JPS6040961B2 - Hole drilling method for synthetic resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on F. R. Regarding the method of machining multiple holes when molding a synthetic resin molded product such as P, upper mold 1 and lower mold 2 are used.
A molding material is put between the molding material and the legs of the molded product.
When the molding material is in a gelled state and a driving device such as a plurality of cylinders 5 is driven to form a plurality of holes into the whole-shaped product 3 using a punching pin 4, a plurality of holes are formed depending on the location where the holes are to be made. The present invention relates to a method for drilling holes in a synthetic resin molded product, which is characterized by shifting the drive timing of a drive device.

Like SMC molding method and BMC method, F. R. P. This is a molding method in which the molding material is made to flow inside the mold and then hardened.When drilling multiple holes during molding using a drive device within the mold, a hydraulic (pneumatic) cylinder is generally used. . As for the timing of punching, it is necessary to punch out when it is in a gel state (semi-hardened state) (10 to 10 minutes after flowing).
2), and if this timing is off, a punching defect will occur. By the way, in the conventional molding apparatus, as shown in FIG. A plurality of cylinders 5 are arranged in a corresponding manner, and a hydraulic pump 7 that sends hydraulic pressure from an oil tank 6 is connected to each cylinder 5 by a hydraulic pipe 8, and the drive of all the cylinders 5 is controlled by the hydraulic pipe 8. One solenoid valve 9 was provided. In such a conventional example, a molding material is put between the upper mold 1 and the lower mold 2, and the upper mold 1 and the lower mold 2 are matched to mold the molded product 3, and the flange 3a of the molded product 3 is molded. When the solenoid valve 9
All the cylinders 5 were driven at the same time, and the punching pins 4 were used to punch holes at the same time. However, when the flange 3a is punched to form a hole, the time for the molding material to flow into the flange 3a differs depending on the location, so if all the cylinders 5 are driven at the same time, there will be locations where the timing will deviate. If the timing is off and the cylinder 5 is driven too quickly (the punching pin rises before the molding material flows), the flow of glass fibers will align around the punching pin 4 as shown in FIG. There is a disadvantage that the strength is reduced, and as shown in Fig. 2b, there is a disadvantage that the molding material is insufficiently filled due to the resistance of the punching pin 4, and if the cylinder 5 is driven too slowly, the material becomes hard. The drawback was that there were no holes. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for drilling holes in synthetic resin molded products, which can eliminate defects in hole drilling.

The present invention will be explained in detail below with reference to Examples.

An upper mold 1 having a concave portion 10 and a lower mold 2 having a convex portion 11 form a mold for molding a molded product 3 such as a mold.
At a position corresponding to the flange 3a of the molded product 3 of the lower mold 2, a cylinder 5 such as a hydraulic cylinder (or a pneumatic cylinder may be used) is arranged as a driving device for drilling. A punching pin 4 is provided for raising a hole such as a bolt hole driven by a screwdriver. Oil tank 6 [
Hydraulic pump 7 that sends hydraulic pressure (air pressure) from [not required in case of pneumatic pressure]
[In the case of pneumatic pressure, the compressor] and each cylinder 5 are connected through separate hydraulic piping 8 [Pneumatic piping in the case of pneumatic pressure], and each hydraulic piping 8 is provided with a solenoid valve 9, respectively. be. If there are many holes to be machined, use multiple cylinders 5 in close proximity.
It may be divided into a plurality of blocks in groups, and each block may be driven by a separate electromagnetic valve 9 via the hydraulic piping 8. The timing of the solenoid valve 9 is controlled by a timer depending on the location. 12 is a motor.

Next, the method of the present invention will be explained using the apparatus of the present invention constructed as described above.

As shown in Fig. 4a, raise the upper mold 1 and
F on top. R. P. Molding material 13 [SMC or B
MC], lower the upper mold 1, and release the molding material 13.
The molding material 13 is forced out to fill the cavity 14 between the upper mold 1 and the lower mold 2 with the molding material 13. After the molding material 13 has flowed, the solenoid valve 9 is activated by a timer, and the punching pin 4 is driven by the cylinder 5 as shown in FIG. 4b to form a hole. At this time, in areas where the molding material 13 flows quickly, the cylinder 5 is driven quickly by the solenoid valve 9, and in areas where the molding material 13 flows slowly, the cylinder 5 is driven slowly by the solenoid valve 9. Note that it is desirable to divide the hydraulic circuit into one circuit per cylinder, but this increases the cost and complicates the circuit, so investigate the flow state of the mold and divide it into blocks as much as possible.

The block-specific method is set for each mold because the flow state changes depending on the shape, size, number of processes, materials used, and material charging method. Usually about 2 to 6 blocks are required. As described above, the present invention shifts the drive timing of multiple drive devices depending on the location where the hole is made, so by setting the drive timing according to the fluidity of the location where the hole is made, the hole machining of each part is formed. This is done before the material is filled and hardened, and has the advantage of eliminating defects caused by drilling holes.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the conventional example, Fig. 2 a and b are perspective views showing the drawbacks of the conventional example, Fig. 3 is a cross-sectional view of an embodiment of the present invention, and Fig. 4 a and b are the same operations as above. FIG. 1 is a cross-sectional view illustrating 1
' is the upper mold, 2 is the lower mold, 3 is the molded product, 4 is the punching pin, 5
is a cylinder. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A molding material is put between an upper mold and a lower mold to form a molded product, and when the molding material is in a gel state, a driving device such as a plurality of cylinders is driven to punch out a plurality of holes with a punching pin. 1. A method for drilling holes in a synthetic resin molded product, which comprises shifting the driving timing of a plurality of drive devices depending on the location where the hole is to be drilled.