KR102287115B1 - Injection Molding Device and Method Thereof for Improving Appearance Quality and Productivity of Plastic Molding Product - Google Patents

Abstract

The present invention relates to a plastic injection molding device and a method thereof for producing high-quality products by efficiently supplying heat by injecting high-temperature and high-pressure gaseous nitrogen into a molding part of a mold. The plastic molding injection device of the present invention comprises: a mold formed with a molding part for injection molding plastic and a cooling part for cooling the molding part; a gas supply means for supplying a high-temperature gas to the molding part of the mold; and a cooling means for supplying cooling water to the cooling part. Nitrogen is selected as the gas and is preheated by the gas supply means and supplied to the molding part of the mold. According to the present invention, the injection molding device and the method thereof can preheat the molding part faster than the indirect preheating method of preheating the mold and can reduce the temperature deviation that occurs when preheating and cooling the molding part, thereby preventing the plastic deformation problem caused by the temperature deviation of the molding part and can solve defects caused by bubbles and gases generated by the oxidation reaction by oxygen in the air.

Description

Injection Molding Device and Method Thereof for Improving Appearance Quality and Productivity of Plastic Molding Product

The present invention relates to a plastic injection molding apparatus and a method thereof, and more particularly, heating and cooling using conventional steam or electric heat in a manner of molding by directly injecting high-temperature gaseous nitrogen into a molding part of a mold. It relates to a plastic injection molding apparatus and method for producing a high-quality product by supplying heat more efficiently than (heat & cool) molding.

In general, when plastics are supplied to a cylinder by putting synthetic resin raw materials in a solid state in a chip or pellet state into a hopper, the heat generated by the heater outside the cylinder and It is melted by shear frictional heat inside the cylinder.

Then, the molten synthetic resin is injected into the mold having a predetermined shape, and has a predetermined shape inside the mold.

When the mold is cooled in that state, the synthetic resin is cooled according to the internal shape of the mold to maintain a solid shape.

Thereafter, when the cooled synthetic resin shape is separated from the mold, a plastic molding having a solidified shape is obtained.

In the related art, Korean Patent Application Laid-Open No. 10-2006-0042404 is disclosed.

In the case of the prior art described above, it relates to a method of heating and cooling a mold by sequentially supplying steam and cooling water alternately through a heating and cooling line formed in a mold.

However, in the prior art, by supplying steam and cooling water to a heating line in the mold to heat and cool the mold, heat is transferred or cooled to the synthetic resin raw material injected into the mold.

At this time, it may take some time for the heat of the mold to be transferred to the raw material of the synthetic resin, resulting in a temperature deviation between heating and cooling, and there is a problem that deformation may occur in the final injection product.

In addition, the conventional heating and cooling method has a problem that productivity is lowered because the time for heating and cooling the mold is more than doubled compared to that of general injection.

Republic of Korea Patent Publication No. 10-2006-0042404

Therefore, an object of the present invention is to solve the problems of the prior art as described above, and high-quality by an efficient method of supplying heat directly to the raw material by injecting _{high-temperature gaseous nitrogen (N 2 ) into the molding part of the mold.} It's about making a product.

In addition, another object of the present invention is to pressurize the pressure in the range of 5 to 40 bar when nitrogen is injected into the molding part of the mold, thereby forming bubbles appearing under the influence of the oxidation reaction by _{oxygen (O 2 ) in the air introduced during molding.} and to improve the problem of generating defective products due to gas.

In addition, another object of the present invention is to directly transfer heat to a plastic raw material, thereby preventing a deformation problem of an injection molded product due to a temperature deviation during heating and cooling of the molding part, and to increase productivity by shortening the heating and cooling time.

According to a feature of the present invention for achieving the above object, a plastic injection molding apparatus according to the present invention comprises: a mold in which a molding part for injection molding plastic and a cooling part for cooling the molding part are formed; a gas supply means for supplying a high-temperature gas to the molding part of the mold; having a configuration including cooling means for supplying cooling water to the cooling unit; Nitrogen is selected as the gas, and it is preheated by the gas supply means and supplied to the molding part of the mold.

The gas supply means includes: a gas tank for storing and storing the gas; a heater tank for preheating the gas stored and stored in the gas tank to a high temperature in the range of 200 to 300° C.; It is characterized in that it has a configuration including a gas supply nozzle for introducing a pressure in the range of 5 to 40 bar into the molding part of the mold.

The cooling means may have a configuration including a cooling water tank for storing and storing the cooling water, and a cooling water supply nozzle for supplying the cooling water stored and stored in the cooling water tank to the cooling unit.

In addition, according to a feature of the present invention, the plastic injection molding method according to the present invention comprises a mold in which a molding part for injection molding plastic and a cooling part for cooling the molding part are formed therein, and a gas to the molding part of the mold Plastic injection molding, characterized in that it has a configuration including a gas supply means for supplying and a cooling means for supplying cooling water to the cooling unit, wherein nitrogen is selected as the gas, and the gas is preheated by the gas supply means and supplied to the molding unit. In the apparatus, the step of introducing a gas of the high-temperature gas preheated into the molding part of the mold closed through the gas supply means, and a plastic raw material into the molding part of the mold into which the preheated high-temperature gas was introduced. A raw material filling step of filling the plastic raw material, applying pressure to the molding part of the mold filled with the plastic raw material, a cooling step of supplying the cooling water to the cooling part of the mold through the cooling means; Injection molding comprising the steps of opening the mold to take out the cooled plastic from the molding part, and taking out the plastic from the molding part of the mold, is characterized in that the injection molding is performed.

In the gas introduction step, when the high-temperature gas is introduced into the molding part of the mold, the gas flows into the molding part of the mold at a pressure in the range of 5 to 40 bar in a state in which the gas is preheated to a temperature in the range of 200 to 300 °C. characterized by being

The plastic injection molding apparatus and method according to the present invention have the following effects.

First, the plastic injection molding apparatus and method according to the present invention use a gas to preheat the molding part of the mold and directly supply heat to the synthetic resin, which is a raw material. Accordingly, there is an advantage in that it is possible to rapidly preheat the molding part of the mold using liquid or steam, thereby increasing the fluidity of the plastic raw material filled in the molding part.

Second, in the plastic injection molding apparatus and method of the present invention, gas is injected into the molding part at a pressure in the range of 5 to 40 bar. Therefore, by this pressure, the plastic raw material can be filled up to a minute part such as a fine pattern of the molding part, so there is an advantage in that the transferability of the molding can be improved.

Third, the plastic injection molding apparatus and method of the present invention inject gaseous nitrogen into the molding part. Nitrogen having such redox properties has a role to clean the mold. Therefore, it is possible to extend the life of the mold and improve the surface defect of the product, so that stable production can be maintained.

Fourth, the plastic injection molding apparatus and method of the present invention are made by supplying a preheated gas to the molding part and directly preheating the molding part, rather than indirectly preheating the molding part by preheating the mold. Therefore, the molded part can be preheated faster than the indirect preheating method of preheating the mold, and the temperature deviation that occurs during preheating and cooling of the molded part can be reduced, thereby preventing the plastic deformation problem caused by the temperature deviation of the molded part. there is.

1 is a schematic configuration diagram for explaining a plastic injection molding apparatus according to an embodiment of the present invention.
2 is a block flow diagram illustrating a plastic injection molding method according to an embodiment of the present invention.

Hereinafter, a preferred embodiment of a plastic injection molding apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram for explaining a plastic injection molding apparatus according to an embodiment of the present invention, and FIG. 2 is a block flow diagram for explaining a plastic injection molding method according to an embodiment of the present invention .

As shown in these figures, the plastic injection molding apparatus according to an embodiment of the present invention includes a molding unit 14 for injection molding plastic therein and a cooling unit 16 for cooling the molding unit 14 . ) may be formed including a mold 1 in which the mold 1 is formed, a gas supply means 2 for supplying gas to the molding part 14 , and a cooling means 3 for supplying cooling water to the cooling part 16 . there is.

The plastic injection molding apparatus of the present invention having such a configuration uses gas and cooling water to preheat and cool the molding part 14, where nitrogen is selected as the gas and preheated by the gas supply means 2 It may be supplied to the molding unit 14 in a state of being.

By supplying the preheated gaseous nitrogen into the molding unit 14 as described above, it is possible to reduce the preheating and cooling temperature deviation compared to the conventional direct heating of the mold, thereby preventing the problem of shape deformation during injection molding, and high temperature By using the gaseous nitrogen of

This will be described in more detail for each configuration as follows.

First, the mold 1 may be for injection molding plastic.

The mold 1 is generally composed of a fixed mold 12 provided on the lower side, and a movable mold 10 provided on the upper side of the fixed mold 12 and configured to open and close the upper surface of the fixed mold 12 . can

A molding part 14 for molding a plastic injection product may be formed in each of the fixed mold 12 and the movable mold 10 .

The forming part 14 may be a space in which plastic raw materials are filled by a cylinder or the like.

When the plastic raw materials are filled in the molding part 14, the plastic may be molded and injected by cooling by cooling water.

A cooling unit 16 may be formed around the molding unit 14 along the circumference of the molding unit 14 as shown in FIG. 1 .

The cooling unit 16 is for cooling the molding unit 14 using cooling water, and a plurality of cooling water moving passages 160 may be formed in the cooling unit 16 .

The cooling water may lower the temperature of the molding unit 14 while moving in the cooling unit 16 through the cooling water movement passage 160 .

Next, the gas supply means 2 may be a means for supplying the gas to the forming part 14 .

The gas supply means 2 may be largely configured to include a gas tank 20 , a heater tank 22 , and a gas supply nozzle 24 .

The gas tank 20 may be a tank for storing and storing the gas, that is, nitrogen.

In addition, the heater tank 22 may be a tank connected to the gas tank 20 to preheat nitrogen introduced from the gas tank 20 .

Next, the gas supply nozzle 24 may be a nozzle connected to the heater tank 22 to introduce nitrogen preheated by the heater tank 22 into the forming part 14 .

Here, the gas supply nozzle 24 has one end connected to the heater tank 22, and the other end of the gas supply nozzle 24 is coupled to the movable mold 10 and the fixed mold 12 as shown in FIG. It can be connected to a gap.

Accordingly, the nitrogen preheated by the heater tank 22 moves into the gap between the movable mold 10 and the fixed mold 12 through the gas supply nozzle 24 and flows into the molding unit 14 . can be

Next, the cooling means 3 may be a means for supplying cooling water to the cooling unit 16 .

The cooling means 3 may be characterized in that it largely includes a cooling water tank 30 and a cooling water supply nozzle 32 .

The coolant tank 30 may be a tank in which coolant for lowering the temperature of the molding unit 14 is stored and stored.

In addition, the cooling water supply nozzle 32 may be a nozzle connected to the cooling water tank 30 to move the cooling water stored and stored in the cooling water tank 30 to the cooling unit 16 .

At this time, the cooling water supply nozzle 32 is connected to the cooling water movement passage 160 of the cooling unit 16 , so that an appropriate amount of the cooling water stored and stored in the cooling water tank 30 is transferred to the cooling water of the cooling unit 16 . It may be supplied through the passage 160 .

As the cooling water is supplied to the cooling unit 16 in this way, the temperature of the molding unit 14 may be lowered.

Hereinafter, a method of plastic injection molding using the plastic injection molding apparatus of the present invention based on the above description will be described with reference to FIG. 2 attached thereto.

First, the mold closing step (S10) of clamping the movable mold 10 on the upper side of the fixed mold 12 for injection molding plastic may be performed.

Next, an appropriate amount of gaseous nitrogen may be moved from the gas tank 20 to the heater tank 22 to heat the nitrogen.

Then, nitrogen in a gaseous state heated by the heater tank 22 may be introduced into the forming part 14 through the gas supply nozzle 24 ( S20 ).

At this time, it is preferable that the nitrogen introduced into the molding unit 14 is in a high temperature range of 200 to 300° C. and the inlet pressure is in the range of 5 to 40 bar. More preferably, the nitrogen introduced into the forming part 14 may be in a high temperature state of 250° C. and an inlet pressure of 10 bar or more.

As such, by introducing high-temperature nitrogen having a temperature in the range of 200 to 300° C. into the molding part 14, the molding part 14 can be preheated faster than in the prior art, and a higher-gloss and high-quality plastic injection molding can be manufactured. there is.

In addition, by increasing the temperature of the molding part 14 by high-temperature nitrogen, there is an advantage in that the fluidity of the plastic raw material to be filled in the molding part 14 can be increased.

In addition, by making the condition of the pressure of nitrogen flowing into the molding part 14 to be in the range of 5 to 40 bar, plastic raw materials can be filled in the fine and detailed parts of the molding part 14 to prevent defects in the injection product. It has the advantage of being able to

Then, after introducing gaseous nitrogen into the molding part 14, a plastic raw material may be filled in the molding part 14 using a cylinder or the like. (S30)

And the molding part 14 may be pressed so that the plastic raw material filled in the molding part 14 is completely replenished by the internal volume of the molding part 14. (S40)

At this time, since nitrogen is introduced into the molding part 14 at a pressure in the range of 5 to 40 bar, the plastic raw material filled in the molding part 14 may be filled to a minute part of the molding part 14 .

Then, cooling water may be supplied to the cooling unit 16 by using the cooling means 3 (S50).

In this case, the cooling water is preferably introduced in an appropriate amount to cool the plastic raw material filled in the molding part 14 to a temperature at which it can be taken out from the mold 1 .

Here, the cooling water is stored and stored in the cooling water tank 30 , and may be moved and flowed through the cooling water supply nozzle 32 to the cooling water movement passage 160 formed in the cooling unit 16 .

Accordingly, the temperature of the molding unit 14 is lowered by the cooling unit 16 so that the plastic raw material filled in the molding unit 14 may be solidified.

Then, the mold opening step (S60) of opening the fixed mold 12 and the movable mold 10 may be performed.

Then, the solidified plastic is injected from the mold 1 (S70).

Accordingly, the plastic injection molding apparatus of the present invention can inject high-quality and high-gloss plastic injection molding, and by using gaseous nitrogen having a mold cleaning component, it suppresses the generation of bubbles and gases due to oxidation of the plastic raw material, thereby reducing the appearance The problem of poor quality can be improved.

The scope of the present invention is not limited to the embodiments illustrated above, and many other modifications based on the present invention will be possible for those skilled in the art within the above technical scope.

1. Mold 2. Gas supply means
3. Cooling means 10. Moving mold
12. Fixed mold 14. Molded part
16. Cooling section 20. Gas tank
22. Heater Tank 24. Gas Supply Nozzle
30. Coolant tank 32. Coolant supply nozzle
160. Coolant flow passage

Claims (5)

a mold in which a molding part for injection molding plastic and a cooling part for cooling the molding part are formed;
a gas supply means for supplying a high-temperature gas to the molding part of the mold;
having a configuration including a cooling means for supplying cooling water to the cooling unit;
Nitrogen is selected as the gas, and the gas is preheated by the gas supply means and supplied to the molding part of the mold to directly preheat the molding part of the mold, and directly supplying heat to the synthetic resin, which is a raw material,
The gas supply means,
a gas tank for storing and storing the gas;
And a heater tank for preheating the gas stored and stored in the gas tank to a high temperature in the range of 220 ~ 300 ℃;
It has a configuration including a gas supply nozzle for introducing the high-temperature gas preheated in the heater tank to the molding part of the mold at a pressure in the range of 5 to 40 bar,
The gas supply means continuously supplies the high-temperature gas to the molding part of the mold until the cooling water is supplied to the cooling part by the cooling means. delete The method of claim 1,
The cooling means,
a cooling water tank for storing and storing the cooling water;
and a cooling water supply nozzle for supplying the cooling water stored and stored in the cooling water tank to the cooling unit. A mold in which a molding part for injection molding plastic and a cooling part for cooling the molding part are formed therein, gas supply means for supplying gas to the molding part of the mold, and cooling means for supplying cooling water to the cooling part Nitrogen is selected as the gas, and it is preheated by the gas supply means and supplied to the molding part to directly preheat the molding part of the mold, and to directly supply heat to the synthetic resin as a raw material. In the plastic injection molding apparatus to
a gas introduction step of introducing the high-temperature gas preheated into the molding part of the mold closed through the gas supply means;
a raw material filling step of filling the plastic raw material into the molding part of the mold into which the preheated high-temperature gas is introduced;
applying pressure to the molding part of the mold filled with the plastic raw material;
a cooling step of supplying the cooling water to the cooling unit of the mold through the cooling means;
opening the mold to take out the cooled plastic from the molding part of the mold;
Injection molding including taking out the plastic from the molding part of the mold,
In the gas introduction step,
When the high temperature gas is introduced into the molding part of the mold, the gas is introduced into the molding part of the mold at a pressure in the range of 5 to 40 bar in a state in which it is preheated to a temperature in the range of 220 to 300 ℃,
The gas inlet step is continued until the cooling step of supplying the cooling water through the cooling means to the cooling part of the mold. delete

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