KR20090101006A - Core unit for preventing weldline and injection mold using the same - Google Patents

Abstract

PURPOSE: A core unit for preventing weld line and an injection mold using the same are provided to prevent weld line of a molded product and reduce the injection time of the molded product. CONSTITUTION: A core unit(100) for preventing weld line comprises a core plate, a heating part, a core body, and a driving part. In the core plate(110), a cooling channel in which cooling water flows is formed and a part of a cavity is formed. The heating part(120) heats the core plate when adhering closely to the core plate. In the core body(130), a sliding space is formed to slide the heating part and the core body is coupled with the core plate. The driving part(140) is installed at the core body and slides the heating part.

Description

Core unit for welding line prevention and injection mold using the same {CORE UNIT FOR PREVENTING WELDLINE AND INJECTION MOLD USING THE SAME}

The present invention relates to an injection mold using a core unit, and more particularly, to a weld line preventing core unit and an injection mold using the same that can prevent the generation of weld lines on the surface of the molded article during injection molding of the resin.

In general, the injection mold forms a cavity having a shape corresponding to the shape of the molded product to be produced by joining a plurality of each other, and a plurality of gates for filling molten resin in the cavity and a runner to facilitate post-processing of the molded product after molding. Is provided.

While filling the molten resin in the cavity formed by the injection mold, a partial temperature change occurs in the molten resin, and a line is formed on the outer surface of the molded part where the molten resin having such a temperature difference meets, which is called a weld line. .

In this way, the weld line of the molded article is formed compared to the other parts, in particular, the strength is weak, the appearance is poor, it is limited to use the injection mold for the molding of the product is important product strength or appearance. In addition, additional processing of post-processing to remove already formed weld lines was required, which required additional costs.

Accordingly, a weld line preventing mold for preventing formation of a weld line has been developed, which is disclosed in Korean Patent Publication No. 0625348.

The weld line prevention mold according to the prior art has a temperature sensor for measuring the temperature of the molten resin filled in the cavity, and a flow path through which a heat exchange fluid for preheating or heating the filled molten resin passes.

Such a prior art is to supply heat exchange fluid to the flow path to prevent partial temperature change of the molten resin in accordance with the melt temperature in the cavity measured by the temperature sensor, by heating the molten resin to prevent the temperature change, It was to prevent the generation of weld lines during molding. High temperature and high pressure steam was used as the heat exchange fluid.

However, the weld line prevention mold of the prior art has to use an expensive high temperature high pressure steam generator, the mold manufacturing cost has increased. In addition, since the use of high temperature and high pressure steam, there is a problem that the life of the mold is shortened and temperature control is difficult.

In addition, the prior art of the weld line prevention mold is disclosed in Korean Patent Publication No. 0428370, which heats the molten resin by mounting a heater on a portion of the mold in which the weld line is formed.

However, the heater was attached to a part of the mold so that the molten resin was locally heated to prevent the weld line. In addition, since the injection molding operation is continuously performed, and it is practically difficult to rapidly cool the mold heated to a high temperature by the heater, the injection time of the molded product is long, and eventually there is a problem that the production efficiency decreases.

The present invention is to solve the problems of the prior art, the object of the present invention is easy to control the temperature, while being able to shorten the injection time of the molded article, the weld line prevention core unit that can prevent the weld line of the molded article and It is to provide an injection mold using the same.

The weld line prevention core unit of the present invention for achieving the above object is a core plate for forming a cooling water passage through which the cooling water passes and forms part of the cavity; A heating unit which heats the core plate when sliding in close contact with the core plate; A core body coupled to the core plate to form a sliding space to slide the heating part; It is installed on the core body includes a drive unit for sliding the heating unit.

The heating unit is slidably installed on the sliding space and is in close contact with or spaced from the core plate; A heater installed to be led in front of the sliding plate and configured to generate heat by receiving external power; A temperature sensor installed on the front surface of the sliding plate and measuring a temperature of the core plate when the sliding plate is in close contact with the core plate; It is installed on the rear of the sliding plate includes a heat sink for radiating heat radiated to the rear of the sliding plate.

The injection mold using the weld line prevention core unit of the present invention includes an upper / lower mold for forming a cavity for molding a molded article; And a weld line preventing core unit positioned on one side of the upper / lower mold to form a part of the cavity.

According to the present invention, since the heater is easy to control temperature and the heater is spaced apart from the core plate when the core plate is cooled, the temperature control of the core plate is easy and the core plate can be rapidly cooled.

In addition, since the use of an expensive high temperature high pressure steam generator reduces the manufacturing cost of the core unit, the life of the core plate is long, and the rapid cooling of the core plate is possible, thereby improving production efficiency.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

1 to 3 show an example of the weld line preventing core unit according to the present invention.

1 to 3, an embodiment of the weld line preventing core unit according to the present invention includes a core plate 110 having a coolant passage 111 through which coolant passes and forming a part of a cavity, and a core plate. A heating unit 120 for heating the core plate when sliding and being in close contact with each other, a core body 130 coupled to the core plate to form a sliding space for sliding the heating unit, and a driving unit installed at the core body to slide the heating unit ( 140).

Grooves 112 and 131 are formed at closely contact portions of the core plate 110 and the core body 130 to form sliding spaces when mutually coupled.

The heating unit 120 is slidably installed on the sliding space, the sliding plate 121 which is in close contact with or spaced from the core plate 110, and the heater 122 which is drawn into the front surface of the sliding plate and receives external power and generates heat. ), A temperature sensor 123 installed on the front of the sliding plate to measure the temperature of the core plate, and a heat sink 124 installed on the rear of the sliding plate.

An inlet groove 121a through which the heater 122 is introduced is formed in the sliding plate 121.

A plurality of heaters 122 are provided, and each of the heaters 122 is individually controlled, thereby partially heating the core plate 110.

The temperature sensor 123 measures the temperature of the second core and provides data for controlling the heater.

As the driving unit 140, a pneumatic actuator 140 is used, and an installation hole 132 in which the pneumatic actuator 140 is installed is communicated with the sliding space in the core body 130.

On the other hand, it is shown in Figure 4 attached to the embodiment of the injection mold using the weld line prevention core unit configured as described above.

Referring to Figure 4, the present embodiment is for preventing the weld line to form a portion of the upper and lower molds (200,300) and the upper and lower molds (200,300) to form a cavity for forming a molded article formed on one side of the cavity (200,300) It consists of a core unit 100.

Upper and lower molds 200 and 300 are located on the upper and lower sides of the frame. And, at least one of the upper and lower molds (200, 300) is installed to be elevated in the frame.

The core unit 100 is located in four sides of the frame and is slidably installed in the transverse direction. That is, the edge of the core plate 110 of the core unit 100 is in close contact with the edges of the upper and lower molds 200 and 300 to form a rectangular cavity therein.

Hereinafter, the operation and effects of the present embodiment configured as described above will be described.

The upper and lower molds 200 and 300 and the core unit 100 are joined to each other to form a cavity. The sliding plate 121 is in close contact with the core plate 110 by driving the pneumatic actuator 140. Then, power is supplied to the heater 122 to preheat the core plate 110 to an appropriate temperature (80 ° to 120 °).

When the core plate 110 is preheated, injection molding is performed by injecting molten resin into the cavity. The molten resin injected into the cavity is heated by the preheated core plate 110 so that a partial temperature change does not occur while the cavity is filled. That is, the core plate 110 is heated to a temperature close to the melting point of the resin to improve the flowability of the molten resin in the cavity. This prevents the occurrence of flow marks and weld lines of the molten resin in the appearance of the molded article, and improves the mechanical strength and structural performance of the molded article.

Meanwhile, before the injection molded molded article is taken out, the sliding plate 121 is separated from the core plate 110 by driving the pneumatic actuator 140. Then, cooling water is supplied to the cooling water passage 111 of the core plate 110 to quench the core plate 110 to approximately 50 °.

In addition, since the sliding plate 121 provided with the heater 122 is spaced apart from the core plate 110, the core plate 110 can be quenched in a short time by the coolant without interrupting power supply to the heater 122. have. Therefore, the injection molding operation time can be shortened by shortening the time for reheating the heater, thereby improving production efficiency.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

1 is an exploded view showing an embodiment of a weld line prevention core unit according to the present invention;

2 is a view showing the structure of the weld line prevention core unit of the embodiment of FIG.

3 is a view illustrating a core plate of a weld line preventing core unit of the embodiment of FIG.

4 is a view illustrating an injection mold using the weld line prevention core unit of the embodiment of FIG.

<Description of Symbols for Main Parts of Drawings>

100: core unit 110: core plate

111: cooling water 120: heating part

121: sliding plate 122: heater

123: temperature sensor 130: core body

140: drive unit 200: upper mold

300: lower mold

Claims (3)

A core plate having a cooling water passage through which the cooling water passes and forming a part of the cavity; A heating unit which heats the core plate when sliding in close contact with the core plate; A core body coupled to the core plate to form a sliding space to slide the heating part; Weld line preventing core unit, characterized in that it comprises a drive unit installed in the core body to slide the heating unit. The method of claim 1, The heating unit A sliding plate slidably installed on the sliding space to closely contact or be spaced apart from the core plate; A heater installed to be led in front of the sliding plate and configured to generate heat by receiving external power; A temperature sensor installed on the front surface of the sliding plate and measuring a temperature of the core plate when the sliding plate is in close contact with the core plate; Weld line prevention core unit is installed on the rear of the sliding plate comprises a heat dissipating heat dissipating heat to the rear of the sliding plate. Upper and lower molds forming a cavity for molding the molded article; A core unit positioned on one side of the upper / lower mold to form part of the cavity, The core unit is A core plate having a cooling water passage through which the cooling water passes and forming a part of the cavity; A heating unit which heats the core plate when sliding in close contact with the core plate; A core body coupled to the core plate to form a sliding space in which the heating part slides; Injection mold using the weld line prevention core unit, characterized in that it comprises a drive unit installed in the core body to slide the heating unit.

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