JP7281190B2 - Skin insert injection mold - Google Patents

Description

The present invention relates to a skin insert injection mold.

Skin insert injection molding is a molding method in which a resin base material is molded by injecting a resin onto the back surface of a skin as an insert part to obtain a resin molded product in which the skin and the resin base material are integrated. The skin insert injection molding mold used in this method comprises a first mold for setting the skin and a second mold having an injection port for injecting the resin.

In the skin insert injection molding mold described in Patent Document 1, a skin (synthetic resin sheet) that has been previously formed into a shape that matches the mold surface of the first mold by vacuum molding or the like is placed on the mold surface of the first mold. to set. The first type does not have a vacuum suction hole because it is not necessary. However, in addition to the injection mold, a vacuum mold for pre-shaping the skin is required, which increases the number of steps. Further, when forming, for example, a leather embossed pattern on the mold surface of the first die, etching is mainly used as the forming method, which is time-consuming.

In the skin insert injection molding mold described in Patent Document 2, a flat skin (thermoplastic synthetic resin film) is vacuum-sucked onto the mold surface of the first mold and shaped. A large number of vacuum suction holes are formed in the first mold. The vacuum suction holes need to be micro holes with a diameter of less than 1 mm so as not to leave suction marks on the epidermis, but forming micro holes in the thick first mold by mechanical processing or laser processing is troublesome. Also, like the above, it takes time and effort to etch the grain pattern of the leather.

Therefore, in the skin insert injection molding mold of Patent Document 3, the first mold is a shell mold having a vacuum suction hole formed by electroforming, and a storage recess that is slightly larger than the back surface of the shell mold. It is proposed that the space between the shell mold and the housing recess is decompressed from the outside of the mold and the skin is vacuum-sucked into the shell mold. Since the shell die alone cannot withstand the injection pressure, the shell die is backed up (back supported) by a plurality of support protrusions protruding from the storage recess of the backup die.
Since the vacuum suction holes are formed at the same time as the electroforming, the machining or laser processing described above is unnecessary. Since the diameter of the vacuum suction hole is small on the front side of the shell type and widened on the back side, the epidermis can be strongly suctioned without leaving suction marks. In addition, when a leather grain pattern is formed on a mold surface, it can be formed by transferring it from a model during electroforming, which saves time and effort. Thus, isomorphism has many advantages.

Japanese Utility Model Laid-Open No. 55-5244 JP-A-1-202415 JP-A-61-14922

However, the shell mold cannot be sufficiently backed up with a plurality of support protrusions protruding from the housing recess of the backup mold, such as the skin insert injection molding mold of Patent Document 3, and the injection pressure of the shell mold is high. There was a risk that the mold surface could deform without being able to withstand the pressure. In addition, since the support protrusions are long and thin, they lack strength and may be deformed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to sufficiently back up a shell mold having a vacuum suction hole with a backup mold so that the shell mold can withstand high injection pressure and prevent mold surface deformation.

The present invention provides a skin insert injection molding mold comprising a first mold for setting a skin and a second mold having an injection port for injecting a resin (including elastomer),
The first type consists of a shell type (shell-shaped type) having a thickness of 2 to 6 mm and having a plurality of vacuum suction holes, and a thickness of 10 mm or more having a shape that matches the back surface of the shell type to back up the shell type. and a backup type of
On either or both of the surface of the backup mold and the back surface of the shell mold, which are opposed to each other and serve as mating surfaces, a plurality of distributed receiving surfaces for receiving the mating surfaces are left, and ventilation grooves connected in a net-like manner are recessed,
The area of one receiving surface is 15 to 500 mm ² ,
The ratio of the total area of the receiving surface to the total opening area of the ventilation grooves is 40:60 to 90:10,
The groove depth of the ventilation groove is 0.2 to 3 mm,
The groove width of the ventilation groove is 1 to 7 mm,
The back-up mold is characterized by forming a ventilation hole communicating from the ventilation groove to the outside of the mold.

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The shell mold is backed up by a plurality of receiving surfaces formed on the front surface of the backup mold or the rear surface of the shell mold and receiving the mating surfaces in contact with each other. Since the shell type has a thickness of 2 to 6 mm, it is easy to manufacture by electroforming or the like, and it is easy to form a vacuum suction hole. More preferably, the thickness of the shell type is 2.5 to 5 mm. Since the backup mold has a thickness of 10 mm or more, it has high rigidity. More preferably, the thickness of the backup mold is 20 mm or more.

When the air holes are evacuated by a vacuum suction device outside the mold, the plurality of vacuum suction holes are evacuated through the air grooves connected in a net shape, and the skin is vacuum-sucked to the surface of the shell mold (mold surface).

Since the area of one receiving surface is 15 to 500 mm ² , the receiving surface sufficiently receives the mating surface without damaging or blocking the vacuum suction hole, and the shell mold is pressed against the mold surface by the injection pressure. Back up enough to prevent deformation. If the same area is less than 15 mm ² , the receiving surface tends to bite into the back surface of one vacuum suction hole, and if the same area exceeds 500 mm ² , one receiving surface tends to block the back surfaces of multiple vacuum suction holes collectively. Become. The area of one receiving surface is more preferably 20-300 mm ² , most preferably 25-200 mm ² .

By setting the ratio of the total area of the receiving surface to the total opening area of the ventilation grooves to 40:60 to 90:10, the shell-type backup performance of the receiving surface and the air permeability of the ventilation grooves can be obtained in a well-balanced manner. If the receiving surface is smaller than 40 at the same ratio, the backup performance is reduced, and if the ventilation groove is smaller than 10 at the same ratio, the air permeability is reduced. The ratio is more preferably 40:60 to 80:20.

By setting the groove depth of the ventilation groove to 0.2 to 3 mm, the air permeability of the ventilation groove and the formation efficiency of the ventilation groove can be obtained in a well-balanced manner. Since the height part up to the receiving surface) is not so high, there is no risk of deformation due to lack of strength as in the case of the support projection piece of Patent Document 3. If the groove depth is less than 0.2 mm, air permeability is reduced, and if the groove depth exceeds 3 mm, the formation efficiency of the ventilation grooves is reduced. The groove depth of the ventilation grooves is more preferably 0.2 to 2 mm, most preferably 0.3 to 1 mm.

According to the skin insert injection molding mold of the present invention, the shell mold having the vacuum suction holes can be sufficiently backed up by the backup mold so that the shell mold withstands high injection pressure and does not deform the mold surface.

FIG. 1 shows an exploded first mold of a skin insert injection molding mold of an embodiment, (a) is a perspective view of a shell mold, (b) is a partially enlarged perspective view of a shell main body, and (c) is a backup mold. and (d) is a partially enlarged perspective view of the backup main body. FIG. 2(a) is an exploded sectional view of the first mold, and FIG. 2(b) is a perspective view of the first mold. FIG. 3(a) is a cross-sectional view when the skin is applied to the first mold, and FIG. 3(b) is a cross-sectional view when the skin is vacuum-sucked to the first mold. FIG. 4(a) is a cross-sectional view when the first mold is closed to the second mold, and FIG. 4(b) is a cross-sectional view when the resin is injected onto the back surface of the skin. FIG. 5(a) is a cross-sectional view of the demolded molded product, and FIG. 5(b) is a cross-sectional view of the trimmed molded product. (a) to (d) of FIG. 6 are partial surface views of Examples 2 to 5. FIG. (a) to (d) of FIG. 7 are partial surface views of Examples 6 to 9. FIG.

1. Shell type The shape of the shell type is not particularly limited.
Examples of shell-type materials include, but are not limited to, metals and ceramics.
The type of the shell type produced by the manufacturing method is not particularly limited, but those formed by electroforming are preferable. This is because the production efficiency is high and the fine uneven pattern can be easily formed by transferring from the model.

The following aspects (1) and (2) can be exemplified as vacuum suction holes.
(1) Vacuum suction hole with a constant diameter in the thickness direction The type of vacuum suction hole is not particularly limited, but machining (drilling, etc.), high-energy beam processing (laser processing, electron beam processing, ion beam processing, etc.) processing, etc.) can be exemplified.

(2) The fixed diameter hole on the surface side of the shell mold and the enlarged diameter hole on the back side of the shell mold with a larger diameter than the fixed diameter hole form a vacuum suction hole. Even if the surface is slightly worn due to polishing or long-term use (small enough to leave no trace of vacuum suction on the skin), a constant diameter can be maintained. Moreover, if there is an enlarged diameter hole portion, ventilation resistance can be reduced, and a strong vacuum suction force can be obtained, and clogging can be reduced.
The constant diameter hole preferably has a diameter of 0.07 to 0.3 mm and a length of 0.5 to 2 mm.
It is preferable that the diameter-enlarging hole portion increases in diameter from the terminal end of the constant-diameter hole portion toward the back surface of the shell shape, and preferably has a maximum diameter of 2 mm or more.

As the vacuum suction holes of the aspect (2), the method described in Japanese Patent Application Laid-Open No. 9-249987 proposed earlier by the present applicant (that is, forming a hole-free shell surface layer by electroforming, forming the shell surface layer a constant diameter hole is formed in the shell by high-energy beam machining or the like, and a shell back surface layer is electroformed on the back surface of the shell surface layer, and an enlarged diameter hole is formed at the same time.).
Further, in this method, a method in which the method of forming the constant diameter hole portion is changed can also be exemplified. For example, a shell surface layer in which the tips of a plurality of filaments are embedded is formed by electroforming, and after forming a shell back layer by electroforming, when the tips of the filaments are pulled out from the shell surface layer, the traces of the pulling out are the constant diameter holes. becomes.

By forming a fine concavo-convex pattern on the surface (mold surface) of the shell mold, a fine concavo-convex pattern can be formed by transferring the fine concavo-convex pattern to the surface of the skin vacuum-sucked to the surface. Examples of the fine uneven pattern include, but are not particularly limited to, a leather embossed pattern, a stitch pattern, and a multiple repeating arrangement of geometric unit patterns.

The shell mold is preferably removably attached to the backup mold. This is because the shell type can be easily replaced with a shell type having the same shape but a different fine uneven pattern. Examples of the detachable mounting structure include threading with screws, fitting with a fitting shape, and the like.

2. Backup type The material for the backup type is not particularly limited, but metals, ceramics and the like can be exemplified. However, considering strength, thermal conductivity, cost, etc. comprehensively, steel is preferable.
The type of the ventilation groove according to the manufacturing method is not particularly limited.

The net shape of the ventilation grooves is not particularly limited, but it may be a square grid (including those in which the width is alternately shifted with respect to the vertical), a triangular grid, a hexagonal grid (honeycomb), or between a plurality of circles. , a net shape formed by a plurality of radial rays from the center and a plurality of concentric circles, and the like.
The shape of the receiving surface is not particularly limited, but may be square, triangular, hexagonal, circular, fan-shaped, or the like.

Among these, it is preferable that the net shape of the ventilation grooves is a square lattice shape and the shape of the receiving surface is a square. This is because the square grid-like ventilation grooves can be easily formed by machining.

The groove width (opening width) of the ventilation groove is preferably 1 to 7 mm if it is constant (more preferably 1 to 5 mm), and if it varies, it is 1 mm or more at the narrowest point and 7 mm or less at the widest point. is preferably If the groove width is less than 1 mm, the shell-type vacuum suction holes tend to be difficult to apply, and if the groove width is greater than 7 mm, the shell-type backup performance tends to decrease.

The aspect ratio of the receiving surface (the ratio between the length in the longest direction and the length in the shortest direction; for example, in the case of a square, the ratio between the long side and the short side) is preferably 1:1 to 3:1. This is because the back-up surface of the back-up type does not have directionality in the back-up property of the receiving surface.

It is preferable that the ventilation holes are open at the net-like intersecting points of the ventilation grooves. This is because the communication with the ventilation groove is high.
Although the diameter of the ventilation hole is not particularly limited, it is preferably 5 to 12 mm.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. Note that the materials, configurations, and numerical values described in the examples are examples and can be changed as appropriate.

As shown in FIGS. 3 and 4, the skin insert injection molding die of the embodiment includes a first mold 1 for setting a skin 31 and a second mold 20 having an injection port 23 for injecting resin. In the illustrated example, the first die 1 is a cavity type (female type) and movable type, and the second die 20 is a core type (male type) and a fixed type, but is not limited to this.

As shown in FIGS. 1 to 4, the first mold 1 includes a shell mold 2 having a thickness of 3 mm and a plurality of vacuum suction holes 5, and a surface for backing up the shell mold 2 that matches the back surface of the shell mold 2. and a backup mold 10 having a thickness of 65 to 100 mm.

The shell mold 2 is made of nickel and formed by electroforming. ancillary parts unrelated to A plurality (a large number) of vacuum suction holes 5 are formed dispersedly throughout the shell body portion 3 , and are not formed in the flange portion 4 . In addition, a leather embossed pattern 8 as a fine uneven pattern is formed only on the surface (mold surface) of the shell main body 3 during electroforming.

The vacuum suction hole 5 is composed of a fixed diameter hole portion 6 on the front side of the shell mold 2 and an enlarged diameter hole portion 7 on the back side of the shell mold 2 having a larger diameter than the fixed diameter hole portion 6 . The constant diameter hole portion 6 has a diameter of 0.1 to 0.3 mm and a length of 1 to 2 mm. The enlarged diameter hole portion 7 increases in diameter from the terminal end of the constant diameter hole portion 6 toward the back surface of the shell mold 2, and has a maximum diameter of 3 to 5 mm. This vacuum suction hole 5 is formed by the method described in the section [Mode for Carrying Out the Invention] or a modified example thereof.

The backup mold 10 is made of steel, and has a backup main body 11 (a main body portion that backs up the shell main body 3) having a concave surface that matches the back surface of the shell main body 3, and a seat around the backup main body 11. and a repeat portion 12 . The shell main body 3 enters the backup main body 11 and abuts thereon, and the flange portion 4 is dropped into the counterbored portion 12 and abuts thereon. The shell mold 2 is detachably attached to the backup mold 10 by screwing the flange portion 4 to the counterbore portion 12 .

Ventilation grooves 13 connected in a net shape are recessed in the entire surface of the backup main body 11, leaving a plurality of dispersed receiving surfaces 14 for receiving the back surface of the shell main body 3. - 特許庁
The net shape of the ventilation grooves 13 is a square lattice shape, and the shape of the receiving surface 14 is a square.
When the groove width of the ventilation grooves 13 is 2 mm and one receiving surface 14 is a square of 10 mm square (area 100 mm ² ), the ratio of the total area of the receiving surfaces 14 to the total opening area of the ventilation grooves 13 is 69: 31.
The groove depth of the ventilation groove 13 is 0.6 mm.
The ventilation grooves 13 are easily formed by machining (such as cutting), but may be formed by electric discharge machining or the like.

The backup mold 10 is formed with a ventilation hole 15 that communicates with the ventilation groove 13 from the outside of the mold. A plurality of ventilation holes 15 are formed by notching a part of the receiving surface 14 at the net-like crossing points of the ventilation grooves 13, and the plurality of ventilation holes 15 are gathered into one in the mold and formed on the outer surface of the mold. It is open. The diameter of the ventilation hole 15 is 8 mm.

The second die 20 is made of steel, and has a protrusion 21 that is one size smaller than the recess of the shell body 3 in order to form a cavity with the recess of the shell body 3 .
The second mold 20 has an injection port 23 on one side of the resin passage 22 and a connection port 24 for an injection nozzle on the other side. The configuration of the resin passage 22 is not particularly limited.

Using this skin insert injection mold, the molded product 30 can be molded by the following method.
As shown in FIG. 3( a ), a skin 31 made of a thermoplastic resin sheet softened by heating is applied to the first die 1 .
As shown in FIG. 3(b), when the ventilation holes 15 are evacuated by a vacuum suction device (not shown) outside the mold, the plurality of vacuum suction holes 5 are evacuated via the ventilation grooves 13 connected in a net shape, The skin 31 is vacuum-sucked to the surface (mold surface) of the shell body 3 . At this time, since the vacuum suction hole 5 having the enlarged diameter hole portion 7 has a strong suction force as described above, the leather grain pattern 8 of the shell main body portion 3 is faithfully transferred to the outer skin 31, resulting in a realistic leather grain pattern. shaped.

As shown in FIG. 4( a ), the first mold 1 is closed to the second mold 20 . A cavity is formed between the shell body 3 and the second mold 20 (strictly speaking, between the skin 31 and the second mold 20).
As shown in FIG. 4B, the resin base material 32 is molded by injecting resin into the cavity. At this time, as described above, the receiving surface 14 sufficiently receives the mating surface and sufficiently backs up the shell mold 2 so that the mold surface is not deformed by the injection pressure.

As shown in FIG. 5(a), the molded product 30 in which the resin base material 32 is integrated with the back surface of the skin 31 is demolded, and as shown in FIG. 5(b), the surplus of the skin 31 is trimmed. .

Next, Examples 2 to 9 shown in FIGS. 6 to 7 are examples in which the ventilation groove 13 and the receiving surface 14 are changed, and other aspects are common to Example 1. FIG.
In Example 2 shown in FIG. 6A, the ventilation grooves 13 are in the form of a square lattice, and the receiving surface 14 is a square of 4 mm×4 mm.
In Example 3 shown in FIG. 6B, the ventilation grooves 13 are in the form of a square lattice, and the receiving surface 14 is a square of 15 mm×15 mm.
In Example 4 shown in FIG. 6(c), the ventilation grooves 13 are in the shape of a square lattice, and the receiving surface 14 is a rectangle of 10 mm×20 mm.
In Example 5 shown in FIG. 6(d), the ventilation grooves 13 have a square lattice shape in which the lateral grooves are staggered with respect to the longitudinal grooves, and the receiving surface 14 is a rectangle of 10 mm×20 mm.

In Example 6 shown in FIG. 7(a), the ventilation grooves 13 are in the form of a triangular lattice, and the receiving surface 14 is an equilateral triangle with a side of 10.4 mm.
In Example 7 shown in FIG. 7(b), the ventilation grooves 13 have a hexagonal lattice shape (honeycomb shape), and the receiving surface 14 has a regular hexagon with a side length of 5.85 mm.
In Example 8 shown in FIG. 7(c), the ventilation grooves 13 are net-like formed between a plurality of circles arranged at square lattice points (pitch 12 mm), and the receiving surface 14 is a circle with a diameter of 10 mm.
In the ninth embodiment shown in FIG. 7(d), the ventilation groove 13 has a net shape formed by a plurality of radial lines from the center and a plurality of concentric circles, and the receiving surface 14 has a sector shape.

Table 1 below shows the area of one receiving surface, the width and depth of the ventilation grooves, and the ratio of the total area of the receiving surface to the total opening area of the ventilation grooves in Examples 1 to 9. The groove width of the ventilation groove 13 of Example 8 varies, but is 2 mm at the narrowest point.

It should be noted that the present invention is not limited to the above-described embodiments, and can be embodied with appropriate modifications within the scope of the invention, for example, as described below.
(1) The vacuum suction holes 5 are dispersedly formed in a predetermined area of the shell main body 3 (main body part related to molding), and the vent groove 13 is formed in the corresponding area of the surface of the backup main body 11 corresponding to the predetermined area. and the receiving surface 14 is preferably formed. That is, when the vacuum suction holes 5 are dispersedly formed over the entire surface of the shell main body 3 as in the above-described embodiment, the ventilation groove 13 and the receiving surface 14 are formed over the entire surface (corresponding area) of the backup main body 11 . preferably. Further, when the vacuum suction holes 5 are dispersedly formed in a partial region of the shell main body 3, ventilation grooves are formed in a partial region (corresponding region) of the surface of the backup main body 11 corresponding to the partial region. 13 and a receiving surface 14 are preferably formed. However, it is permissible to form the ventilation groove 13 and the receiving surface 14 in a wider area that includes the corresponding area. The ratio between the total area of the receiving surfaces and the total open area of the ventilation grooves is the ratio in the area where the ventilation grooves 13 and the receiving surfaces 14 are formed.

(2) The ventilation groove 13 and the receiving surface 14 may be formed on the back surface of the shell main body 3 instead of being formed on the front surface of the backup main body 11. Alternatively, the surface of the backup main body 11 and the shell main body may be formed. 3 can also be formed on both of the back surfaces. In these cases as well, the above (1) can be applied to the area where the ventilation groove 13 and the receiving surface 14 are formed.

REFERENCE SIGNS LIST 1 first die 2 shell die 3 shell main body 4 flange 5 vacuum suction hole 6 constant diameter hole 7 enlarged diameter hole 8 leather grain pattern (as fine uneven pattern) 10 backup die 11 backup main body 12 counterbore 13 Ventilation groove 14 Receiving surface 15 Ventilation hole 20 Second mold 21 Projection 22 Resin passage 23 Injection port 24 Connection port 30 Molded product 31 Skin 32 Resin base material

Claims (7)

A skin insert injection molding mold comprising a first mold (1) for setting a skin and a second mold (20) having an injection port (23) for injecting resin,
The first mold (1) consists of a shell mold (2) having a thickness of 2 to 6 mm and having a plurality of vacuum suction holes (5), and a surface of the shell mold (2) for backing up the shell mold (2). A backup mold (10) having a thickness of 10 mm or more and having a shape matching the back surface,
A plurality of dispersed receiving surfaces (14) are left on either one or both of the surface of the backup mold (10) and the back surface of the shell mold (2), which are opposing surfaces facing each other, to form a net shape. A ventilation groove (13) connected to is recessed,
The area of one receiving surface (14) is 15 to 500 mm ² ,
The ratio of the total area of the receiving surface (14) to the total opening area of the ventilation groove (13) is 40:60 to 90:10,
The groove depth of the ventilation groove (13) is 0.2 to 3 mm,
The groove width of the ventilation groove (13) is 1 to 7 mm,
A skin insert injection molding mold characterized in that a backup mold (10) is formed with a ventilation hole (15) communicating from a ventilation groove (13) to the outside of the mold. 2. The skin insert injection molding mold according to claim 1, wherein the net shape of the ventilation grooves (13) is a square grid shape and the shape of the receiving surface (14) is a square shape. The skin insert injection mold according to claim 1 or 2, wherein the groove width of the ventilation groove (13) is 1 to 5 mm. The vacuum suction holes (5) are a fixed diameter hole (6) on the surface side of the shell (2) and an enlarged diameter hole on the back side of the shell (2) having a larger diameter than the fixed diameter hole (6). 4. A skin insert injection mold according to claim 1, 2 or 3, comprising a portion (7). The skin insert injection mold according to claim 4, wherein the constant diameter hole (6) has a diameter of 0.07 to 0.3 mm and a length of 0.5 to 2 mm. The skin insert injection molding mold according to any one of claims 1 to 5, wherein a fine uneven pattern (8) is formed on the surface of the shell mold (2). Skin insert injection molding mold according to any one of claims 1 to 6, wherein the shell mold (2) is removably attached to the backup mold (10).

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