch portion 15a. In this embodiment, the hot branch runner (branch flow path) 15 is branched into two directions in the upper and lower directions in the figure, and a cavity 16 is provided.

  In the present embodiment, the sprue hole 18a of the sprue bush 18 is configured such that at least a part of the path from the opening 17 of the sprue bush 18 with which the injection nozzle abuts to the branch part 15a of the hot runner 15 is a common flow path. Yes. In the present embodiment, the branch portion 15a is fitted into the branch block plate 21 fixed to the die mounting plate 12, and is connected to the sprue hole 18a and the sprue hole 22a coaxial with each other, and the sprue hole 22a and the hot runner 15 communicate with each other. The branch bush 22 is integrally formed with the branch hole 22b. Further, on the upstream side from the opening 17 to the branching portion 15a, the sprue hole 18a and the sprue hole 22a are coaxially connected, and the cross-sectional area orthogonal to the flow of the molten resin material is the same. Further, in the present embodiment, the branch member 20 is inserted into the sprue hole 18a and the sprue hole 22a, and from the opening 17 which is a common flow path of the molten resin material injected from the injection nozzle to the branch part 15a. It is arranged across the length of the flow path to reach. In the present embodiment, the sprue bush 18 is fixed to the branch block plate 21 by an annular mounting flange 18b. Further, the branch bush 22 is embedded in the branch block plate 21.

  At this time, as shown in FIG. 3 (B), the branch bush 22 has sprue holes 22a formed on the axis of the metal block body formed in a substantially cylindrical shape, and the number of hot runners 15 (this embodiment). Then, the branch holes 22b are formed radially (equally) from the axis according to the two locations. Further, as shown in FIG. 3A, when the branch member 20 is inserted from the opening 17 so that the front end abuts against the bottom (the left end in the drawing) of the sprue hole 22a, as shown in FIG. The downstream side of the branch passage 20c is formed by matching the recessed fitting portion 22a and the branch hole 22b.

  The heater 19 is disposed on the outer peripheral surface of the sprue bush 18 including the sprue hole 18a from the injection nozzle touch part, and heats the molten resin material passing through the sprue hole 18a. A second heater 23 similar to the heater 19 may be disposed in the vicinity of the gate 14. In addition, the temperature of each heater 19 and 23 is controlled according to the detection temperature of a temperature detection sensor. Although not shown in the drawing, the temperature of the molten resin material is maintained in the branch passage 20c by temperature control means such as a heat pipe and a temperature control pipe disposed inside the branch member 20, for example.

  The branch member 20 has a maximum outer diameter that is the same as the inner diameter of the sprue holes 18a and 22a, and a pair of concave fitting portions 20a that extend along the axial direction. ) To form a pair of branch ports 20b in cooperation with the opening portion 17, and in the portion from the midway portion to the most downstream end (near the left end in the figure in FIG. 3A), sprue holes 18a and 22a and branch holes 22b. The branch passage 20c is configured in cooperation with the above.

  At this time, when the molten resin material supply conditions (volume, flow path length, etc.) in the plurality of cavities 16 and the hot runner 15 are the same, the recessed fitting portion 20a is made of the molten resin material in the branch port 20b and the branch passage 20c. The cross-sectional area perpendicular to the flow and the flow path length are preferably the same.

  In the above configuration, the molten resin material injected from the injection nozzle is branched at the opening 17 by the branch port 20b, and passes through the branch passage 20c (the sprue holes 18a, 22a and the branch hole 22b) as it is to the branch portion 15a. Finally, each hot runner 15 that branches up and down in the drawing and communicates with the branch hole 22 b passes through the gate 14 and is shared by the cavity 16.

  At this time, the molten resin material is sufficiently heated on the outside, but is not easily heated on the inside. Therefore, the molten resin material branched along the entire length from the branch port 20b to the branch portion 15a via the branch passage 20c linearly extended is heated by the sprue bush (branch member) heated by the heater 19. In addition, the inner side of the molten resin material becomes the outer side due to the branching and comes into contact with the sprue bush (branching member) and is branched corresponding to the number of hot runners 15 and cavities 16 after the branching. Stagnation and orientation are unlikely to occur, and the entire flow path is sufficiently heated, so that the occurrence of defects and the like can be suppressed.

  4 and 5 show a modified example (Example 2) of the injection mold 10 according to the present invention, in which the above-described branch member 20 is formed integrally with the sprue bush 18. The state where the branch member 20 shown in FIG. 2 is inserted into the sprue hole 18a is apparently the same as the state shown in FIG. 4 and 5, the same reference numerals are given to the same configurations or functionally the same configurations as those of the above embodiment, and the description thereof is omitted.

  FIG. 6 shows another modification (Example 3) of the injection mold 10 according to the present invention, in which the sprue hole 18a of the sprue bush 18 is integrally formed as a branch passage 20c. In FIG. 6, the same components as those in the above embodiment or the functionally same components are denoted by the same reference numerals, and the description thereof is omitted.

  Even with such a configuration, it is possible to achieve the same effects as the above-described embodiment. Moreover, as shown in FIG.7 and FIG.8, for example, the number of the recessed fitting parts 20a can be formed according to the number of the hot runners 15 as a matter of course.

  7 and 8 show a modified example (Example 4) of the injection mold 10 of the present invention. In each of the above-described embodiments, the case where there are two branch passages 20c is shown. As shown in FIG. 8, the number can be three or more (four in the illustrated example) according to the number of hot runners 15. At this time, it is preferable that the recessed fitting portions 20a and the branch holes 22b are radially opened to the outer peripheral side with the axis as the center and are equally disposed. 7 and 8, the same or functionally the same configuration as that of the above embodiment is given the same reference numeral and the description thereof is omitted.

DESCRIPTION OF SYMBOLS 10 ... Injection mold 11 ... Locating ring 12 ... Mold mounting plate 13 ... Hot sprue 14 ... Gate 15 ... Hot runner 15a ... Branching part 16 ... Cavity 17 ... Opening part 18 ... Sprue bush 18a ... Sprue hole 18b ... Mounting flange 19 ... Heater 20 ... Branch member 20a ... Recessed fitting portion 20b ... Branch port 20c ... Branch passage 21 ... Branch block plate 22 ... Branch bush 22a ... Sprue hole 22b ... Branch hole 23 ... Heater

At this time, as shown in FIG. 3 (B), the branch bush 22 has sprue holes 22a formed on the axis of the metal block body formed in a substantially cylindrical shape, and the number of hot runners 15 (this embodiment). Then, the branch holes 22b are formed radially (equally) from the axis according to the two locations. Further, as shown in FIG. 3A, when the branch member 20 is inserted from the opening 17 so that the front end abuts against the bottom (the left end in the drawing) of the sprue hole 22a, as shown in FIG. The downstream side of the branch passage 20c is formed by matching the recessed fitting portion 20a with the branch hole 22b.

Claims (3)

A hot spur to which an injection nozzle for injecting a molten resin material is connected, a hot runner through which the molten resin material injected into the hot sprue passes, and a cavity connected to the hot runner, and a middle part of the hot runner In an injection mold for simultaneously molding a plurality of molded products by branching and supplying molten resin material to the plurality of cavities,
The hot sprue divides the sprue bush forming an opening as a connection portion of the injection nozzle and the molten resin material formed in the opening and injected from the injection nozzle into the same number as the number of branches of the hot runner. An injection mold, comprising: a branch port; and a branch passage for supplying the molten resin material branched at the branch port in association with each of the plurality of hot runners.   The injection mold according to claim 1, wherein the branch port and the branch passage are formed by inserting a branch member formed separately from the hot sprue into the hot sprue. .   The injection mold according to claim 1 or 2, wherein a molded product formed in each of the plurality of cavities is a preform for blow molding.

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