KR101768157B1 - method for making mold core used in forming product with curved surface - Google Patents

Abstract

A method of manufacturing a mold core of a mold for injection molding a product having a curved surface is disclosed. A method of manufacturing a mold core for molding a curved surface product, comprising the steps of: forming a relief block having a relief surface corresponding to a convex curve surface of a curved surface product; forming a relief surface A core block joining step of fixing the core block to the metal layer, and a core block joining step of separating the corrugated block from the metal layer and forming a concave corrugated surface corresponding to the corrugated surface, And an embossing block separating step of exposing the curved surface.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a mold core for molding a curved product,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection mold, and more particularly, to a method of manufacturing a mold core of a mold for injection molding a product having a curved surface.

BACKGROUND OF THE INVENTION [0002] In the field of information communication devices such as smart phones, there are cases where a cover is made in a curved shape in order to facilitate grip, to differentiate a design, or to close a face close to a face during a call. 1A and 1B are cross-sectional views showing an example of a smartphone cover having a curved shape, wherein FIG. 1A is a sectional view taken on a ZX plane, and FIG. 1B is a sectional view taken on a YZ plane.

The smartphone cover (CV) shown in Figs. 1A and 1B shows a curved shape on the YZ plane as well as on the ZX plane. That is, the cover CV is a curved product that extends in a curve in the X-axis direction and extends in a curved line in the Y-axis direction. On the other hand, the smartphone cover (CV) is a product requiring uniform optical characteristics in terms of gloss, transparency and the like, and requires precise polishing and polishing work on the product surface as a post-injection molding process. However, performing additional surface polishing and polishing processes on all products that are injection molded results in decreased productivity and increased production costs.

Accordingly, there has been an attempt to precisely polish and polish the cavity forming surface of the mold corresponding to the shape of the product, and to eliminate the additional product surface polishing and polishing process by injection molding using the mold . In the case where the cavity-forming surface is a convex surface, a person skilled in the art can relatively easily obtain a convex cavity-formed surface with high precision and high gloss by NC (Numerical Control) processing.

On the other hand, if the cavity forming surface is a concave surface extending in a curve only in one of the X-axis direction and the Y-axis direction and extending in a straight line in the other direction, a processing tool in contact with the concave cavity- It is possible to obtain a high-precision, high-gloss cavity-formed surface by polishing while reciprocating only in the direction in which the formed surface extends linearly. However, if the cavity-forming surface is a concave surface extending in a curved line in the X-axis direction and the Y-axis direction, a method of bringing the processing tool into contact with the cavity-forming surface and moving it linearly in one direction provides a high- none.

Korean Patent Publication No. 10-2011-0005584

The present invention relates to a method for producing a mold core for molding a curved product, which is injection-molded by injection molding with a convex curved surface extending in the X-axis direction and the Y-axis direction, to provide.

The present invention also provides a method for producing a mold core for molding a curved product, the cavity forming surface extending in a curved line in the X-axis direction and the Y-axis direction and having a high-precision high-gloss cavity forming surface.

The present invention relates to a method of manufacturing a mold core for injection molding a curved surface article having a convex curved surface, the method comprising the steps of: forming a relief curved surface, Forming a metal layer made of nickel (Ni) or a nickel alloy on a side of the relief surface of the relief block where the relief curved surface is formed so that the relief surface is covered; And a relief block separating step of separating the relief block from the metal layer and exposing a concave depressed curved surface corresponding to the depressed curved surface.

The forming of the embossed block may include forming the embossed curved surface in the embossed block through NC (Numerical Control) processing.

The step of laminating the metal layer may include a step of plating nickel or a nickel alloy on the side surface of the relief block.

The core block bonding step may include a core block forming step of forming a core block having a groove or a dent for hooks formed on at least one side face thereof, a core block closing step of bringing the core block into close contact with the metal layer, And further plating the metal layer in the groove or the dent for the hook with the same metal as the metal layer to form a connecting hook connected to the metal layer and filled in the hook groove or the dent .

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The method of manufacturing a mold core for molding a curved surface product according to the present invention may further include a step of applying a release promoting material for applying a release promoting material to the side of the embossed block on which the embossed curved surface is formed before the step of laminating the metal layer, The block separating step may include the step of applying an external force in a direction in which the metal layer and the relief block are separated from each other.

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The release promoting material may be a material containing one of silver (Ag), copper (Cu), a silver alloy, and a copper alloy.

According to the present invention, the shape of the embossed curved surface is transferred to a metal layer made of nickel or a nickel alloy, which is a hard metal, to produce a mold core having an engraved curved surface. Therefore, when the embossed curved surface that is relatively easy to process is surface-processed with high precision and high gloss, the surface characteristics of the embossed curved surface are transferred to the depressed curved surface of the mold core as it is. Thus, the injection molded product using the mold core is highly accurate, As shown in FIG. Further, even in the case of a so-called four-sided curved surface which extends in a convex curve not only in the X-axis direction but also in the Y-axis direction, it can be manufactured to have a high-precision and high- As a result, the production cost of the curved surface product can be reduced, and productivity is improved.

1A and 1B are cross-sectional views showing an example of a smartphone cover having a curved shape, wherein FIG. 1A is a sectional view taken on a ZX plane, and FIG. 1B is a sectional view taken on a YZ plane.
FIGS. 2 to 6 are sectional views sequentially showing the method for manufacturing a mold core for molding a curved product according to the first embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a mold having a mold core shown in FIG. 6 in a mold.
8 and 9 are sectional views sequentially showing the method for manufacturing a mold core for molding a curved surface product according to a second embodiment of the present invention.

Hereinafter, a method of manufacturing a mold core for molding a curved product according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom in the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

FIGS. 2 to 6 are sectional views sequentially showing the method for manufacturing a mold core for molding a curved product according to the first embodiment of the present invention. Through the method of manufacturing a mold core according to the first embodiment of the present invention, an upper mold core of a mold for injection molding the curved product (CV) shown in Figs. 1A and 1B can be manufactured. The method for manufacturing a mold core for molding a curved surface product according to the first embodiment of the present invention includes steps of forming a relief block, applying a release promoting material, laminating a metal layer, joining a core block, separating a relief block, Respectively.

2, the embossed block forming step includes forming a relief block 2 having an embossed curved surface 3 corresponding to a convex curved surface of a curved product CV (see FIG. 1B) to be injection-molded . As shown by the chain double-dashed line in FIG. 2, the upper side of the hexagonal metal block can be precisely cut and polished by NC (Numerical Control) processing to form the relief surface 3 with high precision and high gloss. In Fig. 2, curved portions 4 are present at both ends in the direction parallel to the Y-axis of the relief surface 3. Although not shown, curved portions may exist in both end portions in the direction parallel to the X-axis of the relief surface 3.

3, the step of laminating the metal layer is a step of laminating a metal layer 6 made of nickel (Ni) or a nickel alloy on the upper surface of the relief surface 2 on which the relief surface 3 is formed. The metal layer 6 may be formed by plating nickel (Ni) or a nickel alloy on the upper side of the relief block 2. The thickness of the metal layer 6 formed by the plating may be slightly larger than the height of the relief surface 3, and may be 1 mm to 10 mm.

The step of applying the release promoting material is a step of applying the release promoting material 9 to the upper side of the relief block 2 on which the relief surface 3 is formed, prior to the step of laminating the metal layer. A metal material having a high conductivity such as silver (Ag), copper (Cu), silver alloy, or copper alloy is formed on the release promoting material 9 in the case of forming the metal layer 6 by plating. . The release promoting material 9 may be sprayed in the form of fine particles and applied on the side of the relief block 2, but the present invention is not limited thereto.

Referring to FIGS. 4 and 5, the core block bonding step is a step of fixing the core block 10 to the metal layer 6. Specifically, the core block bonding step includes a core block forming step, a core block bonding step, and an additional plating step. The mold core 20 (see FIG. 6) includes the metal layer 6 and a metal core block 10 for supporting the metal layer 6. As shown in FIG. 4, A dent 12 for a hook is formed. The dent 12 can be formed by machining. The core block 10 shown in Fig. 4 is provided with a dent 12 stepped at both side edge portions, but in place of the dent 12, the core block 10 has a groove May be formed.

The core block adhesion step is a step of bringing the core block 10 into close contact with the metal layer 6. At this time, the bottom surface of the core block 10 is brought into close contact with the upper surface of the metal layer 6 so that the hook dent 12 can be connected to the upper surface of the metal layer 6. The additional plating is a step of further plating the hook dent 12 and the metal layer 6 with the same metal as the material of the metal layer 6. As a result, as shown in FIG. 5, a hook 15 is formed which is filled in the hook dent 12 and is integrally connected to the metal layer 6.

6, the relief block separation step separates the relief block 2 from the metal layer 6 so that the embossed relief surface 3 is transferred to the metal layer 6 and recessed correspondingly to the relief surface 3, And exposing the intaglio curved surface 21 that has been formed. At this time, the core block 10 and the relief block 2 are independently held using a mechanism, and an external force is applied in a direction in which the metal layer 6 and the relief block 2 separate, (6). 3) is formed between the relief block 2 and the metal layer 6 while the metal layer 6 is fixedly coupled to the core block 10 by the connection hook 15 And the external force is applied by a physical method, the relief block 2 is separated from the metal layer 6. [

In the step of removing the mold promoting material, the release promoting material 9 (see FIG. 3 (a)) remaining on the side of the metal layer 6 on which the concave curved surface 21 of the metal layer 6 is exposed, (See FIG. The core block 10 and the metal layer 6 supported thereon, which are separated and left from the relief block 2, become the mold core 20. [

The convex curved surface 3 of the relief block 2 appears on the concave curved surface 21 of the metal layer 6 from which the release promoting material 9 is removed. As a result, when the embossed curved surface 3 that is relatively easy to process is surface-processed with high precision and high gloss, the surface characteristics of the embossed curved surface 3 are transferred directly to the engraved curved surface 21, It is possible to obtain a convex curved surface with high precision and high gloss without additional polishing polishing work. Further, even in the case of a so-called four-sided curved surface which extends in a convex curve not only in the X-axis direction but also in the Y-axis direction, it can be manufactured to have a high-precision and high-

FIG. 7 is a cross-sectional view showing a mold having a mold core shown in FIG. 6 in a mold. The mold shown in Fig. 7 may be a mold for injection molding the curved product (CV) shown in Figs. 1A and 1B. Referring to FIG. 7, the mold for molding the curved product CV includes an upper core 20 and a lower core 25. Although not shown in FIG. 7, the mold includes an upper disk supporting the upper core 20, a lower disk supporting the lower core 25, an eject plate for ejecting the injection molded product, an eject pin, and the like.

The mold core 20 manufactured according to the manufacturing method described with reference to Figs. 2 to 6 becomes the upper core. The lower core 25 can be manufactured by NC machining a metal block and has a convex curved surface 27 on the upper side. A cavity CA defined by the concave curved surface 21 of the upper core 20 and the concave curved surface 27 of the lower core 25 is formed when the upper core 20 and the lower core 25 are combined . That is, the concave curved surface 21 becomes the upper cavity forming surface, and the convex curved surface 27 becomes the lower cavity forming surface. The molten resin is injected into the cavity CA and the upper core 20 and the lower core 25 are cooled to cure the molten resin and then the upper core 20 and the lower core 25 are molded (Mold opening), a curved surface product (CV) as shown in Figs. 1A and 1B can be obtained.

8 and 9 are sectional views sequentially showing the method for manufacturing a mold core for molding a curved surface product according to a second embodiment of the present invention. Through the mold core manufacturing method according to the second embodiment of the present invention, an upper mold core of a mold for injection molding the curved product (CV) shown in Figs. 1A and 1B can be manufactured. As in the first embodiment of the present invention shown in FIGS. 2 to 6, the method for manufacturing a mold core for molding a curved surface product according to the second embodiment of the present invention includes the steps of forming a relief block, applying a release promoting material, A core block bonding step, a relief block separation step, and a release promoting material removal step. Here, the embossed block forming step, the dissociation promoting material applying step, and the metal layer laminating step are the same as those described with reference to FIG. 2 and FIG. 3, and duplicated description will be omitted.

The core block bonding step is a step of fixing the core block 40 to the metal layer 6 and includes a bonding step of bonding the core block 40 to the metal layer 6 with an adhesive 45 made of a synthetic resin do. The adhesive 45 should be heat resistant so that it does not melt inside the hot mold core 50 (see FIG. 9).

9, the relief block separation step separates the relief block 2 from the metal layer 6 to expose the concave depressed curved surface 51 corresponding to the relief surface 3, . At this time, the core block 40 and the relief block 2 are independently held using a mechanism, and an external force is applied in a direction in which the metal layer 6 and the relief block 2 separate from each other, (6). 8) is provided between the relief block 2 and the metal layer 6, while the metal layer 6 is fixedly bonded to the core block 40 by the adhesive 45, So that the embossed block 2 is separated from the metal layer 6 when an external force is applied by a physical method.

In the step of removing the mold promoting material, the release promoting material 9 (see FIG. 8 (a)) remaining on the side surface of the metal layer 6 on which the concave curved surface 51 of the metal layer 6 is exposed, (See FIG. The core block 40 and the metal layer 6 supported thereon become the mold core 50 with the relief block 2 separated and left.

The convex curved surface 3 of the relief block 2 appears on the concave curved surface 51 of the metal layer 6 from which the release promoting material 9 is removed. As a result, when the embossed curved surface 3 that is relatively easy to process is surface-processed with high precision and high gloss, the surface characteristics of the embossed curved surface 3 are transferred to the intaglio curved surface 51 as it is. It is possible to obtain a convex curved surface with high precision and high gloss without additional polishing polishing work. Further, even in the case of a so-called four-sided curved surface which extends in a convex curve not only in the X-axis direction but also in the Y-axis direction, it can be manufactured to have a high-precision and high-

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

2: Embossed block 3: Embossed surface
6: metal layer 10: core block
12: Dent for hook 15: Hook
20: Upper mold core 21: Negative curved surface

Claims (8)

A method of manufacturing a mold core for injection molding a curved surface article having a convex curved surface,
Forming a relief block having an embossed curved surface corresponding to a convex curved surface of the curved product; A metal layer stacking step of stacking a metal layer made of nickel (Ni) or a nickel alloy on the side of the relief surface of the relief block where the relief surface is formed so that the relief surface is covered; A core block bonding step of fixing the core block to the metal layer; And a relief block separating step of separating the relief block from the metal layer to expose a concave depressed curved surface corresponding to the relief surface,
The step of laminating the metal layer may include the step of plating nickel or nickel alloy on the side surface of the relief block,
The core block bonding step may include a core block forming step of forming a core block having a groove or a dent for hooks formed on at least one side face thereof, a core block closing step of bringing the core block into close contact with the metal layer, And an additional plating step of further plating the metal layer in the groove or the dent for the hook with the same metal as the metal and forming a connecting hook connected to the metal layer and filled in the hook groove or the dent. Of the mold core. The method according to claim 1,
Wherein the forming of the embossed block comprises forming the embossed curved surface in the embossed block through NC (Numerical Control) processing. delete delete delete The method according to claim 1,
Further comprising a step of applying a mold promoting material to the side surface of the relief block on which the relief surface is formed, prior to the step of laminating the metal layer,
Wherein the step of separating the embossed block comprises the step of applying an external force in a direction in which the metal layer and the relief block are separated from each other. delete The method according to claim 6,
Wherein the release promoting material is a material containing one of silver (Ag), copper (Cu), a silver alloy, and a copper alloy.

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