JPS592811A - Manufacture of precise component - Google Patents

Abstract

PURPOSE:To integrally mold a synthetic resin and a metal thereby to obtain a precise component of a watch excellent in strength, form stability and dimensional accuracy, by continuously molding a superplastic alloy and a synthetic resin in the same mold through the utilization of the fact that the molding temperatures of both of them are close to each other. CONSTITUTION:A superplastic alloy 1, e.g., a Zn-Al superplastic alloy is molded into the shape of a female die 6 at a superplastic temperature by blowing in a gas from gas inlets 3 while drawing a vacuum from suction ports 4. Thereafter, a synthetic resin 7, e.g., polycarbonate injected from a synthetic resin inlet 2 is integrally molded with the superplastic alloy 1 by means of a plunger 5 to obtain a precision component, such as a wrist watch case or the like. EFFECT:It is possible to reduce the number of processes and conserve energy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing precision parts such as watch parts that integrate synthetic resin and metal.

BACKGROUND ART In recent years, with the reduction in the cost of watch parts, especially the cost of wristwatches due to the advent of digital watches, many watch parts are being manufactured from synthetic resin. This is because injection molding allows timepiece parts with complex shapes to be easily obtained.

However, in cases where small size and thinness are required, such as in wristwatches, materials with low strength per volume such as synthetic resins are disadvantageous; Inconveniences may occur during the process, resulting in quality defects.

As a measure to strengthen the strength of such synthetic resins, there is a method of embedding metal inside to integrate and composite reinforcement. This deformation causes deformation of the shape and adverse effects on dimensional accuracy. Also, the metal parts used for integration are processed and molded into a predetermined shape in advance.
This requires an additional process.

By the way, superplasticity refers to fine crystals of approximately 10 pm or less.
This is a phenomenon in which metal materials with grains, especially metals with an equiaxed two-phase mixed structure with approximately the same size and strength, exhibit large deformations at a certain temperature with low stress. Various processing methods and products are being developed using this technology.

The present invention aims to eliminate shape defects and adverse effects on dimensional accuracy due to elastic deformation of the metal during processing that occurs when reinforcing by combining and integrating the above-mentioned normal metal and synthetic resin. Continuous molding takes advantage of the fact that the molding temperatures of synthetic resins are similar, and the moldability of superplasticity, which allows relatively complex shapes to be easily formed through plastic wells, and the practical strength of metals, and the extremely superior properties of synthetic resins. By taking advantage of their moldability and combining synthetic resin and superplastic metal, we are able to achieve the same strength and improve the stability of dimensional accuracy and shape due to the absence of springback of superplastic metal, as well as further reduce process steps. It also made it possible to save energy.

This will be explained below using examples.

A eutectoid alloy with a standard composition of 4 wt% At and the balance ztL can be prepared by water quenching and annealing after solution treatment.
It exhibits superplasticity with a two-phase mixed structure as fine as microscopic. This zH-Az superplastic alloy C is hereinafter referred to as Zn-22AL. ), the deformation resistance suddenly decreases from around 200°C and the elongation becomes large (becomes), and after reaching an extreme value around 250°C to 270°C, the deformation resistance increases again and the elongation becomes small.

Zn at around 230℃~270℃
If -22At is a thin plate, it can be deformed even at about 1 to 10 atm, and can be shaped into a blown bottom shape.

At this superplastic temperature of Zn-22AL, injection molding and compression molding of polycarbonate, polypropylene, polyethylene, etc. is possible.

Therefore, a wristwatch case was manufactured by integrally molding Zn-22AL and polycarbonate using a processing device as shown in the schematic cross-sectional view in FIG.

Fig. 1 shows the superplastic alloy Zn-22AL, 2 is a synthetic resin injection port, 3 is a gas injection port, 4 is a vacuum suction port,
5 is a plunger, and 6 is a toothed type. The processing equipment is Z
The area near n-22AL is heated to about 270°C, and the other parts are heated to a temperature lower than this.

First, while drawing a vacuum from the vacuum suction port 4, blow gas through the gas injection port 3 to create the 2n-22Ati
It was molded into mold 6. Then turn off the heating power,
As shown in FIG. 2, a cross-sectional view of a wristwatch case made of polycarbonate injected from the synthetic resin injection port 2 by residual heat and molded by the plunger 5 is made of an outer shell of Zn-22AL.

Ru.

The wristwatch case integrally molded and reinforced with Zn-22At as described above has improved shape stability and dimensional accuracy compared to the conventional case. Furthermore, since it can be processed in one step, the process is simplified, and the residual heat from heating the superplastic alloy is sufficient for molding the synthetic resin, resulting in energy savings.

In addition, if a fine pattern is engraved on the mold, the rough pattern is formed in the first blow molding, and the pressure load is slightly increased during the subsequent pressure molding of the synthetic resin. Even minute patterns can be beautifully transferred.

The above example deals with the case of a wristwatch, but there are other cases as well.
The main plate, dial plate, etc. can be processed in the same way, and it is not limited to wristwatch parts, but also precision parts such as table clocks and alarm clocks that need to be made smaller and thinner, and that require reinforcement of the strength of synthetic resin. This manufacturing method is applicable.

As described above, according to the present invention, the superplastic metal and synthetic resin can be continuously molded by taking advantage of the fact that the molding temperature of the superplastic alloy and the molding temperature of the synthetic resin are the same or in a close range. By integrating synthetic resin with metal and reinforcing it compositely, it is possible to achieve the same shape stability and dimensional accuracy, while also reducing process steps and saving energy.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a processing device of the processing method according to the present invention, and FIG. 2 is a sectional view of a wristwatch case. 10. Superplastic alloy 200 synthetic resin injection inlet, gas inlet 40. Vacuum suction port 50. Plunger 60
．． Applicant for over 700 synthetic resin molds: Daini Seikosha Co., Ltd.

Claims (1)

[Claims] In the manufacture of precision parts, the synthetic resin and metal are integrated by first molding a superplastic alloy at a superplastic temperature and then molding the synthetic resin in a mold containing the superplastic alloy. Manufacturing method for precision parts.