JP2001315168A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding capable of obtaining a dummy surface equivalent to a reflex reflector surface without burden on a cost. SOLUTION: A second molding surface 5a of a second mold 5 is formed by electric-discharge machining. Accordingly, the dummy surface equivalent to the reflex reflector surface is obtained without burden on the cost. Thus, an appearance of a molded resin product is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal mold for injection molding for manufacturing a resin component having a reflex reflector surface and a dummy surface thereof.

[0002]

2. Description of the Related Art The surface of an outer lens used for lamps such as tail lamps and stop lamps of automobiles includes:
A reflex reflector surface that reflects light at night is partially formed (as a similar technique, see JP-A-10-27).
No. 5504). On the surface of the outer lens other than the reflex reflector surface, a dummy surface having the same shape as the reflex reflector surface is formed in consideration of appearance. This dummy surface only looks almost the same as the reflex reflector surface in appearance, but is not formed as accurately as the reflex reflector surface, and therefore does not have the reflection characteristics of the reflex reflector surface at night.

[0003] The outer lens is manufactured by injection molding. The mold forming the reflex reflector surface and the dummy surface side has a first mold having a high-precision first molding surface corresponding to the reflex reflector surface and a second mold having a second molding surface having an accuracy corresponding to the dummy surface. It is formed by combining two molds.

[0004] The first forming the reflex reflector surface
Although the first molding surface of the mold is accurately formed by being accurately transferred by electroforming or the like, the second molding surface of the second mold for forming the dummy surface is formed.
The molding surface is roughly formed by NC processing or the like from the viewpoint of cost.

[0005]

However, in such a conventional technique, since the second molding surface of the second die for forming the dummy surface is roughly formed by NC processing or the like, the re-mounting is difficult. Although a dummy surface having substantially the same shape as the flex reflector surface can be obtained, the appearance quality at daytime is slightly different, and further improvement in appearance is desired.

The present invention has been made by paying attention to such a conventional technique. An injection molding die which does not impose a burden on cost and can obtain a dummy surface equivalent to a reflex reflector surface is provided. To provide.

[0007]

According to the first aspect of the present invention,
A resin part having a reflex reflector surface and a dummy surface thereof is injection-molded. A first mold having a high-precision first molding surface corresponding to the reflex reflector surface, and a second molding having an accuracy corresponding to the dummy surface. An injection molding mold formed by combining a second mold having a surface with the second mold.
The second molding surface of the mold was formed by electric discharge machining.

According to the first aspect of the present invention, since the second molding surface of the second mold is formed by electric discharge machining, it is possible to obtain a dummy surface which is not burdensome in cost and is equivalent to the reflex reflector surface. The appearance of the molded resin product is improved.

According to a second aspect of the present invention, an electric discharge machining electrode is formed by assembling pins having a tip shape corresponding to one element of a dummy surface, and the electric discharge machining electrode forms a second molding surface of a second mold. Electric discharge machining.

According to the second aspect of the present invention, an electric discharge machining electrode is formed by assembling pins each having a tip shape corresponding to one element of the dummy surface, and the electric discharge machining electrode is used to form the second electrode.
Since the second molding surface of the mold is subjected to electric discharge machining, a dummy surface having an arbitrary width can be formed depending on the aggregation state (arrangement or number) of the pins.

According to a third aspect of the present invention, a transfer die is formed by assembling pins having a tip shape corresponding to one element of the reflex reflector surface, and the transfer die is transferred by electroforming to form the first die. Was formed.

According to the third aspect of the present invention, a transfer mold is formed by assembling pins having a tip shape corresponding to one element of the reflex reflector surface, and the transfer mold is accurately transferred by electroforming. In order to form the first molding surface of the first mold, it is possible to form a reflex reflector surface of an arbitrary width depending on the aggregation state (arrangement and number) of the pins.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram schematically showing an outer lens 1 of a lamp provided at the rear of an automobile. The surface of the outer lens 1 has a reflex reflector surface R that reflects light at night and a dummy surface D that does not reflect light at night but has the same shape as the reflex reflector surface R. Each of the reflex reflector surface R and the dummy surface D has a shape in which quadrangular pyramid elements are arranged vertically and horizontally, and only has different areas.

The outer lens 1 includes a pair of dies 2 and 3
(Refer to FIG. 11), and the reflex reflector surface R and the dummy surface D on the surface side thereof are
Formed by The mold 2 includes a first mold 4 and a second mold 5.
The first mold 4 has a first molding surface 4a forming a reflex reflector surface R, and the second mold 5 has a second molding surface 5a forming a dummy surface D.
have.

The first molding surface 4a of the first mold 4 is formed by the transfer mold 6 shown in FIGS.
The molding surface 5a is formed by the electric discharge machining electrode 7 shown in FIG. Both the transfer die 6 and the electric discharge machining electrode 7 are formed by assembling pins 8 and 9 having a tip shape corresponding to one element of the reflex reflector surface R and the dummy surface D. The difference is the material of the pins 8 and 9, the pin 8 for the transfer die 6 is made of hard stainless steel, and the tip is mirror-finished by plating. The pin 9 for the electric discharge machining electrode 7 is
It is made of copper with good conductivity, and this tip is also plated. The transfer die 6 and the electric discharge machining electrode 7 can respond to changes in the size and shape of the reflex reflector surface R and the dummy surface D depending on the aggregate state (arrangement and number) of the pins 8 and 9.

First, when the first die 4 is manufactured by the transfer die 6, the shape of the tip of the transfer die 6 is accurately transferred by electroforming to obtain a highly accurate first molding surface 4a. 1. The base is joined to the molding surface 4a, and the first mold 4 as shown in FIG.
To form

Next, when the second mold 5 is manufactured by the electric discharge machining electrode 7, the second mold 5 before machining as shown in FIG. As shown in FIG. 8, the tip of the pin 9 of the electric discharge machining electrode 7 is brought close to the machining surface 5 while discharging, and as shown in FIG.
A second forming surface 5a corresponding to the electric discharge machining electrode 7 is formed on the mold 5. Although the second molding surface 5a is not as accurate as the first molding surface 4a, it has higher accuracy than the conventional NC processing. In other words, conventionally, the machining surface of the second mold 5 is given a rough shape with high accuracy by the NC machining, but in the present embodiment, the machining surface of the second mold 5 is provided with a high precision by the electric discharge machining. Is given a concave shape. Furthermore, such electric discharge machining is not disadvantageous in cost as compared with conventional NC machining.

The mold 2 is formed by combining the first mold 4 and the second mold 5 manufactured as described above (FIG. 1).
0), and by injecting a resin into a space formed between the mold 2 and the other mold 3 (see FIG. 11), the outer lens 1 desired can be obtained (FIG. 12). The obtained dummy surface D of the outer lens 1 has higher accuracy than that obtained by the conventional NC processing, and the appearance quality in the daytime is not different from the reflex reflector surface R, and the appearance is good.

[0020]

According to the present invention, since the second molding surface of the second mold is formed by electric discharge machining, no burden is imposed on cost.
In addition, a dummy surface equivalent to the reflex reflector surface is obtained, and the appearance of the molded resin product is improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an outer lens of the present invention.

FIG. 2 is a sectional view showing the outer lens of FIG. 1;

FIG. 3 is a plan view showing a transfer mold.

FIG. 4 is a side view showing the transfer mold of FIG. 3;

FIG. 5 is a side view showing an electric discharge machining electrode.

FIG. 6 is a diagram showing a side surface of a transfer mold and a cross section of a first mold.

FIG. 7 is a diagram showing a side surface of an electric discharge machining electrode and a cross section of a second mold before machining.

FIG. 8 is a view showing a side surface of the electric discharge machining electrode and a cross section of the second mold during machining.

FIG. 9 is a view after machining showing a side surface of the electric discharge machining electrode and a cross section of the second mold.

FIG. 10 is a cross-sectional view of a mold combining a first mold and a second mold.

FIG. 11 is a cross-sectional view showing a state in which the outer lens is being injection-molded by a mold.

FIG. 12 is a sectional view showing an outer lens obtained by injection molding.

[Explanation of symbols]

 Reference Signs List 1 outer lens (resin part) 2 mold 4 first mold 4a first molding surface 5 second mold 5a second molding surface 6 transfer mold 7 electric discharge machining electrode 8, 9 pin R reflex reflector surface D dummy surface

Claims (3)

[Claims] 1. A resin part having a reflex reflector surface and a dummy surface thereof is injection-molded, and a first mold having a high-precision first molding surface corresponding to the reflex reflector surface and a dummy surface. An injection molding die formed by combining a second mold having a second molding surface with an accuracy to perform the injection molding, wherein the second molding surface of the second mold is formed by electric discharge machining. Mold. 2. The injection molding die according to claim 1, wherein pins having a tip shape corresponding to one element of the dummy surface are gathered to form an electric discharge machining electrode, and the electric discharge machining electrode is used for forming the electric discharge machining electrode. A mold for injection molding, wherein a second molding surface of a second mold is subjected to electric discharge machining. 3. The injection mold according to claim 1, wherein pins having a tip shape corresponding to one element of the reflex reflector surface are assembled to form a transfer mold. An injection mold, wherein a transfer mold is transferred by electroforming to form a first molding surface of the first mold.