JP3034326B2 - Compression molding method and molding die equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression molding method for obtaining a resin molded product having a plurality of irregularities, which are undercuts in a die-cutting direction, at predetermined locations as a group, and a molding die apparatus used therefor. It is.

[0002]

2. Description of the Related Art A fiber-filled thermosetting resin sheet material impregnated with a thermosetting resin such as an unsaturated polyester resin between a male mold and a female mold is a so-called SMC (Sheet Molding). Compounding material is supplied, and compression molding is performed to form a compression molded product 1 having a plurality of convex undercut portions 1a, 1b, and 1c as shown in FIG. In this case, it is known that the undercut portions 1a, 1b, 1c are formed using a slide core mechanism that slides inside the mold as the mold is opened and closed. Here, each undercut portion 1a, 1
b and 1c are cases where the sliding directions of the forming slide cores are the same direction indicated by the arrow CC and differ by approximately 90 ° from the die-cutting direction indicated by the arrow BB. Is shown.

FIG. 6 shows a cross section taken along the line DD in FIG. 5 when the resin molded article 1 is molded. An integrated slide core 4 for forming each of the undercut portions 1a, 1b, 1c is slidably inserted into the male molding die 3 to be formed. The core 4 is moved by the hydraulic cylinder 5 in the direction of the arrow, and is stopped at a dashed line position where there is no problem in opening the molds 2 and 3.

[0004]

However, the plurality of undercut portions 1a, 1 within a certain range as described above.
Since the integrated slide core 4 is used for b and 1c, a large hydraulic cylinder 5 is required because the resin pressure at the time of molding the slide core 4 is large,
The slide mechanism becomes large. Further, since the cross-sectional shape of the slide core 4 becomes extremely large when it is formed into a circular shape that can include the undercut portions 1a, 1b, 1c, the undercut portions 1a, 1 are formed to reduce the area as much as possible.
It is generally a rectangular shape containing b and 1c,
The mold matching between the slide core 4 having the rectangular cross section and the male mold 3 is more difficult than the one having the circular cross section, the clearance is inevitably increased, and not only burrs are generated but also as described above. In the case of a fiber-filled thermosetting resin, the male molding die 3 and the slide core 4 are worn out, resulting in poor durability. In addition, the concave portion for forming the undercut portion of the slide core 4 is liable to become a gas pool at the time of molding, so that there is a disadvantage that the undercut portions 1a, 1b, and 1c after molding have defects.

[0005] Therefore, the present invention provides a compression molding method and a molding die apparatus which can form an undercut portion having no defect by a compact slide mechanism portion using a small hydraulic cylinder and maintain the durability of a mold and a slide core mechanism. It is a technical task to provide

[0006]

Means for Solving the Problems According to the present invention, as the technical means for achieving the above-mentioned object, molding is performed by the following compression molding method. That is, in a compression molding method of a resin molded product having a plurality of undercut portions as a group, a molding die incorporates each slide core pin for individually forming each of the undercut portions,
After the molding material was charged into the cavity of the molding die, the mold was clamped and pressed, and after the molded product was cured, the respective slide core pins in the same sliding direction were simultaneously slid by a driving source via a connecting body. It is characterized in that a step of removing the molded product by releasing from the molding die is performed later.

[0007] The molding die apparatus is a molding die apparatus for compressively molding a resin molded product having a plurality of undercut parts as a group, wherein each undercut part of a male molding die or a female molding die is formed. The slide core pins are individually provided at the corresponding portions of the above, and the respective slide core pins in the same sliding direction are connected so as to be integrally operated by a connecting body, and the connecting body is connected to a driving source. It is characterized by that.

[0008]

The resin pressure at the time of molding does not become equivalent to the total area of the portion surrounding each undercut portion as in the conventional case, but becomes much smaller than the total area of the individual slide core pins. Therefore, it can be operated by a compact slide mechanism using a drive source such as a small hydraulic cylinder. In addition, since each slide core pin individually corresponds to each undercut portion, each of the slide core pins has a small cross-sectional area, so that it can be a round pin having a circular cross section, which facilitates mold matching with the mold. As a result, the clearance can be made as small as possible, the durability of the mold and the slide core pin can be maintained, and since the clearance between each slide core pin and the mold functions as a gas vent, the undercut portion is broken. Nothing.

[0009]

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view taken along the line DD in FIG. 5 during molding, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, respectively. The same components are denoted by the same reference numerals. Each of the undercut portions 1a, 1b, 1
The slide core pins 7, 8, 9 are respectively slidably inserted into the respective portions where c is formed, and the slide core pins 7, 8, 9 are integrally operated by the connecting body 10. The connecting body 10 is connected to the hydraulic cylinder 11.

In the slide core mechanism of the molding die apparatus, the resin pressure at the time of molding is reduced by each of the undercut portions 1a, 1a.
Since the area surrounding b and 1c, that is, the area corresponding to the projected area of the connecting body 10 is not equivalent to the area corresponding to the total area of the individual slide core pins 7, 8, and 9, it is significantly smaller. As is clear from the comparison with the above, the operation can be performed using a compact slide mechanism using a small hydraulic cylinder.

Further, each slide core pin 7, 8, 9
Since a small cross-sectional area corresponding to each undercut portion 1a, 1b, 1c is sufficient, the cross-sectional shape is circular. Therefore, the mold alignment with the male molding die 6 becomes easy, the clearance can be set extremely small, there is almost no burrs, and the durability of each of the slide core pins 7, 8, 9 and the male molding die 6 is improved. Since the gas can be retained and the gas at the time of molding escapes from each clearance and gas accumulation does not occur, the undercut portions 1a, 1b, 1c after molding are formed.
No loss occurs in

The arrows in FIG. 2 indicate the direction in which the molds 2 and 6 are removed.
9 has a side surface slightly behind the point where the extension line of the end face in contact with the undercut portions 1a, 1b, 1c comes into contact with the male molding die 6, as indicated by the one-dot chain line in FIG. It is set to be located. As a result, after the resin molded article 1 has hardened, the coupling body 1 is driven by driving the hydraulic cylinder 11.
When the respective slide core pins 7, 8, 9 are simultaneously retracted to the positions shown in FIG. 3 via "0", the molding dies 2, 6 can be easily released and the resin molded product 1 can be taken out.

FIG. 4 is a cross-sectional view of another embodiment of the present invention, in which the same components as those shown in FIGS. 5 shows a molding die apparatus when a cut portion 1d exists in a group. A slide core pin 12 slidable in the corresponding slide direction and a hydraulic cylinder 13 for operating the same are separately provided for the undercut portion 1d having a different slide direction. Can be obtained.

[0014]

As described above, according to the compression molding method of the present invention, since each undercut portion is formed by a corresponding slide core pin, a small clearance between each slide core pin and a mold is used for molding. Since the gas escapes, no loss occurs in the undercut portion.
Also, because the clearance is as small as possible,
Burrs hardly occur, and the durability of the slide core pin and the mold can be maintained.

According to the molding apparatus of the present invention, since the resin pressure during molding is limited to only the total area of the individual slide core pins, it is possible to use a drive source such as a small hydraulic cylinder. Thus, the slide mechanism of each slide core pin can be made compact. In addition, since each of the slide core pins has a small cross-sectional area, it can be formed in a circular cross-section, so that the mold can be easily aligned with the mold, and the clearance can be made as small as possible.

[Brief description of the drawings]

FIG. 1 is a cut-away plan view of a compression molded state according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cutaway front view at the time of release from the mold.

FIG. 4 is a cut plan view of another embodiment of the present invention;

FIG. 5 is a perspective view of a resin molded product molded according to the present invention.

FIG. 6 is a cut-away plan view of a conventional molding die apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin molded product 1a-1d Undercut part 2 Female side molding die 6 Male side molding die 7-9,12 Slide core pin 10 Connection body 11,13 Hydraulic cylinder (drive source)

Claims (2)

(57) [Claims] In a compression molding method for a resin molded product having a plurality of undercut portions as a group, each slide core pin for individually forming each of said undercut portions is incorporated into a molding die. After the molding material is charged into the cavity of the mold, the mold is clamped and pressurized, and after the molded product is cured, the respective slide core pins in the same slide direction are simultaneously slid by a driving source via a connecting body. A compression molding method characterized in that a molded product is taken out from a molding die. 2. A molding die apparatus for compression molding a resin molded product having a plurality of undercut portions as a group,
A slide core pin is individually provided at each corresponding position of each undercut portion of the male molding die or the female molding die, and the slide core pins in the same sliding direction are integrally formed by a connecting body. A molding apparatus, operatively connected, wherein the connection is connected to a drive source.