JPH0336651B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an improvement in a mold for processing a thin-walled molded article made of thermoplastic resin by injection molding.

"Conventional technology" Conventionally, the thickness of the thin plate part that can be made when processing a molded object made of thermoplastic resin by the injection molding method is
It is said that the thickness is approximately 1mm, and if it is thinner than that, it is impossible to reliably and uniformly inject every corner of the mold because the heated and molten material is a kneaded fluid. . For this reason, in many cases, thin plate-shaped products and parts are currently formed by processing using thin metal plates.

Therefore, the applicant first discovered a technique that makes it possible to injection mold even extremely thin plate-like objects by devising and improving the position of the spool or runner, the position and shape of the gate part, etc.

This proposal, as shown in Figures 8 and 9,
For example, the thin plate parts 1 and 2 may be placed parallel to each other and the back plate part 3
A mold in which the thin-walled molded body 4 having a U-shaped cross section and connected at are disposed so as to be slidable in a direction perpendicular to the mold clamping direction, and a slide core 7 forming the inner side is disposed on the movable side in the mold clamping direction. The bases of the gate cavity portions 8a and 8b formed thinly on both the left and right sides of the thin-walled molded body 4 communicate with the lower end of the spool or runner 9 without passing through a cold slab well.

"Problems to be Solved by the Invention" However, according to the above-mentioned conventional technology, the slide cores 5 and 6 for forming the outside of the thin plate parts 1 and 2 having a large area are arranged in a direction perpendicular to the mold clamping direction. Because of this, during injection and filling, the slide cores 5 and 6 act in the direction of opening on both sides, causing problems such as burrs and variations in wall thickness. Therefore, sufficient injection pressure could not be applied, and mass productivity could not be improved.

"Means for Solving the Problems" In order to solve the above problems, the present invention takes the following measures.

A mold for processing a thin-walled thermoplastic resin body consisting of a thin plate part and a back plate part by injection molding.
Cores in which product cavity parts for processing the outside of the thin plate part of the thin-walled molded body are respectively formed are arranged on a fixed side and a movable side in the mold clamping direction, and the thin plate part and the back plate part of the thin-walled molded body are placed between the cores. A thin-walled molded product made by injection molding, in which a slide core for processing the inside of the molded product is arranged so as to be slidable in a direction perpendicular to the mold-clamping direction, and an ejection pin for releasing the product is arranged so as to come into contact with the spool or runner of the thin-walled molded product. In the processing mold, gate cavity portions for injection molding the gate portion are formed on both end sides of the back plate portion of the thin-walled molded body, and the product cavity portion of the core and the gate cavity portion communicate with each other. The base of the gate cavity is connected to the base of the gate cavity without going through a cold slab well.

"Example" Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 5 relate to the first embodiment of the present invention, and as shown in FIG. 2, the thin molded body 11 has a thickness of 0.1 mm to 0.6 mm and an area of 40 mm×
Thin plate part 12 with dimensions of 24 mm or more and up to 80 mm x 60 mm,
13 facing in parallel with a distance of 1 mm to 20 mm, and both connected by a back plate part 14, a mold for processing a thin-walled molded body for producing a molded body by injection molding having a U-shaped cross section will be described as an example. do.

FIG. 1 is an exploded perspective view of a mold for processing a thin-walled molded body for this embodiment. In the figure, 15 and 16 are cores for forming the thin plate parts 12 and 13 of the thin molded body 11. These cores 15 and 16 have thin plate parts 1
Product cavity part 1 forming the outside of 2 and 13
5a and 16a are formed, respectively. One core 15 is arranged on the fixed side in the mold clamping direction, and the other core 16 is arranged on the movable side. A slide core 17 is provided between the cores 15 and 16, which forms the inside of the thin plate portions 12, 13 and the back plate portion 14 of the thin molded body 11. This slide core 17 is arranged so as to be slidable in a direction perpendicular to the mold clamping direction.

Incidentally, gate cavity portions 18 for injection molding the gate portions 18 and 19 are provided on both end sides of the back plate portion 14 of the thin molded body 11, as shown in FIG. 3b.
a, 19a are formed. At this time, since the thin-walled gate parts 18 and 19 are formed so as to be continuous with the back plate part 14 and extend on both left and right sides thereof, the product cavity part 1 can also be used as a mold.
5a, 16a and gate cavity part 18a,
19a are formed so as to communicate with each other. Furthermore, the bases of the gate cavity portions 18a and 19a are connected to the lower end of the spool or runner 20 as shown in FIG.
It is formed so as to communicate without going through the cold slab well 21 as shown in Fig. 1, and prevents pressure loss, which is a drawback of kneading fluid, as much as possible, improves pressure transmission, and allows the molten material to flow smoothly to the product cavity part 15.
It is possible to press fit into every corner of a and 16a.

Further, on the lower side of the spool or runner 20 portion communicating with the gate cavity portions 18a, 19a of the thin molded body 11, there are ejecting pins 22, 22 for product release so as to abut the spool or runner 20 after molding. is installed. When taking out the thin-walled molded body 11 as a product, as shown in FIGS. 4 and 5, first open the mold and at the same time pull the slide core 17 to remove the product cavity portion 16a side (A side) of the movable core 16. The product is separated from the product in a telescopic floating type, and the product is held on the spool or runner 20 portion side (B side) of the movable side core 16, and then moved to the movable side. Next, when the mold opening is completed, the spool or runner 20 portion is ejected by the ejecting pins 22, 22 for releasing the product, and the mold is released and the molded product is taken out.

Next, the operation based on the above configuration will be explained.

Thin plate part 1 having a wide area of thin molded body 11
Since the cores 15 and 16 forming the outer sides of the cores 2 and 13 are arranged on the fixed side and the movable side in the mold clamping direction, injection pressure can be received in the mold clamping direction. Therefore, the cores 15 and 16 do not withstand the injection pressure and are not moved, which prevents the occurrence of burrs and reduces variations in wall thickness, improves the dimensional stability of the injection molded product, and improves quality. can be improved.

Furthermore, since sufficient injection pressure and injection speed can be obtained, mass productivity can be improved compared to the conventional method. Furthermore, the slide core 17 portion becomes thinner, and the strength of the entire mold can be improved.

In addition, since the product release ejection pins 22, 22 are arranged so as to come into contact with the spool or runner 20 after molding, no ejection marks will be generated on the product part of the thin-walled molded body 11, and the product will not be damaged. It becomes beautiful and easy to take out.

6 and 7 show a mold for processing a thin-walled molded body according to a second embodiment of the present invention, which can mold four thin-walled molded bodies 31, 31, 31, 31 at once. In these figures, the numbers 32,...,
33, . . . are thin plate portions similar to those in the first embodiment; 34, . . .
is a back plate portion that connects each part. The thin-walled molded bodies 31, . . . are arranged on the same plane and are connected by sub-runners 36, . . . and spool runners 37, . Sign 3
8 is a spool portion.

FIG. 7 is a partial sectional view of a mold for processing a thin-walled molded body for this embodiment. In the figure, product cavity parts 39a and 40a forming the outer sides of the thin plate parts 32, . . . , 33, . . . of the thin molded bodies 31, . And one core 3
9 is arranged on the fixed side in the mold clamping direction, and the other core 40 is arranged on the movable side. Between the cores 39 and 40, there is a thin plate portion 3 of the thin molded body 31,...
2, . . . , 33, . . . and slide cores 41, .
The slide cores 41, . . . are arranged so as to be slidable in both directions perpendicular to the mold clamping direction. Furthermore, product release ejection pins 42, . . . are disposed below the sub-runners 36, . . . of the thin molded bodies 31, . The description of other configurations is the same as that of the first embodiment.

Next, the effect of the above configuration will be explained.

In this embodiment, the injection pressure can be applied in the mold clamping direction, and conventionally, for example, a 75-ton machine could only produce two pieces, but the same machine can now produce four pieces, improving mass productivity. Other operations are similar to those in the first embodiment.

In addition, in each of the above embodiments, the thin-walled molded body 11,
The cores 15, 16, 39, 40 forming the outside of the thin plate portion having a wide area of 31, . . . are arranged on the fixed side and the movable side in the mold clamping direction, and It is sufficient that the slide cores 17, 41, . . . forming the inner side are arranged so as to be slidable in a direction perpendicular to the mold clamping direction. Incidentally, in order to smoothly perform the separating operation by sliding the slide cores 17, 41, . . . , it is preferable to form a draft angle within a predetermined value range in each thickness direction of the thin plate portion.

In addition, although the illustrated thin-walled molded bodies 11, 31, ... are in the shape of a simple plate, they are not limited to this, and may have window holes formed in arbitrary shapes, letters or graphic symbols, etc. It may be engraved on the surface of the thin plate part.

Furthermore, depending on the area of the injection molded product,
A large number (for example, 8) may be used.

"Effects of the Invention" As described above, the present invention is a mold for processing a thin-walled molded body 11 made of thermoplastic resin, which is composed of thin plate parts 12 and 13 and a back plate part 14 by injection molding. Cores 15 and 16, on which product cavity parts 15a and 16a for processing the outer sides of the thin plate parts 12 and 13 of the body 11 are respectively formed, are arranged on a fixed side and a movable side in the mold clamping direction, and between the cores 15 and 16. The thin plate parts 12 and 13 and the back plate part 14 of the thin-walled molded body 11
A slide core 17 for processing the inner side is arranged so as to be slidable in a direction perpendicular to the mold clamping direction, and ejection pins 22, 22 for product release are arranged so as to come into contact with the spool or runner 20 of the thin-walled molded body 11. In a mold for processing a thin-walled molded body by injection molding, gate cavity portions 18a and 19a for injection-molding gate parts 18 and 19 are formed on both end sides of the back plate portion 14 of the thin-walled molded body 11, and the above-mentioned Product cavity parts 15a, 16a of cores 15, 16
and the gate cavity portions 18a and 19a are formed so as to communicate with each other, and the gate cavity portion 1
The bases of 8a and 19a are communicated with each other without going through a cold slab well.

Therefore, the injection pressure can be applied in the mold clamping direction, preventing the occurrence of burrs, reducing variations in wall thickness, etc., and improving the quality of the injection molded product. In addition, sufficient injection pressure and injection speed can be obtained, and mass productivity can be improved.

[Brief explanation of the drawing]

1 to 5 relate to a first embodiment of the present invention, FIG. 1 is an exploded perspective view of a mold for processing a thin-walled molded body, and FIG. 2 is a mold for processing a thin-walled molded body shown in FIG. 1. Fig. 3a and b are partially enlarged sectional views showing the state in which the base of the gate cavity is in communication with the lower end of the spool or runner. , FIG. 4 is a plan view showing the state when the molded product is taken out, and FIG.
The figure is a sectional view of FIG. 4, FIGS. 6 and 7 relate to the second embodiment of the present invention, FIG. The figure is a cross-sectional view of the mold for processing the thin-walled molded body shown in Figure 6, FIG. 8 is a plan view showing the state of the conventional thin-walled molded body when it is taken out from the core, and FIG. 9 is the same as that shown in FIG. FIG. 3 is a sectional view of a mold for processing a thin-walled molded product. 11, 31... thin-walled molded body, 12, 13, 32,
33... Thin plate part, 15, 16, 39, 40... Core,
15a, 16a, 39a, 40a... Product cavity part, 20, 36... Spool or runner, 2
1...Cold slab well, 22, 42...Eject pin.

Claims (1)

[Claims] 1. Thin plate parts 12, 13 and back plate part 1 by injection molding.
A mold for processing a thin-walled molded body 11 made of thermoplastic resin, comprising: a core 15 in which product cavity portions 15a and 16a for processing the outer sides of the thin plate portions 12 and 13 of the thin-walled molded body 11 are respectively formed; , 16 are arranged on the fixed side and the movable side in the mold clamping direction, and a slide core 17 for processing the thin plate parts 12, 13 and the inner side of the back plate part 14 of the thin molded body 11 is placed between the cores 15, 16 in the mold. The spool or runner 2 of the thin-walled molded body 11 is arranged so as to be slidable in a direction perpendicular to the tightening direction.
0, eject pin 22 for product release,
22, gate cavity portions 18a, 19a for injection molding gate portions 18, 19 on both end sides of the back plate portion 14 of the thin-walled molded body 11; The product cavity portion 15 of the cores 15 and 16 is formed.
a, 16a and gate cavity part 18a, 1
9a, and the bases of the gate cavity portions 18a, 19a communicate with each other without going through a cold slab well. 2 Thin-walled molded body 11 has a thickness of 0.1 mm to 0.6 mm,
In order to create a thin plate-shaped injection molded product with an area of 40 mm x 25 mm or more and up to 80 mm x 60 mm,
A mold for processing a thin-walled molded product by injection molding according to claim 1, which comprises forming a product cavity portion. 3 Thin-walled molded body 11 has a thickness of 0.1 mm to 0.6 mm,
Thin plates with an area of 40 mm x 25 mm or more and up to 80 mm x 60 mm are placed parallel to each other with a distance of 1 mm to 20 mm and connected at the back plate to form a U-shaped injection molded product. A mold for processing a thin-walled molded product by injection molding according to claim 1, wherein a product cavity portion is formed.