JP7190921B2 - Manufacturing method of injection molded product and injection mold - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing an injection-molded article and an injection mold.

For example, among large parts such as instrument panels and bumpers of automobiles, instrument panels are generally molded from resin. In recent years, efforts have also been made to make resin bumpers. When molding these large parts, it is customary to carry out injection molding using an injection molding machine equipped with a pair of molding dies consisting of a core and a cavity having a shape corresponding to the molded product, and an injection unit. Common.

Here, for example, when an instrument panel is manufactured by injection molding, for the purpose of improving the quality of the instrument panel, particularly for the purpose of improving the quality of the design surface, the injection molding material is given a desired color, gloss, texture, etc. The use of obtained resins, elastomers, rubbers, etc. has been investigated and development is underway. However, since the instrument panel is a large-sized part, high strength and rigidity are required, and it is difficult to mold the instrument panel only from materials with excellent design quality. In addition, the fact that the above-mentioned injection material is more expensive than general-purpose resins is also a factor that hinders molding using only the above-mentioned injection material.

Therefore, as an instrument panel that satisfies both mechanical properties such as strength and rigidity and design qualities such as color, gloss, and texture, the first layer, which is the base of the instrument panel, is formed in close contact with the first layer, An injection-molded product having a two-layer structure with a second layer having at least a part of the design surface of the instrument panel (for example, the design surface of the upper surface) is conceivable. As a method for manufacturing an injection-molded article having this two-layer structure, after molding the first layer with a first mold, the first layer is moved onto a core for molding the second layer, and A known method is to prepare a cavity for molding the second layer together with the core, and injection mold the second layer onto the first layer in the insert state with a second mold consisting of these cores and the cavity ( For example, see Patent Document 1).

Alternatively, a method for manufacturing an injection-molded product using an injection molding apparatus having one core and two cavities having different molding surface shapes, wherein one cavity and core are used first After the first layer is injection molded, and then one cavity is replaced with the other cavity (for example, the two cavities are rotated or slid around a predetermined axis) and the other cavity is arranged to face the core. , a method is known in which the second layer is injection molded while the first layer is arranged on the molding surface of the core (see, for example, Patent Document 2).

Alternatively, for the purpose of obtaining a two-layered injection-molded product with one type of mold (a pair of core and cavity), the first layer of the injection-molded product is injected with a single mold consisting of a pair of cores and a cavity. After molding, the core was slid in the mold opening direction (backed the core) to form a new space for molding the second layer between the first layer held on the core side and the cavity. A method is known in which a second layer is injection molded over the first layer in a state (see, for example, Patent Document 3).

If the method described in Patent Document 3 is applied to injection molding of an instrument panel, it is possible to obtain an instrument panel having a two-layer structure with one type of mold (a pair of core and cavity), and two or more types of molds are prepared. An improvement in productivity can be expected due to saving labor, cost, and space. On the other hand, in the case of adopting the two-layer molding method using the core back as described above, if the first layer and the second layer are molded using a general direct gate part, the design surface of the second layer Injection gates have to be placed in the back of the mold, which causes a problem that gate traces remain on the design surface.

Therefore, in Patent Document 4, for example, a runner gate portion for injection that connects with the injection space of the first layer at its side edge is provided in a mold clamped state, and after molding the first layer, the core back operation causes the second layer to move. A method has been proposed in which runner gates for injection are formed, which are connected to the two-layer injection space and the second-layer injection space at their side ends, and the injection material is injected into the second-layer injection space through these runner gates. ing.

JP 2015-168110 A JP 2011-84016 A Japanese Patent Application Laid-Open No. 2005-111820 JP 2011-25712 A

By the way, when the second layer is formed on a part of the first layer (for example, in the case of an instrument panel, the upper surface of the instrument panel) by core backing, the side end of the second layer in the emission space of the second layer A structure is required to seal the corresponding portion. That is, as shown in FIGS. 7(a) and 7(b), the first layer 204 is injection-molded with the injection space 203 for the first layer formed between the core 201 and the cavity 202, and then the core When the second layer injection space 205 is formed between the first layer 204 and the cavity 202 by moving (core back) the second layer injection space 201 away from the cavity 202, core back is simply performed to form the second layer injection space. If 205 is formed, the side end 205a of the emission space 205 of the second layer is connected to the space 206, which should not be emitted (see FIG. 7B). As a result, the injection material for the second layer may flow into the space 206, which should not be injected, and the second layer may not be formed in a predetermined position and range. Therefore, in order to prevent such a situation, for example, as shown in FIG. A structure in which a sealing block 207 is provided is conceivable. With such a structure, the sealing block 207 is moved toward the core 201 so that the sealing block 207 is brought into close contact with the surface 204a of the first layer 204 in accordance with the core-back operation. In the state where the injection space 205 is formed, the space 206, which should not be injected, and the injection space 205 of the second layer are sealed (see FIG. 8B). This makes it possible to mold the second layer at a desired position and range by injecting the injection material only into the injection space 205 of the second layer.

However, when the sealing block 207 is used as described above, the side end 205a of the injection space 205 of the second layer is blocked by the sealing block (FIG. 8(b)). Therefore, for example, when an attempt is made to apply the gate structure described in Patent Document 4 to the manufacture of an injection-molded product having the structure described above, the sealing block 207 becomes an obstacle and the second layer of the injection space 205 of the second layer becomes an obstacle. It is difficult to set the injection gate portion at the portion corresponding to the side end portion of the layer.

The above-mentioned problems are not limited to automobile instrument panels, but may also occur in the manufacture of other types of injection-molded products in which the second layer is formed so as to partially cover the first layer.

In view of the above circumstances, the present invention provides a two-layered injection-molded product in which the second layer is formed so as to partially cover the first layer without leaving gate traces on the design surface of the second layer. The technical problem to be solved is to make it easily manufacturable.

The above problems are solved by a method for manufacturing an injection molded product according to the present invention. That is, this manufacturing method is a method for manufacturing an injection-molded article having a first layer and a second layer covering a part of the first layer, and includes a fixed mold and a movable mold having molding surfaces of the first layer. A first molding step of molding the first layer using and moving at least a part of the molding surface of the first layer in a predetermined direction to form a first layer between the molding surface of the first layer and the first layer a second molding step of molding the second layer after forming the injection space of the two layers, and providing a sealing block to one of the fixed mold and the movable mold to form the injection space of the second layer, The sealing block is moved so as to be in close contact with the side of the first layer, the periphery of the injection space of the second layer is sealed with the sealing block, and the first layer is attached to the other of the fixed mold and the movable mold. By providing a communication block that penetrates from the opposite side of the layer and moving the communication block in a direction away from the first layer, the injection space of the second layer and the second layer are connected through the penetrated portion of the first layer. It is characterized in that it communicates with the injection gate section.

As described above, in the method for manufacturing an injection-molded article according to the present invention, at least a part of the molding surface of the first layer is moved in a predetermined direction, and the first layer is formed between the molding surface of the first layer and the first layer. When forming two layers of injection space, a sealing block is provided on one of the fixed mold and the movable mold, and when forming the injection space, the sealing block is moved so as to be in close contact with the side of the first layer. to seal around the injection space of the second layer. This prevents the injection material of the second layer from flowing into a space where it should not be injected, and the second layer can be accurately formed in a predetermined position and range of the first layer. Further, in the present invention, by providing a communication block that penetrates the first layer from the opposite side of the second layer, and moving the communication block in a direction away from the first layer, through the penetrated portion of the first layer The injection space of the second layer and the injection gate portion of the second layer are communicated with each other. According to this configuration, the second layer injection gate portion is arranged at a position away from the second layer design surface and the side end portion of the second layer injection space. A second layer of injection material can be injected into the space. Therefore, even when the periphery of the injection space of the second layer is sealed with a sealing block as described above, it is possible to reliably avoid leaving gate traces on the design surface, and to partially cover the first layer. It becomes possible to mold the second layer. Further, according to the present invention, the injection gate portion of the second layer can be relatively easily set at an appropriate position by changing the shape, size, position, etc. of the communication block. Therefore, there is no possibility that the injection molding apparatus will be greatly complicated, and there is no concern about the increase in cost. As described above, according to the method for manufacturing an injection-molded product according to the present invention, it is possible to mass-produce high-quality automobile instrument panels in which a part of the first layer is covered with the second layer at low cost.

Moreover, the solution of the above problems is also achieved by an injection mold according to the present invention. That is, this injection mold is an injection mold for molding an injection-molded product that includes a first layer and a second layer that covers a part of the first layer. a fixed mold and a movable mold having surfaces; a sealing block provided on one of the fixed mold and the movable mold; When forming the second layer injection space between the first layer molding surface and the first layer by moving at least a part of the first layer molding surface in a predetermined direction, By moving the sealing block so as to be in close contact with the side of the first layer, sealing the periphery of the injection space of the second layer with the sealing block, and moving the communication block away from the first layer. , the injection space of the second layer and the injection gate portion of the second layer are communicated via the penetrated portion of the first layer.

Thus, in the injection mold according to the present invention, at least part of the molding surface of the first layer is moved in a predetermined direction, and the second layer is formed between the molding surface of the first layer and the first layer. When forming the injection space, a sealing block is provided on one of the fixed mold and the movable mold, and when forming the injection space, the sealing block is moved so as to be in close contact with the first layer side, A seal was provided around the injection space of the second layer. This prevents the injection material of the second layer from flowing into a space where it should not be injected, and the second layer can be accurately formed in a predetermined position and range of the first layer. Further, in the present invention, by providing a communication block that penetrates the first layer from the opposite side of the second layer, and moving the communication block in a direction away from the first layer, through the penetrated portion of the first layer The injection space of the second layer and the injection gate portion of the second layer are communicated with each other. According to this configuration, the second layer injection gate portion is arranged at a position away from the second layer design surface and the side end portion of the second layer injection space. A second layer of injection material can be injected into the space. Therefore, even when the periphery of the injection space of the second layer is sealed with a sealing block as described above, it is possible to reliably avoid leaving gate traces on the design surface, and to partially cover the first layer. It becomes possible to mold the second layer. Further, according to the present invention, the injection gate portion of the second layer can be relatively easily set at an appropriate position by changing the shape, size, position, etc. of the communication block. Therefore, there is no possibility that the injection molding apparatus will be greatly complicated, and there is no concern about the increase in cost. As described above, according to the injection molding die according to the present invention, it is possible to mass-produce, at low cost, a high-quality automotive instrument panel in which a part of the first layer is covered with the second layer.

As described above, according to the method for manufacturing an injection-molded article and the injection mold according to the present invention, the second layer is formed so as to partially cover the first layer without leaving gate traces on the design surface of the second layer. It becomes possible to easily produce an injection-molded article having a two-layer structure formed by forming layers.

1 is a schematic perspective view of an instrument panel manufactured by a manufacturing method according to one embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of a main part of an injection molding apparatus for molding the instrument panel shown in FIG. 1; FIG. 3 is a view for explaining an example of injection molding using the injection molding apparatus shown in FIG. 2, and is a cross-sectional view of the main parts of the injection molding apparatus when the first layer is injection molded. FIG. 3 is a diagram for explaining an example of injection molding using the injection molding apparatus shown in FIG. 2, and is a cross-sectional view of the main parts of the injection molding apparatus at the time when the mold opening operation is completed. FIG. 3 is a diagram for explaining an example of injection molding using the injection molding apparatus shown in FIG. 2, and is a cross-sectional view of the main parts of the injection molding apparatus when movement of the communication block is completed. FIG. 3 is a diagram for explaining an example of injection molding using the injection molding apparatus shown in FIG. 2, and is a cross-sectional view of the main parts of the injection molding apparatus when injection molding of a second layer is completed. It is a figure for explaining the manufacturing method of the injection molded product according to the other first invention, (a) a cross-sectional view of the main part of the injection molding apparatus in the mold closing state, and (b) the injection in the state after the mold opening operation. FIG. 3 is a cross-sectional view of a main part of the molding device; It is a figure for explaining the manufacturing method of the injection molded product according to another second invention, (a) a cross-sectional view of the main part of the injection molding apparatus in the mold closing state, and (b) the injection in the state after the mold opening operation FIG. 3 is a cross-sectional view of a main part of the molding device;

Hereinafter, a method for manufacturing an injection-molded article according to an embodiment of the present invention and details of an injection-molding mold will be described, taking the case of injection-molding an instrument panel for an automobile as an example.

FIG. 1 shows a perspective view of an instrument panel 1 manufactured by a method for manufacturing an injection molded product according to one embodiment of the present invention. This instrument panel 1 integrally has a first layer 2 serving as a base of the instrument panel 1 and a second layer 3 formed so as to partially cover the first layer 2 . In the present embodiment, the first layer 2 corresponds to the remaining regions excluding the surface layer regions of the front surface portion 4 of the instrument panel 1 and the upper surface portion 5 of the instrument panel 1, and the second layer 3 corresponds to the surface layer region of the upper surface portion 5 of the instrument panel 1. is supported. Therefore, in this case, the design surface of the front surface portion 4 of the instrument panel 1 is mainly composed of the area of the surface 2a of the first layer 2 that is not covered with the second layer 3, and the design surface of the upper surface portion 5 of the instrument panel 1. is mainly composed of the surface 3 a of the second layer 3 .

FIG. 2 shows a cross-sectional view of an injection molding apparatus 10 having an injection mold for molding the instrument panel 1 shown in FIG. In this embodiment, it is a cross-sectional view of the main parts of the injection molding apparatus 10 that appears when the instrument panel 1 is cut in the same direction as the AA cross section of the instrument panel 1 shown in FIG. As shown in FIG. 2, this injection molding apparatus 10 includes a fixed mold 20, a movable mold 30, and a first injection mold formed between the fixed mold 20 and the movable mold 30, which serves as an injection space for the first layer 2. A space 41, a second injection space 42 (the area indicated by the two-dot chain line in FIG. 2) which is an injection space for the second layer 3, a slide block 50, a sealing block 60, a communication block 70, a second A first injection gate portion (not shown) communicating with the first injection space 41 and a second injection gate portion 80 communicating with the second injection space 42 are provided. Although not shown, the injection molding apparatus 10 includes one or more first injection units for injecting the injection material into the first injection space 41 through the first injection gate portion, and a second injection unit. and one or more second injection units for injecting the injection material into the second injection space 42 through the injection gate portion 80 .

Here, the material of the injection material for the first layer 2 and the second layer 3 is arbitrary, and it is possible to appropriately select the material according to the properties required for the first layer 2 and the second layer 3. . For example, when the first layer 2 serves as the base of the instrument panel 1 as in the present embodiment, the injection material for the first layer 2 may be a general-purpose thermoplastic resin such as polypropylene or an engineering plastic that exhibits the required mechanical properties. A relatively inexpensive resin can be used. When the purpose of the second layer 3 is mainly to improve the design quality (decorativeness), the injection material for the second layer 3 may be rubber, elastomer, etc., in addition to the above resins. It is possible to employ an injectable material that can exhibit predetermined appearance characteristics such as.

In this embodiment, the fixed mold 20 forms a cavity and the movable mold 30 forms a core. Therefore, the injection spaces 41 and 42 are set so that the design surface side of the front portion 4 of the instrument panel 1 as an injection-molded product is on the fixed mold 20 side, and the opposite design surface side is on the movable mold 30 side. The injection spaces 41 and 42 are set so that the design surface side of the upper surface portion 5 of the instrument panel 1 is on the fixed mold 20 side, and the opposite design surface side is on the movable mold 30 side. As a result, after injection molding of the first layer 2 (Fig. 3), the first layer 2 is held by the movable mold 30 as a core, and when the mold is opened, the first layer 2 moves along with the movable mold 30 in the mold opening direction (Fig. 3). 2 is movable in the x direction).

The slide block 50 is arranged in a region of the fixed mold 20 corresponding to the second layer 3 . In this embodiment, the design surface side surface layer region of the upper surface portion 5 of the instrument panel 1 is the second layer 3 (see FIG. 1), so the slide block 50 is arranged above the first injection space 41 . In this case, the lower surface 50 a of the slide block 50 serves as a molding surface for molding the first layer 2 and also serves as a molding surface for molding the second layer 3 . Therefore, in the clamped state shown in FIG. 2, the lower surface 50a of the slide block 50 forms the first injection space 41 with the molding surface 30a provided on the movable mold 30, and in the mold opened state shown in FIG. , and the surface 2 a of the first layer 2 to form a second injection space 42 .

Although illustration is omitted, the fixed die 20 is provided with a slide guide surface for guiding the slide of the slide block 50 and a biasing member for biasing the slide block 50 in a predetermined direction. This slide guide surface is always in contact with the slide block 50, and as the slide block 50 slides on the slide guide surface, the slide block 50 moves vertically upward as it moves toward, for example, the mold opening direction (the x direction in FIG. 2). The slide block 50 is made slidable so as to move in the z direction in FIG.

The sealing block 60 is provided at a position corresponding to the side end portion 3b of the second layer 3 (here, the end portion of the instrument panel 1 in the vehicle width direction). In this embodiment, the sealing block 60 is provided on the stationary mold 20 and arranged in one or a plurality of divided forms according to the shape of the second layer 3 . When forming the second injection space 42 , the sealing block 60 moves together with the slide block 50 and is movable in the direction (here, the z-direction) to follow the movable mold 30 . In this case, the lower surface 60a of the sealing block 60 becomes the molding surface for molding the first layer 2. As shown in FIG. 2, the lower surface 60a of the sealing block 60 forms the first injection space 41 between the lower surface 50a of the slide block 50 and the molding surface 30a of the movable mold 30. As shown in FIG. 5, the lower surface 60a is in close contact with the surface 2a of the first layer 2. As shown in FIG.

Although not shown, the sealing block 60 is provided with a biasing member that biases the sealing block 60 toward the surface 2 a of the first layer 2 . This biasing member is supported by, for example, a support pin (not shown) penetrating the slide block 50, and is always sealed in a predetermined direction (the z direction in this embodiment) regardless of the sliding movement of the slide block 50. The block 60 can be biased.

The communication block 70 is disposed on the opposite side of the sealing block 60 between the fixed mold 20 and the movable mold 30, that is, on the movable mold 30 side in this case. The upper surface 70a of the communication block 70 forms a part of the molding surface 30a of the movable mold 30, and in the mold clamping state shown in FIG. A first injection space 41 is formed between Further, the communication block 70 is provided with a through portion 70 b that penetrates through the first layer 2 . In this embodiment, the penetrating portion 70b protrudes upward (in the z direction in FIG. 2) from the upper surface 70a, which is the molding surface of the first layer 2, and contacts the lower surface 50a of the slide block 50 when the molds are clamped. touch. Thus, by injection molding the first layer 2, the first layer 2 is formed with a hole portion 2b (a portion to be penetrated) having a shape corresponding to the through portion 70b (see FIG. 3). .

Further, the movable die 30 is provided with a driving device (not shown) for moving the communication block 70 away from the first layer 2 . This driving device is composed of, for example, a cylinder or the like, and can be driven independently of the driving of the movable mold 30 (mold opening operation). Therefore, in the present embodiment, the movable mold 30 moves along the mold opening direction (the x direction in FIG. 2), while the communication block 70 moves in the vertical direction perpendicular to the mold opening direction (the x direction in FIG. 2). z direction) and at a timing different from the mold opening operation. When the communication block 70 is moved downward, the through portion 70b is separated from the hole portion 2b of the first layer 2, and a predetermined communication space is formed between the upper surface 70a and the back surface 2c of the first layer 2. 90 is produced. Further, the communication block 70 has a closing surface 70 c that closes the second injection gate portion 80 provided on the fixed mold 20 on the side of the second injection space 42 . The closing surface 70c closes the second injection gate portion 80 in the mold closing state shown in FIG. 2, and is separated from the second injection gate portion 80 in the mold opening state shown in FIG. Therefore, in this case, the second injection gate portion 80 communicates with the second injection space 42 via the communication space 90 and the space within the hole portion 2b.

Next, an example of a method for manufacturing the instrument panel 1 using the injection molding apparatus 10 configured as described above will be described mainly with reference to FIGS. 2 to 6. FIG.

(S1) First molding step First, as shown in FIG. 2, with the fixed mold 20 and the movable mold 30 clamped, a predetermined injection unit is driven to first inject the injection material for the first layer 2. Eject toward the space 41 . As a result, a molded part having a shape corresponding to the first injection space 41, that is, the first layer 2 is formed (see FIGS. 1 and 3). Further, when the first layer 2 is injection molded, the through portion 70b provided in the communication block 70 is arranged in the first injection space 41 in a state of being in contact with the lower surface 50a of the slide block 50, whereby the first layer 2 is 2 is formed in the first layer 2 (see FIG. 3).

At this time (during molding of the first layer 2), the slide block 50 is in a state of being restricted from sliding along the slide guide surface by the first slide restricting surface (not shown) provided on the movable mold 30. . Further, the sealing block 60 is in a state of being restricted from sliding along the mold opening direction by a second slide restricting surface (not shown) provided on the movable mold 30 . In the state shown in FIG. 3, a predetermined biasing force (elastic restoring force in the case of a spring) is accumulated in each of the biasing member of the slide block 50 and the biasing member of the sealing block 60 (not shown). is in good condition.

(S2) Second Forming Step After forming the first layer 2, the movable mold 30 is driven to start the mold opening operation. At this time, the first slide restricting surface moves in the mold opening direction (here, the x direction) as the movable mold 30 opens, so that the slide block 50 is released from the restricting state. As a result, the slide block 50 receives an urging force from an urging member (not shown) and starts to slide along the slide guide surface. In FIG. 3, the slide block 50 starts to slide in a direction inclined upward with respect to the mold opening direction (x direction).

Further, as the movable mold 30 opens the mold, the first layer 2 starts to move in the mold opening direction integrally with the movable mold 30 while being held on the molding surface 30a of the movable mold 30. The second slide control surface provided on the mold 30 also starts to move in the mold opening direction. As a result, the sealing block 60 is released from the regulated slide state, so that the sealing block 60 receives a biasing force from a biasing member (not shown) while moving together with the slide block 50, and starts to slide downward. do. In this case, the sealing block 60 moves in the mold opening direction following the movable mold 30 and the first layer 2 while keeping the lower surface 60a of the sealing block 60 in close contact with the surface 2a of the first layer 2 .

As the slide block 50 slides in this way, a gap is formed in the vertical direction (the z direction in FIG. 4) between the slide block 50 and the first layer 2 positioned below, and expands. . This gap finally becomes the second injection space 42 for molding the second layer 3 . On the other hand, by sliding the sealing block 60 as described above, the contact state between the lower surface 60a of the sealing block 60 and the surface 2a of the first layer 2 is maintained. There is no gap between the sealing block 60 and the first layer 2 (Fig. 4).

Then, the movable mold 30 is moved in a state in which a gap of a predetermined size, which becomes the second injection space 42, is formed between the surface 2a of the first layer 2 held by the movable mold 30 and the slide block 50. End the mold opening operation (stop the movable mold 30). Next, a driving device (not shown) is driven to move the communication block 70 away from the first layer 2, here vertically downward. As a result, the through portion 70b is separated from the hole portion 2b of the first layer 2, and a predetermined communication space 90 is formed between the upper surface 70a and the back surface 2c of the first layer 2. As shown in FIG. Further, by moving downward the closing surface 70c provided on the communication block 70, the closed state of the second injection gate portion 80 is released. As a result, the second injection gate portion 80 communicates with the second injection space 42 via the communication space 90 and the space within the hole portion 2b (see FIG. 5). In this case, the amount of downward movement of the communication block 70 allows the injection material injected from the second injection gate portion 80 to flow into the second injection space 42 via the communication space 90 and the hole portion 2b. are set as appropriate. Further, in this case, since the communication block 70 can be driven independently of the movable mold 30, by moving the communication block 70 as described above, the sealing block 60 and the first layer 2 can be brought into close contact with each other. The condition cannot be alleviated or resolved. In other words, the side end portion 42a of the second injection space 42 is sealed by the sealing block 60 and the first layer 2 even after the communication operation between the second injection space 42 and the second injection gate portion 80. state is maintained.

After the second injection space 42 is formed as described above, the injection unit (not shown) is driven while the movable mold 30 and the communication block 70 are maintained at the positions shown in FIG. of injection material toward the second injection space 42 . As a result, the injection material for the second layer 3 flows from the second injection gate portion 80 provided in the fixed mold 20 into the second injection space 42 through the communication space 90 and then through the hole portion 2b. A shaped part corresponding to 42, ie the second layer 3, is formed (see FIG. 6). Further, by solidifying the injection material filled in the hole 2b and the communication space 90, the communication part 3c connected to the second layer 3 is formed in the region (see FIG. 6).

After injection molding is performed as shown in FIG. 6, the movable mold 30 is further moved in the mold opening direction from the state shown in FIG. As a result, the instrument panel 1, which is an injection-molded article having a two-layer structure, integrally includes the first layer 2 forming most of the front surface portion 4 and the upper surface portion 5, and the second layer 3 forming the surface layer region of the upper surface portion 5. can get.

As described above, in the method of manufacturing the instrument panel 1 according to the present invention, the lower surface 50a of the slide block 50 forming a part of the molding surface of the first layer 2 is separated from the first layer 2 as the movable mold 30 is opened. direction to form the second injection space 42 between the lower surface 50a and the first layer 2, the slide block 50 forming a part of the fixed mold 20 is provided with a sealing block 60 to open the mold. During operation, the sealing block 60 is moved into close contact with the surface 2 a of the first layer 2 to seal the side edge 42 a of the second injection space 42 . As a result, the injection material of the second layer 3 can be prevented from flowing into a space where it should not be injected, and the second layer 3 can be accurately formed in a predetermined position and range of the first layer 2 . In addition, in the present invention, the communication block 70 that penetrates the first layer 2 from the opposite side of the second layer 3 is provided, and by moving the communication block 70 away from the first layer 2, the first layer 2 The second injection space 42 and the second injection gate portion 80 are communicated with each other through the hole portion 2b which is the penetrated portion. According to this configuration, the second injection gate portion 80 is arranged in the second injection space 42 at a position away from the design surface (surface 3a) of the second layer 3 and the area serving as the side end portion 3b. The injection material of the second layer 3 can be injected into the second injection space 42 . Therefore, even when the side end portion 42a of the second injection space 42 is sealed by the sealing block 60 as described above, it is possible to reliably avoid the situation in which gate traces remain on the design surface (surface 3a). It is possible to mold the second layer 3 so as to cover part of 2 . Further, according to the present invention, the second injection gate portion 80 can be set at an appropriate position relatively easily by changing the shape, size, position, etc. of the communication block 70 . Therefore, there is no possibility that the injection molding apparatus 10 will be greatly complicated, and there is no fear of increasing the cost. As described above, according to the present invention, it is possible to mass-produce high-quality automobile instrument panels 1 in which a part of the first layer 2 is covered with the second layer 3 at low cost.

In this embodiment, the upper surface 70a adjacent to the through portion 70b of the communication block 70 is used as the forming surface of the first layer 2, so that when the communication block 70 is moved, the upper surface and the rear surface 2c of the first layer 2 are formed. A communication space 90 can be formed between them (see FIG. 5). As a result, the hole portion 2b and the second injection gate portion 80 can be communicated over a distance as short as possible, and the injection material can be injected (filled) into the second injection space 42 more smoothly and reliably. becomes.

Of course, according to the method for manufacturing the instrument panel 1 according to the present invention, the instrument panel 1 having a two-layer structure can be injection-molded using only one type of mold (a pair of fixed mold 20 and movable mold 30), which reduces manufacturing costs. , the installation space is also good, and since there is no need to replace the molds (the fixed mold 20 and the movable mold 30), the productivity is also good. As described above, according to the present invention, it is possible to mass-produce high-quality automobile instrument panels 1 in which a part of the first layer 2 is covered with the second layer 3 at low cost.

Although one embodiment of the present invention has been described above, the method for manufacturing an injection-molded product according to the present invention can adopt configurations other than those described above without departing from the scope of the present invention.

For example, in the above-described embodiment, the fixed mold 20 is provided with the slide block 50, and the slide block 50 moves in the x direction (mold opening direction) and the z direction (vertical direction) so that the lower surface 50a of the slide block 50 and the Although the case where the second injection space 42 is formed between the surface 2a of the first layer 2 is illustrated, it is of course possible to form the second injection space 42 by means other than this. For example, although not shown, when the thickness direction of the first layer 2 is the mold opening direction, the first layer 2 moves away from the fixed mold 20 as the movable mold 30 opens the mold, and the first layer 2 moves away from the fixed mold 20. A gap serving as the first injection space may be formed between the surface 2a of the mold 2 and the lower surface of the fixed mold 20 that molds the surface 2a. In this case, the closing surface 70c of the second injection gate portion 80 can be provided on the movable mold 30. In other words, the portion having the closing surface 70c can be omitted, so the communication block 70 can be made smaller.

In addition, in the above-described embodiment, the upper surface 70a of the communication block 70 is used as the molding surface of the first layer 2, but the present invention is not limited to this. For example, although not shown, the molding surface of the first injection space 41 on the side of the movable mold 30 is entirely composed of only the surface of the movable mold 30, and the penetrating part 70b is configured to penetrate the first layer 2 and the movable mold 30. By doing so, the communication space 90 can be provided at a position away from the first layer 2 . In this case, since it is not necessary to form the molding surface of the first layer 2 on the communication block 70, the communication block 70 can be manufactured at a lower cost.

In the above embodiment, the communication block 70 is drivable independently of the movable mold 30, but other configurations are possible. For example, although not shown, an urging member is provided to urge the communication block 70 in a predetermined direction (downward in the example shown in FIG. 2). The communication block 70 may be configured to move downward under the biasing force of the biasing member. In this case, the second injection space 42 is formed and the second injection space 42 and the second injection gate portion 80 communicate with each other when the mold opening operation is completed.

Further, in the above-described embodiment, the fixed mold 20 is the cavity and the movable mold 30 is the core, but the fixed mold 20 may be the core and the movable mold 30 may be the cavity. In this case, the movable mold 30 may be provided with the sealing block 60 and the fixed mold 20 may be provided with the communication block 70 .

In the above-described embodiment, the sealing block 60 is urged by the urging member in a direction to come into close contact with the first layer 2 , so that the lower surface 60 a of the sealing block 60 is the first layer during the mold opening operation of the movable mold 30 . Although the case where it is possible to maintain the state of being in close contact with the surface 2a of the layer 2 has been exemplified, it is of course not limited to this. For example, if there is no problem in terms of installation space, it is possible to adopt a configuration in which the sealing block 60 is moved toward the surface 2a of the first layer 2 by a predetermined driving device such as a cylinder. Of course, the slide block 50 may also be configured to be slidable away from the first layer 2 by a predetermined driving device such as a cylinder.

In the above embodiment, the second layer 3 is formed only on the upper surface of the instrument panel 1, but the second layer 3 may be formed from the upper surface of the instrument panel 1 to part of the front surface.

In the above description, the case where the instrument panel 1 is manufactured as an injection-molded product was exemplified, but of course, the present invention can also be applied to the case where an injection-molded product of a type other than the instrument panel 1 has a two-layer structure. It is possible to apply

1 Automotive instrument panel 2 First layer 2b Hole 3 Second layer 3b Side end 3c Communication part 4 Front part 5 Top part 10 Injection molding device 20 Fixed mold 30 Movable mold 30a Molding surface 41 First injection space 42 Second injection Space 42a Side end 50 Slide block 60 Sealing block 70 Communication block 70b Penetrating part 70c Closing surface 80 Second injection gate part 90 Communication space 201 Core 202 Cavity 203 Injection space 204 First layer 205 Injection space 205a Side end Part 206 Space 207 which should not be emitted originally Block for sealing

Claims (2)

A method for manufacturing an injection-molded article comprising a first layer and a second layer covering part of the first layer,
A first molding step of molding the first layer using a fixed mold and a movable mold having molding surfaces for the first layer;
At least a part of the molding surface of the first layer is moved in a predetermined direction with the mold opening operation of the movable mold, and the second layer is injected between the molding surface of the first layer and the first layer. A second molding step of molding the second layer after forming the space,
A sealing block is provided on one of the fixed mold and the movable mold, and when forming the injection space of the second layer, the sealing block follows the movable mold so as to be in close contact with the side of the first layer. to seal the periphery of the injection space of the second layer with the sealing block, and penetrate the other of the fixed mold and the movable mold through the first layer from the opposite side of the second layer. By moving the communication block in a direction away from the first layer, the injection space of the second layer and the injection space of the second layer are formed through the penetrated portion of the first layer. A method for manufacturing an injection-molded product, which communicates with a gate. An injection mold for molding an injection-molded product comprising a first layer and a second layer covering part of the first layer,
a fixed mold and a movable mold having molding surfaces for the first layer;
a sealing block provided on one of the fixed mold and the movable mold;
a communication block provided on the other of the fixed mold and the movable mold and penetrating the first layer from the opposite side of the second layer;
At least a part of the molding surface of the first layer is moved in a predetermined direction with the mold opening operation of the movable mold, and the second layer is injected between the molding surface of the first layer and the first layer. When forming the space, the sealing block is moved following the movable mold so as to be in close contact with the first layer side, and the periphery of the injection space of the second layer is sealed with the sealing block. and by moving the communication block away from the first layer, the injection space of the second layer and the injection gate portion of the second layer are communicated through the penetrated portion of the first layer. an injection mold configured to

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