JPH0411087B2 - - Google Patents

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to an SMC (sheet molding compound) molded product, particularly an SMC in which a plate-shaped insert is arranged in the center of the molded product. It relates to a molding method for molding molded products, and is used for molding parts such as automobile sunroofs.

(Prior art) The prior art related to the present invention is
There is a publication titled No. 31644 "Method for forming SMC molded products".

This product improves the strength of SMC molded products by inserting plate-like or mesh-like inserts between SMC sheets in a sandwich-like manner.
A method of hot pressing is disclosed.

(Problems to be Solved by the Invention) However, in the above method for manufacturing SMC molded products, when a plate-shaped or net-shaped insert is made into a sandwich shape between sheets, the insert is easily deformed by the flow of SMC during molding. Moreover, there is a problem that the insert cannot be stably held and molded in the center.

A technical object of the present invention is to provide a method for manufacturing a molded product that can stably hold and form a plate-shaped insert in the center of the molded product.

[Structure of the invention]

(Means for solving the problems) The technical measures taken to solve the above technical problems are as follows. In other words, (1) inside the lower mold
Place the SMC, and (2) place an insert on the top surface of the SMC, the insert having a convex portion projecting upward and a through hole penetrating vertically, with both ends of the insert protruding outside the lower mold. (3) slide blocks disposed below elastic bodies disposed on both sides of the upper die so as to be biased downward by the elastic bodies; Before the mold is completely closed, press and hold both ends of the insert from above,
(4) After holding, this is a method for molding an SMC molded product, which is characterized in that the lower mold is completely closed and the mold is clamped to perform pressure molding. Furthermore, after the insert is placed, the SMC can also be placed on the top surface of the insert.

(Function) The above technical means functions as follows. That is, before the mold is completely closed, the exposed portion of the insert is held in the mold by the elastic body before the SMC flows due to heating, so it is difficult for the insert to move.

In addition, since the insert has multiple convex portions at least on the upper mold side, the center part of the molded product
SMC is charged to the lower mold, so during molding
The flow of SMC mainly pushes the insert toward the upper mold side, but the insert is reliably held from the surface of the molded product by the protrusion on the upper mold side of the insert.

(Example) Examples will be described below.

In FIGS. 1 and 2, A is an SMC molded product, 1 is an SMC, and 2 is an insert with a mounting hole 2a for fixing it to the mold. 3 is a plurality of convex portions provided on the surface of the insert, and 4 is a through hole passing through the insert. Further, at both ends of the insert 2, there are exposed portions 5 exposed from the molded product.

Figure 3 - Molding of SMC molded product A with insert 2 securely inserted in the center of the molded product
This will be explained with reference to FIG.

11 is the upper mold, 12 is the lower mold, and the upper mold has a spring 16.
There is a slide block 13 supported by the mold, and a support pin 14 for fixing the insert to the lower mold.

(Molding method) The SMC 15 is placed on the plane of the lower mold, the inserts 2 are stacked on its upper surface, and the mounting holes 2a of the inserts are inserted into the support pins 14 of the lower mold.
In this case, the protrusion 3 of the insert is on the upper die side.

Next, the upper mold lowers and the upper mold slide block 13
is fitted into the support pin 14 of the lower die to insert the insert 2.
The resin, which is fluidized by heating, passes through the through hole 4 and flows out onto the upper surface of the insert. This is shown in FIG. As a result, the insert is held in the center of the molded product, and since there is a convex portion on the upper mold side of the insert, the insert remains in the upper mold even when the SMC is pressurized, as shown in Figure 5. Even when pressed, a certain amount of space can be maintained between the upper mold and the lower mold to prevent deformation.
The insert is held in place at the center of the molded product by the pressure applied by the SMC.

The SMC molded product molded in the above molding process is 2±
It was reliably formed within the 1mm range. The molding conditions at this time were a mold temperature of 140° C., a pressing force of 400 tons, and a curing time of 3 minutes, and the SMC used was Daykumat 5100 (manufactured by Dainippon Ink and Chemicals).

Next, when an insert without the convex portion 3 was used, it was largely deformed toward the upper mold side and was largely exposed on the surface of the molded product. Furthermore, when molding was performed using an insert with a convex portion and without using the slide block shown in Fig. 3, the SMC moved the insert and
This resulted in the insert being exposed from the molded product.

Also, although a spring is shown as an example of a means for moving the slide block, a hydraulic cylinder, taper pin, etc. may also be used. Also, although a lower charge is shown as an example of SMC's charge, it is also possible to charge the top and bottom of the insert. It's okay. Further, although support pins are used as a method of fixing the insert to the mold, a method of restricting the outer shape with a mold may also be used.

〔Effect of the invention〕

The present invention has the following effects.

Methods for holding the insert of an SMC molded product in the center include: (1) providing convex portions on both sides of the insert; (2) placing pins on the upper and lower molds to support the insert in the center. However, if method (1) is used, the protrusions of the insert will be visible on both sides of the molded product, which will make the product look bad.
According to method (2), in addition to problems with appearance, the shape of the insert must be strictly controlled to prevent deformation of the pin.

According to the method of the present invention, the protrusion provided on the insert can be provided only in the upper mold, which solves problems in appearance, and also eliminates the need to provide special pins in the upper and lower molds, allowing the shape of the insert to be made strict. There's no need to manage it. Further, according to the present invention, the insert does not deform within the mold and does not move within the mold, so it can be stably held and molded in the center.

[Brief explanation of drawings]

Figure 1 is a simplified plan view of the SMC molded product, Figure 2
The figure is a sectional view from B to B in Figure 1, Figures 3 to 5 are explanatory diagrams of the molding process, Figure 3 is a sectional view before molding, and Figure 4 is a sectional view before molding.
The figure is a cross-sectional view of the process of fixing the insert with a slide block, and FIG. 5 is a cross-sectional view of the completed molding. A... SMC molded product, 1, 15... SMC, 2... insert, 3... convex part, 4... through hole, 11... upper mold,
12...Lower mold, 13...Slide block, 16...Spring (elastic body).

Claims (1)

[Claims] 1. A method of molding an SMC molded product having an insert, (1) placing an SMC in a lower mold, (2) providing an upwardly protruding convex portion and upper and lower parts on the upper surface of the SMC. (3) an insert having a through hole penetrating through the lower mold is fixed to the lower mold with both ends of the insert protruding outside the lower mold; Before the lower die is completely closed, both ends of the insert are pressed and held from above by a slide block disposed below the body so as to be biased downward by the elastic body. 4) After holding, the lower mold is completely closed and the mold is clamped to perform pressure molding.
Molding method for molded products. 2. The method for molding an SMC molded product according to claim 1, wherein after the insert is placed, SMC is also placed on the upper surface of the insert.