JP7068576B2 - Injection molding mold and its manufacturing method - Google Patents

Description

The present invention relates to an injection molding die and a method for manufacturing the same.

Conventionally, as a mold for injection molding, a mold provided with a sintered portion formed by irradiating an inorganic or organic powder with a light beam is known (see Patent Document 1). Specifically, the injection molding die according to this technique includes a sintered portion and a low-density sintered portion having a lower density than the sintered portion.

The sintered portion and the low-density sintered portion are, for example, a layer made of metal, and the low-density sintered portion is formed at a lower density than the sintered portion, so that the air permeability is higher than that of the sintered portion. ing. The sintered portion and the low-density sintered portion are arranged in the same layer.

Japanese Unexamined Patent Publication No. 2003-1715

However, in the prior art, since the sintered portion and the low-density sintered portion are arranged in the same layer, for example, the scanning speed of the light beam must be changed between the sintered portion and the low-density sintered portion. There is a risk that manufacturing will become complicated, such as disappearing.

Therefore, it is an object of the present invention to facilitate the production of injection molding dies having metal layers having different air permeability.

In order to solve the above-mentioned problems, the injection molding die according to the present invention has a first metal layer having a first portion of a molding surface for forming a cavity and a second portion of the molding surface. A second metal layer is provided.
The second metal layer has higher air permeability than the first metal layer, and the first metal layer is provided on the cavity-side surface of the second metal layer.

According to this configuration, since the second metal layer having higher air permeability than the first metal layer constitutes the second portion of the molded surface, it is possible to degas during resin molding. Since the first portion of the molded surface is composed of the first metal layer having lower air permeability than the second metal layer, the molded product has a molded surface as compared with the case where all of the molded surface is composed of, for example, a metal layer having high air permeability. It is possible to suppress sticking to the metal and improve the releasability of the molded product. Since the first metal layer is provided on the cavity-side surface of the second metal layer, for example, as compared with the case where the first metal layer and the second metal layer are provided in the same layer, manufacturing of an injection molding die. Can be easily performed.

Further, the molded surface has a bottom surface and a side surface extending from the bottom surface in a direction intersecting the bottom surface, and the second metal layer includes the bottom surface and a part of the bottom surface side of the side surface. The first metal layer may have another portion of the side surface.

When manufacturing an injection molding die by three-dimensional molding, for example, when the entire bottom surface is composed of a second metal layer and the entire side surface is composed of a first metal layer, the first metal layer is fired. At the time of bundling, the bottom surface portion of the second metal layer is also heated, and the bottom surface may have a non-breathable density. On the other hand, in the present embodiment, since the second metal layer is formed up to a part of the bottom surface side of the side surface in addition to the bottom surface, the bottom surface portion of the second metal layer is heated at the time of sintering the first metal layer. It becomes difficult and the bottom surface can be formed with the density of the second metal layer.

Further, the injection molding die further includes a third metal layer having higher air permeability than the second metal layer, and the third metal layer sandwiches the second metal layer of the first metal layer. It may be located on the opposite side.

According to this, the gas generated during resin molding passes through the second metal layer and then through the third metal layer, which has higher air permeability than the second metal layer. Therefore, for example, the structure for forming the second metal layer thickly. Compared with, degassing can be performed better. Further, since a second metal layer having a lower air permeability than the third metal layer constitutes a part of the molded surface, the molded product has a molded surface as compared with a structure in which a part of the molded surface is composed of the third metal layer, for example. It is possible to suppress sticking to the metal and improve the releasability of the molded product.

Further, the third metal layer has a bottomed hole that opens on the opposite side of the second metal layer and extends toward the second metal layer, and the bottom of the hole corresponds to the bottom surface. It may be arranged at a position.

According to this, the gas generated during resin molding passes through the second metal layer, then passes through the thin part of the third metal layer, specifically the part from the bottom of the hole to the second metal layer, and is discharged into the hole. Therefore, degassing can be performed better.

Further, even if the injection molding die is sintered into both the second metal layer and the third metal layer and further includes a fourth metal layer having a lower air permeability than the second metal layer. good.

According to this, the second metal layer and the third metal layer can be reinforced by the fourth metal layer having low air permeability.

Further, the fourth metal layer may have a rib molding surface for forming plate-shaped ribs of a molded product.

According to this, since the rib forming surface is composed of the fourth metal layer, it is possible to prevent the plate-shaped ribs from sticking to the rib forming surface.

Further, the fourth metal layer may surround the outer periphery of the second metal layer and the third metal layer.

According to this, the second metal layer and the third metal layer can be reinforced more firmly by the fourth metal layer having low air permeability.

Further, the first metal layer may be formed as a plurality of protrusions protruding from the second metal layer.

According to this, for example, a porous speaker grill can be manufactured.

Further, the maximum thickness of the second metal layer may be smaller than the maximum thickness of the first metal layer.

According to this, the gas generated during resin molding can be easily removed in the thickness direction of the second metal layer.

Further, the maximum thickness of the third metal layer may be larger than the maximum thickness of the first metal layer.

According to this, the rigidity of the third metal layer having the highest air permeability can be increased.

Further, the method for manufacturing an injection molding mold according to the present invention has a first metal layer having a first portion of a molding surface for forming a cavity, and the second portion of the molding surface. It is a method for manufacturing an injection molding mold including a second metal layer having a higher air permeability than the first metal layer, and the second metal layer is formed by irradiating the powder layer with a light beam. By irradiating the powder layer laminated on the cavity side surface of the second metal layer with a light beam, and the step of laminating the powder layer on the cavity side surface of the second metal layer. The step of forming the first metal layer is provided.

According to this, since the first metal layer may be formed on the surface of the second metal layer on the cavity side, injection molding is performed as compared with the case where the first metal layer and the second metal layer are formed in the same layer, for example. The metal mold can be easily manufactured.

According to the present invention, it is possible to facilitate the production of injection molding dies having metal layers having different air permeability.

Further, by forming the bottom surface and a part of the bottom surface side of the molded surface on the bottom surface side with the second metal layer, it is possible to prevent the bottom surface from being blocked by the first metal layer.

Further, by arranging the third metal layer having higher air permeability than the second metal layer on the opposite side of the first metal layer with the second metal layer interposed therebetween, degassing can be performed more satisfactorily.

Further, the third metal layer is opened on the opposite side of the second metal layer to form a bottomed hole extending toward the second metal layer, and the bottom of the hole is arranged at a position corresponding to the bottom surface. Therefore, degassing can be performed better.

Further, by sintering the fourth metal layer, which has lower air permeability than the second metal layer, into both the second metal layer and the third metal layer, the second metal layer and the third metal layer are breathable. Can be reinforced with a lower fourth metal layer.

Further, by forming the rib molding surface for forming the plate-shaped rib of the molded product with the fourth metal layer, it is possible to prevent the plate-shaped rib from sticking to the rib molding surface.

Further, by surrounding the outer periphery of the second metal layer and the third metal layer with the fourth metal layer, the second metal layer and the third metal layer can be reinforced more firmly by the fourth metal layer having low air permeability. can.

Further, by forming the first metal layer as a plurality of protrusions protruding from the second metal layer, for example, a porous speaker grill can be manufactured.

Further, by making the maximum thickness of the second metal layer smaller than the maximum thickness of the first metal layer, the gas generated during resin molding can be easily removed in the thickness direction of the second metal layer.

Further, by making the maximum thickness of the third metal layer larger than the maximum thickness of the first metal layer, the rigidity of the third metal layer having the highest air permeability can be increased.

Further, the second metal layer is provided with a protruding portion protruding from the bottom surface, and the amount of protrusion from the bottom surface of the protruding portion is reduced to 0.6 mm or less, 0.3 mm or less, or 0.1 mm or less as much as possible. Since the ratio of the first metal layer constituting the side surface can be increased, it is possible to satisfactorily suppress the molded product from sticking to the side surface.

Further, by setting the thickness of the base having the bottom surface of the second metal layer to 3 mm or less or 2 mm or less, the gas generated during resin molding can be easily removed in the thickness direction of the second metal layer. be able to.

In addition, by setting the distance from the second metal layer to the bottom of the hole to 1 to 3 mm, the thin part of the third metal layer, specifically the part from the bottom of the hole to the second metal layer, has an appropriate thickness. Therefore, the second metal layer can be satisfactorily reinforced with a thin portion of the third metal layer, and the gas generated during resin molding can be satisfactorily discharged into the holes.

It is sectional drawing which shows the injection molding die which concerns on one Embodiment of this invention. It is sectional drawing which enlarges and shows the structure around the 1st metal layer and 2nd metal layer. It is a figure (a)-(c) for showing the manufacturing method of the injection mold. A diagram (a) showing a step of forming a protrusion on the base of the second metal layer, a diagram (b) showing a step of forming a first metal layer on the protrusion, and a plurality of protruding first metals. It is a figure (c) which shows the state which all the layers were formed. It is sectional drawing which shows the injection molding die which concerns on the modification.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the injection molding die M is a die for molding a porous speaker grill having a speaker portion having a plurality of holes, and is a first mold 1 and a second mold. 2 and nesting 3 are provided.

The first mold 1 is made of a non-breathable metal and has a first molded surface F1 for forming a part of a speaker grill which is a resin molded product. Further, the first mold 1 has a plurality of protrusions 11 for forming a part of a plurality of holes in the speaker portion. The outer peripheral surfaces of the plurality of protrusions 11 form a part of the first forming surface F1.

The second mold 2 is made of non-breathable metal and has a fitting hole 21 into which the nest 3 is fitted and a ventilation hole 22 that escapes from the bottom surface of the fitting hole 21 to the outside. The second mold 2 and the nest 3 have a second molding surface F2 for forming another portion of the speaker grill. Then, when the first mold 1 is aligned with the second mold 2 into which the nest 3 is fitted, the molding surfaces F1 and F2 form a cavity C which is a space for molding the speaker grill.

The second molded surface F2 has a bottom surface F21 and a side surface F22 extending from the bottom surface F21 in a direction intersecting the bottom surface F21. The bottom surface F21 is a surface for forming the surface of the speaker portion, and is arranged so as to face the first mold 1. The side surface F22 is a surface for forming a plurality of holes in the speaker portion, and is formed on each of the plurality of protrusion-shaped first metal layers 31, which will be described later. The side surface F22 extends from the bottom surface F21 toward the first mold 1 and is inclined with respect to the bottom surface F21.

The nesting 3 includes a first metal layer 31, a second metal layer 32 having a higher air permeability than the first metal layer 31, a third metal layer 33 having a higher air permeability than the second metal layer 32, and a second metal. It includes a fourth metal layer 34, which is less breathable than layer 32, and a base 35. Specifically, the second metal layer 32 is formed to have a lower density than the first metal layer 31 and the fourth metal layer 34, so that the second metal layer 32 has higher air permeability than the first metal layer 31 and the fourth metal layer 34. ing. Further, the third metal layer 33 is formed to have a lower density than the second metal layer 32, so that the third metal layer 33 has higher air permeability than the second metal layer 32. The first metal layer 31, the fourth metal layer 34, and the base 35 are formed at a higher density than the second metal layer 32, so that the air permeability is lower than that of the second metal layer 32.

In this embodiment, the first metal layer 31, the fourth metal layer 34, and the base 35 are formed of a non-breathable metal. However, the present invention is not limited to this, and the air permeability of the first metal layer 31, the fourth metal layer 34, and the base 35 may be lower than that of the second metal layer 32, and the first metal layer 31, the fourth metal. The air permeability of each of the layer 34 and the base 35 may be different.

The base 35 is arranged so as to come into contact with the bottom surface of the fitting hole 21 of the second mold 2. The base 35 is formed with a through hole 35A penetrating from the bottom surface side of the fitting hole 21 to the third metal layer 33 side. The through hole 35A communicates with the ventilation hole 22 of the second mold 2.

The third metal layer 33 is laminated on the base 35. Further, the second metal layer 32 is laminated on the third metal layer 33, and the first metal layer 31 is laminated on the second metal layer 32. That is, the third metal layer 33 is arranged on the opposite side of the first metal layer 31 with the second metal layer 32 interposed therebetween.

The third metal layer 33 has a plurality of bottomed holes 33A and a passage 33B connected to the plurality of holes 33A. The hole 33A opens on the side opposite to the second metal layer 32 and extends from the opening toward the second metal layer 32. The bottoms of the plurality of holes 33A are arranged at positions corresponding to the bottom surface F21. Specifically, the bottoms of the plurality of holes 33A are arranged at positions facing the bottom surface F21 (positions directly behind) in the stacking direction of the layers 31 to 33. The passage 33B is formed so as to connect the openings of the plurality of holes 33A and the through holes 35A of the base 35.

The fourth metal layer 34 is arranged on a part of the outer periphery of the second metal layer 32 and the third metal layer 33, and is sintered on both the second metal layer 32 and the third metal layer 33. The fourth metal layer 34 has a rib forming surface 34A for forming a plate-shaped rib of the speaker grill. Specifically, the fourth metal layer 34 is formed in an L shape, and the rib forming surface 34A having an L shape in cross section is aligned with the side surface of the fitting hole 21 of the second mold 2 to form a plate-shaped rib. A concave surface for forming is formed.

The first metal layer 31 is provided on the surface of the second metal layer 32 on the cavity C side, and is formed as a plurality of protrusions protruding from the second metal layer 32. The plurality of protrusion-shaped first metal layers 31 are provided corresponding to the plurality of protrusions 11 of the first mold 1 and are formed so as to abut against the plurality of protrusions 11. The plurality of protrusions of the first metal layer 31 and the plurality of protrusions 11 make it possible to form a plurality of holes in the speaker portion.

The maximum thickness T2 of the second metal layer 32 is smaller than the maximum thickness T1 of the first metal layer 31. Here, the thickness means the size of each layer 31 to 33 in the stacking direction. Further, the maximum thickness T3 of the third metal layer 33 is larger than the maximum thickness T1 of the first metal layer 31.

As shown in FIG. 2, the second metal layer 32 has a base portion 32A having a bottom surface F21 of the second molding surface F2 and a protruding portion 32B protruding from the bottom surface F21. The base 32A is formed to have a constant thickness. Here, the thickness means the size of each layer 31 to 33 in the stacking direction. The thickness L1 of the base portion 32A may be any value as long as it can secure sufficient air permeability while ensuring the rigidity of the base portion 32A. For example, the lower limit value is 0.5 mm or more, 1 mm or more, or 2 mm or more. The upper limit can be 3 mm or less, or 2 mm or less.

The protrusion 32B is formed in a truncated cone shape, and its outer peripheral surface forms a part of the side surface F22 of the second molding surface F2. That is, the second metal layer 32 has a bottom surface F21 and a part of the side surface F22 on the bottom surface F21 side. Here, the bottom surface F21 and a part of the side surface F22 correspond to the second portion of the second molded surface F2. It is sufficient that the amount of protrusion L2 from the bottom surface F21 of the protrusion 32B is equal to or greater than the thickness of one layer of the powder layer in three-dimensional modeling, preferably equal to or greater than the thickness of a plurality of layers. For example, the lower limit is 0. It can be 0.01 mm or more, 0.02 mm or more, or 0.04 mm or more, and the upper limit value can be 0.6 mm or less, 0.3 mm or less, or 0.1 mm or less. The maximum thickness T2 of the second metal layer 32 described above is the sum of the thickness L1 of the base 32A and the protrusion amount L2 of the protrusion 32B.

The first metal layer 31 is provided on the protruding portion 32B of the second metal layer 32, and has another portion of the side surface F22 of the second molded surface F2. Here, the other portion of the side surface F22 corresponds to the first portion of the second molded surface F2.

Further, in the third metal layer 33, the portion from the bottom of the hole 33A to the second metal layer 32 is a thin layer portion 33C having a thickness smaller than that of the other portions. The thickness L3 of the thin layer portion 33C, that is, the distance from the second metal layer 32 to the bottom of the hole 33A can be, for example, 1 to 3 mm.

Next, a method for manufacturing the injection molding die M according to the present embodiment will be described.
As shown in FIG. 3A, first, the base 35 is set in the three-dimensional modeling apparatus 4. Here, the three-dimensional modeling device 4 includes an elevating device (not shown) that elevates the base 35 with respect to the reference surface 41. Further, a jig 42 for filling the through hole 35A is put in the through hole 35A of the base 35.

With the upper surface of the base 35 placed at a position lower than the reference surface 41 by a predetermined amount, powder containing an inorganic or organic metal is put into the upper surface of the base 35, and a blade (not shown) is placed along the reference surface 41. By moving the powder layer, the upper surface of the powder is leveled to form the powder layer 5. The thickness of the powder layer 5 can be, for example, a size equal to or less than the protrusion amount L2 of the protrusion 32B described above. After that, by irradiating a suitable place of the powder layer 5, specifically, a part other than the hole 33A and the passage 33B of the third metal layer 33 with a laser beam, the irradiated part is sintered and the third metal layer 33 is used as a base 35. Laminate on top.

By repeatedly forming the powder layer 5 and irradiating it with laser light, as shown in FIG. 3B, a third metal layer 33 having a plurality of holes 33A and passages 33B is formed. Further, as shown in FIG. 3B, layers having different densities, specifically, the third metal layer 33 and the fourth metal layer 34, within the same layer, that is, within the same range of height from the base 35. When is present, in the step of irradiating the laser beam, the output of the laser beam, the scanning speed of the laser beam, and the like are set to different values in the third metal layer 33 and the fourth metal layer 34, so that the density is increased. Form different layers within the same layer.

Specifically, when the output of the laser beam is increased, a high-density layer is formed, and when the output of the laser beam is decreased, a low-density layer is formed. Further, when the scanning speed of the laser beam is slowed down, a high-density layer is formed, and when the scanning speed of the laser beam is increased, a low-density layer is formed.

After that, by repeating such an operation, as shown in FIG. 3C, the base portion 32A of the second metal layer 32 is formed on the third metal layer 33. Then, as shown in an enlarged manner in FIG. 4A, after the powder layer 5 is laminated on the base portion 32A of the second metal layer 32, the portion of the powder layer 5 corresponding to the protruding portion 32B is formed by the laser device LM. By irradiating the laser beam, a plurality of protruding portions 32B are sequentially formed.

Then, as shown in FIG. 4B, a new powder layer 5 is laminated on the plurality of protrusions 32B and the powder layer 5 filling the space between them. That is, the powder layer 5 is laminated on the surface of the plurality of protrusions 32B on the cavity C side. Then, a part of the first metal layer 31 is formed by irradiating the powder layer 5 laminated on the surface of the plurality of protrusions 32B on the cavity C side with a light beam.

After that, by forming a part of the first metal layer 31 so as to be sequentially stacked in the same manner, as shown in FIG. 4C, a plurality of protruding first metal layers 31 are formed. Nesting 3 in a state where the powder layer 5 is packed in the internal space is manufactured. After that, the jig 42 is removed from the nest 3, and the powder layer 5 inside the nest 3 is broken and removed to the outside of the nest 3, so that the production of the nest 3 is completed.

Based on the above, the injection molding die M of the present embodiment can exert each of the following effects.
Since the second metal layer 32, which has higher air permeability than the first metal layer 31, forms the second portion of the second molding surface F2 (a part of the bottom surface F21 and the side surface F22), degassing during resin molding is performed. Can be done. Since the first metal layer 31, which has lower air permeability than the second metal layer 32, constitutes the first portion of the second molded surface F2 (the other part of the side surface F22), for example, all of the second molded surface has high air permeability. Compared with the case of being composed of a metal layer, it is possible to suppress the molded product from sticking to the second molded surface F2, and it is possible to improve the releasability of the molded product.

Since the first metal layer 31 is provided on the surface of the second metal layer 32 on the cavity C side, the injection molding die is compared with the case where the first metal layer and the second metal layer are provided in the same layer, for example. The mold M can be easily manufactured. In particular, in a situation where it is necessary to form a number of protruding first metal layers 31 corresponding to a large number of holes in the speaker portion as in the present embodiment, for example, the first metal layer and the second metal layer are the same. When the powder layer is arranged in the above layer, the irradiation conditions such as the scanning speed of the laser beam must be changed many times in the step of irradiating the powder layer of one layer with the laser beam, which complicates the production. On the other hand, in the present embodiment, when the protruding first metal layer 31 is formed, it is not necessary to change the irradiation conditions of the laser beam, so that the production can be facilitated.

In the case of manufacturing the injection molding die M by three-dimensional molding, for example, when the entire bottom surface F21 is composed of the second metal layer 32 and the entire side surface F22 is composed of the first metal layer 31, the first metal layer 31 is used. When the 1 metal layer 31 is sintered, the portion of the bottom surface F21 of the second metal layer 32 is also heated, and the bottom surface F21 may have a non-breathable density. On the other hand, in the present embodiment, in addition to the bottom surface F21, a part of the side surface F22 on the bottom surface F21 side is composed of the second metal layer 32. Therefore, when the first metal layer 31 is sintered, the second metal layer 32 The portion of the bottom surface F21 is less likely to be heated, and the bottom surface F21 can be formed at the density of the second metal layer 32.

Further, for example, when the entire bottom surface F21 is composed of the second metal layer 32 and the entire side surface F22 is composed of the first metal layer 31, the corners formed by the bottom surface F21 and the side surface F22 have different densities. Since it is formed of the layers 31 and 32, cracks are likely to occur in the corners. On the other hand, in the present embodiment, in addition to the bottom surface F21, a part of the side surface F22 on the bottom surface F21 side is composed of the second metal layer 32, so that the corners formed by the bottom surface F21 and the side surface F22 have the same density. Since it is formed of a metal layer (second metal layer 32), the occurrence of cracks can be suppressed and the durability can be improved.

By arranging the third metal layer 33, which has higher air permeability than the second metal layer 32, on the opposite side of the first metal layer 31 with the second metal layer 32 interposed therebetween, the gas generated during resin molding is second. After passing through the metal layer 32, it passes through the third metal layer 33, which has higher air permeability than the second metal layer 32. Therefore, for example, the degassing is performed better than the structure in which the second metal layer 32 is formed thicker. Can be done. Further, since the second metal layer 32 having lower air permeability than the third metal layer 33 constitutes a part of the second molded surface F2, for example, the structure is such that a part of the second molded surface is formed of the third metal layer. In comparison, it is possible to prevent the molded product from sticking to the second molded surface F2, and it is possible to improve the releasability of the molded product.

A bottomed hole 33A that opens on the opposite side of the second metal layer 32 and extends toward the second metal layer 32 is formed in the third metal layer 33, and the bottom of the hole 33A is arranged at a position corresponding to the bottom surface F21. By doing so, the gas generated during resin molding passes through the second metal layer 32, then passes through the thin layer portion 33C of the third metal layer 33, and is discharged into the hole 33A, so that the degassing is better. Can be done.

Since the fourth metal layer 34, which has lower air permeability than the second metal layer 32, was sintered into both the second metal layer 32 and the third metal layer 33, the second metal layer 32 and the third metal layer 33 were sintered. Can be reinforced with a fourth metal layer 34 having low air permeability.

Since the rib forming surface 34A is formed by the fourth metal layer 34, it is possible to prevent the plate-shaped ribs from sticking to the rib forming surface 34A.

Since the maximum thickness T2 of the second metal layer 32 is smaller than the maximum thickness T1 of the first metal layer 31, the gas generated during resin molding can be easily removed in the thickness direction of the second metal layer 32. can.

Since the maximum thickness T3 of the third metal layer 33 is made larger than the maximum thickness T1 of the first metal layer 31, the rigidity of the third metal layer 33 having the highest air permeability can be increased.

By reducing the amount of protrusion L2 from the bottom surface F21 of the protrusion 32B to 0.6 mm or less, 0.3 mm or less, or 0.1 mm or less as much as possible, the proportion of the first metal layer 31 constituting the side surface F22 is increased. Therefore, it is possible to satisfactorily prevent the molded product from sticking to the side surface F22.

By setting the thickness L1 of the base portion 32A to 3 mm or less or 2 mm or less, the gas generated during resin molding can be easily removed in the thickness direction of the second metal layer 32.

By setting the thickness L3 of the thin layer portion 33C of the third metal layer 33 to 1 to 3 mm, the second metal layer 32 can be satisfactorily reinforced by the thin layer portion 33C of the third metal layer 33, and the resin can be satisfactorily reinforced. The gas generated during molding can be satisfactorily discharged into the hole 33A.

Although the embodiment of the present invention has been described above, the present invention can be appropriately modified and carried out as shown in the following other embodiments.

In the above embodiment, the fourth metal layer 34 is arranged on a part of the outer periphery of the second metal layer 32 and the third metal layer 33, but the present invention is not limited to this, and as shown in FIG. 5, the fourth metal layer 34 is arranged. The 4 metal layer 34 may surround the outer periphery of the second metal layer 32 and the third metal layer 33. According to this, the second metal layer 32 and the third metal layer 33 can be reinforced more firmly by the fourth metal layer 34 having low air permeability.

Further, as shown in FIG. 5, the fourth metal layer 34 may have a reinforcing portion 34C extending from the surface of the base portion 32A of the second metal layer 32 on the cavity C side to the base 35. For example, a concave rib forming surface 34B for forming a rib that is thinner and higher than the rib formed by the rib forming surface 34A may be formed on the reinforcing portion 34C having such a thickness. Here, for example, when a portion between the bottom surface of the rib forming surface 34B and the base 35 is formed by the third metal layer 33, a crack may occur in that portion, but this portion is formed by the fourth metal layer 34. By forming it, the occurrence of cracks can be suppressed.

The fourth metal layer is not limited to the outer periphery of the second metal layer and the third metal layer, and may be provided inside the second metal layer and the third metal layer.

In the above embodiment, the holes 33A are formed along the stacking direction, but the present invention is not limited to this, and for example, the holes may be formed so as to be inclined with respect to the stacking direction.

In the above embodiment, the injection molding die M for molding the speaker grill is exemplified, but the present invention is not limited to this, and what kind of injection molding die is used for molding. May be.

In the above embodiment, the second metal layer 32 is composed of the base portion 32A and the plurality of protruding portions 32B, but the present invention is not limited to this, and for example, the second metal layer may be composed of only the base portion. good.

In the above embodiment, the bottomed hole 33A is formed in the third metal layer 33, but the present invention is not limited to this, and a hole is formed through the third metal layer 33 in the stacking direction, and the hole is the first. 2 The opening on the metal layer side may be arranged at a position corresponding to the bottom surface.

In the above embodiment, the jig 42 is inserted in the through hole 35A of the base 35, but the present invention is not limited to this, and for example, instead of the jig 42, a powder containing an inorganic or organic metal may be inserted.

Each element described in the above-described embodiment and modification may be arbitrarily combined and carried out.

31 1st metal layer 32 2nd metal layer 33 3rd metal layer 34 4th metal layer C Cavity F2 2nd molding surface F21 Bottom surface F22 Side surface M Injection molding die

Claims (9)

An injection molding die comprising a first metal layer having a first portion of a molding surface for forming a cavity and a second metal layer having a second portion of the molding surface.
The second metal layer is more breathable than the first metal layer.
The first metal layer is provided on the cavity-side surface of the second metal layer.
Further provided with a third metal layer having higher air permeability than the second metal layer,
The third metal layer is arranged on the opposite side of the first metal layer with the second metal layer interposed therebetween.
The molded surface has a bottom surface and side surfaces extending from the bottom surface in a direction intersecting the bottom surface.
The second metal layer has the bottom surface and has the bottom surface.
The third metal layer has a bottomed hole that opens on the opposite side of the second metal layer and extends toward the second metal layer.
An injection molding die characterized in that the bottom of the hole is arranged at a position corresponding to the bottom surface . The second metal layer has a part of the bottom surface side of the side surface.
The injection molding die according to claim 1, wherein the first metal layer has another portion on the side surface. The first or second aspect of the present invention is characterized in that a fourth metal layer which is sintered into both the second metal layer and the third metal layer and has a lower air permeability than the second metal layer is further provided. The described mold for injection molding. The injection molding die according to claim 3 , wherein the fourth metal layer has a rib molding surface for forming plate-shaped ribs of a molded product. The injection molding die according to claim 3 or 4 , wherein the fourth metal layer surrounds the outer periphery of the second metal layer and the third metal layer. The injection molding die according to any one of claims 1 to 5 , wherein the first metal layer is formed as a plurality of protrusions protruding from the second metal layer. The injection molding die according to any one of claims 1 to 6 , wherein the maximum thickness of the second metal layer is smaller than the maximum thickness of the first metal layer. The injection molding die according to any one of claims 1 to 7 , wherein the maximum thickness of the third metal layer is larger than the maximum thickness of the first metal layer. A first metal layer having a first portion of a molded surface for forming a cavity, and a second metal layer having a second portion of the molded surface and having a higher air permeability than the first metal layer. A third metal layer arranged on the opposite side of the first metal layer with the second metal layer interposed therebetween and having higher air permeability than the second metal layer is provided , and the molded surface is a bottom surface and the bottom surface. It has a side surface extending from the bottom surface in a direction intersecting the bottom surface, the second metal layer has the bottom surface, and the third metal layer opens on the side opposite to the second metal layer. A method for manufacturing an injection molding mold, which has a bottomed hole extending toward the second metal layer and the bottom of the hole is arranged at a position corresponding to the bottom surface .
A step of forming the third metal layer having the holes by irradiating the powder layer with a light beam to a portion other than the holes.
The step of laminating the powder layer on the surface of the third metal layer on the cavity side, and
A step of forming the second metal layer on the cavity-side surface of the third metal layer by irradiating the powder layer laminated on the cavity-side surface of the third metal layer with a light beam.
The step of laminating the powder layer on the surface of the second metal layer on the cavity side, and
A step of forming the first metal layer on the cavity-side surface of the second metal layer by irradiating the powder layer laminated on the cavity-side surface of the second metal layer with a light beam. A method for manufacturing an injection molding die.

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