JPH04329885A - Etching method of external parts - Google Patents

Abstract

PURPOSE:To obtain the processing method which can form patterns and marks on the surfaces of external ornamental parts having stereoscopic structures by photoetching. CONSTITUTION:A jig plate 4 which is formed with a recessed part 2 on a base plate to the same shape as the outside shape of a rear cap 1 for a wrist watch which is the material to be treated and can set the material to be treated inserted into the recessed part 2 so as to make its surface flush with the front surface of the recessed part 2, is used as the jig to be exclusively used for the parts to be treated. A dry resist film having 25 to 75 micron film thickness is laminated on the surface of such plate to form a resist film 3; thereafter, the film is subjected to a photoetching stage to form the patterns and marks on the surface of the external ornamental parts. The good continuous resist film consisting of the resist film sticking to the surface of the jig and the surface of the parts to be treated is obtd. in this way. Since the material to be treated is fixed into the recessed part of the base plate even in the subsequent etching stage and the resist film simultaneously exhibits a good matching effect, there is an effect in the etching of the external ornamental parts having the stereoscopic structures with which the etching is heretofore difficult.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming fine patterns or marks on the surface of an exterior component such as a wristwatch by photo-etching.

0002

[Prior Art] Markings on external parts of watches such as cases and back covers have traditionally been formed by mechanical stamping or photo-etching, but for markings with delicate designs, photo-etching has been used. It was used. The photo-etching method involves dipping, spraying, or spraying a liquid resist onto the required part or the entire part of the material to be treated.
The method used was to coat the film by brushing or the like, bake it through a film with a desired etching pattern, develop it, and then etch it with a ferric chloride solution or the like. Also, for those using dry film resist,
It was limited to parts that could be laminated, such as dials.

0003

[Problems to be Solved by the Invention] However, in conventional photo-etching processing, liquid resist tends to cause pinholes, and it is difficult to uniformly coat resist on items with three-dimensional structures such as exterior parts. There was a problem in that it was difficult to do so, and accumulations occurred in some areas, resulting in poor development and poor adhesion of the resist film. Dry film resist, on the other hand, can coat a uniform resist film with fewer pinholes, but on the other hand, for exterior parts with three-dimensional structures, there are parts that are not laminated, and the shape of the processed parts is extremely restricted. There was a problem. Therefore,
The purpose of the present invention is to provide a processing method capable of forming patterns and marks on exterior parts of a wristwatch such as a case and a back cover by photo-etching using a photoresist in order to solve these conventional problems. It is in.

0004

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a three-dimensional structure, which has been difficult to achieve in the past, by selecting a dedicated jig for the part to be processed and the film thickness of the dry film resist. This enables etching of exterior parts. That is, as a special jig, the recess provided on the substrate has approximately the same shape as the outer shape of the material to be processed, and the jig can be set so that the surface of the material to be processed inserted into the recess and the upper surface of the recess are approximately on the same plane. The gap between the plate and the part in which the material to be treated is set in the recess shall be 2 mm or less based on the upper wall of the recess.
The difference in height between the surface of the material to be treated and the upper surface of the recess is preferably 2 mm or less. After that, a film thickness of 25~
The above problem was solved by laminating a 75 micron dry film resist, baking the desired etching pattern through the film, developing it, and then etching it.

[0005]

[Function] By setting the parts to be processed in the dedicated jig configured as above and laminating the dry film resist, a good continuous resist film is formed in which the dry film resist adheres to the jig surface and the surface of the parts to be processed. obtained,
In the subsequent etching process, the material to be processed is fixed within the recessed portion of the substrate, and at the same time, the resist film exhibits a good masking effect. The reason for limiting the film thickness of the dry film resist and the gap value between the recess and the processed part is that if the above values are exceeded, the resist film will be torn during the development and etching steps, resulting in poor etching. Further, as the thickness of the dry film resist becomes thicker, the resolution of the etching pattern deteriorates, so the upper limit is set to 75 microns.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. In FIG. 1, a wristwatch back cover 1 made of SUS304 material was set in a recess 2 provided on a jig plate 4 made of a glass epoxy substrate of a jig dedicated to processing parts. The gap between the set back cover and the top wall of the board recess is 1.0
~1.5 mm, and the difference in height between the surface of the treated material and the upper surface of the recess was MAX 2.0 mm. A dry film resist with a thickness of 50 microns is bonded by thermocompression using a roll coater to the surface of the jig plate on which the back cover is set in this way to form a resist film 3, and the desired shape is formed through a known photo-etching process of exposure, development, and etching. After forming an etching pattern on the back cover surface, the resist film was peeled off.

[0007] With the back cover obtained in this manner, it was possible to obtain an etching process for the exterior component that was satisfactory in terms of quality, with no skipping of etching due to damage to the resist film during the photoetching process.

[0008]

Effects of the Invention As explained above, the recess provided on the substrate as a dedicated jig for the parts to be processed has approximately the same shape as the outer shape of the part to be processed, and the part to be processed is inserted into the recess. Using a jig plate that can be set so that the surface and the upper surface of the recess are almost on the same plane, a dry resist film with a thickness of 25 to 75 microns is laminated on these surfaces to form a resist film, so that the resist film is the same as the jig surface. A good continuous resist film that adheres to the surface of the part to be processed can be obtained, and in the subsequent etching process, the material to be processed is fixed in the recess of the substrate and at the same time the resist film shows a good masking effect, which is difficult to do in the past. This method is effective for etching exterior parts with three-dimensional structures.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing a state in which a wristwatch back cover 1 is set in a substrate recess 2 and coated with a dry film resist film 3 in an embodiment of the present invention.

[Explanation of symbols]

1　Watch back cover 2 Recess provided on the board 3 Dry film resist film 4 Jig plate

Claims (1)

[Claims] Claim 1: A jig dedicated to processing parts, in which a recess provided on a substrate has approximately the same shape as the outer shape of the workpiece, and the surface of the workpiece inserted into the recess and the top surface of the recess are approximately flush with each other. Using a jig plate that can be set so that A method for etching exterior parts, characterized by forming.