JP2000087284A - Production of electrocast shell for molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an electrocast shell for a molding die at the number of stages, labor, time and cost more reduced than heretofore. SOLUTION: This method includes a stage where a model 1 is plated with a sheet 8 with a rugged pattern, a stage where an electrically conductive coating film is formed on the surface of the sheet 8 and an electrocasting shell forming stage where the model 1 stuck with the sheet 8 is directly dipped into an electrocasting soln., and electrocasting is executed onto the electrically conductive coating film to form an electrocasting shell 11. At the time of the electrocasting, the sheet 8 is prevented from floating and peeling from the model 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vacuum forming, vacuum pressure forming, blow forming, stamping forming, roll forming,
The present invention relates to a method for producing an electroformed shell used for various molding dies such as injection molding, reaction injection molding, and compression molding.

[0002]

2. Description of the Related Art An automobile glove box lid 31 shown in FIG. 5 is formed by injection molding of a resin, and has a grain pattern 32 formed on the surface thereof. FIG. 11 shows an example of a surface-side split mold of a molding die 61 for injection molding. An electroformed shell 58 is used in a molding surface portion for molding the front side of the glove box lid 31. The pair of electroformed shells 58 has been conventionally manufactured by the following method (process).

As shown in FIG. 6, a model 51 having the same shape as the glove box lid 31 is formed. As shown in FIG. 7, a real leather 52 as a sheet with a concavo-convex pattern is attached to a model 51. As shown in FIG. 8, a parting table 5 having a parting surface 53a that matches a parting surface set around the model 51.
Create 3. As shown in FIG.
Is set with its surface facing up, and a low-adhesion material such as silicone rubber is injected into the surface of the model 51 and the parting surface 53a of the parting table 53 (the injection frame and the like are not shown), and the concave mold 5 is formed.
4 is formed. As shown in FIG. 9, a mandrel 56 is formed by injecting an epoxy resin or the like into the concave mold 54. As shown in FIG. 10, a conductive film (not shown) is formed on the surface of the mandrel 56, and the mandrel 56 is immersed in an electroforming solution to perform electroforming on the conductive film, thereby forming an electroformed shell 58.

[0004] The electroformed shell 58 manufactured by the above method is attached to a frame 62 and reinforced by a back-up body 63 from the back as shown in FIG. Assembled as a split mold.

[0005]

As described above, a large number of steps are required until the electroformed shell 58 for forming the surface of the glove box lid 31 is formed. The formation of the concave mold 54 by the method and the like, and the formation of the mandrel 56 by the epoxy resin or the like in the process require a lot of trouble, time and cost.

Accordingly, an object of the present invention is to make it possible to manufacture an electroformed shell for a molding die with a smaller number of steps, labor, time and cost.

[0007]

In order to achieve the above object, a method for producing an electroformed shell for a molding die according to the present invention comprises the steps of: adhering a sheet with a concavo-convex pattern to a model; A step of forming a conductive film on the surface, and an electroformed shell forming step of forming an electroformed shell by directly immersing the model with the textured sheet in an electroforming solution and performing electroforming on the conductive film. Including.

[0008] The following (a) to (d) are preferred to prevent the sheet with the concavo-convex pattern from floating or turning up from the model during electroforming. (A) A sheet with an embossed pattern is firmly attached to the model with an appropriate adhesive that does not peel off due to penetration of the electroforming liquid or heat. (B) After attaching the sheet with the textured pattern to the model with an adhesive, the model and the sheet with the textured pattern are preheated to generate gas between them, and the gas is opened on the sheet with the textured pattern. Pull out from the hole and make the model and the sheet with uneven pattern adhere closely. Since gas is generated in advance by preheating, it is not generated by the heat of the electroforming liquid. (C) Electroforming is performed while vacuum-sucking the sheet with the concavo-convex pattern on the model. (D) Any two or three of the above (a) to (c) are used in combination.

[0009] It is preferable that the sheet with an uneven pattern is non-water-swellable so as not to swell by the electroforming solution. Examples of the material of the non-water-swellable sheet with a concavo-convex pattern include a vinyl chloride resin and a polyurethane resin.

The uneven pattern is not particularly limited,
Examples include a grain pattern, a cloth pattern, a rishi ground pattern, a wood texture, a rock texture, a geometric pattern, and the like.

The conductive film is not limited to a specific one,
Examples thereof include those formed by a method such as application of a conductive powder paste of silver, copper, aluminum or the like, silver mirror reaction, electroless plating, or the like. The electroformed metal is not limited to a specific one, and examples thereof include nickel, nickel-cobalt alloy, copper, and copper-cobalt alloy.

The electroformed shell may be either nonporous or porous. When forming a nonporous electroformed shell, the electroformed shell forming step can be performed by a general electroforming method. When forming a porous electroformed shell, the electroformed shell forming step can be performed, for example, by the following methods (1) to (3).

(1) A large number of minute non-conductive portions are provided on the surface of the conductive film, and fine non-electrodeposited portions are generated in the non-conductive portion at the beginning of electroforming, and the non-electrodeposited portions are formed as the electroforming proceeds. A method of forming a large number of through holes in an electroformed shell by penetrating by growing (JP-B-2-14434). (2) Instead of providing a large number of fine non-conductive portions on the surface of the conductive film, the electroforming is performed in an electroforming solution to which a surfactant is not substantially added, so that the conductive film can be formed early in the electroforming. A method in which a fine non-electrodeposited portion is generated on the surface and a large number of through holes are formed in the electroformed shell by penetrating the non-electrodeposited portion as the electroforming progresses (Japanese Patent Publication No. 5-39698). . (3) In an electroforming solution to which a surfactant is substantially added,
A first electroforming step of forming an electroformed shell surface layer having no holes by electroforming the model, and removing the model and the electroformed shell surface layer from the electroforming solution, and forming an inner diameter of the electroformed shell surface layer having a hole length. Processing a micro straight hole that is substantially constant in the direction, and in an electroforming solution in which a surfactant is not substantially added, electroforming the electroformed shell back surface layer by performing electroforming on the back surface of the electroformed shell front layer. At the same time as the formation, a non-electrodeposited portion is generated at the opening of the fine straight hole at the beginning of the electroforming, and the non-electrodeposited portion is grown as the electroforming proceeds, so that the inner diameter of the electroformed shell back layer is on the back side. And a second electroforming step of forming a larger diameter enlarged hole (Japanese Patent Laid-Open No. 9-2
No. 49987).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention embodied in a method for manufacturing an electroformed shell used for an injection mold for a glove box lid of an automobile will be described with reference to FIGS. It will be described in the order of steps. The glove box lid 31 to be injection-molded is the same as that shown in FIG.
FIG. 4 shows a molding die 21 for the injection molding, and an electroformed shell 11 is used in a molding surface portion for molding the front side of the glove box lid 31. The pair of electroformed shells 11 is manufactured by the following method (process).

As shown in FIG. 1, the model 1 is formed of a resin (workable resin) capable of machining such as cutting. Model 1 is formed integrally with the parting table and model surface 2
A parting surface 3 is provided around the periphery. Further, a suction hole 4 is formed inside the model 1. The suction holes 4 extend inward from one location on the base surface of the model 1, branch into many pieces on the way, and each has a small opening on the model surface 2.

As shown in FIG. 2, a sheet 8 with a concavo-convex pattern is attached to the model surface 2 of the model 1. The unevenly patterned sheet 8 is not particularly limited as described above, but a non-water-swellable vinyl chloride resin sheet having a grain pattern 9 on the surface is used here. Also, in order to prevent the unevenly patterned sheet 8 from floating or turning over from the model surface 2 during the electroforming described below, an appropriate adhesive is used to prevent the unevenly patterned sheet 8 from being peeled off the model surface 2 by permeation of the electroforming liquid or heat. And stick it firmly.

After attaching the sheet 8 with a concavo-convex pattern to the model surface 2 with an adhesive, the model surface 2 and the sheet 8 with a concavo-convex pattern
Is preheated to generate a gas between them, and the gas is drawn out from a needle hole (not shown) opened in the unevenly patterned sheet 8 to bring the model surface 2 and the unevenly patterned sheet 8 into close contact with each other. . The gas is generated in advance by the preheating, so that the gas is not generated by the heat of the electroforming liquid later.

A conductive coating (not shown) is formed on the sheet 8 with the concavo-convex pattern on the model surface 2 and the parting surface 3. The conductive film is not particularly limited as described above, but is formed here by applying a conductive silver powder paste.

As shown in FIG. 3, the model 1 provided with the sheet 8 having a concavo-convex pattern is directly immersed in an electroforming liquid (not shown) and electroformed on the conductive film, thereby forming the concavo-convex pattern on the model surface 2. An electroformed shell 11 having a molding surface 13 and a mold surface 14 respectively copied from the sheet 8 and the parting surface 3 is formed. Here, the electroformed shell 11 is formed non-porous by a general electroforming method. As electroformed metal, copper, nickel,
Nickel-cobalt alloy, copper-cobalt alloy and the like can be exemplified. On the molding surface of the electroformed shell 11, a reverse grain pattern formed by transferring the grain pattern 9 of the sheet 8 with the uneven pattern is formed.

At the time of this electroforming, the sheet 8 with a concavo-convex pattern is firmly attached to the model surface 2 as described above, and the generation of gas due to the heat of the electroforming liquid is no longer generated by the generation of gas by the preheating. Since it is not present, it does not float or turn over from the model surface 2. Moreover, in the present embodiment, electroforming is performed while vacuuming the sheet 8 with the concavo-convex pattern from the suction hole 4 to the model 1 by a decompression device (not shown) such as a vacuum pump. Not only when the gas is vented later, but also when the gas is not vented, the sheet 8 with the uneven pattern does not float or turn over from the model surface 2. Further, since the sheet 8 with uneven pattern is non-water-swellable, it does not swell with the electroforming liquid.

The electroformed shell 11 manufactured by the above method is attached to a frame 22 as shown in FIG.
By being reinforced from the back with the backup body 23, it is assembled as a surface side split mold of the molding die 21. Examples of the backup body 23 include, but are not particularly limited to, cast concrete, poured epoxy resin, lamination of the epoxy resin and sand, filled granular material, processed metal block, assembled support plate, stud bolt, and the like. it can.

According to the method for manufacturing an electroformed shell of the present embodiment,
Since the complicated steps such as the formation of a concave shape made of silicon rubber or the like and the formation of a mandrel made of epoxy resin or the like, which are required in the above-described conventional example, become unnecessary, the electroformed shell 1 for a molding die is required.
1 can be manufactured with fewer steps, labor, time and cost than ever before.

It should be noted that the present invention is not limited to the configuration of the above-described embodiment, and may be embodied with the following modifications without departing from the spirit of the invention. (1) In addition to injection molding dies, various moldings such as vacuum molding, vacuum pressure molding, blow molding, stamping molding, roll molding, injection molding, reaction injection molding (urethane molding, urethane foam molding, etc.), and compression molding. Of the method for manufacturing an electroformed shell used in a metal mold for a vehicle.

[0024]

As described in detail above, according to the method for producing an electroformed shell for a molding die according to the present invention, the number of steps, labor, time and time required for the electroformed shell for the molding die can be reduced. Can be manufactured at cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a model created and used in an embodiment of the present invention.

FIG. 2 is a perspective view when a sheet with a concavo-convex pattern is attached to the model.

FIG. 3 is a sectional view when an electroformed shell is formed on the same model.

FIG. 4 is a cross-sectional view of a molding die assembled using the same electroformed shell.

FIG. 5 is a perspective view of a molded product (glove box lid) injection-molded with the molding die.

FIG. 6 is a cross-sectional view of a model used in a conventional method for manufacturing an electroformed shell.

FIG. 7 is a cross-sectional view when a sheet with a concavo-convex pattern is attached to the model.

FIG. 8 is a concave cross-sectional view formed using the model and the parting table.

FIG. 9 is a cross-sectional view of a mandrel formed using the concave mold.

FIG. 10 is a cross-sectional view of an electroformed shell formed using the mandrel.

FIG. 11 is a sectional view of a molding die assembled using the same electroformed shell.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 model 2 model surface 3 parting surface 4 suction hole 8 sheet with uneven pattern 9 grain pattern 11 electroformed shell 13 molding surface 14 mold split surface 21 molding die 22 frame 23 backup body 31 glove box lid 32 grain pattern

Claims (5)

[Claims] 1. A step of attaching a sheet with a concavo-convex pattern to a model; a step of forming a conductive film on the surface of the sheet with a concavo-convex pattern; and directly immersing the model with the concavo-convex pattern sheet in an electroforming liquid. An electroforming shell forming step of forming an electroforming shell by performing electroforming on the conductive film. 2. The method for producing an electroformed shell for a molding die according to claim 1, wherein the sheet with a concavo-convex pattern is firmly adhered to the model with an appropriate adhesive which does not peel off due to penetration of the electroforming liquid or heat. . 3. After attaching a sheet with a concavo-convex pattern to the model with an adhesive, the model and the sheet with a concavo-convex pattern are preheated to generate gas between them, and the gas is converted into a sheet with a concavo-convex pattern. The method for producing an electroformed shell for a molding die according to claim 1 or 2, wherein the model and the sheet with a concavo-convex pattern are brought into close contact with each other by being pulled out from the opened needle hole. 4. The method for producing an electroformed shell for a molding die according to claim 1, wherein the electroforming is performed while vacuum-sucking the sheet with a concavo-convex pattern on the model. 5. The method for producing an electroformed shell for a molding die according to claim 1, wherein the sheet with a concavo-convex pattern is non-water-swellable.