JP2865186B2 - Method for producing electroformed body having micro holes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a porous mold used for performing, for example, vacuum molding of a resin product.

[0002]

2. Description of the Related Art Conventionally, a pattern such as a grain pattern may be transferred to a resin product such as an instrument panel, which is an interior part of an automobile, for example. A method of performing vacuum forming using a mold is known. In order to manufacture such a mold by an electroforming method, for example, a technique such as Japanese Patent Publication No. 14434/1990 is known. In this case, paste-like silver is applied to the surface of a model made of a non-electrodepositable member. A mixture of lacquer and vinyl chloride lacquer is sprayed to form a conductive layer having a small non-conductive portion on the model surface. Then, electroforming is performed on the surface of the model to generate a non-electrodeposited portion in the non-conductive portion, and the non-electrodeposited portion is grown to form a large number of fine holes.

[0003]

However, in the case of the above technique, even if a non-electrodeposited portion is initially formed in the non-conductive portion, the non-electrodeposited portion may be crushed and the hole may be closed as the electroforming grows. There was a problem that it was difficult to control the formation of holes. There is also a disadvantage that the rate of occurrence of holes is not constant depending on the part of the mold.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to form an inverted mold having a surface of silicon rubber from a master model, apply a release agent to the surface of the inverted mold, and then apply the mold to the inverted mold. And a number of fine concave portions were formed on the surface of the mandrel by the particles of the release agent. After the surface of the mandrel is degreased, the surface is subjected to a conductive treatment, and the mandrel is immersed in an electrolytic solution and subjected to an electroforming process, so that the fine concave portions act as non-electrodeposited portions, and a large number of fine particles are formed. An electroformed body having a large hole was formed.

[0005]

When a mandrel is transferred and molded from a silicon rubber inversion mold, fine concave portions are formed on the mandrel surface by particles of a release agent applied to the surface of the inversion mold. After the surface of the mandrel is degreased to elute the particles of the release agent remaining and adhered, and then subjected to a conductive treatment, a conductive layer is formed on the fine concave portion by the surface tension of the conductive treatment liquid. If it is not formed, or if formed, it will be formed as a very thin film at the entrance of the recess. For this reason,
If this mandrel is subjected to electrolytic treatment in an electrolytic solution, even if a thin film is formed at the entrance of the concave portion, the thin conductive film is destroyed by expansion of the mandrel due to the temperature of the electrolytic solution, and the fine concave portion is non-electrolytic. Acts as an attachment. In addition, as the electroforming process proceeds, the nickel ion concentration in the fine recesses becomes extremely lower than the surrounding concentration, the current efficiency decreases, and the electrolysis of water becomes severe. Therefore, a large amount of hydrogen gas generated by electrolysis of water is generated in the mandrel on the cathode side, particularly in the concave portion p, and this hydrogen gas grows a non-electrodeposited portion. Therefore, a large number of fine holes are formed in the electroformed shell thus formed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for producing an electroformed body having minute holes according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a process diagram of a method for manufacturing an electroformed body according to the present invention, and FIG.

For example, there is known a method of forming a grain pattern on the surface of an instrument panel component of an automobile by vacuum forming using a mold having a large number of minute holes.

At this time, for example, a heat-softened sheet-like skin is sucked from a number of minute holes of a mold and is closely adhered to the mold to form the sheet. In such a case, a problem occurs that the holes are transferred together and the surface becomes rough. For this reason, it is necessary to form a hole as fine as possible to prevent the hole portion from being transferred.

In view of the above, the method of manufacturing an electroformed body according to the present invention is to surely form minute holes which do not affect the external appearance of the product.

That is, in the present invention, a mold for molding a product having the same shape as the master model O as shown in FIG. 1A is manufactured by electroforming. As shown in FIG. For example, an inverted mold C of the master model O is made of a material such as silicon rubber. It should be noted that the material of the inverted type C does not need to be all silicon rubber, but may be silicon rubber only as the surface portion.

Next, as shown in FIG.
Silicon or fluorine release agent R on product surface
Is applied to a necessary portion in a necessary amount, as shown in FIG. 2A, particles r of the release agent R adhere to the application surface.

In this case, since the reversing type C has the effect of the release agent on the silicone rubber itself, it is not necessary to use the release agent R for the purpose of release. Mandrel M using particles r instead of
Since the purpose is to form the concave portion p on the surface, such a step is provided.

Next, a resin such as epoxy is cast into the inverted mold C to form a mandrel M as shown in FIG. Then, on the surface of the mandrel M, FIG.
As shown in FIG. 5, a concave portion p is formed at a position where the particle r exists.

Here, since there is a possibility that the particles r of the release agent R may remain in the concave portions p on the surface of the formed mandrel M, as shown in FIG. The surface is washed with D to elute remaining particles r.

Then, as shown in FIG. 1F, when the conductive layer E is formed by applying a conductive treatment such as silver plating to the surface of the mandrel M, as shown in FIG. Due to the tension, the conductive layer E is not formed in the fine concave portion p, or even if it is formed, it is formed as a very thin film at the entrance.

The mandrel M thus subjected to the conductive treatment is immersed in an electrolytic solution A raised to, for example, about 45 ° C. as shown in FIG. Electroforming is performed by connecting N to the anode. Incidentally, the electrolyte solution A is, for example, a solution containing nickel sulfamate as a main component and an additive such as boric acid and chloride added thereto.

At this time, it is assumed that a thin conductive layer E is provided at the entrance of the concave portion p.
Is formed, the mandrel M expands due to the temperature of the electrolytic solution A, and is broken as shown in the example of the concave portion p on the right side in FIG. Therefore, the conductive layer E is not formed in the concave portion p, and nickel metal molecules are not deposited during electroforming.

At the time of electroforming, the cathode side (mandrel M
Side) takes in the nickel ions in the electrolytic solution A and precipitates as nickel metal molecules on the conductive layer E. Instead, nickel ions from the anode side (the nickel material N side) However, nickel ions are hardly replenished in the concave portion p, and as the electroforming process proceeds, the nickel ion concentration in the concave portion p becomes extremely low as compared with the periphery.

When the nickel ion concentration decreases, the current efficiency (the ratio of the actual deposition amount to the theoretical deposition amount) decreases, and this decrease is used for electrolysis of water.
Then, hydrogen gas is generated on the cathode side (mandrel M side) by the electrolysis of the water, and hydrogen gas is generated on the anode side (nickel material N).
On the side), oxygen gas is generated.

For this reason, a large amount of hydrogen gas is generated particularly in the concave portion p, and this hydrogen gas grows a non-electrodeposited portion.

In the thus formed electroformed shell K, a number of fine holes h are formed corresponding to the non-electrodeposited portions, and the electroformed shell K is formed with a mold W as shown in FIG. And a backup B having air permeability are attached to form a vacuum mold.

Further, since the hole diameter, the number of holes, the position of the holes, and the like can be freely adjusted depending on the application range and the amount of the release agent, and the type of the release agent, the influence of the holes appears on the product during vacuum forming. Can be easily formed.

[0023]

As described above, according to the method for producing an electroformed product of the present invention, a mold release agent is applied to the surface of a reversing product shape, and fine recesses are formed on the mandrel surface by the particles of the mold release agent. Since the surface of the mandrel is subjected to a conductive treatment while being molded, the concave portion can be rendered non-conductive using the surface tension of the conductive treatment liquid. Further, even if the concave portion is closed by a thin conductive layer, it can be broken by thermal expansion of the mandrel in the electrolytic solution. For this reason, the concave portion on the mandrel surface acts as a non-electrodeposited portion, and further, the non-electrodeposited portion grows due to the generation of hydrogen gas due to a decrease in current efficiency in the concave portion, and many fine holes are reliably formed in the electroformed shell. Can be formed.
In addition, the hole diameter, the number of holes, the position of the holes, etc. can be freely adjusted depending on the application range and amount of the release agent, the type of the release agent, etc. The shell is easy to mold.

[Brief description of the drawings]

FIG. 1 is a process diagram of a method for manufacturing an electroformed body of the present invention.

FIG. 2 is an enlarged view of the same part.

[Explanation of symbols]

 A electrolyte C inversion type D degreasing agent E conductive layer K electroformed shell M mandrel O master model R release agent h hole p concave part r particle

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-59-74289 (JP, A) JP-A-56-80410 (JP, A) JP-A-1-2222041 (JP, A) JP-A-2- 175893 (JP, A) JP-A-64-17888 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 1/00 C25D 1/08 B29C 51/36 B29C 33/38

Claims (1)

(57) [Claims] 1. A step of molding an inverted mold of silicon rubber having a surface from a master model, a step of applying a release agent to the surface of the inverted mold, and forming a mandrel from the inverted mold to form particles of the release agent. Forming a large number of fine recesses on the surface of the mandrel, degreased the surface of the mandrel, and then conducting a conductive treatment on the surface, and immersing the mandrel in an electrolytic solution to perform electroforming. A method for producing an electroformed body having minute holes, comprising a step of forming an electroformed body having a large number of fine holes by using a concave portion as a non-electrodeposited portion.