JP2003200468A - Injection molding tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in order to impart a special design-like luster to the surface of a resin product molded by an injection molding tool, a hologram sheet or the like needs to be applied to the surface of the resin product, but instead the resin product is heavy and the product cost is lowered. <P>SOLUTION: Microgrooves are formed at the same pitch of 0.7 to 2 μm on the surface of an insert of the molding tool and the shape of the microgrooves is transferred to the resin by injection molding. The light emitted to the resin product molded by the molding tool generates a light diffraction phenomenon by the microgrooves on the surface of the resin product and the angle of the diffractive light changes due to the color wavelength of the light. Thus the rainbow-color luster obtained by spectrally analyzing the color, is generated. Consequently, it is possible to provide the resin product which has the rainbow-color luster on the surface and an excellent design only by injection molding. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an injection molding die.

[0002]

2. Description of the Related Art Conventionally, a synthetic resin having easy moldability and excellent water resistance and moisture resistance has been used as a material for a speaker cone or the like, and a resin product is molded by injection molding. Has been done.

The injection mold used for molding these resin products will be described below with reference to FIG. In the figure, 1 is a sprue bush, 2 is a fixed-side insert, 3 is a movable-side insert, 4 is a protruding pin, 5 is a space for resin product molding formed between the fixed-side insert 2 and the movable-side insert 3, In the example, a speaker cone-shaped space is formed.

The resin injected from the injection molding machine passes through the sprue bush 1, and the fixed-side nest 2 and the movable-side nest 3
The space 5 formed between them is filled, and after cooling and solidification, the mold is opened, and is projected by the projecting pin 4 to mold the resin product.

[0005]

The surfaces of the fixed-side insert 2 and the movable-side insert 3 which form the product part of the conventional injection molding die are a surface having a surface roughness of about 0.4 s, The textured surface is generally textured, and the light reflection state of the resin product surface produced by these molds is glossy if the mold surface is a ledge, and the mold surface has a textured surface. If so, it is in a matte state.

Therefore, in order to give the surface of the resin product a rainbow-colored luster and give it a design characteristic, it is necessary to attach a hologram sheet or the like to the surface of the resin product, in which case the resin product becomes heavy, In addition, the number of manufacturing steps increases and the cost increases. For example, when the resin product is a speaker cone, there is an adverse effect that the performance of the speaker deteriorates.

It is an object of the present invention to provide a resin product having a rainbow-colored surface and an excellent design, without increasing the weight of the resin product such as a speaker cone.

[0008]

In the injection molding die of the present invention, fine grooves having the same pitch of 0.7 μm to 2 μm are formed on the surface of the mold insert, and the shape is formed by injection molding. It is designed to be transferred to.

The light illuminated on the resin product molded by this mold is generated by the fine grooves formed on the surface of the resin product.
The angle of the diffracted light changes depending on the wavelength of the light, which causes a diffraction phenomenon. At this time, because the grooves have a uniform pitch, the angle of the diffracted light becomes constant for each color wavelength, and the colors are dispersed and the iridescent luster To occur. Therefore, a resin product such as a speaker cone having an iridescent luster and excellent in design can be supplied only by injection molding.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is as follows.
In an injection molding die for molding a resin product in a space formed between a fixed side and a movable side nest, a pitch width of 0.7 μ or more and 2 μ or less on either the fixed side or the movable side or both of the nesting surfaces. The uniform groove is formed in the resin product by transferring the fine groove shape of the insert surface to the resin product by injection molding, and the resin product with the groove shape transferred causes a light diffraction phenomenon, Since the angle of the diffracted light changes depending on the difference in the wavelength of the color of the light, it has the function of dispersing the color and generating a rainbow-colored gloss on the surface of the resin product.

In the invention according to claim 2, the groove has a depth of 0.
It is characterized by being 1 μm or more, and by setting the depth of the groove to be 0.1 μm or more, there is an effect that a light diffraction phenomenon can be accurately caused.

The invention according to claim 3 is characterized in that the resin product is a speaker cone, which does not increase the weight of the speaker cone and does not deteriorate the performance, and the surface of the speaker cone is colored rainbow-colored. It has an effect of providing a speaker cone having a gloss and an excellent design.

FIG. 1 shows an embodiment of the present invention.
Will be explained. (Embodiment 1) FIG. 1 shows a product side insert 3 on the movable side of a speaker cone injection molding die. In this embodiment, a groove having a depth of 0.2 μ and a pitch of 0.8 μ is formed on the entire surface thereof. The speaker cone is injection-molded by the insert having the groove processing.

Laser machining and precision lathe machining are used as the groove machining method for the insert 3. In the case of lathe processing using a diamond bite, in order to prevent the adhesion of carbon between steel material and diamond carbon during processing, the nest itself is made of non-ferrous metal such as aluminum, or the nest is made of copper material, It is desirable to coat the surface with a non-ferrous metal such as nickel and perform groove processing on the nickel layer.

When a speaker cone is injection-molded by the injection molding die shown in FIG. 1, the fine groove shape of the movable side insert 3 is transferred to the surface of the speaker cone to form the fine pitch groove. Therefore, the light illuminated on the speaker cone causes a diffraction phenomenon of the light by the groove on the surface of the speaker cone as shown in FIG. 2, and the angle of the diffracted light changes depending on the wavelength of the color of the light. Since it is formed with the pitch of, the angle of the diffracted light is constant for each color wavelength, and light interference does not occur, and it is split into B (blue), G (green), R (red), etc. Produces a gloss of.

The angle of the diffracted light when the light illuminates the surface of the speaker cone is represented by θ = ArcSin (λ / P), and the angle of the diffracted light is determined by the wavelength λ of the light and the pitch P of the grooves. When the wavelength of visible light is 400 nm to 700 nm, the groove pitch P is required to be 0.7 μm or more at the minimum, and the groove pitch is about 2 μm at the maximum in order to obtain a spectral difference of diffracted light at a level at which humans perceive color differences. Must be:

Further, in order to accurately realize the light diffraction phenomenon, it is preferable that the depth of the groove is 0.1 μm or more.

The same effect can be obtained by forming the groove on the stationary insert and molding it with a transparent or translucent resin.

In the above embodiment, an example of molding a speaker cone has been described, but the present invention is not limited to this, and in a resin product obtained by injection molding, the design effect of the product surface is enhanced, and Similar effects can be obtained when a resin product having a rainbow-colored gloss on the surface is molded in order to improve the appearance characteristics.

Further, depending on the characteristics and application of the resin product, a groove is formed on either the movable side or the fixed side, or both of the nesting surfaces.

[0021]

As described above, according to the present invention, a resin product having a rainbow-colored gloss on the surface and an excellent design can be obtained by ordinary injection molding without increasing the weight.
When applied to a speaker cone, it is possible to provide a speaker cone excellent in design without deteriorating the performance of the speaker.

[Brief description of drawings]

FIG. 1 is a shape view of a movable side insert according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a light diffraction phenomenon.

FIG. 3 is a full sectional view of a general speaker cone injection molding die.

[Explanation of symbols]

1 sprue bush 2 Fixed side nesting 3 Movable side nesting 4 protruding pin 5 spaces

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinya Tabata             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Shinya Mizone             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Teruo Doi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 4F202 AF05 AF14 AF16 AH39 AR12                       AR13 CA11 CB01 CK11 CK42

Claims (3)

[Claims] 1. An injection molding die for molding a resin product in a space formed between a fixed side and a movable side nest, wherein 0.7 μ or more is present on either or both of the fixed side and the movable side of the nesting surface. An injection mold, wherein a uniform groove having a pitch width of 2 μm or less is formed and a resin product having a rainbow-colored surface is molded. 2. The injection molding die according to claim 1, wherein the groove has a depth of 0.1 μm or more. 3. The injection molding die according to claim 1, wherein the resin product is a speaker cone.