JP2002144381A - Mold for molding resin molded item having punching portion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance appearance design of a speaker by improving a structure of an electrode for electric discharge machining used for shaping a cavity side insert forming a punching portion in a mold for molding a resin molded item having a punching portion such as a speaker grill or the like. SOLUTION: An electrode 60 for electric discharge machining to shape a cavity side insert 44 by means of electric discharge machining is composed of a donut-shaped outer circumferential cylinder 61 and an inner cylinder 62 put in the outer circumferential cylinder 61 wherein the jointed portion (connected portion) 63 of both the cylinders 61 and 62 is positioned at a position corresponding to the corner portion 46 of the cavity side insert 44 to enhance design of the speaker grill 20 without conspicuousness of the connected portion 63 of both the cylinders 61 and 62 on the product surface of the speaker grill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a resin molded article having a punched portion having a large number of punched holes, such as a speaker grill, and more particularly, to enhance the appearance of the punched portion. The present invention relates to a molding die for a resin molded article.

[0002]

2. Description of the Related Art FIG. 8 is a front view showing an automobile door trim 1 installed in a door panel. The automobile door trim 1 is provided with a door trim upper in order to achieve a comparative effect on appearance and to simplify a molding die. The door trim upper 1a and the door trim lower 1b are often composed of upper and lower divided bodies of a door trim lower 1b and a door trim lower 1b.
It is molded into a desired curved shape by injection molding or mold press molding of a general-purpose synthetic resin such as (polypropylene) resin, and after inserting the ultrasonic boss provided on one side into the mounting hole on the other side By crimping the tip of the ultrasonic boss, the door trim upper 1a and the door trim lower 1b are joined along both joining lines.

[0003] The door trim lower 1b is formed into a required shape by an injection molding method having excellent moldability. And is integrally formed as a punching portion at the same time.

A conventional molding method of the door trim lower 1b will be described with reference to FIG. 9. The molding die 3 used in this molding method comprises a cavity mold 4a on the fixed side and a core mold 4b on the movable side. The molten resin supplied from the injection machine 5 is injected and filled into the product cavity formed between the cavity mold 4a and the core mold 4b through the sprue 5a and the runner 5b, and the door trim lower 1b is formed in a required shape. You.

Further, in order to form the speaker grille 2 on the door trim lower 1b, nests 6, 7 for forming punching holes are fitted and fixed in the cavity mold 4a and the core mold 4b, respectively.

FIG. 10 shows a carbon electrode when a nest 6 fitted and fixed in the cavity mold 4a is manufactured by electric discharge machining. This carbon electrode has a punching hole in the outer peripheral portion formed into a semicircular shape. In order to achieve this, a donut-shaped outer cylinder 8 and an inner cylinder 9 fitted and fixed in a hole 8a of the outer cylinder 8 are provided. Is formed.

[0007]

As described above, the shape of the punching hole of the speaker grille 2 is constituted by the outer peripheral cylinder 8 and the inner peripheral cylinder 9 in order to form the outer peripheral punching hole into a semicircular shape. When the electric discharge machining is performed on the nest 6 using the electric discharge machining electrode, the nest 6 is subjected to the electric discharge machining in conformity with the end face shapes of the electrodes 8 and 9 as shown in FIG. A joint a between the outer cylinder 8 and the inner cylinder 9 is formed as a1 in the insert 6,
As a result, as shown in FIG. 12, a problem has been pointed out in that the product surface of the speaker grill 2 is conspicuous as an annular convex portion a2, giving a sense of incongruity in appearance, and impairing the appearance design.

The present invention has been made in view of such circumstances, and in a molding die of a resin molded article having a punched portion such as a speaker grill, a projection or the like that reduces the appearance of the punched portion is formed on the periphery of the punched portion. It is an object of the present invention to provide a mold for molding a resin molded article having a punched portion in which the appearance and design of a product are enhanced without being performed.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a mold for molding a resin molded article having a punched portion in which a large number of punched holes are formed in a concentrated manner. The mold includes a cavity mold and a core mold capable of opening the mold, and a nest is provided in the cavity mold and the core mold corresponding to a punching part. A corner portion forming a highlight line of the product is formed by the electrode for electric discharge machining, and a joint between the outer cylinder and the inner cylinder constituting the electrode for electric discharge is formed by joining a corner line of each cylinder. A cavity-side insert is produced by making a joint portion correspond to the corner of the cavity-side insert.

As is apparent from the above configuration, the cavity-side insert inserted into the cavity mold corresponding to the punching portion is such that, at the time of electric discharge machining, the electric discharge machining electrode has both joint lines between the outer cylinder and the inner cylinder. Because it is joined along the corner of the cylinder, the highlight line around the perforated part hits this joint line,
A projection or the like that gives a sense of incongruity is not formed on the periphery of the punched portion, which is preferable in appearance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a mold for molding a resin molded article having a punched portion according to the present invention will be described.
This will be described in detail with reference to the accompanying drawings.

FIG. 1 is a front view showing an automobile door trim manufactured by using a molding die according to the present invention, FIG. 2 is a sectional view showing a punching portion of the automobile door trim, and FIG. Schematic diagram showing the overall configuration of such a molding die,
FIG. 4 is an explanatory view showing the arrangement of the cavity-side insert and the core-side insert in the molding die, and FIGS. 5 and 6 are explanatory views showing the structure of the electric discharge machining electrode of the cavity-side insert in the molding die according to the present invention. FIG. 7 is an explanatory view showing the electric discharge machining process.

1 and 2, a door trim 10 for an automobile includes a door trim upper 11 and a door trim lower 12
The door trim upper 11 is formed into a desired curved surface shape by injection molding or mold press molding of a PP (polypropylene) resin mixed with a filler such as talc.
An insulated skin 11a, such as a cloth, is attached to the insulated portion of the door trim 10 to improve the appearance performance and the feeling of touch.

On the other hand, the door trim lower 12 is similarly formed into a desired curved shape by injection molding or mold press molding of a PP resin mixed with an inorganic filler such as talc. In addition, a door pocket 13 is opened, and a speaker grill 20 having a large number of punching holes is integrally formed on the front side.

The speaker grill 20 has a large number of punching holes 21 formed in a concentrated manner and an annular highlight line 22 formed so as to divide the area of the speaker grill 20 from a general portion of a door trim. ,
The punching hole 21 of the speaker grille 20 is a perfect circle, but the punching hole 21a on the outer periphery is formed in a semicircular shape by a highlight line 22 to improve the appearance performance in combination with the highlight line 21.

The molding die according to the present invention is used for molding the door trim lower 12 integrally formed with the speaker grille 20 having such excellent appearance performance. Explaining the basis, the molding die 30 is such that a cavity mold 40 as a fixed mold plate is attached to the lower surface of a cavity-side attachment plate 41, and a sprue bush is provided on both the cavity-side attachment plate 41 and the cavity mold 40. A guide pin bush 43 having a guide function of the core mold 50 is provided.

On the other hand, a core type 5 capable of moving a predetermined stroke
Numeral 0 is attached to a core-side attachment plate 51 via a spacer block 51a and a receiving plate 51b, and a core 52 to which a product shape is formed is attached to a core mold 50.

The core mold 50 includes a cavity mold 40.
Guide pin 53 inserted into the guide pin bush 43
The ejector pin 54a and the sprue lock pin 54b which can accurately close and open the cavity mold 40 and the core mold 50, and which cooperate with the movement of the core mold 50 to eject the product. , Return pin 5
4c is attached to the upper and lower ejector plates 54.

In the molding of the door trim lower 12, the core mold 50 is clamped to the cavity mold 40, and in fact, the product cavity formed between the cavity mold 40 and the core 52 of the core mold 50 is formed. The molten resin is injected and filled in C through a sprue 42a of the sprue bush 42 and a runner 42b between both dies from an injection machine (not shown), and the door trim lower 12 is formed into a required shape.

At this time, the speaker grill 20 is integrally formed with the molding of the door trim lower 12. As shown in FIGS. 3 and 4, a cavity side insert 44 is fitted and fixed to the cavity mold 40. , Core 5 of core type 50
2, core-side inserts 55 are fitted respectively.

In particular, the cavity side insert 44 facing the product surface has a plurality of trapezoidal projections 45 formed on the opposing surface of the core side insert 55 to form the punching holes 21. In order to form the highlight line 22 for regulating the peripheral portion, the corner portion 46 is formed.
Are formed. The core side insert 55 has a projection 56 facing the projection 45.

Next, FIGS. 5 and 6 show an electric discharge machining electrode used for producing the cavity side insert 44.
FIG. 7 shows the electric discharge machining process.

In other words, the electric discharge machining electrode 60 includes a donut-shaped outer cylinder 61 and an inner cylinder 62 that is inserted into the outer cylinder 61 in such a manner that the punching hole 21a at the outer periphery is set in a semicircular shape. It is composed of divided bodies,
The inner peripheral cylinder 62 has a circular concave portion 62a for forming the projection 45 on the cavity side insert 44 and a semicircular concave portion 62b on the outer peripheral surface.
Finally correspond to the punching holes 21 of the speaker grille 20, and the semicircular concave portions 62b correspond to the semicircular punching holes 21a along the outer periphery.

The round hole 61 of the outer peripheral cylinder 61
a of the electric discharge machining electrode 6
0, but as shown in FIG.
Since the joint (joint) 63 between the inner cylinder 1 and the inner peripheral cylinder 62 is adjusted so as to coincide with the corner 46 of the cavity side insert 44, the cavity side insert 44 is used by using the electric discharge machining electrode 60. When the electric discharge machining is performed, the corner portion 46 of the cavity side insert 44 is formed by the joining portion 63.
Is formed, and the joint between the outer peripheral cylinder 61 and the inner peripheral cylinder 62 does not stand out.

Therefore, the cavity side insert 44 produced by using the above-mentioned electric discharge machining electrode 60 is
Speaker grill 20 of the door trim lower 12
Is integrally formed, the joint portion (joint) 63 of the electrode 60 becomes the highlight line 22, so that the appearance design of the speaker grill 20 can be improved.

For reference, the electric discharge machining process will be described with reference to FIG. 7. A brass block W, which is a material of the cavity side insert 44, is set on a jig 71 in a solution 70, and an electric discharge machining electrode is set on this. By causing the electrodes 60 to approach each other and discharge them for a predetermined time, the cavity-side inserts 44 can be formed with high accuracy in conformity with the end face shape of the electrode 60 for electric discharge machining.

[0027]

As described above, according to the present invention, the molding die for a resin molded article having a punched portion is such that the cavity-side insert for forming the punched portion is formed by a combination of an outer cylinder and an inner cylinder. The joint line between the two cylinders is formed to be the corner of the cavity side insert by the electric discharge machining using the electric discharge machining electrode, so the joint line of the electric discharge machining electrode is conspicuous on the product surface This has the effect of improving the appearance of the punched portion and improving the design of the product.

[Brief description of the drawings]

FIG. 1 is a front view showing an automobile door trim formed using a molding die according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a schematic view showing the overall configuration of a molding die according to the present invention.

FIG. 4 is a sectional view showing a main part of a molding die according to the present invention.

5 is a configuration explanatory view showing an electric discharge machining electrode used when performing electric discharge machining of the cavity side insert shown in FIG. 4;

FIG. 6 is an explanatory view showing a relationship between the electric discharge machining electrode shown in FIG.

FIG. 7 is an explanatory view showing a work procedure for performing electric discharge machining of the cavity side insert using the electric discharge machining electrode shown in FIG. 5;

FIG. 8 is a front view showing a conventional automobile door trim.

9 is a schematic configuration diagram showing a molding die for molding a door trim lower in the automobile door trim shown in FIG.

FIG. 10 is an explanatory view showing a configuration of an electric discharge machining electrode for performing electric discharge machining on the cavity side insert shown in FIG. 9;

11 is an explanatory view showing a relationship between the electrode for electric discharge machining shown in FIG. 10 and nesting on the cavity side.

FIG. 12 is an explanatory view showing a problem when a conventional electric discharge machining electrode is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Automobile door trim 11 Door trim upper 12 Door trim lower 20 Speaker grill 21 Punching hole 21a Punching hole (outer peripheral part) 22 Highlight line 30 Molding mold 40 Cavity mold 41 Cavity side mounting plate 44 Cavity side insert 45 Projection 46 Corner part 50 Core mold 51 Core-side mounting plate 52 Core 55 Core-side nesting 60 Electrode for electrical discharge machining 61 Outer cylinder 62 Inner cylinder 62a Circular recess 62b Semicircular recess 63 Joint 70 Solution 71 Jig

Claims (1)

[Claims] 1. A resin molding (12) having a punched portion (20) in which a number of punching holes are intensively drilled.
A mold (30) comprising a cavity mold (40) and a core mold (50) that can be mutually clamped and opened, and correspond to the punching part (20). ) And core type (50) nested (44,55)
The cavity side insert (44) has a plurality of protrusions (45) for forming punching holes and a corner (46) for forming a product highlight line (22) formed by an electric discharge machining electrode (60). The joint between the outer peripheral cylinder (61) and the inner peripheral cylinder (62) which is formed and constitutes the electric discharge machining electrode (60) is formed by each cylinder (61, 6).
The corner line of 2) is joined, and this joint (63)
To the corner (4) of the cavity side nest (44).
A mold for molding a resin molded article having a punched portion, wherein a cavity-side insert (44) is produced corresponding to (6).