JPH01317654A - Production of wrist watch case - Google Patents

Abstract

PURPOSE:To drastically decrease the number of units of press machines and dies by providing means of producing the rough shape of a product by an investment casting method, then executing the stage of cold forging for which dimensional accuracy can be requested with one stroke. CONSTITUTION:A lower die 5 worked with a recess for forming the surface shape of the product and a knock-out 6 forming the surface window shape of the product are mounted to the lower die 1 of the die set. An upper die 4 worked with a projecting part forming the rear surface of the product shape is mounted to the upper die 2 of the die set. Guide posts 3 are the posts to mate the upper and lower dies of the die set. Ball retainers 8 prevent wear and a head 7 connects the vertical movements of the press machine. The hermetic state is attained when the lower die 5 and the upper die 5 are mated. The work obtd. by the investment casting method is mounted to the dies and is continuously worked under specified load. The product having the excellent shape and dimensional accuracy complying with the shape of the die is obtd. in this way and the small-quantity production of diversified kinds is effectively executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a manufacturing method in which a material having excellent ductility is continuously molded by cold casting after investment casting to form a product.

[Summary of the Invention 1] The present invention reduces the number of manufacturing steps and simplifies the production equipment by combining investment casting and cold casting in the production of wristwatch cases.

[Prior art 1] Typical materials used for wristwatch cases include stainless steel, copper alloy, aluminum, plastic, and gold alloy, and these materials are used to form and manufacture the shape of the wristwatch case. Methods include cold forging, hot forging, injection molding, etc.

Among these manufacturing methods, the cold forging method, which has no material restrictions and guarantees precise dimensional accuracy, is the mainstream for manufacturing wristwatch cases.

[Problem to be solved by the invention] However, the production method using cold forging requires various molds to shape the product, and the process requires 10 to 13
The press machines used for those molds, which are also processes, are 3
~4 types are required, and the costs associated with mold production and press machinery and equipment are enormous, making it unsuitable for high-mix, low-volume production of products. In order to solve these drawbacks, the present invention aims to provide a production method that is compatible with high-mix, low-volume production.

[Means for Solving the Problems] In order to solve the above problems, the present invention first produces a rough shape of a product using an investment casting method, and then performs a cold forging process that requires dimensional accuracy in the shape of the product. The structure has been designed so that it can be carried out in stages, making it possible to handle high-mix, low-volume production.

[Function] In the investment casting method, it is difficult to require complete dimensional accuracy of the product, so cold forging is set as one step, and the product shape is formed by this cold forging, and continuous constant pressure is applied instead of conventional compression processing. By inventing a method and gradually forming a material with excellent ductility, it is possible to obtain the desired product shape and dimensional accuracy.

[Examples] Examples of the present invention will be described below based on the drawings. In Fig. 1, a lower mold 5 with a recessed part for forming the surface shape of the product shape and a knockout 6 for forming a window shape on the product surface are assembled into the lower mold 1 of the Guiset, and then attached to the lower mold 1 of the Guiset, and then the upper mold 2 of the Guiset An upper mold 4 having a convex portion formed on the back side of the product shape is attached to the upper mold 4. The guide post 3 is a pillar that connects the lower mold 1 and the upper mold 2, and the pole retainer 8 protects against wear that occurs when the lower mold 1 and the upper mold 2 move up and down continuously and slide against the guide post 3. The head 7 serves to connect the vertical movement of the press machine. When the lower die 5 and the upper die 4 are put together, they become airtight, and if a work piece obtained by the investment casting method is placed inside and continuously machined under a constant load, it will turn into gold when made of highly ductile materials such as gold alloys and aluminum alloys. It extends to fit the shape of the mold, making it possible to manufacture products with excellent shape and dimensional accuracy.6 [Effects of the Invention] If a product is produced using the production method configured as described above,
The number of press machines and molds required in conventional cold forging can be significantly reduced, making it possible to produce high-mix, low-volume production.

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal sectional view of a cold forging die for continuously applying constant pressure to a workpiece after investment casting according to the present invention. 1...Lower die set 2...Upper die set 3...Guide boss 4...Upper die 5...Lower die 6...Knockout 7...Head 8...Pole retainer and above Applications People Seiko Electronics Industries Co., Ltd.

Claims (1)

[Claims] It consists of a process using the investment casting method for machining the rough shape of the workpiece, and a process of cold casting the workpiece after the investment casting using a mold in order to improve the dimensional accuracy of the workpiece. A method for manufacturing a wristwatch case characterized by continuous molding in combination with casting.