JP2019136941A - Injection mold and its manufacturing method - Google Patents

Abstract

To facilitate the manufacture of injection molds having metal layers with different air permeability.SOLUTION: An injection mold M of this invention includes: a first metal layer 31 having a first portion (most part of the side surface F22) of the molding surface (second molding surface F2) for forming a cavity C; a second metal layer 32 having a second portion (mainly bottom surface F21) of the molding surface. The second metal layer 32 has higher air permeability than the first metal layer 31, and the first metal layer 31 is provided on the cavity C side surface of the second metal layer 32.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, an injection mold having a sintered part formed by irradiating an inorganic or organic powder with a light beam is known (see Patent Document 1). Specifically, the injection mold according to this technique includes a sintered part and a low density sintered part having a density lower than that of the sintered part.

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

JP 2003-1715 A

  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 the manufacturing will be complicated.

  Then, an object of this invention is to make easy manufacture of the metal mold | die for injection molding which has a metal layer from which air permeability differs.

In order to solve the above-described problem, an injection mold according to the present invention includes 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.
The second metal layer has higher air permeability than the first metal layer, and the first metal layer is provided on a surface of the second metal layer on the cavity side.

  According to this configuration, since the second portion of the molding surface is configured by the second metal layer having higher air permeability than the first metal layer, it is possible to perform degassing during resin molding. Since the first portion of the molding surface is composed of the first metal layer having lower air permeability than the second metal layer, for example, the molded product has a molding surface compared to a case where all of the molding surface is composed of a metal layer having high air permeability. It can suppress sticking to, and can improve the mold release property of a molded product. Since the first metal layer is provided on the surface of the second metal layer on the cavity side, for example, compared with the case where the first metal layer and the second metal layer are provided in the same layer, manufacture of an injection mold Can be easily performed.

  The molding surface includes 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 side surface on the bottom surface side. The first metal layer may have the other part of the side surface.

  When manufacturing an injection mold by three-dimensional modeling, for example, when the entire bottom surface is composed of the second metal layer and the entire side surface is composed of the first metal layer, the first metal layer is sintered. The part of the bottom surface of the second metal layer is also heated at the time of bonding, and there is a possibility that the bottom surface has a density with no air permeability. On the other hand, in this embodiment, in addition to the bottom surface, a part of the bottom surface side of the side surface is constituted by the second metal layer, so that the bottom surface portion of the second metal layer is heated during the sintering of the first metal layer. The bottom surface can be formed with the density of the second metal layer.

  The injection mold further includes a third metal layer having higher air permeability than the second metal layer, and the third metal layer is formed on the first metal layer with the second metal layer interposed therebetween. It may be arranged on the opposite side.

  According to this, since the gas generated at the time of resin molding passes through the third metal layer having higher air permeability than the second metal layer after passing through the second metal layer, for example, a structure in which the second metal layer is formed thickly As compared with the above, degassing can be performed better. In addition, since a part of the molding surface is constituted by the second metal layer having lower air permeability than the third metal layer, for example, the molded product has a molding surface compared to a structure in which a part of the molding surface is constituted by the third metal layer It can suppress sticking to, and can improve the mold release property of a molded product.

  The third metal layer has an opening on the side opposite to the second metal layer and has a bottomed hole extending 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, after the gas generated during resin molding passes through the second metal layer, it is discharged into the hole through the thin part of the third metal layer, specifically, the part from the bottom of the hole to the second metal layer. Therefore, degassing can be performed more favorably.

  The injection mold may further include a fourth metal layer that is sintered to both the second metal layer and the third metal layer and has lower air permeability than the second metal layer. Good.

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

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

  According to this, since the rib molding surface is constituted by the fourth metal layer, it is possible to suppress the plate-like ribs from sticking to the rib molding surface.

  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 strongly with the fourth metal layer having low air permeability.

  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.

  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 at the time of resin molding can be easily extracted in the thickness direction of the second metal layer.

  The maximum thickness of the third metal layer may be greater 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.

  In addition, the method for manufacturing an injection mold according to the present invention includes a first metal layer having a first portion of a molding surface for forming a cavity, and a second portion of the molding surface, An injection mold manufacturing method comprising: a second metal layer having a higher air permeability than the first metal layer, wherein the second metal layer is formed by irradiating the powder layer with a light beam. Irradiating a light beam to the powder layer laminated on the cavity side surface of the step, laminating a powder layer on the cavity side surface of the second metal layer, Forming the first metal layer.

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

  ADVANTAGE OF THE INVENTION According to this invention, manufacture of the injection mold which has a metal layer from which air permeability differs can be made easy.

  Moreover, it can suppress that a bottom face is blocked | closed with a 1st metal layer by comprising a bottom face and a part of the bottom face side in a side surface among a shaping | molding surface with a 2nd 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, it is possible to perform gas venting better.

  Also, a hole with a bottom that opens toward the second metal layer and extends toward the second metal layer is formed in the third metal layer, and the bottom of the hole is disposed at a position corresponding to the bottom surface. Therefore, it is possible to perform degassing better.

  In addition, by sintering the fourth metal layer having a 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 made to be air permeable. Can be reinforced with a low fourth metal layer.

  Moreover, it can suppress that a plate-shaped rib adheres to a rib molding surface by comprising the rib molding surface for forming the plate-shaped rib of a molded article with a 4th metal layer.

  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 strongly with the fourth metal layer having low air permeability. it can.

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

  Moreover, 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 extracted in the thickness direction of the second metal layer.

  Moreover, the rigidity of the 3rd metal layer with the highest air permeability can be improved by making the maximum thickness of the 3rd metal layer larger than the maximum thickness of the 1st metal layer.

  In addition, the second metal layer is provided with a protruding portion that protrudes from the bottom surface, and the protruding amount from the bottom surface of the protruding portion is as small as 0.6 mm or less, 0.3 mm or less, or 0.1 mm or less, Since the ratio of the 1st metal layer which comprises a side surface can be increased, it can suppress favorably that a molded article sticks to a side surface.

  Moreover, the gas generated at the time of resin molding is easily extracted in the thickness direction of the second metal layer by setting the thickness of the base portion having the bottom surface of the second metal layer to 3 mm or less or 2 mm or less. 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 portion of the third metal layer, specifically, the portion from the bottom of the hole to the second metal layer can be made to an appropriate thickness. Therefore, the second metal layer can be favorably reinforced at the thin portion of the third metal layer, and the gas generated during resin molding can be discharged well into the hole.

It is sectional drawing which shows the metal mold | die for injection molding which concerns on one Embodiment of this invention. It is sectional drawing which expands and shows the structure around a 1st metal layer and a 2nd metal layer. It is figure (a)-(c) for showing the manufacturing method of the metal mold | die for injection molding. The figure which shows the process of forming a protrusion part on the base part of a 2nd metal layer, the figure which shows the process of forming a 1st metal layer on a protrusion part, and a some 1st metal of protrusion shape It is a figure (c) which shows the state where all the layers were formed. It is sectional drawing which shows the metal mold | die for injection molding which concerns on a modification.

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

  The first mold 1 is made of a non-breathable metal and has a first molding surface F1 for forming a part of a speaker grill which is a resin molded product. Moreover, the 1st metal mold | die 1 has several protrusion 11 for forming a part of several hole of a speaker part. In addition, the outer peripheral surface of the some protrusion 11 comprises a part of 1st shaping | molding surface F1.

  The 2nd metal mold | die 2 consists of a metal with no air permeability, and has the fitting hole 21 in which the nest | insert 3 is inserted, and the ventilation hole 22 which goes out from the bottom face of the fitting hole 21 outside. The second mold 2 and the insert 3 have a second molding surface F2 for forming the other part of the speaker grill. And when the 1st metal mold | die 1 is match | combined with the 2nd metal mold | die 2 in which the nest | insert 3 was inserted, the cavity C which is a space for shape | molding a speaker grille is formed by each molding surface F1, F2.

  The second molding surface F2 has a bottom surface F21 and a side surface F22 extending from the bottom surface F21 toward the direction intersecting the bottom surface F21. The bottom surface F21 is a surface for forming the surface of the speaker portion, and is disposed 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 a plurality of protruding first metal layers 31 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 nest 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. A fourth metal layer 34 having a lower air permeability than the layer 32 and a base 35 are provided. Specifically, the second metal layer 32 has a lower air permeability than the first metal layer 31 and the fourth metal layer 34 by being formed at a lower density than the first metal layer 31 and the fourth metal layer 34. ing. Further, the third metal layer 33 is formed at a lower density than the second metal layer 32, and therefore has a 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 with 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 the present embodiment, the first metal layer 31, the fourth metal layer 34, and the base 35 are formed of a metal having no air permeability. 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 only needs to be lower than that of the second metal layer 32. The air permeability of each of the layer 34 and the base 35 may be different.

  The base 35 is disposed so as to contact the bottom surface of the fitting hole 21 of the second mold 2. A through hole 35 </ b> A that penetrates from the bottom surface side of the fitting hole 21 to the third metal layer 33 side is formed in the base 35. The through hole 35 </ b> A communicates with the vent hole 22 of the second mold 2.

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

  The third metal layer 33 includes a plurality of bottomed holes 33A and a passage 33B connected to the plurality of holes 33A. The hole 33 </ b> A opens to the opposite side of the second metal layer 32 and extends from the opening toward the second metal layer 32. And the bottom of the several hole 33A is arrange | positioned in the position corresponding to the bottom face F21. Specifically, the bottoms of the plurality of holes 33 </ b> A are arranged at positions facing the bottom surface F <b> 21 (true positions) in the stacking direction of the layers 31 to 33. The passage 33 </ b> B is formed so as to connect the openings of the plurality of holes 33 </ b> A and the through holes 35 </ b> A of the base 35.

  The fourth metal layer 34 is disposed on a part of the outer periphery of the second metal layer 32 and the third metal layer 33, and is sintered to both the second metal layer 32 and the third metal layer 33. The fourth metal layer 34 has a rib molding surface 34A for forming a plate-like rib of the speaker grill. Specifically, the fourth metal layer 34 is formed in an L shape, and the rib-shaped 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 so that a plate-shaped rib is formed. 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 protruding first metal layers 31 are provided so as to correspond to the plurality of protrusions 11 of the first mold 1 and are formed so as to abut against the plurality of protrusions 11. A plurality of holes in the speaker portion can be formed by the plurality of protruding first metal layers 31 and the plurality of protrusions 11.

  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 refers to the size of the layers 31 to 33 in the stacking direction. 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 with a constant thickness. Here, the thickness refers to the size of the layers 31 to 33 in the stacking direction. The thickness L1 of the base portion 32A may be a value that can secure sufficient air permeability while securing 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 the outer peripheral surface thereof 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 molding surface F2. The protruding amount L2 from the bottom surface F21 of the protruding portion 32B is sufficient if it is not less than the thickness of one layer of the powder layer in the three-dimensional modeling, desirably not less than the thickness of a plurality of layers. 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 a value obtained by adding the thickness L1 of the base portion 32A and the protrusion amount L2 of the protrusion portion 32B.

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

  Further, in the third metal layer 33, a portion from the bottom of the hole 33A to the second metal layer 32 is a thin layer portion 33C having a smaller thickness than 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 set to 1 to 3 mm, for example.

Next, a method for manufacturing the injection mold M according to this embodiment will be described.
As shown in FIG. 3A, first, the base 35 is set on the three-dimensional modeling apparatus 4. Here, the three-dimensional modeling apparatus 4 includes a lifting device (not shown) that lifts and lowers the base 35 with respect to the reference surface 41. A jig 42 for filling the through hole 35A is placed in the through hole 35A of the base 35.

  With the upper surface of the base 35 disposed at a position lower than the reference surface 41 by a predetermined amount, powder containing an inorganic or organic metal is introduced into the upper surface of the base 35, and a blade (not shown) is moved along the reference surface 41. The powder layer 5 is formed by leveling the upper surface of the powder. In addition, the thickness of the powder layer 5 can be made into the magnitude | size below the protrusion amount L2 of the protrusion part 32B mentioned above, for example. After that, by irradiating an appropriate portion of the powder layer 5, specifically, a portion other than the hole 33 </ b> A and the passage 33 </ b> B of the third metal layer 33, the irradiated portion is sintered to sinter the third metal layer 33 to the base 35. Laminate on top.

  By repeatedly forming the powder layer 5 and irradiating the laser beam, the third metal layer 33 having a plurality of holes 33A and passages 33B is formed as shown in FIG. 3B. Further, as shown in FIG. 3B, layers having different densities, specifically, the third metal layer 33 and the fourth metal layer 34 in the same layer, that is, in the same height range from the base 35. In the step of irradiating the laser beam, the third metal layer 33 and the fourth metal layer 34 have different values for the output of the laser beam, the scanning speed of the laser beam, and the like. Different layers are formed in the same layer.

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

  Thereafter, by repeating such an operation, the base 32A of the second metal layer 32 is formed on the third metal layer 33 as shown in FIG. Thereafter, as shown in an enlarged view in FIG. 4A, after the powder layer 5 is laminated on the base portion 32A of the second metal layer 32, the portion corresponding to the projecting portion 32B of the powder layer 5 is applied to the laser device LM. By projecting the laser beam, a plurality of protrusions 32B are formed sequentially.

  Thereafter, as shown in FIG. 4B, a new powder layer 5 is laminated on the plurality of projecting portions 32 </ b> B and the powder layer 5 filling between these. That is, the powder layer 5 is laminated on the cavity C side surface of the plurality of protrusions 32B. Then, a part of the first metal layer 31 is formed by irradiating the powder layer 5 stacked on the cavity C side surface of the plurality of protrusions 32B with a light beam.

  Thereafter, in the same manner, by forming a part of the first metal layer 31 so as to be sequentially stacked, a plurality of protruding first metal layers 31 are formed as shown in FIG. The insert 3 in which the powder layer 5 is packed in the internal space is manufactured. Thereafter, the jig 42 is removed from the insert 3, and the powder layer 5 inside the insert 3 is broken and removed to the outside of the insert 3, thereby completing the manufacture of the insert 3.

According to the above, the following effects can be produced in the injection mold M of the present embodiment.
Since the second metal layer 32 having higher air permeability than the first metal layer 31 constitutes the second part of the second molding surface F2 (a part of the bottom surface F21 and the side surface F22), degassing is performed during resin molding. Can do. Since the first metal layer 31 having a lower air permeability than the second metal layer 32 constitutes the first portion of the second molding surface F2 (the other part of the side surface F22), for example, the entire second molding surface has a high air permeability. Compared with the case where it is composed of a metal layer, it is possible to suppress the molded product from sticking to the second molding surface F2, and to improve the releasability of the molded product.

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

  When manufacturing the injection mold M by three-dimensional modeling, for example, when the entire bottom surface F21 is configured by the second metal layer 32 and the entire side surface F22 is configured by the first metal layer 31, When the first 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 density without air permeability. On the other hand, in the present embodiment, in addition to the bottom surface F21, the second metal layer 32 is configured up to a part of the side surface F22 on the side of the bottom surface F21. Therefore, when the first metal layer 31 is sintered, The portion of the bottom surface F <b> 21 becomes difficult to be heated, and the bottom surface F <b> 21 can be formed with the density of the second metal layer 32.

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

  By disposing the third metal layer 33 having 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 the resin molding is changed to the second metal layer 32. After passing through the metal layer 32, the gas passes through the third metal layer 33, which has higher air permeability than the second metal layer 32. Therefore, for example, degassing is performed better than a structure in which the second metal layer 32 is formed thick. Can do. In addition, since the second molding surface F2 is partly composed of the second metal layer 32 having a lower air permeability than the third metal layer 33, for example, a part of the second molding surface is composed of the third metal layer. In comparison, the molded product can be prevented from sticking to the second molding surface F2, and the mold release property of the molded product can be improved.

  A bottomed hole 33A that opens to 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 disposed at a position corresponding to the bottom surface F21. As a result, the gas generated during the resin molding passes through the second metal layer 32 and then passes through the thin layer portion 33C of the third metal layer 33 and is discharged into the hole 33A. Can be done.

  Since the fourth metal layer 34 having lower air permeability than the second metal layer 32 is 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 are sintered. Can be reinforced by the fourth metal layer 34 having low air permeability.

  Since the rib molding surface 34A is formed of the fourth metal layer 34, it is possible to prevent the plate-like ribs from sticking to the rib molding surface 34A.

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

  Since the maximum thickness T3 of the third metal layer 33 is 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 protrusion amount 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 ratio of the first metal layer 31 constituting the side surface F22 is increased. Therefore, it is possible to satisfactorily suppress 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 extracted 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 favorably reinforced by the thin layer portion 33C of the third metal layer 33, and resin The gas generated at the time of molding can be discharged well into the hole 33A.

  Although the embodiments of the present invention have been described above, the present invention can be implemented with appropriate modifications as shown in other embodiments below.

  In the said embodiment, although the 4th metal layer 34 was arrange | positioned in a part of outer periphery of the 2nd metal layer 32 and the 3rd metal layer 33, this invention is not limited to this, as shown in FIG. The fourth metal layer 34 may surround the outer periphery of the second metal layer 32 and the third metal layer 33. According to this, the 2nd metal layer 32 and the 3rd metal layer 33 can be reinforced more firmly with the 4th metal layer 34 with low air permeability.

  As shown in FIG. 5, the fourth metal layer 34 may have a reinforcing portion 34 </ b> C extending from the surface on the cavity C side of the base portion 32 </ b> A of the second metal layer 32 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 thick reinforcing portion 34C. Here, for example, when the portion between the bottom surface of the rib forming surface 34 </ b> B and the base 35 is formed with the third metal layer 33, there is a possibility that the portion may crack, but this portion is formed with the fourth metal layer 34. By forming, generation | occurrence | production of a crack 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 embodiment, the holes 33A are formed along the stacking direction. However, 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 said embodiment, although the injection mold M for shape | molding a speaker grill was illustrated, this invention is not limited to this, What kind of molded article is shape | molded with what kind of injection mold It may be.

  In the said embodiment, although the 2nd metal layer 32 was comprised by 32 A of base parts and the some protrusion part 32B, this invention is not limited to this, For example, even if a 2nd metal layer is comprised only by the base part. Good.

  In the embodiment, the bottomed hole 33A is formed in the third metal layer 33. However, the present invention is not limited to this, and a hole penetrating the third metal layer 33 in the stacking direction is formed. You may arrange | position the opening by the side of 2 metal layers in the position corresponding to a bottom face.

  In the above embodiment, the jig 42 is inserted into the through-hole 35A of the base 35. However, the present invention is not limited to this. For example, instead of the jig 42, a powder containing an inorganic or organic metal may be added.

  You may implement combining each element demonstrated by embodiment mentioned above and the modification arbitrarily.

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 mold

Claims (11)

An injection mold 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 has higher air permeability than the first metal layer,
The mold for injection molding, wherein the first metal layer is provided on a surface of the second metal layer on the cavity side. The molding surface has a bottom surface and a side surface extending from the bottom surface in a direction intersecting the bottom surface,
The second metal layer has the bottom surface and part of the bottom surface side of the side surface,
The injection mold according to claim 1, wherein the first metal layer has the other part of the side surface. A third metal layer having higher air permeability than the second metal layer;
The injection mold according to claim 2, wherein the third metal layer is disposed on the opposite side of the first metal layer with the second metal layer interposed therebetween. The third metal layer has a hole with a bottom that opens to the opposite side of the second metal layer and extends toward the second metal layer;
The injection mold according to claim 3, wherein the bottom of the hole is disposed at a position corresponding to the bottom surface.   5. The fourth metal layer according to claim 3, further comprising a fourth metal layer sintered to both the second metal layer and the third metal layer and having lower air permeability than the second metal layer. The mold for injection molding as described.   6. The injection mold according to claim 5, wherein the fourth metal layer has a rib molding surface for forming a plate-like rib of a molded product.   The injection mold according to claim 5 or 6, wherein the fourth metal layer surrounds the outer periphery of the second metal layer and the third metal layer.   The injection mold according to any one of claims 1 to 7, wherein the first metal layer is formed as a plurality of protrusions protruding from the second metal layer.   9. The injection mold according to claim 3, wherein a maximum thickness of the second metal layer is smaller than a maximum thickness of the first metal layer.   The injection mold according to any one of claims 3 to 9, 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 molding surface for forming a cavity; a second metal layer having a second portion of the molding surface and having higher air permeability than the first metal layer; A method of manufacturing an injection mold with
Irradiating the powder layer with a light beam to form the second metal layer;
Laminating a powder layer on the cavity-side surface of the second metal layer;
Irradiating the powder layer laminated on the cavity side surface of the second metal layer with a light beam to form the first metal layer, Mold manufacturing method.

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