KR101381871B1 - Mold for injection molding thin plate shaped product - Google Patents

Abstract

A thin product injection molding die is disclosed that can mold a large area thin product without using a large-capacity injection molding die having a large clamp force. The disclosed thin product injection molding die is supported by a lower disc, an upper disc positioned above the lower disc, and a lower disc, and includes a gate through which molten resin introduced from the outside is discharged, and a molten resin is introduced and filled from the gate. The cavity has a lower core formed on the upper side, and an upper core supported by the upper disc and being in close contact with or spaced from the upper side of the lower core. The interface between the lower core and the upper core is inclined with respect to the horizontal plane.

Description

Mold for injection molding thin plate shaped product

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die, and more particularly to an injection molding die applied to molding a thin product such as a protective plate or a light guide plate of a display panel.

Injection molding is a method in which a molten resin is injected into a mold and cooled to form a product. Compared with other molding methods such as compression molding and extrusion molding, And the size is limited, and productivity and workability are excellent, and it is widely used for molding of plastic products.

When injection molding a thin product having a large thickness and a large area such as a protective plate or a light guide plate of a display panel, the thickness is so thin that the injection pressure of the molten resin is large and the area of the injection product is large, thereby increasing the clamping force required. Therefore, in order to overcome this problem and to form a thin product without an error, injection molding must be performed using a large-capacity injection molding mold having a large clamping force due to a large contact pressure between the upper plate and the lower plate, and a large investment is required.

On the other hand, the conventional injection molding mold for forming a thin sheet product has a thin thickness of the upper and lower cores (corresponding to the thin thickness of the sheet), but in order to satisfy the minimum thickness required for the injection molding mold to prevent injection failure A support block is further provided. Therefore, the process of manufacturing an injection molding die is cumbersome, and the cost rises.

The present invention provides a sheet product injection molding mold capable of molding a sheet product of 30 inches or more without using a conventional large-capacity injection molding mold.

The present invention provides a sheet product injection molding mold capable of molding a sheet product without providing a support block.

The present invention is for injection molding a thin plate product having a thickness of 1 mm to 5 mm and a maximum width of the product is greater than 10 times the thickness, and includes a lower disc, an upper disc positioned on the lower disc, and a lower disc. Is supported by a gate (gate) for discharging the molten resin introduced from the outside, the cavity (melt) in which the molten resin is filled from the gate is filled in the upper side, and the upper disc is supported, An upper core in close contact with or spaced from the upper side of the core, wherein the interface between the lower core and the upper core provides a sheet product injection molding die that is inclined with respect to the horizontal plane.

The inclination angle of the interface may be 10 ° to 45 ° with respect to the horizontal plane.

The lower core includes a lower core base having an open upper side, and an insertion block inserted into and fixed to the lower core base. A gate core portion having a gate formed therebetween with a cavity formed therein, at least one peripheral core portion positioned around the other side of the central core portion in which the gate core portion is not located, the center portion And a core portion, a gate core portion, and an inner core portion disposed under and supporting the at least one peripheral core portion.

In the laminate product injection molding die of the present invention, the gate core portion, the at least one peripheral core portion, and the inner core portion are fixed to the central core portion by bolts to form the insertion block, and the inner core. The bolt may be fixedly fastened to the lower core base so that the insertion block is inserted and fixed to the lower core base.

In the thin product injection molding mold of the present invention, the molded product, wherein the molten resin is filled in the gate and the cavity and cured, may be configured to be taken out in the normal direction of the inclined interface after the upper core is spaced apart from the lower core.

The flow path formed between the gate and the cavity so that the molten resin flows into the cavity may have a narrow portion having a narrower cross-sectional area than the periphery thereof.

The thin-walled product injection molding mold of the present invention separates the molding cured in the cavity and the molding cured in the gate by closing a flow path formed between the gate and the cavity before the molten resin filled in the gate and the cavity is cured. A shutter may be further provided.

The flow path formed between the gate and the cavity so that the molten resin flows into the cavity may have a stepped channel whose cross sectional area is narrowed in steps.

According to the thin-walled product injection molding mold of the present invention, by forming a cavity inclined to reduce the clamping force, a thin-walled product of 30 inches or more can be formed without using a large-capacity injection molding mold. Therefore, the large investment cost for having a large-capacity injection molding mold can be reduced.

In addition, the thin-walled injection molding mold of the present invention can be thickened by the inclined cavity to meet the minimum thickness required for the injection molding mold. Therefore, it is possible to easily manufacture a thin product injection molding die without a support block.

1 is a cross-sectional view schematically showing a sheet product injection molding mold according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the upper core and the lower core of FIG. 1.
3 is a cross-sectional view illustrating a state in which the upper core and the lower core of FIG. 2 are spaced apart from each other.
4 is an enlarged cross-sectional view illustrating an upper core and a lower core of a laminate product injection molding mold according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a thin-walled product injection molding mold according to an embodiment of the present invention. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom of the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

1 is a cross-sectional view schematically showing a thin product injection molding mold according to an embodiment of the present invention, Figure 2 is an enlarged cross-sectional view of the upper core and lower core of Figure 1, Figure 3 is an upper core and A cross-sectional view showing a state in which the lower cores are spaced apart from each other. Referring to Figure 1, a thin product injection molding mold 10 according to an embodiment of the present invention is the thickness of the product 1mm to 5mm, the maximum width of the product is a thin product (1) greater than 10 times the product thickness, For example, it is a mold used for injection molding a front protective plate of a display panel of 30 inches or more, or a light guide plate.

The thin product injection molding mold 10 has an upper mold and a lower mold which are in close contact or spaced apart from each other. The lower mold includes a lower fixing plate 12, a lower disc 16 fixedly coupled to the lower fixing plate 12, and a lower core 20 fixedly supported by the lower disc 16. The upper mold has an upper fixing plate 11, an upper disk 14 fixedly coupled to the upper fixing plate 11 and positioned on the lower disk 16, and an upper core 18 fixedly supported by the upper disk 14. It is provided. Although not shown, the upper mold further includes a resin discharging unit for discharging the molten resin to the gate 34 inside the injection molding mold 10.

2 and 3, when the upper core 18 and the lower core 20 are in close contact with each other on the upper side of the lower core 20, they are injected into the injection molding mold 10 from the outside through the resin discharge unit. A gate 34 through which the introduced molten resin is discharged and a cavity 36 through which the molten resin flows in and out from the gate 34 are formed. The interface BS1, which is in contact with each other and the lower core 20 and the upper core 18, is inclined by an angle A1 with respect to the horizontal plane. The angle A1 is 10 degrees to 45 degrees. Table 1 below is a computer simulation result showing the magnitude of the clamping force according to the angular size of the interface (BS1) and the thickness of the thin product (1). The sheet product 1 has a square shape of constant thickness and has a diagonal length of 822 mm.

Angle (°) Clamping force (N) according to thickness (mm) 2.0T 2.5T 3.0T 0 2950 2270 1440 10 2910 2240 1420 20 2770 2140 1350 30 2580 1960 1250 40 2290 1740 1100

The clamping force of the injection molding die 10 required for forming the thin product 1 is proportional to the horizontal projection area of the cavity 36 and the injection pressure of the molten resin. The horizontal projection area of the cavity 36 is lower than the lower core 20 and the upper core 18 when the lower core 20 and the upper core 18 are inclined contact, that is, the angle A1 is 0 ° It is smaller when the angle A1 is greater than 0 ° than. On the other hand, the injection pressure of the molten resin should be larger the thinner the thickness of the thin product (1). Accordingly, the injection molding mold 10 in which the interface BS1 is inclined at an angle A1 with respect to the horizontal plane is used to injection-molten the thin product 1 having the same area as compared to the conventional injection molding mold having the interface BS1 horizontal. It requires less clamping force. Therefore, without large investment in large-capacity injection molding molds having a large clamping force, it is only necessary to deform the upper and lower discs 14 and 16 and the upper and lower cores 18 and 20 of existing small-capacity injection molding molds. A thin sheet product 1 of area can be produced.

In addition, since the boundary surface BS1 is inclined by an angle A1, the thickness of the lower core 20 and the upper core 18 becomes thicker. Thus, the lower disc 16 (see FIG. 1), the upper disc 14 (see FIG. 1), the lower fixing plate 12 (see FIG. 1), and the upper fixing plate 11 (see FIG. 1) supporting them are The total thickness of the combined injection molding die 10 exceeds the minimum thickness required for the injection molding die, and thus does not require a support block between the lower disc 16 and the lower fixing plate 12. The mold 10 can be designed.

The lower core 20 includes a lower core base 21 having an open upper side and an insertion block 22 inserted into and fixed to the lower core base 21. The insertion block 22 includes a central core portion 25 having a cavity 36 formed on an upper side thereof, a gate core portion 30 and a gate core portion 30 positioned around one side of the central core portion 25. A plurality of peripheral core portions 27 located around the other side of the central core portion 25 that is not located, and below the central core portion 25, the gate core portion 30, and the plurality of peripheral core portions 27. And an inner core portion 23 arranged at and supporting them.

On the upper side of the gate core portion 30, a gate 34 facing the molten resin ejected from the resin discharge unit is formed. A molten resin flow passage 38 is formed between the cavity 36 and the gate 34. In FIG. 2, the gate core part 30 is positioned higher than the central core part 25, but the present invention is not limited thereto. The gate core part 30 may be located lower than the central core part 25. The gate core part 30 is in contact with one side of the square center core part 25, and one peripheral core part 27 is in contact with three other sides of the center core part 25. 2 and 3, a pair of peripheral core portions abutting two sides of the central core portion 25 are not shown. On the other hand, the inner core portion 23 is inclined by an angle A1 so that the center core portion 25, the gate core portion 30, and the plurality of peripheral core portions 27 are inclined contact-supported by the angle A1.

The gate core portion 30 is fixedly fastened to the central core portion 25 by a first bolt 41 directed from the gate core portion 30 to the central core portion 25, and the plurality of peripheral core portions 27 The second core 42 is fixedly fastened to the central core portion 25 by the second bolt 42 from each peripheral core portion 27 to the central core portion 25, and the inner core portion 23 is centered on the inner core portion 23. The third bolt 43 facing the core portion 25 is fixedly fastened to the central core portion 25. The insertion block 22 formed by the fastening of the first, second, and third bolts 41, 42, 43 is inserted into the lower core base 21 through the open upper side of the lower core base 21, It is inserted into and fixed to the lower core base 21 by a fourth bolt 44 penetrating through the lower core base 21 toward the inner core part 23.

When the upper core 18 and the lower core 20 are in close contact with each other and the molten resin is ejected to the gate 34, it is filled in the cavity 36 through the flow path 38, and the molding 8 is formed by cold curing. Referring to FIG. 3, after the upper core 18 and the lower core 20 are spaced apart, the molding 8 is configured to be taken out in the normal direction (see arrow) of the inclined boundary surface BS1. This is to quickly take out the molding 8 without interrupting the boundary of the cavity 36 and to resume the next work quickly. Specifically, the molded article 8 may be taken out by using a molded article robot arm (not shown) or an eject pin, or by a method of high pressure air injection.

On the other hand, the narrow passage portion 32 having a narrower cross-sectional area than the peripheral flow passage 38 is provided in the flow passage 38 between the cavity 36 and the gate 34. The molded article 8 taken out from the lower core 20 has a gate scrap 4 corresponding to the shape of the gate 34 on one side thereof. Due to the influence of the gate scrap 4, the bar gate scrap 4, which may cause a shape deformation such as bending, may occur until the ejected molding 8 is completely cured without being completely cured. It is cut immediately after being taken out from 20). Since the injection molding die 10 has a narrow portion 32, a thinner portion 6 is formed in the gate scrap 4 than the periphery, the molding 8 is taken out and the operator easily follows the C1 line along the gate scrap 4. Can be removed.

In addition, at the periphery of the cavity 36 of the lower core 20, a stepped portion 39 thinner than the thickness of the thin product 1 is formed. When the molten resin is injected, the molten resin may not reach the corner portion spaced apart from the gate 34 due to partial injection pressure, and thus, the stepped portion 39, which is a surplus portion of the cavity 36, may occur. ) To prevent the melted resin from filling in the corner portion of the cavity 36. Step scraps 3 formed by the step 39 and flow path scraps 2 formed by the flow path 38 are removed by cutting along the lines C2 and C3 after taking out the molding 8, and the thin product having the correct dimensions. (1) is obtained.

4 is an enlarged cross-sectional view illustrating an upper core and a lower core of a laminate product injection molding mold according to another embodiment of the present invention. The upper core 50 and the lower core 52 of FIG. 4 may replace the upper core 18 and the lower core 20 of FIG. 1. Referring to FIG. 4, when the upper core 50 and the lower core 52 are in close contact with the upper side of the lower core 52, an injection molding mold 10 (FIG. 1) a gate 64 through which the molten resin introduced into the chamber is discharged, and a cavity 66 through which the molten resin flows from the gate 64 and is discharged. The flow path 68 of molten resin is formed between the cavity 66 and the gate 64. The cavity 66 is formed on the upper surface of the central core portion 55, and the gate 64 is formed on the upper surface of the gate core portion 60 positioned around one side of the central core portion 55. A plurality of peripheral core portions 57 are formed around the other side of the central core portion 55 where the gate core portion 60 is not located. When closely contacted with each other, the boundary surface BS2 between the lower core 52 and the upper core 50 is inclined by an angle A2 with respect to the horizontal plane. The angle A2 is 10 degrees to 45 degrees.

The lower core 52 is closed in the cavity 66 by closing the flow path 68 between the gate 64 and the cavity 66 before the molten resin filled in the gate 64 and the cavity 66 is cured. A shutter 70 is further provided to separate the molding from the molding cured by the gate 64. The shutter 70 is liftable and ascends such that its end 72 contacts the bottom surface of the upper core 50 to close the flow path 68 between the gate 64 and the cavity 66, and then lower to lower the upper core. The flow path 68 between the gate 64 and the cavity 66 is opened by being spaced apart from the lower surface of the 50. The shutter 70 can be elevated by a power of a hydraulic cylinder (not shown). In-mold cutting of the sheet product 1 (see FIG. 3) and the gate scrap 4 (see FIG. 3) is achieved by separating the molten resin filled in the cavity 66 and the molten resin filled in the gate 64 before curing. In this way, unnecessary cutting marks, burrs, and the like can be prevented from occurring in the gate connection portion of the thin product 1.

On the other hand, the flow path 68 formed between the gate 64 and the cavity 66 has a stepped channel 62 whose cross sectional area is narrowed step by step. When molten resin flows into the cavity 66, the flow velocity is rapidly increased in the narrow flow passage 68, so that the jetting of the melt flows in the region close to the flow passage 68 of the thin product 1 (see FIG. 3). The molten resin collides with the stepped channel 62 in which the cross-sectional area is narrowed step by step along the flow direction of the molten resin, and passes through the flow path 68 in a state in which the flow rate of the molten resin is reduced. Therefore, the flow trace formation is suppressed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

10: lamination product injection molding mold 14: upper disc
16: lower disc 18: upper core
20: lower core 21: lower core base
22: insertion block 23: inner core portion
25: center core portion 27: peripheral core portion
30: gate core portion 36: cavity

Claims (8)

delete delete For injection molding a thin product having a thickness of 1 mm to 5 mm and a maximum width of the product greater than 10 times the thickness,
Lower disc;
An upper disc positioned on the lower disc;
A lower core supported by the lower disc and having a gate on which the molten resin introduced from the outside is discharged, and a cavity in which the molten resin is filled and filled from the gate; And
And an upper core supported by the upper disc and in close contact with or spaced from an upper side of the lower core.
The interface between the lower core and the upper core is inclined with respect to the horizontal plane,
The lower core includes a lower core base having an open upper side, and an insertion block inserted into and fixed to the lower core base.
The insertion block may include a central core portion having the cavity formed on an upper side thereof, a gate core portion having a gate formed therebetween with a cavity formed between the central core portion, and a flow path formed between the cavity and the gate core. And at least one peripheral core portion located around the other side of the central core portion where no additional position is located, the central core portion, the gate core portion, and an inner core portion disposed below and supporting the at least one peripheral core portion. Laminated product injection molding mold. The method of claim 3,
The gate core portion, at least one peripheral core portion, and the inner core portion are fixed to the central core portion by bolts to form the insertion block, and the inner core portion is bolted to the lower core base. And the insertion block is inserted into and fixed to the lower core base. The method of claim 3,
A molded product molded product according to claim 1, wherein the molded product, wherein the molten resin is filled in the gate and the cavity and cured, is configured to be taken out in the normal direction of the inclined interface after the upper core is separated from the lower core. For injection molding a thin product having a thickness of 1 mm to 5 mm and a maximum width of the product greater than 10 times the thickness,
Lower disc;
An upper disc positioned on the lower disc;
A lower core supported by the lower disc and having a gate on which the molten resin introduced from the outside is discharged, and a cavity in which the molten resin is filled and filled from the gate; And
And an upper core supported by the upper disc and in close contact with or spaced from an upper side of the lower core.
The interface between the lower core and the upper core is inclined with respect to the horizontal plane,
Thin-walled product injection molding mold, characterized in that the flow path formed between the gate and the cavity so that the molten resin flows into the cavity has a narrower cross-sectional area narrower than the periphery. For injection molding a thin product having a thickness of 1 mm to 5 mm and a maximum width of the product greater than 10 times the thickness,
Lower disc;
An upper disc positioned on the lower disc;
A lower core supported by the lower disc and having a gate on which the molten resin introduced from the outside is discharged, and a cavity in which the molten resin is filled and filled from the gate; And
And an upper core supported by the upper disc and in close contact with or spaced from an upper side of the lower core.
The interface between the lower core and the upper core is inclined with respect to the horizontal plane,
The shutter may further include a shutter configured to close a flow path formed between the gate and the cavity before the molten resin filled in the gate and the cavity is cured to separate the molding cured from the cavity and the molding cured from the gate. Lamination product injection molding mold. For injection molding a thin product having a thickness of 1 mm to 5 mm and a maximum width of the product greater than 10 times the thickness,
Lower disc;
An upper disc positioned on the lower disc;
A lower core supported by the lower disc and having a gate on which the molten resin introduced from the outside is discharged, and a cavity in which the molten resin is filled and filled from the gate; And
And an upper core supported by the upper disc and in close contact with or spaced from an upper side of the lower core.
The interface between the lower core and the upper core is inclined with respect to the horizontal plane,
The flow path formed between the gate and the cavity so that the molten resin flows into the cavity has a stepped channel in which the cross-sectional area is narrowed step by step.

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