JP6978560B1 - Multicolor molding mold with movable core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding die for a multicolor molded product provided with a movable core, which can be stably molded. SOLUTION: The target is a multicolor molding die (1) provided with a movable core (15) whose position is changed in three or more steps. A predetermined plate (16) is provided on the mold (1), and a core side plate portion (17) is provided on the rear end surface of the movable core (15). A predetermined step pattern (20) composed of a plurality of steps whose height changes in three or more steps is repeatedly formed on one of the plate (16) and the core side plate portion (17). On the other hand, another step pattern (22) having the same width as the step pattern (20) and having a predetermined step is repeatedly formed. When the plate (16) is molded by changing the slide position, the meshing state of the stepped pattern (20) and the other stepped pattern (22) changes, and the holding position of the movable core (15) changes in three steps. As a result, a multicolor molded product is molded. [Selection diagram] Fig. 2

Description

The present invention is for multicolor molding, which comprises a movable core that can move forward and backward in the cavity, forms a cavity while changing the position of the movable core, and sequentially injects three or more different resins to form a multicolor molded product. It is about the mold.

So-called multicolor molded products made of a plurality of types of resins are molded by various molding methods. For example, in the case of a two-color molded product composed of two types of resin, insert molding in which a primary molded product previously molded with the first resin is inserted into a predetermined mold and a second resin is injected to integrate the product. It can also be molded by the so-called die slide injection method using a slide mold. It can also be molded by a mold equipped with a movable core that can move forward and backward.

Japanese Unexamined Patent Publication No. 2018-192765 Japanese Unexamined Patent Publication No. 3-130121 Japanese Unexamined Patent Publication No. 2010-094943

When molding a two-color molded product using a mold equipped with a movable core that can move forward and backward, a cavity is formed with the movable core in the primary position, primary molding is performed, and the movable core is moved to the secondary position. A cavity is formed and secondary molding is performed. However, in the mold provided with the movable core, there is a problem that the position of the movable core tends to shift due to the injection pressure acting on the movable core. Patent Documents 1, 2 and 3 describe a two-color molding die that can solve this problem and surely prevent the movable core from retreating in the primary molding. The mold described in Patent Document 1 will be described with reference to FIG.

As shown in FIGS. 6A and 6B, the two-color molded product molded by the mold described in Patent Document 1 is the cover 50 of the smartphone, and the main body portion made of the first resin. It is composed of 51 and a flat plate portion 52 made of a second resin. As shown in FIG. 6C, the mold 54 for molding the cover 50 is provided on the fixed side mold 56 provided on the fixed plate 55 of the injection molding machine and on the movable plate 58. It consists of a movable side mold 59. The movable mold 59 is composed of a receiving plate 60 and a mold plate 62, and a spring is provided between them. When the mold is opened, the mold plate 62 is spaced apart from the receiving plate 60 by a spring force. The receiving plate 60 and the mold plate 62 are in close contact with each other at the time of mold clamping. A hollow is formed in the central portion of the template 62, and a movable core 64 is provided in the hollow so as to be able to move forward and backward. A core-side step portion 66 is formed on the back surface of the movable core 64, and a predetermined step plate 67 is provided so as to face the core-side step portion 66. The step plate 67 is adapted to slide up and down by the drive mechanism 68 in a state of being in contact with the receiving plate 60. Both the core-side step portion 66 and the step plate 67 are formed with strip-shaped peaks and strip-shaped valleys alternately at equal pitches, and depending on the slide position of the step plate 67, the peaks may come into contact with each other or the peaks may be formed. The part and the valley part are designed to mesh with each other. The movable core 64 and the step portion 66 on the core side are urged by the springs 70 and 70, and the movable core 64 retreats from the parting line. A two-color molded product is molded using this mold 54 as follows. First, as shown in FIG. 6D, the step plate 67 is fixed at a predetermined position by the drive mechanism 68. Then, the step plate 67 and the step portion 66 on the core side are in contact with each other at the mountain portions, and the movable core 64 is in the first position where the movable core 64 advances, and a cavity is formed in the mold 54. The first resin is injected from the first injection device 71 to mold the primary molded product, that is, the main body 51 of the cover. When the mold is slightly opened, the template 62 and the receiving plate 60 are separated by the spring urging, and the movable core 64 is retracted by the springs 70 and 70 urging. The step plate 67 is slightly slid by the drive mechanism 68 and molded. Then, as shown in FIG. 6 (E), the step plate 67 and the core side step portion 66 mesh with each other in the mountain portion and the valley portion, and the movable core 64 is maintained in a retracted state. That is, it is in the second position and a cavity is formed in the mold 54. The second resin is ejected from the second injection device 72. A two-color molded product, that is, a smartphone cover 50 is molded. Although the mold 54 described in Patent Document 1 has been described, also in the molds described in Patent Documents 2 and 3, members similar to the core side step portion 66 and the step plate 67 are provided, and the movable core is placed at two positions. Since it can be maintained, a two-color molded product can be molded in the same manner as the molding method described in Patent Document 1.

When two-color molding is performed by the mold 54 described in Patent Document 1, the movable core 64 is restricted from retreating by the core side step portion 66 and the step plate 67, so that the position may shift due to the injection pressure at the time of injection. No. That is, a good product can be stably molded. As a molding method for obtaining a two-color molded product, since the primary molding and the secondary molding are carried out in one mold, it is possible to prevent the adhesion of stains, which can be said to be excellent. .. That is, it is excellent as a mold for molding a two-color molded product. Similarly, the molds described in Patent Documents 2 and 3 are also excellent because they can form a two-color molded product by performing primary molding and secondary molding in one mold. However, depending on the molds described in Patent Documents 1 to 3, it is not possible to mold a multicolor molded product having three or more colors. Explaining the mold described in Patent Document 1 as an example, the movable core 64 is placed in one of the two positions by allowing the step plate 67 and the core side step portion 66 to take two states of whether or not they mesh with each other. This is because it can be held, but it is not supposed to be held at each position for three or more positions. That is, there is no technical idea of holding the movable core at three or more positions. Therefore, even if an attempt is made to mold a multicolor molded product by performing third-order or higher injection, a good product cannot be stably obtained.

An object of the present invention is to provide a mold for molding a multi-color molded product having three or more colors, which solves the above-mentioned problems, and to carry out a plurality of third-order molding in one mold. An object of the present invention is to provide a molding die for a multicolor molded product, which can stably obtain a good multicolor molded product.

In order to achieve the above object, the present invention comprises a movable core that moves back and forth in the cavity, and injects resin a plurality of times while sequentially changing the position of the movable core to obtain a multicolor molded product. set to target. A predetermined plate that slides in the mold is provided in the mold, and a core side plate portion is provided on the rear end surface of the movable core. A predetermined step pattern composed of a plurality of steps whose height changes in three or more steps is provided on one of the plate and the core side plate portion, and this step pattern is repeatedly formed. On the other hand, another step pattern having the same width as the step pattern and having a predetermined step is repeatedly formed. When the plate is changed in position and molded, the meshing state of the step pattern and the other step patterns changes, whereby the position of the movable core is held in the three-step position. As a result, a multicolor molded product having three or more colors is molded.

Thus, the invention according to claim 1 is provided with a movable core that moves back and forth in the cavity in order to achieve the above object, and the resin is injected a plurality of times while sequentially changing the position of the movable core to obtain a multicolor molded product. A mold for multicolor molding, the mold is provided with a predetermined plate that slides in the mold, and a core side plate portion is provided on the rear end surface of the movable core, and the mold is provided with the plate. A predetermined step pattern composed of a plurality of steps whose height changes in three or more steps is repeatedly formed on one of the core side plate portions, and the other is predetermined with the same width as the step pattern. The other stepped pattern provided with the stepped portion is repeatedly formed, and when the multicolor molding die is molded, the stepped portion pattern and the other two stepped portions are formed according to the slide position of the plate. It is configured as a multicolor molding die characterized in that the patterns are meshed with each other in different meshing states, whereby the movable core is held at three or more different positions.
The invention according to claim 2 is for multicolor molding, wherein in the multicolor molding die according to claim 1, the other step pattern is a pattern having the same shape as the step pattern. It is configured as a mold.

As described above, the present invention is intended for a multicolor molding die provided with a movable core that moves back and forth in the cavity and injects resin a plurality of times while sequentially changing the position of the movable core to obtain a multicolor molded product. .. According to the present invention, the mold is provided with a predetermined plate that slides in the mold, a core side plate portion is provided on the rear end surface of the movable core, and one of the plate and the core side plate portion is provided. A predetermined step pattern consisting of a plurality of steps whose height changes in three or more steps is repeatedly formed on the surface thereof, and the other step pattern having the same width as the step pattern and having a predetermined step is provided on the other side. Is repeatedly formed. Then, when the multicolor molding die is molded, the stepped pattern and the other stepped patterns mesh with each other in different meshing states according to the slide position of the plate, whereby the movable core is different at three or more positions. It is designed to be retained. Since the movable core is held at three or more different positions, the resin can be injected by changing the position of the movable core in primary molding, secondary molding, and tertiary molding, and the movable core retracts due to injection pressure. It is possible to mold a non-defective multicolor molded product. By the way, the movable core is held at three or more positions, but it is not always necessary to carry out the third or higher molding. For example, two-color molding consisting of primary and secondary molding can also be performed. It can be said that it is an easy-to-use multicolor molding die that can perform various moldings in this way.

It is a figure which shows the multi-color molded article molded by the molding method which concerns on embodiment of this invention, (A) is the perspective view of the multi-color molded article, (B) is the cross section XX in (A). It is a side sectional view of the cut multicolor molded article. It is a figure which shows the part of the mold and the injection molding machine which concerns on embodiment of this invention, the mold is the cross section, and the injection molding machine is a front view which shows the part. It is a figure which shows typically the method of molding a multicolor molded article by the mold which concerns on embodiment of this invention, and (A)-(D) are the front sectional views of the mold in each step. It is a figure which shows typically the method of molding a multicolor molded article by the mold which concerns on embodiment of this invention, and (A)-(C) are the front sectional views of the mold in each step. It is a figure which shows the plate which is a part of the mold which is a part of the mold which concerns on other Embodiments of this invention, and (A) to (D) are about the mold which concerns on 2nd Embodiment, respectively. , And (E) to (H) are front sectional views showing the plate and the core side plate portion of the mold according to the third embodiment, respectively. In the figure which shows the conventional example, (A) is the perspective view which shows the two-color molded article which is the object of molding, (B) is the sectional view of the two-color molded article cut by the cross section ZZ in (A). (C) is a front sectional view of a two-color molding die, and (D) and (E) are front sectional views of a two-color molding die showing each stage of molding a two-color molded product.

Hereinafter, embodiments of the present invention will be described. The multicolor molded product molded by the molding method according to the present embodiment is a cover C of a smartphone made of three types of resins, and is shown in FIGS. 1A and 1B. The cover C is composed of a cover main body portion C1 made of a first resin, a cover front surface portion C2 made of a second resin, and a cover back surface portion C3 made of a third resin. The peripheral portion of the cover main body portion C1 rises and curves at a predetermined height in one direction, and the rising portion grips the smartphone on its side. By this gripping, the cover C is attached to the smartphone. The center of the cover main body portion C1 is hollowed out in a rectangular shape, and the cover front surface portion C2 and the cover back surface portion C3 are integrally provided here.

The multicolor molding die 1 according to the present embodiment for molding the cover C will be described. As shown in FIG. 2, the multicolor molding die 1 according to the present embodiment is provided on the fixed side mold 5 provided on the fixed plate 3 of the injection molding machine 2 and on the movable plate 6. It is composed of a movable side mold 7 which is formed. The injection molding machine 2 is provided with the first to third injection devices 9, 10 and 11. In the first and second injection devices 9 and 10, the respective injection nozzles come into contact with the sprue of the fixed-side mold 5 from the back surface of the fixed plate 3, and the first and second resins are ejected. On the other hand, the injection nozzle of the third injection device 11 comes into contact with the sprue provided on the side of the movable mold 7, and the third resin is injected. In the third injection device 11, the injection nozzle abuts on the sprue at the time of injection and is separated when the injection is not performed. However, the touch / separation of the injection nozzle will be omitted below.

In the present embodiment, the movable side mold 7 includes a movable side receiving plate 12 and a movable side mold plate 13. Although not shown in FIG. 2, a spring is provided between the movable side receiving plate 12 and the movable side template 13, and when the mold is opened, the movable plate template 13 receives the movable side by spring tension. It floats with respect to the plate 12 by a predetermined interval, and when the mold is fastened, the spring is compressed and comes into close contact with the movable side mold plate 13. A hollow is formed in the central portion of such a movable side template 13, and a movable core 15 is provided in the hollow so as to be able to move forward and backward.

In the molding die 1 according to the present embodiment, the movable core 15 moves in three stages, and the retreat of the movable core 15 is restricted at each moving position, that is, the first to third core positions. It is characterized by points. Since the retreat is restricted, the position is maintained even if the injection pressure acts on the movable core 15. The mechanism that enables the operation of the movable core 15 includes a predetermined plate 16, a core-side plate portion 17, and a piston cylinder unit 18 that slides the plate 16. The back surface of the plate 16 is in contact with the movable side receiving plate 12, and the plate 16 is slidable. That is, it is slid in parallel with the parting line of the movable mold 7. A predetermined step pattern 20 composed of a combination of a plurality of steps is repeatedly formed on the surface of the plate 16. As shown in FIG. 2, the step portion pattern 20 includes first to fourth step portions a1, a2, a3, and a4 having different heights. The heights of the first step portion a1 are low, the third step portion a3 is high, and the second and fourth step portions a2 and a4 are all medium, and are high in the present embodiment. The height has changed in three stages. The core side plate portion 17 is a member fixed to the rear end portion of the movable core 15, and another step pattern 22 is repeated on the surface corresponding to the rear end surface of the movable core 15, that is, the surface facing the plate 16. It is formed. In the present embodiment, the other stepped pattern 22 is formed of stepped portions having the same pattern as the stepped portion pattern 20. The stepped pattern 20 of the plate 16 and the other stepped pattern 22 of the core side plate 17 are in a state of meshing with each other when the multicolor molding die 1 is molded. The meshing state changes depending on the slide position of 16. Specifically, there are three types of meshing states, but when the meshing state changes, the position of the movable core 15 also changes. That is, the position of the movable core 15 changes in three stages. By the way, such a core side plate portion 17 and a movable core 15 are urged in the retracting direction by the spring bodies 24 and 24. However, although not shown in the figure, since a member for limiting the amount of retreat of the core side plate portion 17 is provided, the core side plate portion 17 and the movable core 15 cannot be retreated further after retreating by a predetermined amount. It does not come off from the movable side template 13.

In the parting line of the movable side mold 7, a movable side recess 25 is formed around the movable core 15. A fixed-side recess 26 is also formed in the parting line of the fixed-side mold 5 so as to correspond to the movable-side recess 25. A cavity for forming the cover main body C1 is formed from these recesses 25 and 26 and the side surface of the movable core 15, and a cavity for forming the cover surface C2 is formed from the fixed side recess 26 and the top of the movable core 15. Is formed, and a cavity for forming the back surface portion C3 of the cover is formed from the top of the movable core 15.

A method of molding the cover C, which is a multicolor molded product, with the molding die 1 according to the present embodiment will be described. As shown in FIG. 3A, the molding die 1 is opened. Then, the movable side template 13 is lifted from the movable side receiving plate 12 by a predetermined height by being urged by a spring (not shown in the figure). That is, they are separated. The core side plate portion 17 and the movable core 15 are retracted by the spring bodies 25, 25, but the amount of recession is regulated as described above. The piston cylinder unit 18 is driven to slide the plate 16 to the first slide position. In the first slide position, the stepped portions patterns 20, 20, ... Of the plate 16 and the other stepped portion patterns 22, 22, ... Of the core side plate portion 17 face each other in a predetermined positional relationship. Specifically, in the respective patterns 20 and 22, the highest step portions a3 and a3 face each other. Tighten the mold. Then, as shown in FIG. 3B, the fixed-side mold 5 and the movable-side mold 7 are closed, and the movable-side receiving plate 12 and the movable-side mold plate 13 of the movable-side mold 7 are closed. The plate 16 and the core side plate portion 17 come into close contact with each other. That is, it becomes a predetermined meshing state. As a result, the core side plate portion 17 and the movable core 15 move forward. Then, the upper surface of the movable core 15 comes into contact with the fixed-side recess 26 of the fixed-side mold 5. That is, the movable core 15 becomes the first core position, and the cavity for primary molding is formed. The cover main body portion C1 is molded by injecting the first resin from the first injection device 9 by the primary molding. At this time, the resin pressure due to injection does not act on the upper surface of the movable core 15, but since the movable core 15 is restricted from retreating by the plate 16 and the core side plate portion 17, there is a possibility that the movable core 15 retreats. It can be molded stably without any problem.

After the cover main body C1 is cooled and solidified, the molding die 1 is slightly opened as shown in FIG. 3 (C). When the mold is slightly opened, the movable side mold 5 and the movable side mold 13 are kept closed, and the movable side mold 13 floats from the movable side receiving plate 12 by a predetermined interval. Then, the plate 16 and the core side plate portion 17 are separated from each other, and the core side plate portion 17 and the movable core 15 are retracted by the urging of the spring bodies 25 and 25. The piston cylinder unit 18 is driven to slide the plate 16 to the second slide position. Then, the step pattern 20 of the plate 16 and the other step pattern 22 of the core side plate portion 17 oppose each other in a predetermined positional relationship. Specifically, the step portion a2 having a height in one and the step portion a3 having the highest height in the other face each other. When the molding die 1 is clamped in this state, the movable die 13 is brought into close contact with the movable receiving plate 12 in the movable die 7 as shown in FIG. 3D. At this time, the stepped pattern 20 of the plate 16 and the other stepped pattern 22 of the core side plate 17 come into contact with each other in a predetermined meshing state. The core-side plate portion 17 and the movable core 15 are pushed by the plate 16 and slightly advance. That is, the movable core 15 is at the second core position, and a cavity for secondary molding is formed. The second resin is injected from the second injection device 10 to form the cover surface portion C2. At this time, the resin pressure due to injection acts on the movable core 15, but since the plate 16 and the core side plate portion 17 are fixed in a predetermined meshing state, the retreat of the movable core 15 is restricted. That is, the secondary molding can be stably carried out.

After the cover surface portion C2 is cooled and solidified, the molding die 1 is slightly opened as shown in FIG. 4A. When the mold is slightly opened, the movable side mold 5 and the movable side mold 13 are kept closed, and the movable side mold 13 floats from the movable side receiving plate 12 by a predetermined interval. Then, the plate 16 and the core side plate portion 17 are separated from each other, and the core side plate portion 17 and the movable core 15 are retracted by the urging of the spring bodies 25 and 25. The piston cylinder unit 18 is driven to slide the plate 16 to the third slide position. Then, the step pattern 20 of the plate 16 and the other step pattern 22 of the core side plate portion 17 oppose each other in a predetermined positional relationship. Specifically, one of the highest step portions a3 and the other lowest step portion a1 face each other. When the molding die 1 is clamped in this state, the movable die 13 is brought into close contact with the movable receiving plate 12 in the movable die 7 as shown in FIG. 4 (B). At this time, the stepped pattern 20 of the plate 16 and the other stepped pattern 22 of the core side plate 17 come into contact with each other in a predetermined meshing state. At this time, the core side plate portion 17 and the movable core 15 are not pushed by the plate 16. That is, the movable core 15 is maintained at the third core position, and a cavity for tertiary molding is formed. The third resin is injected from the third injection device 11 to form the cover back surface portion C3. That is, the cover C is molded. At this time, the resin pressure due to injection acts on the movable core 15, but since the plate 16 and the core side plate portion 17 are in a predetermined meshing state, the retreat of the movable core 15 is restricted. That is, the tertiary molding can be stably carried out. The molding die 1 is opened. Then, as shown in FIG. 4 (C), the cover C is projected by a protrusion device (not shown). The cover C of the three-color molded product is molded in the same manner below.

The molding die 1 according to the present embodiment can be deformed in various ways. For example, the stepped pattern 20'formed on the plate 16'and the core side plate 17'and the other stepped pattern 22'can be deformed as shown in FIG. 5 (A). Even with such patterns 20'and 22', as shown by (B), (C) and (D) in FIG. 5, three types of meshing states can be obtained at the time of mold clamping. The movable core 15, not shown in the figure, is maintained in three different positions. Furthermore, the step pattern 20'and the other step patterns 22' need not be formed from the same pattern. As shown in FIG. 5 (E), the stepped pattern 20 ″ and the other stepped pattern 22 ″ may be formed into different patterns from each other. In this case, at least one of the stepped pattern 20 ″ or the other stepped pattern 22 ″ needs to be formed from a plurality of stepped portions whose height changes in three or more steps. The plate 16 ″ and the core side plate portion 17 ″ of this embodiment are also molded by changing the slide position of the plate 16 ″, as shown in FIGS. 5 (F), (G), and (H). As shown in the above, three types of meshing states are obtained, and the movable core 15 (not shown in the figure) is maintained at three positions. As can be easily understood by those skilled in the art, another step pattern 22 ″ may be formed on the plate 16 ″ and a step pattern 20 ″ may be formed on the core side plate portion 17 ″. In the present embodiment, the stepped pattern 20 and the other stepped pattern 22 are described so that the meshing state changes in three stages, whereby the movable core 15 is maintained in three positions, but in four or more stages. The movable core 15 can also be positioned at four positions by changing the meshing state. In this case, a four-color molded product can be molded. Specifically, the stepped pattern 20 may be formed from stepped portions whose height changes in four steps. Further, the shapes of the individual steps constituting the respective step patterns 20 and 22 can be deformed. For example, the step portion can be formed into a trapezoidal shape or a rounded shape. Other deformations are possible, and the core side plate portion 17 and the movable core 15 do not need to be formed from different members and may be integrally formed.

The molding method for molding using the molding die 1 according to the present embodiment can also be modified. In the present embodiment, the movable core 15 is maintained at three positions to perform the first to third moldings, but the movable core 15 is set to the first position, which is the most advanced position, and the primary molding is performed. It may be carried out, and then the secondary molding may be carried out at the third position, which is the last retracted position, to form the two-color molded product. The molding method using the molding die 1 can be variously deformed in this way.

1 Molding mold 2 Injection molding machine 3 Fixed plate 5 Fixed side mold 6 Movable plate 7 Movable side mold 9 1st injection device 10 2nd injection device 11 3rd injection device 12 Movable side receiving plate 13 Movable Side mold plate 15 Movable core 16 Plate 17 Core side plate part 18 Piston cylinder unit 20 Step part pattern 22 Other step part pattern 24 Spring body C cover C1 Cover body C2 Cover front surface C3 Cover back surface

Claims (2)

A multicolor molding die provided with a movable core that moves back and forth in the cavity and injects resin multiple times while sequentially changing the position of the movable core to obtain a multicolor molded product.
The mold is provided with a predetermined plate that slides in the mold, and a core-side plate portion is provided on the rear end surface of the movable core.
A predetermined step pattern composed of a plurality of steps whose height changes in three or more steps is repeatedly formed on one of the plate and the core side plate portion, and the other is the same as the step pattern. Other step patterns with a predetermined step in width are repeatedly formed.
When the multi-color molding die is molded, the stepped pattern and the other stepped pattern are meshed with each other in different meshing states according to the slide position of the plate, whereby the movable core is different. 3 A multicolor molding die characterized in that it is held at the above positions. The multicolor molding die according to claim 1, wherein the other step pattern is a pattern having the same shape as the step pattern.

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