KR101623030B1 - Rapid heat spreading injection mold - Google Patents

Abstract

The present invention relates to a rapid thermal diffusion-type injection mold, and more specifically, to a rapid thermal diffusion-type injection mold which has a core (1) with a cavity (15) and a thermal means (25), wherein the core (1) is divided into a first core (10) with the cavity (15) and a second core (2) with the thermal means (25). A thermal spreader (30) is formed between the first core (10) and the second core (20) and has more excellent thermal conductivity than a material for the core (1). The first core (10) and the second core (20) embedding the thermal spreader (30) are integrated by diffusion bonding. Accordingly, thermal energy is quickly transferred to the cavity (15) or the thermal means (25) by the thermal spreader (30) during heating and cooling processes of the core (1), so the cycle time of production is reduced to maximize productivity. Furthermore, the uniformity of resin flow is secured in the cavity (15) by the horizontal thermal equilibrium action of the thermal spreader (30) so the quality of a molded product is enhanced. Meanwhile, energy efficiency can be increased by guiding the flow of thermal energy to the cavity (15) and shutting off the same with respect to the direction of a core plate.

Description

RAPID HEAT SPREADING INJECTION MOLD

[0001] The present invention relates to a rapid thermal diffusing injection mold, and more particularly, to a heat spreader which maximizes the thermal conductivity inside a core of an injection mold to form a thermal means (heating means / cooling means) It is possible not only to prevent the occurrence of weld lines, sink marks, warpage, voids, crazing, deforming defects and the like by expediting the heat conduction between the cavities, , Which ultimately shortens the cycle time for producing the product, thereby improving the productivity and drastically reducing the equipment cost and the maintenance cost.

In recent years, the spread of flat panel display devices such as TVs has become popular, and as the demand for larger and thinner products increases rapidly, the top cover and cover bottom ) And support main (Support Main) are also continuously increasing. In the following, the outline of "Steam-Mold" and "E-Mold" which are typical injection molds used in domestic and overseas display industry Will be described with reference to FIGS. 1 and 2. FIG.

One. STEAM - MOLD

Steam-mold is an injection mold for forming a product in a state of heating core with high-temperature steam, cooling the core with cooling water, solidifying the molded product, and then extracting it. Or more, the surface of the product can be formed with high gloss, and the defect of the weld line and the like can be prevented without post-processing such as coating or plating since the core is heated.

1A schematically shows a rapid heat cycle molding (RHCM) mold as an example of the steam mold. The steam line 110 and the cooling line 120 are formed in the core 100a, The core 100a is heated by supplying the steam at a temperature of 150 DEG C to the steam line 110 using the boiler provided therein and the cooling water is circulated through the cooling line 120 when the core 100a is cooled, And then ejected. At this time, the cooling line 120 is formed closer to the cavity C of the core 100a than the steam line 110 because the cooling time is generally longer than the heating of the core 100a.

However, when the core 100a is heated, since the cooling water exists in the cooling line 120 to increase the thermal volume to be heated, the heating time of the core 100a is delayed and unnecessary heat loss is caused The cooling time is also delayed due to the steam remaining in the steam line 110 even when the core 100a is cooled.

The steam mold shown in Fig. 1B is another example of the RHCM mold which has overcome the disadvantages of the above-mentioned one example. The steam mold has a steam / cooling water line 150 serving also as heating and cooling in the core 100b When the core 100b is heated, the steam is introduced into the common line 150. When the core 100b is cooled, the compressed air is injected into the common line 150 to discharge the steam first, So as to cool the core 100b.

It is known that the improved RHCM mold can reduce the operating cost of the boiler by about 75% compared to the conventional RHCM mold in which the steam line and the cooling line are separated.

2. E- MOLD

The E-Mold is an injection mold for heating a core using an electric heater and cooling the core using cooling water. As shown in FIG. 2, a heating core 201 having an electric heater 210, And the cooling core 202 in which the cooling water pipe 220 is formed are separated from each other to form the core 200 of the injection mold.

That is, when the core 200 is heated for molding the product, the heating core 201 and the cooling core 202 are separated from each other to reduce the thermal volume required for injection, thereby enabling rapid heating of the cavity C, The cooling core 202 is brought into close contact with the heating core 201 so as to cool the core 200 in order to cool and take out the molded product in the cooling core 201. That is, The core 200 can be heated at a temperature of 150 to 350 占 폚 by using the electric heater 210 having a smaller thermal volume than the core 100a and 100b of the RHCM mold and being suitable for injection molding of a high gloss unpainted product .

However, even if the heating core 201 and the cooling core 202 are brought into contact with each other during cooling of the core 200, since they are physically separated from each other, the thermal resistance is large and thermal conduction is limited. There is a tendency that the cooling rate varies depending on the degree of close contact between the cooling core 201 and the cooling core 202 and the deviation tends to increase as the operation continues. In order to uniformly produce a high quality product, .

As mentioned above, "Steam-Mold" and "E-Mold", which are mainly used in domestic and overseas display industries, have advantages and disadvantages. In order to meet the needs of the display industry, In particular, it is possible to improve the productivity and product quality by solving the following common problems in the conventional injection molds.

First, the thermal means T formed on the core of the conventional injection mold is formed with a plurality of lines spaced apart (see FIGS. 3 and 4), not only is there a temperature variation in each line of the spaced thermal means T, In particular, thermal equilibrium within the cavity C is not achieved due to the temperature difference between the inlet and outlet sides of each line (the 'P' zone in FIG. 3), which consequently prevents a constant flow or even cooling of the resin, . In this case, the thermal means T includes heating means (steam line, electric heater) and cooling means (cooling line, cooling water tube) or a combined line.

Second, the core of the injection mold according to the prior art forms a thermal means T with a thickness of 8 mm to 14 mm in the cavity C so as not to deform the product by injection pressure and mold clamping force (see FIG. 4) The thermal conduction is delayed by the thickness between the cavity C and the thermal means T, which leads to a delay in the cycle time of producing the product, which is a main cause of the productivity deterioration.

Thirdly, during the thermal conduction between the thermal means T formed in the core of the conventional injection mold and the cavity C, the thermal energy of the thermal means T is conducted and lost to the core plate side (see FIGS. 3 and 4 ) As a result, the cycle time is delayed due to the loss of heat energy, which leads to an increase in operating costs such as boilers due to loss of heat energy.

Meanwhile, the problem of the conventional injection mold as described above causes a big problem due to the recent trend of enlarging the size of the display device. This is because the square cover of the display device has a top cover and a cover bottom If the width of the cover bottom and the support main is increased, the volume of the injection mold that produces the injection mold becomes larger than that of the volume of the injection mold. Therefore, not only does the production equipment such as the injection molding machine become larger, The increase in the thermal volume increases the problem of the injection mold related to the heat conduction, and the productivity deterioration due to the delay of the cycle time becomes more serious.

The problem of such a large-sized facility and deteriorated productivity leads to a burden of a huge additional equipment cost due to facility enlargement in terms of producers, which leads to an economic burden on consumers who purchase the product.

Patent Registration No. 10-0644920 (published on November 10, 2006)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an injection molding machine capable of rapidly transferring heat between a thermal means (heating means / cooling means) formed inside a core of an injection mold and a cavity formed on a surface of the core, On the other hand, the heat conduction between the cavity and the thermal means, as well as the heat transmitted to the core plate, are blocked, ultimately improving the productivity by shortening the cycle time for producing the product The present invention has an object of providing a rapid thermal diffusion injection mold capable of improving the quality of the finished product and improving the energy efficiency and reducing the maintenance cost.

In order to achieve the above object, the rapid thermal diffusing injection mold according to the present invention comprises a cavity 15 on one side and a core plate 5 on the other side, and a core (not shown) 1), wherein the core (1) is divided into a first core (10) having a cavity (15) and a second core (20) having the thermal means (25) A thermal diffusion spreader 30 having a higher thermal conductivity than the material of the core 1 is formed between the first core 10 and the second core 20 and the first core 10 and the second core 10, By integrating the second cores 20 by diffusion bonding, productivity is improved by rapid heating and rapid cooling of the core 1, and the quality of the finished product is improved by rapid thermal equilibrium of the cavities 15 Characterized by the construction of a rapid thermal diffusion injection mold.

The present invention is characterized in that the thermal means 25 formed in the second core 20 is divided into a heating means 25a made of an electric heater or a steam line and a cooling line 25b circulating the cooling water, There is another feature in the structure of the rapid thermal diffusion injection mold formed by the steam / cooling water combined line 25c into which the steam and the cooling water alternately flow.

The thermal diffusion spreader 30 may have a structure in which both side ends of the thermal diffusion spreader 30 are bent and brought close to or in contact with the thermal means 25 and a structure in which the thermal diffusion spreader 30 is formed in the housing 31, 32 and Wick are embedded in the housing 31 and a support body 33 for reinforcing the housing 31 of the thermal diffusion spreader 30 is further formed inside the housing 31 There are other features.

In the present invention, the first core 10 and the second core 20, which are integrated by the diffusion bonding 30 through the thermal diffusion spreader 30, cover the heat insulating material 40 on the outer surface of the second core 20, There is another feature in the rapid thermal spraying injection mold having a constitution in which the heat conducted to the core plate 5 is blocked.

According to the present invention having the above-described structure, since the thermal energy of the heating means is rapidly transferred to the cavity through the thermal diffusion spreader during core heating, rapid heating of the core is possible, So that rapid cooling of the core is possible. Therefore, since the cycle time of product production is shortened, productivity is maximized.

By minimizing the temperature deviation inside the cavity by the horizontal thermal diffusion action of the thermal spreader and realizing the thermal equilibrium state, the flow of the resin during the molding of the product is facilitated and uniform solidification of the resin during cooling is enabled, It has the effect of improving the quality of the product and preventing the defect.

In addition, when the thermal energy spreads smoothly to the cavity side due to the thermal diffusion spreader, the flow of heat energy is limited to the core plate having a relatively large thermal resistance. As a result, the thermal volume can be reduced. On the other hand, By blocking the conduction of heat energy to the core plate by integrating, it is possible to improve the productivity due to the shortening of the cycle time, as well as to improve the energy efficiency and reduce the maintenance cost.

1 and 2 are sectional views showing a schematic configuration of a conventional injection mold
3 is a schematic view showing a planar configuration of a thermal means of a conventional injection mold
Fig. 4 is a cross-sectional view showing the thermal diffusivity of the thermal means of the conventional injection mold
5 is a cross-sectional view showing the configuration and thermal diffusion state of the rapid thermal diffusing injection mold according to the present invention
6A to 6C are cross-sectional views showing respective embodiments of the rapid thermal diffusing injection mold according to the present invention
7 is a cross-sectional view showing the internal structure of the thermal diffusion spreader in the present invention
8 is a comparative photograph showing the thermal conductivity of the heat spreader in the present invention
9 is a schematic view showing the configuration of diffusion bonding in the present invention

Hereinafter, a configuration of a rapid thermal diffusing injection mold according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 5 to 9. FIG.

5, a cavity 15 for molding an injection product is formed on one surface of the core 1, and the other bottom surface of the core 1 is connected to the core plate 5 And a thermal means 25 is formed in the interior of the core 1. In this case, the thermal means 25 is exemplified as a steam line in FIG. 5 so as to be easily compared with FIG. 4 showing a conventional injection mold. However, the thermal means 25 according to the present invention may include heating And includes both a cooling line through which cooling water circulates or a steam / cooling water line through which steam and cooling water are alternately introduced.

The characteristic configuration of the core 1 is that a thermal diffusion spreader 30 is formed between the cavity 15 of the core 1 and the thermal means 25, The cavity 15 is formed in the shape of a plate having a better thermal conductivity than the material and is formed close to the lower side of the cavity 15 so that rapid heating and rapid cooling of the cavity 15 can be achieved and a rapid thermal equilibrium state inside the cavity 15 can be maintained, To improve the quality and prevent defects.

5, when the thermal diffusion spreader 30 having an excellent thermal conductivity is placed on the upper side of the thermal means 25, the thermal energy supplied from the thermal means 25 is higher than the lower side of the thermal means 25 As shown in FIG. That is, the thermal energy of the thermal means 25 is preferentially conducted to the side of the cavity 15 having a low thermal resistance by forming the thermal diffusion spreader 30 on the side of the core plate 5 having a relatively large thermal resistance, It is possible to expect the effect of reducing the thermal volume of the core 1 to be heated in the injection molding as a result of completing the injection of the injection object in the state that only the cavity 15 is heated before being heated.

As described above, when the core 1 is cooled after the injection of the injection molding material is completed in the state where only the cavity 15 of the core 1 is heated, the thermal energy to be recovered is smaller than when the entire core 1 is heated, Cooling is possible.

In addition, since the thermal diffusion spreader 30 of the present invention is formed long in the form of a plate on the lower side of the cavity 15, thermal energy is transferred horizontally and rapidly along with the vertical heat conduction (see FIG. 8) The thermal equilibrium state of the entire interior of the cavity 15 can be quickly maintained despite the temperature difference between the inlet and outlet sides of the thermal means 25, During the heating, the flow of the resin is made constant, and uniform cooling of the resin during the cooling of the core (1) is achieved, thereby improving the quality of the finished product and preventing defects.

6, the core 1 includes a first core 10 having a cavity 15 and a second core 10 having the thermal means 25 formed thereon, The first core 10 and the second core 20 are integrated with each other while the thermal diffusion spreader 30 is interposed between the first core 10 and the second core 20, do.

In this case, the thermal means 25 formed in the second core 20 is composed of a heating means 25a composed of an electric heater or a steam line and a cooling line 25b (See FIG. 6A and FIG. 6B), or a steam / cooling water line 25c (see FIG. 6C) in which steam and cooling water are alternately introduced, It is not limited to the shape, dimensions and arrangement of the heating means 25a and the cooling line 25b or the combination line 25c, and it can be variously modified depending on the characteristics of the injection product and various factors of the mold design.

Further, the present invention may bend both side ends of the thermal diffusion spreader 30 to approach or touch the thermal means 25 (see FIGS. 6A and 6B) or as shown in the drawing The shape of the thermal diffusion spreader 30 may be formed in a stepped shape or a wave shape by bending or bending the shape of the thermal diffusion spreader 30 corresponding to the shape of the cavity 15. [

7 and 8, the thermal diffusion spreader 30 may be formed as a single body having a good thermal conductivity, but it is preferable to use the principle of a heat pipe, The housing 31 is formed in a thin and long plate shape by vacuum, and a wick 32, which is a core in the form of a mesh, is built in the housing 31. In addition, (Water, alcohol, refrigerant gas, or the like) that transfers heat energy to form the thermal diffusion spreader 30.

According to the thermal diffusion spreader 30 constructed as described above, the heating medium is heated and vaporized at one side of the vacuum-reduced housing 31, and then the heating medium vaporized to the other side of the housing 31 is radiated while being transferred, The heat transferring material can be maximized by repeating circulation of the discharged heat medium through the wick 32 to the original position through the wick 32. The thermal diffusion spreader 30 has a relatively high thermal conductivity, And the copper plate, the thermal conductivity is much better than that of the copper plate.

The thermal diffusion spreader 30 may be formed so as not to deform the product due to injection pressure and mold clamping force during molding of the injection product even if the thermal diffusion spreader 30 is formed close to the lower side of the cavity 15, It is preferable that a supporting member 33 such as a post or a honeycomb structure is additionally provided so as to be able to cope with the injection pressure during molding of the article of production. However, the present invention is not limited to the shape of the support 33.

Since the thermal resistance of the first core 10 and the second core 20, which are integrated with each other through the thermal diffusion spreader 30, is physically divided, the first core 10 and the second core 20 20 are preferably integrated by diffusion bonding. As shown in FIG. 9, the diffusion bonding is a technique of bonding different materials at a high temperature and a high pressure in a vacuum state as shown in FIG. 9, and the detailed technical structure is protected by trade secrets based on a high level of technical experience. The first core 10 and the second core 20 and the thermal diffusion spreader 30 are physically and completely integrated by the diffusion bonding, thereby minimizing the thermal resistance.

The present invention further includes a heat insulating material 40 on the outer surfaces of the first core 10 and the second core 20 integrated with the thermal diffusion spreader 30 by diffusion bonding, . This prevents the thermal energy from the thermal means 25 of the core 1 from being conducted to the core plate 5 side, thereby enabling rapid heating and rapid cooling of the injection mold, as well as enhancing the energy efficiency and reducing the maintenance cost can do.

In this case, the core 1 may include a core 15, a core 15 and a thermal diffusion spreader 30, as well as a first core 10 and a second core 20, A portion fixedly installed on the plate 5 is separately formed.

When the core 1 is heated by the thermal means 25 during injection molding, the thermal energy is rapidly transferred to the cavity 15 through the thermal diffusion spreader 30, The thermal energy of the cavity 15 is quickly recovered through the thermal diffusion spreader 30 even during the cooling of the core 1 so that rapid cooling of the core 1 is possible Do.

Particularly, when the flow of heat energy toward the cavity 15 by the thermal diffusion spreader 30 is smooth, the flow of thermal energy is limited to the core plate 5 having a relatively large thermal resistance, Cycle time can be shortened and productivity can be maximized.

By minimizing the temperature variation inside the cavity 15 by the horizontal thermal diffusion action of the thermal diffusion spreader 30 and realizing the thermal equilibrium state, the flow of the resin during the heating of the core 1 is smooth, Since uniform solidification is possible, it is possible to improve the quality of injection products and prevent defects. On the other hand, by integrating the heat insulating material 40 in the core 1 and preventing the thermal energy from being conducted to the core plate 5, the energy efficiency is improved along with the shortening of the cycle time, and the maintenance cost can be reduced.

1: core 5: core plate
10: first core 15: cavity
20: second core 25: thermal means
25a: heating means 25b: cooling line
25c: Combination line 30: Thermal diffusion spreader
31: Housing 32: Wick
33: Support 40: Insulation

Claims (6)

A rapid thermal diffusion injection mold comprising a core (1) having a cavity (15) formed on one side, a core (5) fixed on the other side and a thermal means (25)
The core 1 is divided into a first core 10 having a cavity 15 and a second core 20 having the thermal means 25 formed thereon.
Forming a thermal diffusion spreader (30) having a higher thermal conductivity than the material of the core (1) between the first core (10) and the second core (20);
The thermal diffusion spreader 30 has a wick 32 embedded in a vacuum housing 31 and filled with a heating medium;
The first core 10 and the second core 20 in which the thermal diffusion spreader 30 is interposed are integrated by diffusion bonding to improve productivity by rapid heating and rapid cooling of the core 1 Wherein rapid thermal equilibrium of the cavity (15) improves the quality of the finished product.
The method according to claim 1,
The thermal means 25 formed in the second core 20 may be divided into a heating means 25a formed of an electric heater or a steam line and a cooling line 25b circulating the cooling water, And a line (25c) for both steam / cooling water alternately flowing.
The method according to claim 1,
Wherein both ends of the thermal diffusion spreader (30) are bent and brought close to or in contact with the thermal means (25).
delete The method according to claim 1,
Wherein a support body (33) for reinforcing the housing (31) of the thermal diffusion spreader (30) is further formed inside the housing (31).
The method according to claim 1,
The first and second cores 10 and 20 integrated with the thermal diffusion spreader 30 by diffusion bonding are integrally formed by covering the heat insulating material 40 by diffusion bonding. Rapid Thermal Diffusion Injection Mold.

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