JPH0634469B2 - Method for manufacturing electromagnetic shield housing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a housing having an electromagnetic shield function suitable for a case of electronic equipment and the like.

(Prior Art) In a housing for an electronic device formed by using a plastic material, an electromagnetic wave from an external peripheral device enters the housing or an electromagnetic wave from an electronic device in the housing transmits to the external peripheral device to There is a problem that the device or the electronic device in the housing malfunctions. For this reason, this type of housing using a plastic material is coated with a conductive paint on its back surface, a metal film is formed by thermal spraying or vacuum deposition, an aluminum foil is attached, or a plastic material is used. Shielding is provided by mixing conductive filler (Nikkei Electronics, 1982 7-19 (No. 2
95) pp.145-158).

However, since the above-mentioned conductive paint imparts the required shielding performance, it requires a thick coating, so it easily peels off during use, and the one by thermal spraying has a weak adhesion strength between the plastic material and the sprayed metal. It is easy to peel off at the time of impact, and it takes a lot of time to form a metal film in vacuum deposition, and the workability is bad because it is a batch process.Because the aluminum foil is manual, it is poor in mass productivity and shields the details. It has problems such as incomplete sex. further,
The one using the plastic material mixed with the conductive filler has a problem that if the amount of the filler is increased to improve the shielding property, the original strength of the plastic material is reduced and the insulation performance of the housing surface is also reduced. .

In order to solve such a problem, a technique has been proposed in which a composite plate in which a superplastic metal plate and an alloy resin plate are integrated is used, and this is thermoformed to manufacture a housing (Japanese Patent Laid-Open No. 59-59). -178
No. 799).

According to such a method, since it is possible to form the shield plate at the same time as forming the synthetic resin material, there is an advantage that a high-strength housing can be manufactured while maintaining the simplification of the manufacturing process. Since the deep drawing of the plate material is required, the corners such as the shoulders are likely to be unevenly extended, and there is a problem that cracks are generated.

(Purpose) The present invention has been made in view of such a problem, and its object is to use a composite plate material of a polymer resin plate material and a superplastic alloy that does not cause local deformation. It is to propose the manufacturing method of the electromagnetic shield housing.

The details of the present invention are described above based on the illustrated embodiments.

FIG. 1 shows an embodiment of an electromagnetic wave shield housing of the present invention. In the figure, reference numeral 1 is an electromagnetic wave shield housing integrally molded by a manufacturing method described later, and this shield housing 1 has a thermoforming temperature Tg of 80 ° C. to 280 ° C. ABS resin, Polycarbonate, Polysulfone, Polyamide, Modified PPO, Polyamideimide, Polyethylene, Polypropylene, Polyvinyl chloride and other thin thermoplastic resin 2 and superplasticity in the thermoforming temperature Tg region of this thermoplastic synthetic resin 2 Zn-based Zn-Al based alloy, for example, Zn-4-5% A containing 4-5% by weight of aluminum
1, Zn-40% Al, Zn-50% Al-based alloy and Zn
In addition to -AL co-folding alloy, Zn-21.5% Al-0.5% Cu
It is composed of a laminated body 4 with a thin superplastic alloy 3 such as a quaternary alloy of -0.01% Mg.

FIGS. 2 (a) and 2 (b) show the manufacturing method thereof, in which the laminate 4 of the thermoplastic synthetic resin 2 and the superplastic alloy 3 is
The synthetic resin 2 is placed on the die 5 having a heater therein (FIG. 2 (a)) so that the synthetic resin 2 is on the lower side.
The heaters 6 and 8 heat the laminated body 4 and its flange portion to the thermoforming temperature range of the thermoplastic synthetic resin 2. As a result, the thermoplastic synthetic resin material 2 is in a thermoformable state, while the superplastic alloy 3 has a reduced deformation resistance and is in a superplastic state.
In other words, since a very large elongation is exhibited, if a punch 9 having no built-in heater is processed at a speed according to the plate thickness of the superplastic alloy 3 and a load is applied to maintain the deformation stress at a constant level. The thermoplastic synthetic resin material 2 and the superplastic alloy 3 are both deformed while being narrowed down by the punch 9 (FIG. 2 (b)).

By the way, the superplastic alloy 3 in the portion contacting the shoulder portion 10 of the punch 9 during this forming process is locally subjected to a large deformation action, as pointed out in Japanese Patent Laid-Open No. 32475/51. However, as described above, the punch 9 does not have a built-in heater,
Since it is left at room temperature at the beginning of molding, the temperature of the superplastic alloy 3 in this portion becomes lower than the temperature in other portions due to the contact with the punch 9, and the deformation resistance increases. As a result, the stress caused by the shoulder portion 10 of the punch 9 is dispersed, local deformation is suppressed, and uniform deformation progresses throughout, so that the predetermined housing 1 is molded.

In this molding, if the laminated body 4 adhered with a synthetic resin adhesive that exhibits fluidity in the thermoforming temperature range of the synthetic resin material 2 is used, the thermoplastic synthetic resin material 2 and the thermoplastic synthetic resin material 2 are superposed by the adhesive fluidized during molding. The plastic alloy 3 does not peel off, absorbs the stress at the time of molding with some deviation in both directions, and more excellent moldability can be obtained.

In addition, although the above-described embodiment is composed of one thermoplastic resin material and one superplastic alloy, the thermoplastic alloy synthetic resin material is laminated on both sides of the superplastic alloy to form three sheets. It is also possible to use a superplastic alloy with a superplasticity development temperature of 120 ° C.
It is also possible to use a tin-based alloy Sn-9.8% Zn (eutectic) having a temperature of 180 ° C to 180 ° C.

[Example 1] A polycarbonate plate having a thickness of 1 mm and Zn- having a thickness of 0.1 mm
A laminated body of 50 × 80 mm made of a superplastic alloy plate of 21.5% Al-0.5% Cu-0.01% Mg was used, and this laminated body and the flange portion were formed between the die 5 and the holding plate 7 at a polycarbonate molding temperature. When the laminate was molded by heating to ℃ and lowering the punch 9 at room temperature during molding in this state at a speed of 2 mm per minute, cracks and pinholes were not generated.
It was possible to mold a housing of x50x9 mm.

[Example 2] 1 mm thick polycarbonate plate (Taquilon (trade name) PC
1600) and a thickness of 0.1 mm Zn-21.5% Al-0.5%
Cu-0.01% Mg superplastic alloy plate, softening temperature 1
A hot melt adhesive of 10 ° C (111H of Toagosei Co., Ltd.) was interposed, and a load of 1 kgf / cm ² was applied under heating at 130 ° C to form a laminate 4, and then this laminate was heated to 160 ° C. In addition, when a punch left at room temperature was used and a maximum load of 1500 kgf was applied and molding was performed at a speed of 100 mm / min, a 25 × 40 × 9 mm flanged housing could be formed without cracking or the like.

[Example 3] While heating the same laminate as in Example 2 to 160 ° C,
When the punch maintained at a temperature of 0 ° C. was lowered at a speed of 100 mm / min for molding, the same casing as that obtained in Example 2 could be molded without causing cracks or the like.

Moreover, 20 × 50 from the casing molded in Examples 2 and 3.
When a laminated body of mm was cut out and measured using an electromagnetic wave generator spectrum analyzer IR4172 manufactured by Advantest Co. and a measuring instrument TD17301, both of them showed a shielding performance of 60 dB or more in an electric field mode in a frequency range of 200 to 1000 MHz.

(Effect) As described above, in the present invention, a laminate of a plate-shaped thermoplastic synthetic resin and a superplastic alloy that exhibits superplasticity in the thermoformable temperature range of the thermoplastic synthetic resin is heated on the die. Since it has a step of heating to a formable temperature region and a step of deep drawing by bringing the superplastic alloy side into contact with the punch by a punch maintained at a temperature at which the superplastic alloy does not exhibit superplasticity, a deep drawing step However, the punching cooling effect can partially increase the deformation resistance of the laminate compared to thermoforming alone, so that even if a local force is applied to the superplastic alloy during deep drawing, it can be dispersed. As a result, cracking can be prevented.

[Brief description of drawings]

1 is a perspective view showing a partially cutaway view of an electromagnetic shield housing manufactured by the manufacturing method of the present invention, and FIG. 2 (a).
(B) is a figure which shows the manufacturing method of the electromagnetic-shielding housing of this invention, respectively. 1 ... Enclosure, 2 ... Thermoplastic synthetic resin material, 3 ... Thermoplastic alloy, 4 ... Laminated body, 5 ... Die, 6, 8 ... Heater, 7 ... Holding plate, 9 ... Punch

Continuation of the front page (56) Reference JP-A-60-120596 (JP, A) JP-A-59-178799 (JP, A) JP-A-55-82499 (JP, A) JP-A-62-65499 (JP , A) JP 54-29308 (JP, B2) JP 54-29306 (JP, B2) JP 55-43394 (JP, B2)

Claims (1)

[Claims] 1. A laminate of a plate-shaped thermoplastic synthetic resin and a superplastic alloy that exhibits superplasticity in the thermoformable temperature range of the thermoplastic synthetic resin is provided on the die in the thermoformable temperature range. A method of manufacturing an electromagnetic shield casing, comprising: a step of heating; and a step of bringing the superplastic alloy side into contact with the punch and deep-drawing with a punch maintained at a temperature at which the superplastic alloy does not exhibit superplasticity.