KR101814413B1 - Injection molding machine integrated vacuum and pressure control system - Google Patents

Abstract

The present invention is integrally formed with an injection molding apparatus to selectively perform a vacuum and pressurization environment in a mold during an injection molding process, thereby preventing an injection failure and a quality deterioration due to vaporization of gas and moisture generated in the mold And more particularly to a mold vacuum and pressurization control system for a molding machine.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection molding machine,

The present invention relates to a vacuum and pressurization control system, and more particularly, to a vacuum and pressurization control system, which is integrally formed with an injection molding apparatus to selectively perform a vacuum and pressurization environment in a mold during an injection molding process, And to a mold vacuum and pressure control system with an injection molding machine capable of preventing deterioration and quality deterioration caused by a mold.

Injection molding (injection molding) is a method of producing various products by melting and injecting raw materials into molds. It is capable of mass production of products requiring high precision. It is developed along with mold technology and demand is continuously increasing have.

Such injection molding is commonly performed by heating a raw material to which a pigment, a stabilizer, a plasticizer, a filler or the like is added to a synthetic resin in a molten state at a high temperature, injecting it into a mold through a cylinder and a screw, and then solidifying.

In this case, as the raw material is injected into the injection cavity at a relatively low temperature under atmospheric pressure through the plasticizing process at a high temperature, the moisture contained in the raw material is vaporized or gas is generated, which adversely affects the resin flow and mold adhesion, And the quality of the product is deteriorated. The defective appearance of these products affects post-processing painting, plating, coating, and deposition, thus causing a final defective product.

In order to solve such a problem, conventionally, a method of sufficiently drying a resin used as a raw material before melting is used. However, since a separate device for drying the raw material must be provided, there is a disadvantage that the cost of the product is increased due to a high initial cost and an increase in power consumption and maintenance cost due to driving, and even if the raw material is dried, There is still a problem that the surface quality of the product is deteriorated due to the gas generated due to the characteristics of the chemical raw material as well as the vaporization in the inside of the male mold.

Korean Patent Laid-Open No. 10-2008-0020774 (published on Mar. 6, 2008)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide an injection molding machine which is built in an injection molding machine and vacuum and pressurized in a mold during an injection molding process, thereby suppressing vaporization of moisture in a raw material, And to provide a mold vacuum and pressure control system with an injection molding machine for discharging gas to obtain a good surface quality.

In order to achieve the above-mentioned object, the present invention provides an injection molding machine comprising: an injection part having a hopper supplied with a raw material and a heater for melting a supplied raw material to pressurize and supply molten raw materials; a first mold for forming an injection cavity by mutual coupling, A mold vacuum and pressurization control system applied to an injection molding machine comprising a main body having a mold and a mold part in communication with the injection part on one side to form a supply hole for supplying a raw material in a molten state, A first pressurizing pipe for supplying the stored compressed air to the first through-hole, a second pressurizing pipe for supplying the stored compressed air to the first through-hole, ; A vacuum ejector, and a first vacuum pipe for sucking air through the second through hole, the vacuum ejector, and the cavity; A switching valve unit selectively opening the first pressurizing pipe or the first vacuum pipe according to a control signal; A control unit interlocked with the control system of the injection molding machine to control the compressor, the vacuum ejector, and the switching valve unit; .

A pressure sensing unit for sensing a pressure inside the injection cavity; and a controller for monitoring the sensing result of the pressure sensing unit according to time and judging whether or not the leakage occurs And the control unit sequentially controls the vacuum ejector and the switching valve unit based on the operation state of the operation unit and the determination result of the determination unit.

A second pressurizing pipe connected to the first pressurizing pipe connected to the first through hole on one side and a first vacuum pipe connected to the second through hole and connected to the storage tank on the other side, Way valve in which the first vacuum pipe and the second vacuum pipe connected to the vacuum ejector are respectively connected to the first vacuum pipe and the second vacuum pipe, .

Wherein the first pressurizing pipe and the second pressurizing pipe are automatically opened at an internal pressure higher than a predetermined pressure to discharge the compressed air inside the first and second pressurizing pipes and the second pressurizing pipe, wherein the pressurizing unit further includes a drier for removing moisture in the air discharged from the storage tank, The first and second vacuum pipes may further include a check valve for unidirectionally controlling air flow so as to pressurize the inside of the injection cavity or to form a vacuum, respectively.

It is preferable that the mold portion is sealed by surrounding the outside of the contact portion between the first mold and the second mold while the first sealing member formed on the first mold portion and the second sealing member formed on the second mold portion are sealed to each other Do.

By forming a vacuum in the injection cavity through injection molding according to the present invention, it is possible to observe the pressure and cooling effect together with the removal of foreign substances and residual gas, and pressurize the inside of the injection cavity constantly during the injection of the raw material, The surface quality of the product can be improved. In particular, these two functions are integrally mounted in the injection molding machine and implemented as a single system to selectively perform vacuum and pressurization, thereby reducing the burden on the user and improving the quality of the injection molding product and minimizing the defect rate.

1 is a side sectional view showing the structure of an injection molding machine according to a preferred embodiment of the present invention,
FIG. 2 is a sectional side view showing the structure of a mold according to a preferred embodiment of the present invention, FIG.
3 is a flow diagram illustrating an air flow according to a preferred embodiment of the present invention,
4 is a block diagram illustrating a configuration and a connection relationship according to a preferred embodiment of the present invention.
5 is a flowchart illustrating a control procedure according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view showing the structure of an injection molding machine according to a preferred embodiment of the present invention. And a first mold 111 and a second mold 113 forming the injection cavity 118 by mutually coupling the first mold 111 and the second mold 113. The supply hole communicates with the injection part on one side and is supplied with the molten raw material, And a main body 100 on which a mold part to be formed is mounted.

Since the injection part 101 is substantially the same as the means for melting the raw material at a high temperature in a conventional injection molding machine and injecting it at a high pressure, a detailed description thereof will be omitted in order to prevent blurring of the gist of the present invention. A pressing part 120, a vacuum 130, a switching valve part 140, and a control part 150 are provided as main components according to the features.

FIG. 2 is a side sectional view showing the structure of a mold according to a preferred embodiment of the present invention, FIG. 3 is a flow diagram illustrating an air flow according to a preferred embodiment of the present invention, and FIG. 4 is a cross- And FIG.

The mold unit 110 includes a first mold 111 and a second mold 113 forming the injection cavity 118 by being coupled to each other as described above, .

At this time, a supply hole 115 connected to the injection part 101 to receive the molten raw material is formed to allow the raw material to be filled in the injection cavity 118, while the injection cavity 118 is connected to the other side A first through hole 116 and a second through hole 117 are formed in the cavity 118 so as to communicate with the outside and pressurize and evacuate the cavity 118, respectively.

2, a supply hole 115 is formed in the first metal mold 111 and a second through hole 117 is formed in the first metal mold 111 and a second through hole 117 is formed in the second metal mold 113 And the first through holes 116 are formed, respectively, but various modifications of the forming positions are possible.

It is preferable that the first through hole 116 used for pressing the inside of the injection cavity 118 and the second through hole 117 used for forming a vacuum in the injection cavity 118 are formed at different positions, The second through hole 117 is formed on the side opposite to the supply hole 115 to suppress the vaporization of moisture in the raw material or to enhance the effect of the present invention to discharge generated steam and gas.

In contrast, in the case of the first through hole 116 for pressurization, the position restriction is relatively small and the installation point is determined according to the shape of the mold and the injection cavity 118.

In the conventional injection molding apparatus, although not limited thereto, the first mold 111 may be fixed and the second mold 113 may be of a moving type. As molten resin is injected from the injection nozzle, And a cooling water passage for cooling and solidifying the resin injected into the injection cavity 118 is formed in the first and second molds 111 and 113.

In the present invention, similarly, there is an operation part 151 for joining or separating the first metal mold 111 and the second metal mold 113 by moving the second metal mold 113 movable by hydraulic pressure, pneumatic pressure, do. That is, the first mold 111 is injected into the hopper through the injection part 101 in a fixed state to inject molten resin, and the second mold 113 can be moved in a horizontal direction in a predetermined section And the other side of the injection product is formed while being in contact with the first mold 111.

In addition, in the preferred embodiment of the present invention, air is introduced or leaked through the contact portions of the first mold 111 and the second mold 113 by selectively forming or pressurizing the inside of the injection cavity 118 The first metal mold 111 and the second metal mold 113 are sealed by the sealing member.

A first sealing member 112 is formed along the outer edge of the first mold part 110 and a second sealing member 114 is formed along the outer edge of the second metal part 110 So that the first sealing member 112 and the second sealing member 114 are engaged with each other to seal the injection cavity 118.

At this time, the first sealing member 112 and the second sealing member 114 are formed of a double material, the portion contacting the mold side is formed of urethane material resistant to heat, and the first sealing member 112 and the second sealing member 114 (114) are formed of a silicon material, sealing performance and durability can be secured at the same time.

The pressurizing unit 120 includes a compressor 121, which is a conventional air compressor for producing compressed air, and is configured to supply compressed air to the inside of the injection cavity 118 literally and pressurize the compressed air, A storage tank 122 for storing compressed air produced from the storage tank 122 and a first pressurizing pipe 123 for supplying compressed air stored in the storage tank 122 to the first through hole 116 do.

At this time, since condensation of water in the air compressed air occurs, water condensed in the discharge pipe of the compressor 121 and in the storage tank 122 may exist, and this moisture may be mixed with the compressed air, The pressurization unit 120 may remove moisture from the air discharged from the compressor 121 and the storage tank 122. In this case, And a dryer (124).

At this time, the dryer (124) is operated by power and is filled with a dehumidifying agent for removing moisture, such as silica gel, not a mechanical system to which a refrigeration cycle principle is applied, so that no separate power is required for dehumidification / drying do.

The vacuum chamber 130 includes a vacuum ejector 131 for forming a vacuum and a second vacuum chamber 132 for forming a vacuum between the second through hole 117 and the vacuum ejector, And a first vacuum pipe 132 for sucking air inside the cavity.

In this case, the vacuum ejector 131 is a vacuum pump, and unlike the compressor 121 operated by a motor, a pneumatic motor is used as a power source to operate through compressed air discharged from the storage tank 122 An ejector for sucking a low-energy fluid by the kinetic energy of the fluid ejected from the nozzle at a high flow velocity, or both of the vacuum and the pressurization are performed through a single power system.

In the latter case, similarly, the air injected through the storage tank 122 is injected through the nozzles to form a low pressure to suck air in the cavity 118, so that a single power system is used, The structure is simple, easy maintenance, easy operation, and long life.

To this end, a solenoid valve (V) which is opened and closed by a control signal is provided in a pipe connecting the storage tank (122) and the vacuum ejector (131) to control the operation of the vacuum ejector (131).

The switching valve unit 140 selectively opens the first pressurizing pipe 123 or the first vacuum pipe 132 to selectively press the pressurizing unit 120 or the vacuum 130 to the mold unit 110 To selectively pressurize the inside of the injection cavity 118 or to form a vacuum.

 In the preferred embodiment of the present invention, the switching valve unit 140 includes a first pressurizing pipe 123 connected to the first through hole 116 on one side and a second pressurizing pipe 123 connected to the second through hole 117, And a second vacuum pipe 142 connected to the vacuum ejector 131 are connected to the first pressure pipe 141 and the second pressure pipe 142, respectively, to which the piping 132 is connected and the other is connected to the storage tank 122, And a valve (4-way valve).

The compressed air can be selectively injected into the injection cavity 118 by connecting the first and second pressurization pipes 123 and 141 to the first vacuum pipe 132 and the second vacuum pipe 141, And operates in accordance with an electronic control signal to communicate the two vacuum pipes 142 to form a vacuum inside the injection cavity 118.

The control unit 150 is basically a control panel for controlling the solenoid valve V including the compressor 121, the vacuum ejector 131 and the switching valve unit 140. In the present invention, the control unit 150 is interlocked with the control system of the injection molding machine The pressure sensing unit 152 and the determination unit 153 are configured to control the vacuum or pressurization of the inside of the injection cavity 118 in accordance with the injection process.

If leakage of air occurs in any part of the process of vacuum or pressurization in the injection cavity 118 through the present invention, the present invention becomes virtually useless and an excessive load of the pressing unit 120 .

In particular, in the case of the mold part 110 having a closed structure according to the surface contact of the metal, there is a possibility of leakage of air. As mentioned above, the first and second sealing members 112 and 114 are provided, And it is very difficult for the manager to check if any unexpected leakage occurs during the pressing process.

The pressure sensing unit 152 may be formed in the first through hole 116 or the second through hole 117 to sense the pressure inside the injection cavity 118 through an electronic sensor, The controller 153 monitors the detection result of the pressure sensing unit 152 according to the time flow to determine whether or not the leakage occurs.

Specifically, the determination unit 153 monitors the pressure decrease rate or the pressure increase rate per hour. When the inside of the injection cavity 118 is in the vacuum state, the pressure increase rate is detected. In the state where the injection cavity 118 is pressurized, It is judged that air leakage occurs somewhere if the pressure change rate is equal to or higher than the set rate. At this time, according to the leakage judgment of the judgment unit 153, it is possible for the manager to perceive it through means such as a separate beacon or buzzer.

In addition, in order to prevent damage to the system due to excessive air pressure in the process of pressurizing the injection cavity 118, the first pressurizing pipe 123 and the second pressurizing pipe 141 are provided with an internal pressure equal to or higher than a set pressure A control valve 150 for automatically opening the compressed air inside the valve 143 is installed. This may be an option considering the capacity of the compressor 121 and the maximum pressure. However, since excessive injection of excess injection pressure into the injection cavity 118 may adversely affect the injection process, It is preferable that the automatic pressure control valve 143 is operated so that the automatic pressure control is performed.

In addition, as the first pressurizing pipe 123 and the first vacuum pipe 132 are interlocked with the injection cavity 118, reverse flow of air may occur in the opposite side pipe according to a pressurization or vacuum process. In order to achieve this, in the present invention, a check is made to control the flow of air in each of the first pressurizing pipe 123 and the first vacuum pipe 132 so as to pressurize the inside of the injection cavity 118 or to create a vacuum, And further includes a valve 125.

5 is a flowchart illustrating a control procedure according to a preferred embodiment of the present invention.

The control unit 150 sequentially controls the vacuum ejector 131 and the switching valve unit 140 by reflecting the operation state of the actuating unit 151 and the determination result of the determining unit 153. In this case, And control can be made in a manner in accordance with the procedure shown in FIG.

The first step S 110 is a step of sensing the engagement state of the first mold 111 and the second mold 113 through the actuating part 151. The vacuum of the cavity 118 required in the present invention And pressurization can be performed just before the injection molding is performed, that is, basically, the first mold 111 and the second mold 113 can be engaged with each other, so that the operation can be performed only when the mold is engaged.

The second step S 120 is a step of confirming the closed state in a state where the first mold 111 and the second mold 113 are coupled to each other and the pressure sensing unit 152 and the determination unit 153 A change in the pressure inside the injection cavity 118 is sensed to determine whether or not it is leaked.

As described above, there are two methods of measuring the pressure rising speed in the vacuum state of the cavity 118 and monitoring the pressure drop rate in the state where the cavity 118 is pressurized In the preferred embodiment of the present invention, the vacuum ejector 131 operates through the compressed air of the pressurizing unit 120, so that the latter is preferably used for power saving.

If it is determined that there is no leakage for a predetermined period of time, a vacuum is formed in the cavity 118 by operating the vacuum 140 in a third step S 130, and at the same time, 118) so that raw material injection molding is performed. Thus, by forming a vacuum in the injection cavity prior to injection molding, it is possible to remove the foreign substances and the residual gas, and to see the pressure and cooling effect.

In the next step (S 140), the raw material is injected at a certain level, and the inside of the cavity 118 is uniformly pressed through the pressing part 120. Thus, the surface quality of the product can be improved by suppressing vaporization and gas generation of moisture mixed in the raw material melted at a high temperature.

After completion of the injection molding and cooling in the fifth step S 150, the first mold 111 and the second mold 112 are separated through the operation part 151 and the molded product is separated from the cavity 118 .

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

100: main body 101:
110: mold part 111: first mold
112: first sealing member 113: second mold
114: second sealing member 115: supply hole
116: first through hole 117: second through hole
118: cavity 120:
121: compressor 122: storage tank
123: first pressurizing piping 124: dryer
130: Evolution 131: Vacuum ejector
132: first vacuum piping 140: switching valve part
141: second pressure piping 142: second vacuum piping
143: relief valve 125: check valve
150: control unit 151:
152: pressure sensing unit 153:
V: Solenoid valve

Claims (5)

An injection part 101 provided with a hopper which is supplied with a raw material and a heater which melts the supplied raw material and pressurizes the molten raw material and a first mold 111 and a second mold 111 which form an injection cavity 118 by mutual coupling, And a main body 100 on which a mold part 110 having a mold 113 and communicating with the injection part 101 on one side to form a supply hole for supplying a raw material in a molten state is mounted, And a pressure control system,
A first through hole 116 and a second through hole 117 for communicating the injection cavity 118 with the outside are formed separately from the supply hole in the mold part 110,
And a first pressurizing pipe 123 for supplying the stored compressed air to the first through hole 116. The compressor 121 generates compressed air, A pressing portion 120;
A vacuum ejector 131 operated by pneumatic pressure applied from the storage tank 122 and a first vacuum pipe 132 for sucking the air through the second through hole 117 and the vacuum ejector and the cavity, (130);
A first pressurizing pipe 123 connected to the first through hole 116 and a first vacuum pipe 132 connected to the second through hole 117 are connected to one side and the first pressurizing pipe 123 is connected to the other side of the storage tank Way valve in which a second pressurizing pipe 141 connected to the vacuum ejector 131 and a second vacuum pipe 142 connected to the vacuum ejector 131 are respectively connected to the first pressurizing pipe 141, A switching valve portion 140 for communicating the piping 123 and the second pressurizing pipe 141 or for communicating the first vacuum pipe 132 and the second vacuum pipe 142;
A control unit 150 interlocked with the control system of the injection molding machine and controlling the compressor 121, the vacuum ejector 131 and the switching valve unit 140; And a control unit for controlling the injection molding machine.
The method according to claim 1,
An actuating part 151 for engaging or disengaging the first mold 111 and the second mold 113, a pressure sensing part 152 for sensing a pressure inside the injection cavity 118, And a determination unit (153) for monitoring the detection result of the sensor (152)
Wherein the control unit 150 sequentially controls the vacuum ejector 131 and the switching valve unit 140 based on an operation state of the actuating unit 151 and a determination result of the determining unit 153. [ Installable mold vacuum and pressure control system.
delete The method according to claim 1,
The pressurization unit 120 may further include a dryer 124 for removing moisture from the air discharged from the storage tank 122,
The first pressurizing pipe 123 and the second pressurizing pipe 141 include a relief valve 143 that automatically opens at an internal pressure higher than a set pressure to discharge the compressed air therein,
The first pressurizing pipe 123 and the first vacuum pipe 132 may further include a check valve 125 for controlling the air flow in one direction so as to pressurize the inside of the injection cavity 118 or to form a vacuum, Features a mold vacuum and pressure control system with injection molding machine.
The method according to claim 1,
The mold part 110 is provided with a first sealing member 112 formed on the first mold part 110 and a second sealing part 112 formed on the second mold part 110 to seal the outside of the contact part between the first mold 111 and the second mold 113, And the second sealing member (114) formed on the second sealing member (110) are in contact with each other to seal the mold.

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