JP2016141123A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding where a metal layer is laminated on a metal substrate through a heat insulating layer and is served as a cavity surface and which can suppress deformation of the metal layer due to the in-mold pressure of a molten resin injected from a gate into a cavity.SOLUTION: A mold 1a for injection molding comprises: a metal substrate 2 having a surface corresponding to the shape of a product 6 to be molded in a cavity 1; a heat insulating layer 3 made of a material softer than the substrate 2 and formed on the surface of the substrate 2; and a metal layer 4 formed on a surface of the heat insulating layer 3 to form a surface of the cavity 1. A reinforcing material 11 made of a material harder than that of the heat insulating layer 3 is partially interposed between the metal layer 4 and the substrate 2. The reinforcing material 11 is arranged at a part of a gate 5 injecting a molten thermoplastic resin into the cavity 1. The in-mold pressure of the thermoplastic resin immediately after being injected from the gate 5 into the cavity 1 is supported by the reinforcing material 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an injection mold for forming a cavity filled with a molten thermoplastic resin (hereinafter also referred to as resin).

  In injection molding, heat-melted resin is injected and filled into a cavity formed inside an injection mold (hereinafter also referred to as a mold), and after cooling and solidification, the mold is opened and a molded product (hereinafter referred to as a product). This is a method of molding resin.

  Conventionally, as a mold for injection molding, as shown in FIG. 1, a metal base 2 having a surface corresponding to the shape of a product molded in a cavity 1, and heat insulation provided on the surface of the base 2 There is known a heat insulating mold 1J including a layer 3 and a metal layer 4 provided on the surface of the heat insulating layer 3, and the metal layer 4 forms the surface of the cavity 1 (see Patent Document 1). As the material of the heat insulating layer 3, a heat resistant plastic or a plastic composite material having a lower thermal conductivity than the metal layer 4 is used.

  In this heat insulating mold 1J, the metal layer 4 forming the surface of the cavity 1 is insulated from the base material 2 by the heat insulating layer 3, and the heat capacity of the metal layer 4 is thermally blocked from the base material 2 in a limited manner. It has become a thing. Therefore, when molten resin is injected into the cavity 1 from the gate 5, the metal layer 4 is quickly heated by the heat of the resin, and the fluidity of the resin in the cavity 1 is improved. As a result, defects such as short shots can be suppressed, and transferability of the surface of the cavity 1 to the product is improved.

JP 2000-25046 A

  However, in the conventional heat insulating mold 1J, since the heat insulating layer 3 is made of heat resistant plastic or plastic composite material and cannot be said to have high rigidity, molten resin is injected into the cavity 1 from the gate 5. In this case, the metal layer 4 in the vicinity of the gate 5 is bent by the pressure inside the mold of the resin (for example, 700 kgf / cm 2) (see the phantom line X in FIG. 1). This leads to deterioration in accuracy of the product molded in the cavity 1. Further, every time the molten resin is injected from the karate 5 into the cavity 1, that is, every time one shot of injection molding, the metal layer 4 in the vicinity of the gate 5 is bent, so that metal fatigue accumulates over time, The durability of the mold 1J is reduced.

  The object of the present invention created in view of the above circumstances is to form a cavity from a gate in an injection mold in which a metal layer is laminated on a metal base material via a heat insulating layer, and the metal layer serves as a cavity surface. An object of the present invention is to provide an injection mold that can suppress deformation of the metal layer due to the pressure inside the mold of the molten resin injected into the mold.

  According to the present invention created to achieve the above-mentioned object, an injection mold for forming a cavity filled with a molten thermoplastic resin, depending on the shape of the product molded in the cavity. A metal base material having a surface, a heat insulating layer made of a material softer than the base material provided on the surface of the base material, and a metal layer provided on the surface of the heat insulating layer and forming the surface of the cavity, the metal layer, A reinforcing material made of a material harder than the material of the heat insulating layer is interposed between the base material and the surface of the cavity, and the reinforcing material injects molten thermoplastic resin into the cavity. There is provided an injection mold characterized in that it is disposed at least in an injection portion of a gate for supporting a pressure inside the mold of a thermoplastic resin immediately after being injected into the cavity from the gate.

  In the injection mold according to the present invention, a plurality of reinforcing materials are disposed at intervals in the surface direction of the cavity between the metal layer and the base material, and between the metal layer and the base material. You may serve as the spacer which determines the layer thickness of a heat insulation layer.

  In the injection mold according to the present invention, the reinforcing material may be a metal mesh.

  In the injection mold according to the present invention, the mesh is composed of a plurality of types of mesh pieces having different stitch sizes, and the resin is formed at the gate portion for injecting molten thermoplastic resin into the cavity. A fine mesh piece may be provided at the inflow portion, and a coarse mesh piece may be provided at the downstream side in the resin flow direction.

  In the injection mold according to the present invention, an opposing mold that faces the metal layer, a pressing part that is provided in the opposing mold so as to protrude into the cavity, and for forming a hole in the product, And a reinforcing region part in which a reinforcing material is disposed between the metal layer and the base material at a portion where the pressing part is opposed, and the pressing force in the pressing part is supported by the reinforcing region part.

  In the injection molding mold according to the present invention, between the metal layer and the base material, a heat insulating region portion of only the heat insulating layer is provided so as to surround the portion where the pressing portion is opposed, and the reinforcing material is not provided. You may make it improve the fluidity | liquidity of the thermoplastic resin which flows so that the circumference | surroundings of a press cut part may wrap around in a cavity by a heat insulation area | region part.

  In the injection mold according to the present invention, a heat-insulating layer in which a textured part is formed on a part of the surface of the metal layer, and no reinforcing material is disposed on the part of the textured part between the metal layer and the substrate. In addition to providing a heat insulating region only, a reinforcing region having a reinforcing material disposed in the vicinity of the embossed portion is provided, and the heat flowing in the cavity due to the difference between the heat insulating property of these reinforcing region portions and the heat insulating property of the heat insulating region portion. You may make it guide a plastic resin to the embossed part.

  In the injection mold according to the present invention, an opposing mold facing the metal layer, and a raised part provided on the opposing mold so as to protrude into the cavity and for molding a thin part on the product, Between the metal layer and the base material, a heat insulating region portion having only a heat insulating layer not provided with a reinforcing material is provided at a portion where the raised portion faces, and a reinforcing material is disposed so as to surround the portion where the raised portion faces. The provided reinforcing region portions may be provided, and the thermoplastic resin flowing in the cavities may be guided to the raised portions by the difference between the heat insulating properties of these reinforcing region portions and the heat insulating properties of the heat insulating region portions.

  According to the present invention, a gate for injecting a thermoplastic resin into a cavity between a metal layer and a base material in an injection mold using a metal layer laminated on a base material via a heat insulating layer as a cavity surface Since the reinforcing material that is harder than the heat insulating layer is interposed in this portion, the pressure inside the mold of the thermoplastic resin injected from the gate into the cavity can be supported by the reinforcing material. As a result, the deformation of the metal layer due to the pressure inside the mold of the molten resin injected from the gate into the cavity can be suppressed, and the accuracy of the product molded in the cavity can be improved. Further, since the bending of the metal layer for each shot of injection molding can be suppressed, the durability of the mold can be improved.

It is a sectional side view which shows the metal mold | die for injection molding which shows a prior art example. It is explanatory drawing of the injection mold which concerns on 1st Embodiment of this invention, (a) is a sectional side view of an injection mold, (b) IIa-IIa sectional view taken on the line, (b) These are the plane sectional views which show arrangement | positioning of the reinforcement material of the injection mold, and are the IIb-IIb sectional view taken on the line of (a). It is a perspective view of the product shape | molded with the injection die of FIG. It is sectional drawing which shows the heat insulation layer and reinforcement material of the metal mold | die for injection molding of FIG. 2, (a) shows the type of a metal mesh made of a reinforcement, and (b) shows the type of a sphere made of a ceramic. . It is a graph which shows compression rigidity in the case where a mesh is not put into a heat insulation layer, when a coarse mesh is put, and when a fine mesh is put. It is explanatory drawing of the injection mold which concerns on 2nd Embodiment of this invention, (a) is a cross-sectional view of an injection mold, (b) VIa-VIa sectional view taken on the line, (b) These are the plane sectional views which show arrangement of the reinforcing material of an injection mold, and are the VIb-VIb line sectional views of (a). It is a perspective view of the product shape | molded with the injection die of FIG. It is explanatory drawing of the metal mold | die for injection molding which concerns on 3rd Embodiment of this invention, (a) is a cross-sectional view of a metal mold | die for injection molding, (b) VIIIa-VIIIa sectional view taken on the line, (b) These are the plane sectional views which show arrangement of the reinforcing material of an injection mold, and are the VIIIb-VIIIb line sectional views of (a). It is a perspective view of the product shape | molded with the injection die of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First Embodiment: Outline of Injection Mold 1a)
FIG. 2 shows an outline of an injection mold 1a according to the first embodiment of the present invention. The injection mold 1a according to the present embodiment forms a cavity 1 filled with a molten thermoplastic resin, and corresponds to the shape of a product 6 (see FIG. 3) molded in the cavity 1. A metal base 2 having a surface, a heat insulating layer 3 made of a material softer than the base 2 provided on the surface of the base 2, and a metal layer 4 provided on the surface of the heat insulating layer 3 and forming the surface of the cavity 1 And. This mold is referred to as a cavity mold 7.

  In addition to the cavity mold 7 described above, the injection mold 1 a includes an opposing mold (core mold 8) that faces the metal layer 4 of the cavity mold 7. The core mold 8 and the cavity mold 7 are openable and closable (contactable and separable). When the core mold 8 and the cavity mold 7 are closed, molten thermoplastic resin is injected from the gate 5 into the cavity 1 formed inside thereof. After the resin is cured, the core mold 8 and the cavity mold 7 are opened, and the product 6 (see FIG. 3) is taken out from the cavity 1. The gate 5 is formed at the end of the core mold 8.

  The core mold 8 is provided with a cylindrical pressing part 9 so as to protrude into the cavity 1. When the core mold 8 and the cavity mold 7 are closed, the top surface of the pressing part 9 provided in the core mold 8 is in a state of lightly contacting the surface of the metal layer 4 of the cavity mold 7. This pressing part 9 forms the hole 10 in the product 6 (thin plate, about 2 mm thick) shown in FIG.

  A reinforcing material 11 made of a material harder than the material of the heat insulation layer 3 is interposed between the metal layer 4 of the cavity mold 7 and the base material 2 along the surface direction of the cavity 1. The reinforcing material 11 is disposed at least in the injection portion of the gate 5 for injecting the molten thermoplastic resin into the cavity 1, and the pressure inside the mold of the thermoplastic resin immediately after being injected into the cavity 1 from the gate 5. Support. Further, the reinforcing material 11 is also disposed on the part of the core die 8 facing the pressing part 9. The reinforcing material 11 supports the pressing pressure at the pressing part 9 when the core mold 8 and the cavity mold 7 are closed. The reinforcing material 11 will be described in detail later.

(Thermoplastic resin)
The thermoplastic resin injected into the cavity 1 from the gate 5 shown in FIG. 2A is a resin that becomes soft when heated to the melting point and can be formed into a desired shape. Specific examples include amorphous plastics such as polyethersulfone (PES), polycarbonate (PC), acrylic (PMMA), ABS, and other engineering plastics, as well as crystalline resins such as PEEK, PPS, polyethylene (PE), and polypropylene. (PP) or the like is used. The thermoplastic resin is injected into the cavity 1 from the gate as a molten material. The pressure in the mold of the resin injected into the cavity 1 is, for example, about 700 kgf / cm 2.

(Substrate 2)
The surface of the substrate 2 is formed in accordance with the basic shape of the product 6 (see FIG. 3) molded in the cavity 1, whereby the basic shape of the product 6 is molded. In the case where fine irregularities (textures, patterns, etc.) are provided on the surface of the product 6, not only the surface of the base material 2, but also the surface of the metal layer 4 is provided with irregularities corresponding to the textures, patterns, etc. The embossed portion is used to transfer and emboss a texture and pattern on the surface of the product 6. As the material of the base material 2, metals such as pre-hardened steel, carbon steel, and aluminum are used. The thickness of the substrate is about 20 mm.

(Insulation layer 3)
A heat insulating layer 3 is formed on the surface of the substrate 2. The heat insulating layer 3 suppresses the transfer of the thermal energy of the molten resin injected into the cavity 1 to the base material 2 and suppresses a decrease in fluidity due to a decrease in the temperature of the molten resin. As the heat insulating layer 3, an epoxy resin mixed with a glass filler is used, which also serves as an adhesive for joining the base material 2 and the metal layer 4. In addition to the epoxy resin, phenol resin, PEEK resin, melanin resin, polyurethane resin, PPS, polyethersulfone (PES) or the like may be used for the heat insulating layer 3, and glass filler, ceramic powder or the like may be used. A mixture may be used. The heat insulation layer 3 has a thickness of about 0.1 mm to 1 mm (preferably 0.4 mm to 0.7 mm).

(Metal layer 4)
A metal layer 4 is formed on the surface of the heat insulating layer 3. The metal layer 4 forms the surface of the cavity 1. The metal layer 4 is insulated from the base material 2 by the heat insulating layer 3, and the heat capacity of the metal layer 4 is limited to be thermally shielded from the base material 2. For this reason, when the metal layer 4 receives thermal energy from the molten resin injected into the cavity 1, the metal layer 4 is easily heated to its full heat capacity and rises in temperature. Therefore, the fluidity | liquidity fall by the temperature of the molten resin in the cavity 1 falling can be suppressed. Moreover, since the metal layer 4 covers the heat insulating layer 3, the deterioration of the heat insulating layer 3 caused by the molten resin injected into the cavity 1 directly contacting the heat insulating layer 3 is prevented. The function of protecting the heat insulating layer 3 from heat is also exhibited.

  The metal layer 4 is made of prehardened steel, stainless steel, aluminum, copper alloy, nickel alloy, carbon steel or the like in consideration of strength and specific heat. The layer thickness of the metal layer 4 is about 0.2 mm to 1 mm (preferably 0.5 to 0.6 mm). In addition, when providing a fine unevenness | corrugation (texture, a pattern, etc.) on the surface of the product 6 (refer FIG. 3) shape | molded in the cavity 1, the decoration part according to the surface, the pattern, etc. on the surface of the metal layer 4 Are formed on the surface of the product 6 by this decorative portion.

(Reinforcing material 11)
As shown in FIGS. 2A and 2B, the material of the heat insulating layer 3 is partially formed along the surface direction of the cavity 1 between the metal layer 4 of the cavity mold 7 and the base material 2. A reinforcing material 11 made of a harder material is interposed. The reinforcing material 11 is disposed at least in the injection portion of the gate 5 for injecting the molten thermoplastic resin into the cavity 1, and the pressure inside the mold of the thermoplastic resin immediately after being injected into the cavity 1 from the gate 5. Support.

  That is, the high mold pressure (for example, 700 kgf / cm 2) of the thermoplastic resin immediately after being injected into the cavity 1 from the gate 5 is supported by the reinforcing material 11. As a result, the deformation of the metal layer 4 at the gate injection portion due to the pressure inside the mold of the molten resin injected from the gate 5 into the cavity 1 can be suppressed, and the accuracy of the product 6 molded in the cavity 1 (see FIG. 3). Can be improved. Moreover, since the bending of the metal layer 4 in the gate injection part for each shot of injection molding can be suppressed, the durability of the mold (cavity mold 7) can be improved.

  In addition, since the molten resin which has passed through the portion of the reinforcing material 11 of the gate injection portion from the gate 5 and entered the ridge of the cavity 1 is in a reduced pressure state, the metal layer 4 is deformed even without the reinforcing material 11. In other words, the temperature and fluidity of the molten resin can be maintained by the high heat insulating property of only the heat insulating layer 3 without the reinforcing material 11, and problems such as short shots can be suppressed.

(mesh)
The reinforcing material 11 is made of a metal mesh. The mesh 11 is configured by knitting vertical mesh lines and horizontal mesh lines in a lattice shape, and is disposed between the base material 2 and the metal layer 4 together with the heat insulating layer 3 (epoxy resin or the like). . By pressing the base material 2 and the metal layer 4 together with the material of the heat insulating layer 3 (such as an epoxy resin before curing) and the mesh 11 sandwiched between the base material 2 and the metal layer 4, FIG. In the state a), the material of the heat insulating layer 3 (epoxy resin or the like) enters between the mesh lines of the mesh 11, the upper surface of the mesh 11 is in contact with the base material 2, and the lower surface of the mesh 11 is in contact with the metal layer 4. As a result, the distance between the substrate 2 and the metal layer 4 is twice the diameter of the mesh line, and the mesh 11 serves as a spacer that determines the distance between the substrate 2 and the metal layer 4.

  With this mesh 11, when molten resin is injected from the gate 5 into the cavity 1 and pressure in the mold is applied to the cavity inner surface (metal layer 4) near the gate 5, the compression rigidity of the cavity inner surface can be increased. . In FIG. 4A, even if the material of the heat insulating layer 3 (epoxy resin or the like) is interposed between the upper surface of the mesh 11 and the base material 2 and between the lower surface of the mesh 11 and the metal layer 2. I do not care. Thus, even when the mesh 11 is in a floating state in the heat insulating layer 3 between the base material 2 and the metal layer 4, the mesh 11 is not present in the heat insulating layer 3 between the base material 2 and the metal layer 4. , The amount of bending of the material of the heat insulating layer 3 (such as epoxy resin) due to the pressure in the mold is reduced, and the amount of bending of the metal layer 4 can be reduced.

  The reinforcing material 11 is not limited to the mesh 11 described above, and may be a sphere 12 made of metal or ceramic as shown in FIG. Similarly to the mesh 11, the spherical body 12 can suppress the bending of the metal layer 4 due to the pressure in the mold, and can increase the compression rigidity of the cavity inner surface. In FIG. 4B, the spheres 12 are adjacent to each other so as to be in contact with each other, but a slight interval may be generated between the spheres 12. The diameter of the sphere 12 is, for example, about 0.6 mm.

(Fine mesh piece 11a, coarse mesh piece 11b)
As shown in FIG. 2 (b), the metal mesh 11 constituting the reinforcing material 11 has a plurality of types of mesh pieces 11 a and 11 b having different stitch sizes, and injects molten thermoplastic resin into the cavity 1. In the injection part of the gate 5 for this purpose, a fine mesh piece 11a is arranged at the resin inflow portion, and a coarse mesh piece 11b is arranged at the downstream side in the resin flow direction. The coarse mesh piece 11b has a material SUS304, a wire diameter of 0.34 mm, and a mesh size (number of meshes per inch (25.4 mm)) of 14. The fine mesh piece 11a has a coarse mesh piece and a material and wire diameter. It is the same and has a scale of 30.

  The fine mesh pieces 11a and the coarse mesh pieces 11b are in a state in which the material (epoxy resin or the like) of the heat insulating layer 3 is inserted between the mesh lines (see FIG. 4A). Accordingly, the amount of the material of the heat insulating layer (epoxy resin or the like) entering between the mesh lines is different, and the coarse mesh 11b is made of the material (epoxy resin or the like) of the heat insulating layer 3 entering between the mesh lines than the fine mesh 11a. Large amount. For this reason, as for heat insulation, the coarse mesh piece 11b is higher than the fine mesh piece 11a. On the other hand, the compression mesh (the amount of displacement with respect to the compression force) is higher in the fine mesh piece 11a than in the coarse mesh piece 11b. This point will be described with reference to FIG.

  FIG. 5 is a graph showing the compression rigidity of the mold (cavity mold 7) when the mesh 11 is not included in the heat insulating layer 3, when the coarse mesh 11b is included, and when the fine mesh 11a is included. The displacement amount under the same compression force is “no mesh”> “coarse mesh”> “fine mesh”, and the compression rigidity is “fine mesh”> “coarse mesh”> “no mesh”. That is, the fine mesh 11a having a high lattice density of mesh lines has higher compression rigidity than the coarse mesh 11b having a low lattice density. On the other hand, since the coarse mesh 11b has a larger amount of material (epoxy resin, etc.) of the heat insulating layer 3 entering between the mesh lines than the fine mesh 11a, the coarse mesh piece 11b is more thermally insulating than the fine mesh piece 11a. Is expensive. That is, the heat insulating property is “no mesh”> “coarse mesh”> “fine mesh”.

In consideration of such a difference in heat insulation and compression rigidity, as shown in FIG. 2 (b), a fine mesh piece 11a is disposed at the resin inflow portion of the gate 5, and the downstream side portion of the gate in the resin flow direction. Is provided with a coarse mesh piece 11b. By disposing the fine mesh piece 11a at the resin inflow portion of the gate 5, the high pressure in the mold immediately after being injected into the cavity 1 (for example, 700 kgf / cm 2, see FIG. 5) is more accurately caused by the fine mesh piece 11a. The deformation of the metal layer 4 can be suppressed by supporting. Further, by arranging the coarse mesh pieces 11b on the downstream side of the gate 5 in the resin flow direction, the heat insulation can be gradually changed, and the transferability is deteriorated due to the sudden change in the heat insulation (of the product 6). Dullness, gloss deterioration, etc.) can be avoided. Further, the pressure of the molten resin flowing through the portion where the coarse mesh piece 11b is disposed (the downstream side portion in the resin flow direction of the gate 5) is lower than the portion immediately after injection (the resin inflow portion of the gate 5). Therefore, the coarse mesh 11b can be sufficiently supported, and the deformation of the metal layer 4 can be suppressed. It should be noted that a plurality of types of mesh pieces having different stitch sizes of three or more stages may be used, and the gate 5 may be arranged in order from the fine mesh to the coarse mesh along the resin flow direction. .

(Reinforcement region portion 13 of the pressing portion 9)
As shown in FIGS. 2A and 2B, the top surface of the pressing part 9 of the core mold 8 is located between the metal layer 4 of the cavity mold 7 and the base material 2 so as to face each other. Thus, a reinforcing region portion 13 provided with the reinforcing material 11 is provided. When the core mold 8 and the cavity mold 7 are closed, the reinforcing region portion 13 supports the pressing pressure on the top surface of the pressing portion 9 and the metal layer 4 at the portion facing the pressing portion 9 bends. Suppress. Therefore, it can suppress that the metal layer 4 of this part bends for every shot of injection molding, and can improve durability of a metal mold | die (cavity type | mold 7). Further, since the molten resin can be prevented from entering between the top surface of the pressing part 9 of the core die 8 and the metal layer 4 of the cavity die 7, the generation of burrs in the hole 10 of the product 6 shown in FIG. it can. In addition, although the fine mesh piece 11a is used for the reinforcement area | region part 13, if there is no problem in intensity | strength and rigidity, you may use the coarse mesh piece 11b.

(Heat insulation region 14 around the presser 9)
As shown in FIGS. 2A and 2B, a reinforcing material (mesh) 11 is provided between the cavity-type 7 metal layer 4 and the base material 2 so as to surround a portion where the pressing part 9 faces. The heat insulation area | region part 14 only of the heat insulation layer 3 which does not arrange | position is provided. The heat insulating region 14 maintains the temperature of the molten resin (see the one-dot chain line arrow) that flows around the press-cut portion 9 in the cavity 1 to improve the fluidity, and the weld line in the molten resin junction 15 Suppresses the occurrence of

(Other reinforcement areas)
As shown in FIGS. 2A and 2B, a reinforcing material (mesh) 11 is provided between the metal layer 4 of the cavity mold 7 and the base material 2 with a space in the plane direction of the cavity 1. Reinforcing region portions 16 and 17 are provided. The mesh 11 is not limited to the coarse mesh piece 11b, and may be a fine mesh piece 11a. The mesh 11 of the reinforcing region portions 16 and 17 functions as a spacer that determines the layer thickness of the heat insulating layer 3 between the metal layer 4 and the substrate 2. That is, when the cavity mold 7 is manufactured, the base material 2 and the metal layer 4 are pressed together with the heat insulating layer 3 interposed therebetween. At this time, a plurality of meshes 11 are arranged at intervals in the surface direction of the cavity 1. Thus, the mesh 11 serves as a spacer, and the thickness of the heat insulating layer 3 can be easily made constant along the surface direction of the cavity 1, and the manufacturing accuracy of the cavity mold 7 is improved.

  Further, as shown in FIG. 2B, the reinforcing region portion 16 (mesh 11) is between the metal layer 4 of the cavity mold 7 and the base material 2 in the flow direction of the molten resin flowing in the cavity 1. It is arrange | positioned in the right and left of the downstream side of the pressing part 9. FIG. That is, between the metal layer 4 of the cavity mold 7 and the base material 2, reinforcing region portions 16 (mesh 11) are arranged on the left and right sides of the pressing portion 9 in the flow direction of the molten resin flowing in the cavity 1. It is installed. Due to the mesh 11 of the reinforcing region portion 16, the heat insulating property of the portion is lowered. Therefore, in the cavity 1, the temperature of the molten resin flowing through the reinforcing region portion 16 is lowered, and the fluidity of the molten resin is deteriorated. Therefore, the molten resin injected from the gate 5 and flowing around the pressing part 9 in the cavity 1 is directed toward the joining part 15 due to poor fluidity in the reinforcing region parts 16 disposed on the left and right sides of the pressing part 9 on the downstream side. Is deflected. As a result, a sufficient amount of molten resin can be supplied to the junction 15 and the occurrence of weld lines can be suppressed.

(Second Embodiment: Injection Mold 1b)
FIG. 6 shows an outline of an injection mold 1b according to the second embodiment of the present invention, and FIG. 7 shows a product 6 (thin plate, plate thickness of about 2 mm) molded with the mold. The injection mold 1b according to the second embodiment shown in FIG. 6 has basically the same configuration as the injection mold 1a according to the first embodiment described with reference to FIGS. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  As apparent from a comparison between FIG. 6 and FIG. 2, in the injection mold 1 b according to the second embodiment, the pressing part 9 of the core mold 8 is omitted, and the cavity mold 7 has a textured part instead. 18 is formed. That is, the embossed portion 18 is formed on a part of the surface of the metal layer 4 of the cavity mold 7. Further, between the metal layer 4 of the cavity mold 7 and the base material 2, a heat insulating region 19 of only the heat insulating layer 3 in which no reinforcing material is disposed is provided in the portion of the embossed portion 18, and in the vicinity of the embossed portion 18. A reinforcing region portion 20 in which a reinforcing material (mesh) 11 is disposed is provided. According to this configuration, due to the difference between the heat insulating property of the reinforcing region portion 20 and the heat insulating property of the heat insulating region portion 19, the thermoplastic resin flowing in the cavity 1 (see the dashed line arrow) is guided to the embossed portion 18. become. As a result, the transferability of the embossed portion 19 is improved, and in the product 6 shown in FIG. 7, the forming accuracy of the embossed portion 21 to which the embossed portion 19 is transferred is improved.

  In FIG. 6B, the reinforcing material (mesh) 11 of the reinforcing region 20 is not limited to the coarse mesh piece 11b, but may be a fine mesh piece 11a. Further, the fine mesh piece 11a may be disposed outside the coarse mesh piece 11b in the left-right direction so that the difference in heat insulation property is stepped, and the thermoplastic resin flowing in the cavity 1 may be more easily guided to the embossed portion 18. .

(Third Embodiment: Injection Mold 1c)
FIG. 8 shows an outline of an injection mold 1c according to the third embodiment of the present invention, and FIG. 9 shows a product 6 (thin plate, plate thickness of about 2 mm) molded with the mold. The injection mold 1c according to the third embodiment shown in FIG. 8 has basically the same configuration as the injection mold 1a according to the first embodiment described with reference to FIGS. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  As is clear from the comparison between FIG. 8 and FIG. 2, in the injection mold 1 c according to the third embodiment, the pressing part 9 of the core mold 8 is omitted, and the raised part is formed in the core mold 8 instead. 22 is formed. That is, a raised portion 22 for forming the thin portion 23 on the product 6 is formed on the core mold 8 so as to protrude into the cavity 1. Further, between the metal layer 4 of the cavity mold 7 and the base material 2, a heat insulating region 24 only of the heat insulating layer 3 not provided with the reinforcing material (mesh) 11 is provided in a portion where the raised portion 22 faces, A reinforcing region portion 25 is provided in which a reinforcing material (mesh) 11 is disposed so as to surround a portion where the raised portion 24 faces. According to this configuration, the thermoplastic resin flowing in the cavity 1 is guided to the raised portion 22 by the difference between the heat insulating property of the reinforcing region portion 25 and the heat insulating property of the heat insulating region portion 24. As a result, the forming accuracy at the raised portion 22 is improved, and in the product 6 shown in FIG. 9, it is possible to prevent the thin portion 23 formed by the raised portion 22 from being short-circuited or welded. In addition, the thickness of the thin part 23 of the product 6 is about 0.5 mm.

  The reinforcing material (mesh) 11 in the reinforcing region 25 may be either the coarse mesh piece 11b or the fine mesh piece 11a. As shown in FIG. 8B, both the coarse mesh piece 11b and the fine mesh piece 11a. May be used. In this embodiment, as shown in FIG. 8B, the fine mesh pieces 11a are arranged on the two sides near the gate 5, and flow in the cavity 1 by giving a stepwise inclination to the heat insulating property. The thermoplastic resin is more easily guided to the raised portion 22.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various modifications within the scope of the claims. Needless to say, examples and modifications also belong to the technical scope of the present invention. For example, all the molds of the first to third embodiments may be combined, or any two embodiments may be combined.

  The present invention can be used for an injection mold for forming a cavity filled with a molten thermoplastic resin.

DESCRIPTION OF SYMBOLS 1a Injection mold 1b Injection mold 1c Injection mold 1 Cavity 2 Base material 3 Heat insulation layer 4 Metal layer 5 Gate 6 Product 7 Cavity mold 8 Opposite mold (core mold)
9 Pressing part 10 Hole part 11 Reinforcing material (mesh)
11a Fine mesh piece 11b Coarse mesh piece 13 Reinforcement area part 14 Heat insulation area part 18 Wrinkle part 19 Heat insulation area part 20 Reinforcement area part 22 Raised part 23 Thin part 24 Heat insulation area part 25 Reinforcement area part

According to the present invention created to achieve the above-mentioned object, an injection mold for forming a cavity filled with a molten thermoplastic resin, depending on the shape of the product molded in the cavity. A metal base material having a surface, a heat insulating layer made of a material softer than the base material provided on the surface of the base material, and a metal layer provided on the surface of the heat insulating layer and forming the surface of the cavity, the metal layer, A reinforcing material made of a material harder than the material of the heat insulating layer is interposed between the base material partly along the cavity surface direction, and the reinforcing material is made of a metal mesh and melts in the cavity. An injection mold characterized in that it is disposed at least in an injection portion of a gate for injecting a thermoplastic resin, and supports the pressure in the mold of the thermoplastic resin immediately after being injected into the cavity from the gate. A mold is provided.

In the injection mold according to the present invention, the mesh is composed of a plurality of types of mesh pieces having different stitch sizes, and the resin is formed at the gate portion for injecting molten thermoplastic resin into the cavity. A fine mesh piece may be provided at the inflow portion, and a coarse mesh piece may be provided at the downstream side in the resin flow direction .

In the injection mold according to the present invention, a plurality of meshes are arranged at intervals in the surface direction of the cavity between the metal layer and the base material, and heat insulation between the metal layer and the base material. It may also serve as a spacer for determining the layer thickness .

In the injection mold according to the present invention, the heat insulating layer may also serve as an adhesive for joining the base material and the metal layer .

In the injection mold according to the present invention, an opposing mold that faces the metal layer, a pressing part that is provided in the opposing mold so as to protrude into the cavity, and for forming a hole in the product, There may be provided a reinforcing region portion in which a mesh is disposed in a portion where the pressing portion is opposed between the metal layer and the base material, and the reinforcing region portion supports the pressing force in the pressing portion.

In the injection mold according to the present invention, between the metal layer and the base material, there is provided a heat insulating region only of a heat insulating layer that does not dispose a mesh so as to surround a portion where the pressing part is opposed to each other. You may make it improve the fluidity | liquidity of the thermoplastic resin which flows so that the circumference | surroundings of a notch part may wrap around in a cavity by a part.

In the mold for injection molding according to the present invention, only a heat insulating layer in which a textured part is formed on a part of the surface of the metal layer and no mesh is disposed on the textured part between the metal layer and the base material. In addition to providing a heat insulating region, a reinforcing region having a mesh disposed in the vicinity of the embossed portion is provided, and the thermoplastic resin flowing in the cavity is caused by the difference between the heat insulating property of the reinforcing region and the heat insulating property of the heat insulating region. You may make it guide to a grain part.

In the injection mold according to the present invention, an opposing mold facing the metal layer, and a raised part provided on the opposing mold so as to protrude into the cavity and for molding a thin part on the product, Between the metal layer and the base material, a heat-insulating region portion of only the heat-insulating layer that does not dispose the mesh is provided at the portion where the raised portion faces, and the mesh is arranged so as to surround the portion where the raised portion faces. A reinforcing region portion may be provided, and the thermoplastic resin flowing in the cavity may be guided to the raised portion by the difference between the heat insulating property of the reinforcing region portion and the heat insulating property of the heat insulating region portion.

According to the present invention, a gate for injecting a thermoplastic resin into a cavity between a metal layer and a base material in an injection mold using a metal layer laminated on a base material via a heat insulating layer as a cavity surface Since a reinforcing material (metal mesh) that is harder than the heat insulating layer is interposed, the pressure inside the mold of the thermoplastic resin injected from the gate into the cavity can be supported by the reinforcing material. it can. As a result, the deformation of the metal layer due to the pressure inside the mold of the molten resin injected from the gate into the cavity can be suppressed, and the accuracy of the product molded in the cavity can be improved. Further, since the bending of the metal layer for each shot of injection molding can be suppressed, the durability of the mold can be improved.

Claims (8)

An injection mold for forming a cavity filled with a molten thermoplastic resin,
A metal substrate having a surface corresponding to the shape of the product molded in the cavity;
A heat insulating layer made of a material softer than the base material provided on the surface of the base material;
A metal layer provided on the surface of the heat insulating layer and forming a surface of the cavity;
A reinforcing material made of a material harder than the material of the heat insulating layer is interposed between the metal layer and the base material partially along the surface direction of the cavity,
The reinforcing material is disposed at least in the injection portion of the gate for injecting the molten thermoplastic resin into the cavity, and the pressure inside the mold of the thermoplastic resin immediately after being injected into the cavity from the gate is reduced. An injection mold characterized by supporting.   A plurality of the reinforcing materials are disposed between the metal layer and the base material at intervals in the surface direction of the cavity, and determine a layer thickness of the heat insulating layer between the metal layer and the base material. The injection mold according to claim 1, which also serves as a spacer.   The injection mold according to claim 1 or 2, wherein the reinforcing material is a metal mesh. The mesh is composed of a plurality of types of mesh pieces having different stitch sizes,
In the gate portion for injecting the molten thermoplastic resin into the cavity, a fine mesh piece is arranged at the resin inflow portion, and a coarse mesh piece is arranged at the downstream side in the resin flow direction. The injection mold according to claim 3, wherein the mold is an injection mold. An opposing mold facing the metal layer, and a pressing part that is provided in the opposing mold so as to protrude into the cavity and for forming a hole in the product,
Between the metal layer and the base material, a reinforcing region portion in which the reinforcing material is disposed is provided in a portion where the pressing portion is opposed, and the pressing pressure in the pressing portion is supported by the reinforcing region portion. The injection mold according to any one of claims 1 to 4, wherein the mold is for injection molding.   Between the metal layer and the base material, a heat insulating region only of the heat insulating layer not provided with the reinforcing material is provided so as to surround a portion where the pressing part is opposed, and the heat insulating region in the cavity The injection mold according to claim 5, wherein the fluidity of the thermoplastic resin that flows so as to wrap around the pressing part is increased. Forming a textured portion on a portion of the surface of the metal layer;
Between the metal layer and the base material, a heat-insulating region portion of only the heat-insulating layer not provided with the reinforcing material is provided in the portion of the embossed portion, and the reinforcing material is disposed in the vicinity of the embossed portion. Provide a reinforcement area,
The thermoplastic resin flowing in the cavity is guided to the textured portion by a difference between the heat insulating property of the reinforcing region and the heat insulating property of the heat insulating region. The mold for injection molding as described in the item. An opposing mold facing the metal layer, and a protruding part provided on the opposing mold so as to protrude into the cavity, and for forming a thin part on the product,
Between the metal layer and the base material, a heat-insulating region portion of only the heat-insulating layer not provided with the reinforcing material is provided in a portion where the raised portion faces, and the raised portion surrounds the opposed portion. Providing a reinforced area with a reinforcing material,
The thermoplastic resin flowing in the cavity is guided to the raised portion by the difference between the heat insulating property of the reinforcing region and the heat insulating property of the heat insulating region. The mold for injection molding as described in the item.

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