JPS631515A - Structure of fitting part of resin compression molded product - Google Patents

Abstract

PURPOSE:To facilitate postprocessing without generating a weld mark, by a method wherein a long hole part obtained by combining a long hole and round hole in the direction of a thickness is molded at a time at the time of molding, in a form of the hole at a fitting part. CONSTITUTION:A long hole of a blind hole is molded at a time at the time of resin molding as a form of the hole of a fitting part. The undersurface of the fitting part 5 is a protrusion D1 for forming a long hole 6 molten resin flows smooth down to an end part 5a of the fitting part and boring is performed after the molding by a drill whose diameter is larger than the width of the long hole 6, in the molding based on a top force C and bottom force D.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to the structure of a mounting part of a compression molded product made of resin material, which is molded with a sheet molding compound or a stamping sheet. It is used in the structure of the mounting part of automobile sunroofs, etc.

(Prior art) As a prior art related to the present invention, molten resin flows in a mold when molding a hole in a mounting portion of a resin compression molded product such as a sheet molding compound (SMC) or a stamping sheet. In this case, if the mounting holes are formed at the same time as the molding, weld marks, which are wave phenomena, will occur as the molten resin butts against each other. This is shown in Figure 8 (A
Z D EL product design, Ube Nitto Kasei materials).

The cause of this weld mark can be explained with reference to Figures 6 and 7. 1 is a resin compression molded product, 2 is a mounting part, and 3 is an elongated hole. A protrusion B1 is provided on the lower mold B to form the hole 3. When molded using the mold, a weld mark 4, which is a butt of the resin, is generated at this edge due to the convex portion B1 provided on the mounting portion 2,
This weld mark causes cracks.

As a method for preventing the weld marks 4, a method is used in which the mounting portion is formed into a blind hole and then processed afterward in order to smooth the flow of the molten resin and eliminate the butt.

(Problem to be Solved by the Invention) However, when a blind hole is formed in the attachment part using the above method, as shown in FIG. It is necessary to form a long hole 3, which cannot be easily machined with a normal round drill, and requires a large amount of time for post-processing.

In addition, in order to prevent weld marks, it is necessary to add thick wall to the opening to create a blind hole, and there is a problem in that the machining time is increased due to the large thickness of the cutting wall.

A technical object of the present invention is to provide a structure for a mounting part of a compression molded product made of a resin material, which does not produce weld marks on the mounting part and is easy to process.

[Structure of the invention]

(Means for solving the problem) The means for solving the above technical problem are as follows. In other words, the shape of the hole in the attachment part of the resin compression molded product is a combination of an elongated hole and nine holes in the thickness direction, and the elongated hole is molded at the same time as the molding process, so that it has a diameter larger than the width of the elongated hole. This is the structure of the attachment part of a resin split compression molded product that is processed after molding with nine holes on the top surface of the elongated hole.

(Operation) The technical means operates as follows. In other words, by simultaneously molding a blind elongated hole during resin molding, the hole shape of the mounting part eliminates the butting phenomenon of molten resin and prevents weld marks. Holes are drilled with a larger diameter drill, which reliably prevents weld marks that occur during molding, and since the nine holes are processed after molding, it is extremely easy to cut, and only the blank-sized dimensions can be cut with a drill. This reduces the machining time considerably, and since the mounting portion is in the form of an elongated hole, the degree of freedom in mounting dimensions using the elongated hole shape is not impaired.

(Example) Examples will be described below.

In FIGS. 1 to 5, 1 is a resin compression molded product, 5 is a mounting portion, and 6 is an elongated hole. Molding was performed in an upper mold C and a lower mold D. D1 is a convex portion for forming a long hole provided on the lower surface of the attachment portion 5, and the molten resin can smoothly flow to the end portion 5a of the attachment portion.

The shape of the elongated hole 6 in the mounting part is 7 w x 9 m, and the depth T =
DICMAT5200 (manufactured by Dainippon Ink and Chemicals) is used as the resin material, and the mold temperature is 140! , pressure 1
Molding was carried out under the following molding conditions: 0.0 kg/cd and pressurization time of 3 minutes.

Figure 4 shows the mounting part formed by the upper and lower molds in Figure 3, which has an elongated hole shape and has a blind hole depth T. After molding, nine holes 8 are drilled with a drill 7 as shown in Figure 5. processed.

Table 1 is a study of cracks and weld marks caused by dimensional changes in the blank hole T.
The same materials and molding conditions as above were used.

Table 1 X-ray observation was performed using soft X-ray non-destructive inspection equipment at 30KVA, 3m.
A. Irradiation was performed for 1 minute. As shown in Table 1, the present invention does not cause any cracks during demolding, and since there is no weld, no cracks occur due to vibration during use.

〔Effect of the invention〕

The present invention has the following effects.

In the FR construction of the mounting part of a compression molded product made of resin material, a shape that does not cause weld marks on the mounting part and is also easy to process is to provide a slit 9 in the weld mark generation part of the mounting part 2, as shown in Fig. 9. A structure that prevents the materials from butting together by inserting a There is a possibility that the strength will further decrease.

According to the present invention, the hole size during molding is stable, and since there are no slits, the attachment strength does not decrease, resulting in a safe attachment part shape.

[Brief explanation of the drawing]

Figure 1 is an external view of the mounting part of the resin compression molded product of this example.
Figure 2 is a plan view of the mounting part shown in Figure 1, Figure 3 is a sectional view of the mold for molding the mounting part shown in Figure 1, and Figure 4 is the mounting part molded with the mold shown in Figure 3. 5 is a sectional view of this embodiment, FIG. 6 is an external perspective view of the conventional example, FIG. 7 is a sectional view of the mold in the 6th case, and FIG. FIG. 9, an external view of the weld mark, is a plan view of one in which a slit is provided in the mounting hole. 1...Resin compression molded product, 5...Mounting part, 6...Elongated hole, 8...Round hole

Claims (1)

[Claims] In the structure of the mounting hole in the mounting part of a resin compression molded product, a long hole is simultaneously formed in the thickness direction of the mounting part during molding of the resin compression molded product, and then a hole is formed next to the long hole. A structure of a mounting part of a resin compression molded product, which is formed by machining a round hole having a diameter larger than the width on the upper surface of the elongated hole.