JP3109163B2 - Electric mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die using an electroformed shell as a molding surface, and more particularly to an electroforming mold having a hole forming portion.

[0002]

2. Description of the Related Art An electroforming mold using an electroformed shell formed by nickel plating or the like on a molding surface of a mold forms a cavity with the electroformed shell placed on the upper and lower mold parting surfaces.
A copper pipe for temperature control is attached to the back of each electroformed shell, and a backing material such as resin concrete is filled between the back and the mold to form a mold. Using this mold, a glass fiber mat is set in the cavity, a thermosetting resin is injected, and a resin transfer molding (RT) is performed by reaction-hardening by the heat of the mold kept at a constant temperature.
According to M), an FRP product is formed. By RTM, for example, the front end panel 2 of the automobile shown in FIG.
When molding 0, the headlamp portion 21 is included in the shape of the product.
And the grill portion 22, the holes need to be formed in these portions. Conventionally, in forming these holes, male and female steel nests are separately manufactured and attached to the molding surface of the mold later.

[0003] In Japanese Utility Model Laid-Open Publication No. 61-15120, FIG.
As shown in the figure, an insert mold 14 in which a nest 14 having an elastic body 15 fixed at the tip is disposed in a cavity 13 formed by the split molds 11 and 12, and a punch hole is formed in a product using this mold. Is described.

[0004]

A conventional electroformed mold has a structure in which a temperature control pipe is attached to the back of an electroformed shell, and hot water is circulated through the pipe to heat the mold to maintain a constant temperature. Has a three-dimensional shape, the thickness thereof is not constant, and the electroformed shell is slightly deformed due to insufficient rigidity of a backup material such as resin concrete. For this reason, even if the abutment surface (parting surface) of the nest is set to a gap (for example, 0.1 mm or less) at which resin leakage does not occur at room temperature, the mold is kept at the specified temperature (for example, 60 ° C.). When the resin is injected by heating, the molding surface of the electroformed shell is deformed, the gap between the parting surfaces becomes large (for example, 0.2 mm or more),
Resin leakage occurs from this portion, which causes molding failure, such as an unfilled portion of resin called a short circuit in a molded product. In the mold described in the above-mentioned publication, the nest is provided in the cavity which is the molding part of the product, so that the elastic body fixed to the nest has heat and pressure (2 to 10 kg) of the injected resin.
/ Cm ² ) and deformed, resulting in a molded article having a defective shape. In addition, the nested elastic body comes into contact with and adheres to the injected resin, or causes a chemical reaction, thereby causing problems in workability and nesting durability.

An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive electroforming mold which does not cause molding failure due to resin leakage at a portion where a hole is formed.

[0006]

According to the present invention, there is provided a molding die in which the molding surfaces of a core mold and a mold are formed by electroforming shells, and a nest is mounted in a hole-forming portion of the mold later. And a female mold insert made of an elastomer fitted to the male mold insert is attached to the other mold.

[0007]

Since the female mold of the insert is made of an elastomer and is attached to the mold later, the contact with the male insert can be easily corrected, and the gap on the parting surface can be adjusted to zero or minute. Also, when the molten resin is injected into the electroforming mold, even if the electroformed shell near the parting surface of the nest is deformed due to heat and pressure, the female mold nest has high elasticity, which may cause resin leakage. No molding defects.

[0008]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 4 shows the front end panel 20 of the vehicle shown in FIG.
FIG. 4 is a cross-sectional view of a mold for molding a part, showing a partial cross-section along line XX in FIG. 3. The molding surfaces of the core mold 1 for molding the back surface of the product and the mold mold 2 for molding the surface of the product are each constituted by an electroformed shell, and the core mold 1 and the mold mold 2 are parted by the parting plane PL.
To form the cavity 3. Since the front end panel 20 of the molded product has a round hole of the head lamp portion 21 and a long hole of the grill portion 22, a nest separately manufactured in a mold is installed later to mold these portions.
Although not shown, a temperature control pipe is fixed to the back of the cavity 3 of the mold, and a backup material is filled between the pipes and the mold. FIG. 4 shows a portion where two round holes are formed in the headlamp portion 21 of the mold. The back of the core mold 1 where the male and female nests 7 and 9 are disposed is connected to a vacuum device. The core mold 1 is provided with pores 5.
Is provided with a resin injection port 6.

FIG. 1 is a sectional view of a punched hole forming portion of a mold.
The nests for forming the holes are two steel disks 7A and 7A.
A male mold 7 in which B is fixed with bolts is separately prepared, and this is set on the parting surface 4 of the mold 2 and fixed to the mold with bolts 8. On the other hand, the nested female mold 9 is made of a highly elastic elastomer, and is fitted and attached to a concave portion formed behind the parting surface PL of the core mold 1, and a deaeration hole 5 is opened in this concave portion. Manufacturing an electroformed shell so that the gap between the parting surface PL of the entire surface of the core mold 1 and the mold mold 2 is 0 requires high-precision processing and makes the mold extremely expensive. Therefore, the nest manufactured separately from the mold is attached later, and the female mold 9 of the nest is made of an elastomer, so that after the mold is manufactured, the shape of the female mold 9 is polished and the hardness of the material is changed. Thereby, it is possible to easily correct the contact between the mounting recess of the core mold 1 and the male mold 7. Therefore, the core mold 1 and the mold mold 2 are connected to the parting surface P
In the state where the mold is clamped at L, as shown in FIG. 1, the gap on the parting surface PL can be easily adjusted to zero or minute.

When a synthetic resin is molded using this mold, a temperature controller is connected to a temperature control pipe, and a heat medium is circulated to set the electroformed shell of the mold at a specified temperature (for example, 60 ° C.). ), And when the molten resin is injected at 2 to 10 kg / cm, the cavity 3 is filled with the molten resin because the inside of the cavity 3 is evacuated under vacuum. Even if the electroformed shell near the parting surface PL of the nests 7 and 9 is slightly deformed by the pressure of the molten resin, the nested female mold 9 has high elasticity, so that there is no risk of causing resin leakage and short-circuiting of the product, etc. Does not cause molding failure. In addition, since the female mold 9 made of elastomer is disposed outside the cavity 3 which is a molded portion, it does not directly contact the molten resin, and may cause a defective shape of the product, and may cause a chemical reaction with the molten resin. Not even.

FIG. 2 shows another embodiment of the present invention. A butt 10 is attached to a nested male mold 7 and the tip of the butt 10 is brought into contact with a concave portion of the core mold 1.
The male mold 7 has a positioning function. The fact that the nested female mold 9 is made of an elastomer is the same as the embodiment of FIG. The contact correction in this case can be easily performed by polishing the butting 10 or the contact surface. In the above embodiment, the nest was installed in the core-shaped concave portion serving as the back surface of the product.However, the present invention is not limited to this, and the nest that forms a round hole such as a headlamp was described. Of course, the present invention can also be applied to a nest for forming a long hole such as a grill portion.

[0012]

According to the present invention, since one of the male and female nests is made of an elastomer, it is possible to easily adjust the gap of the parting surface of the punched hole forming portion of the mold, and set this gap to 0 or minute. Therefore, there is no danger of molding failure due to resin leakage, and the production cost of a mold that does not cause resin leakage by using an electroformed shell can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the present invention.

FIG. 3 is a perspective view of a molded product.

FIG. 4 is a sectional view of an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional molding die.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Core type 2 Cavity type 3 Cavity 7 Male nesting 9 Female nesting PL Parting surface

Claims (1)

(57) [Claims] 1. A molding die in which molding surfaces of a core mold and a mold are formed by an electroformed shell, and a nest is mounted later on a hole forming portion thereof, and a male mold nest is attached to a parting surface of one of the dies. An electroforming mold, wherein an elastomer female nest fitted to the male nest is attached to the other mold.