JPS6150157B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mold by electroforming in which a plating film is formed by composite plating on the inner surface of a cavity.

Recently, composite plating (referred to as dispersion plating) in which one or more nonmetallic phases (or other metal phases) is eutectoided into a metal matrix on the surface of an article by electroplating or chemical plating has been developed. ) to impart properties appropriate to the intended use of the article. For example, by applying composite plating of nickel and Teflon to the surface of an article, wear resistance, lubricity, mold releasability, etc. can be improved. However, when trying to apply the above-mentioned composite plating to the inner surface of the cavity of a plastic mold, the plating has a property that it is difficult to adhere to the recessed part. It was very difficult to form a plating layer of uniform thickness.

In addition, if the inner surface of the mold cavity has a fine uneven pattern such as a leather pattern or a grain pattern, if composite plating is applied after the cavity is formed, the fine uneven pattern will be buried by the plating film. This makes it difficult to add the necessary pattern to the surface of the molded product.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to form a plating layer by composite plating with an even film thickness on the inner surface of the cavity with an extremely simple operation, and to also form a plating layer on the inner surface of the cavity using composite plating. To provide a method for manufacturing a mold by electroforming, which allows a fine uneven pattern to be accurately and easily added to the surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to, for example, a mold used for blow molding plastic will be described with reference to the drawings. That is, a mold for blow molding usually consists of a pair of upper and lower molds that are divided into upper and lower halves at the parting line.
One type will be explained below. Figure 1 shows a prototype 1 having a shape that matches the external shape of the molded product, and Figure 2 shows a replica 2 formed by placing the prototype 1 in an appropriate frame and pouring plaster or resin into it. This has a concave portion 2a having a concave and convex shape opposite to that of the original mold 1. FIG. 3 shows a master mold 3 for electroforming formed by injecting epoxy resin into the recess 2a of the replica 2 or by applying multiple layers of epoxy resin. First, a conductive layer 4 is formed on the surface of the manufactured mother mold 3 by, for example, silver mirror plating. In this case, the conductive layer 4 may be formed by chemical copper plating, which is commonly used when resin plating is performed. Then, on the surface of the matrix 3 on which the conductive layer 4 has been formed, a plating film 5 made of a composite plating of nickel and Teflon is formed to a predetermined film thickness by, for example, an electroplating method. Composite plating is a well-known technology.
In order for Teflon particles to be positively charged and dispersed in the plating bath, they are stored together with a dispersion aid and made into a suspended state by mechanical stirring, and nickel is used as the metal matrix, and the plating film 5 is made of Teflon. The nickel layer 7 is formed so as to surround the particles 6 (see FIG. 6). Next, a cavity 8 is formed by depositing an electroformed metal layer of a predetermined thickness, such as nickel, on the plating film 5 on the surface of the mother mold 3 by an electroforming process (see FIGS. 4 and 6). . Cavity 8, which has been electroformed
The matrix 3 is released from the mold. In this case, the bond between the cavity 8, the plating film 5, and the conductive layer 4 is an alloy bond with a strong bonding force, whereas the bond between the matrix 3 and the conductive layer 4 is that the matrix 3 is made of epoxy. Since it is a resin, there is no alloy bonding, and therefore,
When releasing the mother mold 3 from the cavity 8, the mother mold 3
The conductive layer 4 is easily peeled off, and the plating film 5 and the conductive layer 4 remain on the surface of the unevenness 8a of the cavity 8, bonded by an alloy bonding force. After this,
For example, the cavity 3 is placed in a dilute nitric acid solution and the conductive layer 4 is dissolved first, then the nickel layer which is the metal phase on the surface of the nickel layer 7 of the plating film 5 is dissolved to a predetermined thickness, and then taken out from the dilute nitric acid solution. The manufacturing of the cavity 8 is then completed (see FIGS. 5 and 8). Thus, the plating film 5 formed by composite plating
In this case, the Teflon particles 6 are surrounded by the nickel layer 7, but since the nickel layer 7 of the plating film 5 is melted to a predetermined thickness after the conductive layer 4 is melted, the plating film 5 on the surface of the recess 8a of the cavity 8 is A large number of Teflon particles 6, which are non-metallic phases, are directly exposed on the surface (see FIG. 7).

The cavity 8 manufactured as described above has the following effects. That is, even if the shape of the cavity 8 is complicated, the matrix 3 has a shape that is opposite to the recess 8a and the surface is exposed to the outside, so that plating can easily adhere to it, and therefore, plating can be easily applied without any special treatment. The film 5 can be formed to have a uniform film thickness. Furthermore, the inner surface of the plating film 5 remaining on the cavity 8 side due to the bonding force of the alloy can form an accurately opposite uneven shape even if the mother die 3 has a fine uneven shape on the surface, and it can be Unlike the case where a plating film is attached to the surface of the cavity 8 after it is formed, there is no problem that the fine irregularities on the surface are buried. Since the nickel layer 7 on the surface of the plating film 5 is partially dissolved to expose the Teflon particles 6 directly on the surface of the recess 8a of the cavity 8, the wear resistance of the surface of the recess 8a is improved.
The properties of the Teflon particles 6 significantly improve lubricity, mold releasability, etc. For this reason, when applied to a blow molding mold, the parison has a concave portion 8a during molding.
It is possible to prevent the material from adhering to the surface as much as possible, and it is possible to obtain a blow-molded product with uniform wall thickness. In addition to blow molding, the same effect can be obtained in the case of vacuum molding, and even when applied to molds for injection molding and other molding methods, it has the excellent effect of making it possible to release the molded product extremely easily.

In the above embodiment, the composite plating film 5 was explained using nickel and Teflon particles as an example, but copper, zinc, etc. may also be used in addition to nickel, and ferrocarbon may be used instead of Teflon particles. Particles of , indium oxide, ceramic, and various other oxides and resins can be used, and properties unique to each particle can be extremely easily imparted to a mold by electroforming.

As is clear from the embodiments described above, the present invention is a method for manufacturing a mold by electroforming, which allows a composite plating film with an even thickness to be formed on the inner surface of a cavity with an extremely simple operation. can be provided.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of the original model, FIG. 2 is a side view of the replica, FIG. 3 is a side view of the matrix, and FIGS. 6 is an enlarged sectional view of the portion shown in FIG. 4, and FIG. 7 is an enlarged sectional view of the portion shown in FIG. 5. In the drawings, 1 is the original model, 2 is the replica, 3 is the matrix,
4 is a conductive layer, 5 is a plating film, 6 is a Teflon particle, 7 is a nickel layer, and 8 is a cavity.

Claims (1)

[Claims] 1. A step of forming a plating film on the outer surface of the electroforming matrix by composite plating in which a metallic phase and a non-metallic phase are co-deposited, and a process of forming a plating film on the outer surface of the plating film by this composite plating by an electroforming processing method. A step of producing a cavity by depositing a thick electroformed metal layer, and releasing the mother mold from the cavity with the plating film attached to the inner surface of the cavity, and removing the plating film from the inner surface of the cavity. A method for producing a mold by electroforming, comprising the steps of exposing the metal phase on the inner surface of the plating film to the outside to a predetermined thickness and exposing the non-metal phase to the outside.