JP2010083123A - Compound high-speed molding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound high-speed molding system in which a molding die is heated jointly with a high-temperature fluid and an induction heating coil to shorten the heating cycle of the molding die and improve production efficiency of an injection molded article. <P>SOLUTION: The molding die is heated by the induction heating coil and further, fluid passages are arranged in the molding die. The high-temperature fluid passes through the respective passages and heats the molding die. The molding die is simultaneously heated by the high-temperature fluid and the induction heating coil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to high-speed molding, and more particularly to a combined high-speed molding system that combines induction heating and steam heating.

  In the manufacturing process of injection molding, the liquid resin is molded by the cavity of the molding die, but it must be ensured that it flows sufficiently and fills the entire cavity with the liquid resin. However, the molding die is made of a metal having high heat conduction characteristics, and the temperature rapidly decreases after the liquid resin comes into contact with the molding die. The liquid resin after cooling has an increased viscosity coefficient and poor fluidity, and is difficult to flow into relatively small pores (corresponding to the fine structure of the plastic molded product) in the cavity. Furthermore, the liquid resin may solidify quickly, and the liquid resin may even be prevented from continuously flowing and filling the cavities. Even if the liquid resin has not yet solidified or incompletely filled, the liquid resin has poor fluidity even at the point where the flow of the two low-temperature liquid resins merges, so the two liquid resins are fully fused. In other words, traces of bonds and structural cross sections are generated. Not only is the appearance of the finished plastic molded product inferior, but stress defects are also formed, and the finished plastic molded product tends to tear.

  In order to solve the above-mentioned problems, the liquid resin is heated to a relatively high temperature before being injected into the molding die, and the liquid resin is quickly cooled and solidified after contacting the relatively low temperature die. It is necessary not to have. The heated high-temperature molding die can maintain the fluidity of the liquid resin and accelerate the process of filling the cavity with the liquid resin. In the prior art, there are mainly two types of methods for rapidly heating the mold. The first is a method in which high temperature steam is introduced into a passage inside the molding die and the molding die is heated using the high temperature steam. The second is a method in which an induction heating coil is used to approach the molding die surface (particularly the cavity surface), eddy current is generated on the die surface, and the die itself generates heat.

  FIG. 1 shows a cross-sectional view of a conventional molding die 1. The molding die 1 includes a plurality of passages 2. These passages 2 can connect the head and tail in series, and can be connected to the water inlet / outlet pipe. The passages 2 can also be connected in parallel to the inlet / outlet water lines. Before closing the molding die 1, high-temperature steam is injected into the passage 2, thereby heating the molding die 1 and then closing the die to perform molding. After the molding is completed, cooling water is introduced into the passage 2 to accelerate the cooling rate so that the molding die 1 can be opened as quickly as possible. The passage 2 can be used for passage of high-temperature steam or cooling water, and is used simultaneously for heating and cooling of the molding die 1. However, the structure of the passage 2 is limited by the straight hole drilling technique, and the passage 2 can only be a straight passage and is embedded in the molding die 1. For this reason, the passage 2 cannot be truly approached everywhere on the cavity surface, and the thermal energy of the high-temperature steam needs to be conducted to the cavity surface through the material of the mold 1 and the cavity surface is heated to the working temperature. The time to do is extended.

  FIG. 2 shows a three-dimensional exploded view of another molding die 3 in the prior art. Heating is performed via the induction heating coil 4. After the mold 3 is opened, the induction heating coil 4 is moved between the male mold 3a and the female mold 3b until the mold is closed again and before the liquid resin is injected, and corresponds to the position of the cavity 3c. The induction heating coil 4 is supplied with a high-frequency alternating current, thereby generating a magnetic field, and the surface of the cavity 3c is induced by the magnetic field to generate an eddy current. The molding die 3 itself generates heat under the action of eddy current, thereby heating the surface of the cavity 3a. However, the magnitude of the eddy current is inversely proportional to the distance between the induction heating coil 4 and the surface of the molding die 3, and the recessed portion of the cavity 3a has a relatively small eddy current and the heating rate is relatively slow. The time during which the cavity 3a surface is heated to the working temperature is extended.

  An object of the present invention is to provide a composite high-speed molding system in which a high-temperature fluid and an induction heating coil can jointly heat a molding die, shorten the heating cycle of the molding die, and improve the production efficiency of injection molding. It is to provide.

  In order to achieve the above-mentioned object, the composite high-speed molding system of the present invention includes a molding die and an induction heating coil, and the molding die is used for injecting a liquid resin therein to solidify and molding. The induction heating coil is used to receive the working current and heat the mold. Among them, the molding die further includes a plurality of passages, and the high-temperature fluid from the high-temperature fluid supply source is passed through each passage and used to heat the molding die from the inside. The induction heating coil and the high temperature fluid simultaneously heat the surface and the inside of the molding die, and the time required for the molding die to be heated to the working temperature can be shortened.

  In the present invention, the high-temperature fluid and the induction heating coil can jointly heat the molding die, shorten the heating cycle of the molding die, and improve the production efficiency of injection molding. At the same time, the high-temperature fluid heats the entire mold, slows the temperature drop rate of the mold cavity surface during the injection process, maintains the fluidity of the raw material liquid, and further causes plastic molding caused by poor flow of the liquid resin. Defects can be avoided.

  3 and 4 show a composite high-speed molding system according to an embodiment of the present invention. The composite high-speed molding system includes a work table 10, a molding die 20, an induction heating coil 30, a high-temperature fluid supply source 40, a cooling fluid supply source 50, a drainage device 60, and a cooling plate 70.

  As shown in FIG. 4, the work table 10 includes a seat portion 11, a mold opening / closing device 12, a moving device 13, and a molding machine 14. The seat 11 is used for mounting the molding die 20, the mold opening / closing device 12, the moving device 13, the molding machine 14, and the cooling plate 70 thereon. The mold opening / closing device 12 is installed on the seat portion 11 and is used to linearly actuate the molding die 20 so that the molding die 20 can be opened or closed. The mold opening / closing device 12 can be a hydraulic device, a link type actuator, or a feed screw assembly. In this embodiment, the mold opening / closing device 12 is a hydraulic device, and a support body 121 installed on the seat portion 11 and A plurality of hydraulic cylinders 122 are included, of which the support body 121 and the hydraulic cylinder 122 are installed on the seat portion 11, and the driving rod 123 of the hydraulic cylinder 122 is penetrated through the support body 121 and connected to the molding die 20. The mold 20 is operated linearly. The moving device 13 is installed on the seat portion 11 and is used for moving the cooling plate 70 at the seat portion 11 to contact the molding die 20 or to move it away from the molding die 20. The moving device 13 can be a hydraulic device, a link actuator, or a feed screw assembly. In this embodiment, the moving device 13 is a hydraulic device and is installed on the seat portion 11 and its drive rod 131 is a support. It is penetrated by 121 and connected to the cooling plate 70, and the cooling plate is supported and moved on one side of the molding die 20.

  As shown in FIGS. 3 and 4, the molding die 20 includes a male die 21 and a female die 22, and the male die 21 and the female die 22 are closed together to form a cavity 23, and a liquid resin is contained therein. And then cooled in the cavity 23, solidified and used for molding. Among them, the male mold 21 is fixedly installed on the seat portion 11, and the male mold 21 includes an injection path 211, and the outer surface of the male mold 21 and the cavity 23 are communicated with each other. The molding machine 14 is connected to an injection path 211 and is used to inject a molding material (liquid plastic) melted at a high temperature into the cavity 23 from the injection path 211. The female die 22 is movably installed on the seat portion 11, and the driving rod 123 of the mold opening / closing device 12 is connected to the female die 22 and used to move the female die 22 linearly. Can be moved and closed to the male mold 21 to close the mold, or separated from the male mold 21 to open the mold. In addition, the molding die 20 includes a plurality of passages 24, and is penetrated by any one of the male die 21 and the female die 22 of the molding die 20. The passage 24 is used for passing a high-temperature fluid, a low-temperature fluid, or a dry gas for heating or cooling the molding die 20.

  As shown in FIGS. 3 and 4, the induction heating coil 30 is movably installed and connected to an actuator such as a mechanical arm 32 and supported on the seat 11 by the mechanical arm 32. Is moved between the male mold 21 and the female mold 22 to heat the inner side surfaces of the male mold 21 and the female mold 22, that is, the surface of the cavity 23. The induction heating coil 30 is driven by a mechanical arm 32 and is moved between the male mold 21 and the female mold 22 in a two-dimensional direction and approaches the surface of the cavity 23 but does not come into contact therewith. When the induction heating coil 30 receives a working current, it generates a magnetic field, generates an eddy current by induction of the magnetic field on the surface of the cavity 23 of the molding die 20, and the flow of the eddy current causes the surface of the molding die 20 to generate heat by itself. The effect of heating the surface of the cavity 23 of the molding die 20 is achieved.

  As shown in FIGS. 3 and 4, the high-temperature fluid supply source 40 is used to provide a high-temperature fluid. For example, the high-temperature fluid supply source 40 can be a boiler, and pure water can be heated to generate high-pressure high-temperature steam. A hot fluid supply 40 is connected to the passages 24 of the mold 20 and provides a hot fluid to pass through each passage 24 to heat the mold 20 to the working temperature.

  As shown in FIGS. 3 and 4, the induction heating coil 30 described above directly heats the surface of the cavity 23, and rapidly raises the temperature of the surface of the cavity 23 that directly contacts the liquid resin. The induction heating coil 30 is relatively inferior in heating efficiency to the recessed portion 23a of the cavity 23. However, since the recessed portion 23a is relatively close to the passage 24, the high temperature fluid can quickly heat the recessed portion 23a. it can. For this reason, the high-temperature fluid and the induction heating coil 30 jointly heat the molding die 20, thereby shortening the heating cycle of the molding die 20 and increasing the production efficiency of injection molding. At the same time, since the high temperature fluid heats the entire molding die 20, the rate at which the temperature of the cavity 23 surface of the molding die 20 decreases during the injection of the raw material liquid is slowed to maintain the fluidity of the raw material liquid. It is possible to avoid the appearance of bond traces and structural cross sections at the place where the two flows of the resin merge.

  In order to achieve rapid injection molding, the molding die 20 is heated quickly, and after the molding raw material is completely injected into the molding die 20, the molding die 20 is rapidly cooled to a temperature at which the die can be opened. There is a need.

  As shown in FIGS. 3 and 4, the cooling fluid supply source 50 is used to provide cooling fluid. For example, the cooling fluid supply source 50 is a condenser connected to a water tank and is used to provide low-temperature cooling water. Can do. The cooling fluid supply source 50 is connected to the passage 24 of the molding die 20 and provides cooling fluid to pass through each passage 24 to cool the molding die 20 to the mold opening temperature.

  As shown in FIG. 3 and FIG. 4, the drainage device 60 is a pressure difference generating device. For example, the drainage device 60 can be a blower device, a high-pressure gas supply source, or a vacuum pump. Used to feed and flow in a predetermined direction. The drainage device 60 is connected to the passage 24 of the molding die 20. When the drainage device 60 provides a positive pressure difference, high pressure air can be fed from the inlet end of the passage 24. When the drainage device 60 provides a negative pressure difference, suction can be performed from the outlet end of the passage 24. The high-pressure and dry gas that can be generated by the drainage device 60 passes through each passage 24, and the cooling liquid or high-temperature vapor remaining in the passage 24 can be discharged.

  In order to provide the molding die 20 with sufficient stress strength and to cope with the high pressure during the molding process, the passage 24 is usually a small hole diameter and does not form an air core structure that is too large in the molding die 20. In addition, the number of passages 24 needs to cover the entire molding die 20 on average. Under such circumstances, the small-diameter passage 24 itself generates a large flow resistance, and the same flow resistance occurs when the cooling fluid is divided into the plurality of passages 24. In particular, the molding die 20 is relatively large. Sometimes, the quantity of the passages 24 also increases. The presence of the large flow block decreases the flow rate of the cooling fluid, the cooling power generated for the actual molding die 20 of the cooling fluid supply source 50 is decreased, and the temperature drop time is relatively extended. In order to solve the problem that the substantial cooling power of the cooling fluid supply source 50 is limited, the embodiment of the present invention enhances the cooling rate of the molding die 20 with the cooling plate 70.

  As shown in FIGS. 3 and 4, the cooling plate 70 is movably installed on the seat portion 11, of which the drive rod 131 of the moving device 13 is connected to the cooling plate 70 and supports the cooling plate on the seat portion 11. The cooling plate 70 is disposed outside the female die 22, that is, is positioned between the female die 22 and the support 121 of the mold opening / closing device 12. The moving device 13 is used to move the cooling plate 70, brings the cooling plate 70 into contact with the female die 22 of the molding die 20, causes the cooling plate 70 to absorb heat with respect to the female die 22, and Accelerate the rate at which the overall temperature drops to the mold opening temperature. The cooling plate 70 may be a metal plate including a thermoelectric generator or a metal plate provided with a cooling pipe line. Since the cooling plate 70 is not a part of the molding die 20, the stress intensity does not need to match the requirements of the molding conditions. Since it is not necessary to consider the stress requirement of the cooling plate 70, the cooling structure in the cooling plate 70 can easily reach the requirement of the maximum cooling power, and the cooling process of the molding die 20 can be accelerated.

  The operation flow of the embodiment of the present invention will be described next.

  As shown in FIG. 4, when the injection molding operation is started or after the previous injection molding operation is completed, the molding die 20 is in an open state. In other words, the moving device 13 first moves to drive the cooling plate 70 and separates the molding die 20 from the female die 22. Subsequently, the mold opening device 12 drives the female die 22 so as to be detached from the male die 21, the surface of the cavity 23 is exposed, and the plastic molded product P completed by the previous injection molding operation can be taken out. At the same time, the hot fluid supply source 40 begins to provide hot fluid and begins to heat the mold 20 through the passage 24.

  As shown in FIG. 5, the mechanical arm 32 moves the induction heating coil 30 between the male mold 21 and the female mold 22, and the induction heating coil 30 approaches the surface of the cavity 23 so as to correspond to the surface of the cavity 23. Is kept at a set distance that does not touch. Subsequently, a working current is passed through the induction heating coil 30 to generate an eddy current on the surface of the cavity 23 to start heating. Although only one induction heating coil 30 is illustrated in this figure, in practice, the number of induction heating coils 30 can be set to a plurality, and each can correspond to a different area on the surface of the cavity 23.

  When the temperature of the surface of the cavity 23 reaches the working temperature, the high-temperature fluid supply source 40 stops supplying the high-temperature fluid, and at the same time, the working current is turned off to the induction heating coil 30 and the heating to the molding die 20 is stopped. Is done. Whether or not the surface of the cavity 23 has reached the working temperature can be obtained by measuring the temperature of the surface of the cavity 23 by measuring a temperature sensor such as a thermocouple. Alternatively, the heating time is determined based on the experimental results, and when the heating time is reached, it can be considered that the temperature of the surface of the cavity 23 has already reached the working temperature.

  As shown in FIG. 6, the mechanical arm 32 moves the induction heating coil 30 to separate from the male mold 21 and the female mold 22, and the mold opening / closing device 12 drives the female mold 22 to change to the male mold 21. The closing and mold closing operations are completed. After the mold closing operation is completed, the moving device 13 further moves the cooling plate 70, brings the cooling plate 70 into contact with the female die 22, and starts to cool the surface of the female die 23.

  As shown in FIG. 7, the molding machine 14 injects a liquid resin into the molding die 20 and fills the cavity 23 with the liquid resin. Since the cooling plate 70 starts to cool down from the surface of the female mold 23, the surface temperature of the cavity 23 does not change immediately, so that the liquid resin maintains a high temperature and flows sufficiently to fill the cavity 23. Can do. After the injection is completed and the cavity 23 is filled with the liquid resin, the cooling fluid supply source 50 provides the cooling fluid and passes it through the passage 24 to cool the molding die 20 and at the same time activate the cooling plate 70. Then, the molding die 20 is continuously cooled.

  The pressure in the cavity 23 is maintained, and the cooling of the molding die 20 is continued with the cooling fluid supply source 50 and the cooling plate 70. When the temperature of the surface of the cavity 23 reaches the mold opening temperature, the cooling fluid supply source 50 stops supplying the cooling fluid. Whether or not the surface of the cavity 23 has reached the mold opening temperature can be obtained by measuring the temperature of the surface of the cavity 23 by measuring a temperature sensor such as a thermocouple. Alternatively, the cooling time is determined based on the experimental result, and when the cooling time is reached, it can be considered that the temperature of the surface of the cavity 23 has already reached the mold opening temperature.

  Finally, the mold opening operation is performed, and the moving device 13 first moves to drive the cooling plate 70 to separate the molding die 20 from the female die 22. Subsequently, the mold opening device 12 drives the female mold 22 to separate it from the male mold 21 and exposes the surface of the cavity 23 as shown in FIG. At the same time, the high-temperature fluid supply source 40 starts providing the high-temperature fluid, passes through the passage 24, starts heating the molding die 20, and prepares for the next injection molding operation.

  The spirit of the present invention is to heat the inside and the surface of the molding die 30 simultaneously with the high-temperature fluid and the induction heating coil 30, respectively, and make the heat receiving state of the molding die 30 more uniform. The amount of heat input to the molding die 30 does not need to conduct heat through a long path, shortens the overall temperature rise time, and accelerates the entire heating process. Similarly, in the cooling process, the inside and the surface of the molding die 30 are simultaneously cooled by the low-temperature fluid and the cooling plate 70, respectively, and the amount of heat that needs to be released does not need to be conducted through a long path, and the entire cooling time is reduced. And the entire cooling process can be accelerated.

It is sectional drawing of the shaping die of a prior art. It is a three-dimensional exploded view of another molding die for heating with an induction heating coil in the prior art. It is a block diagram of the system of the Example of this invention. It is sectional drawing 1 of the Example of this invention. It is sectional drawing 2 of the Example of this invention. It is sectional drawing 3 of the Example of this invention. It is sectional drawing 4 of the Example of this invention.

Explanation of symbols

1 ··················································································· Induction heating coil 3a ················································· Work table 11 ··· Seat 12 ··· Mold opening / closing device 121 ··· Support 122 · · · Hydraulic cylinder 123 ··· Drive Rod 13 ... Movement device 14 ... Molding machine 20 ... Molding die 21 ... Male die 211 ... Injection path 22 ... Female die 23 ··· Cavity 23a ··· Recessed portion 30 ··· Induction heating coil 32 ··· Mechanical arm 40 · · · High-temperature fluid supply source 50 · · · Cooling fluid supply source 60 ... Drainage device 70 ... Cooling plate 131 ... Drive rod 24 ... Passage P ... Plastic molded product 3c Activity

Claims (17)

A complex high-speed molding system,
Including a mold, an induction heating coil, and a high temperature fluid source;
The molding die is used for injecting and solidifying a liquid resin therein, and has a plurality of passages,
The induction heating coil receives a working current and is used to heat the mold;
The high temperature fluid supply source is used to provide a high temperature fluid, pass through each of the passages, and heat the mold.
Combined high speed molding system.   The combined high speed molding system of claim 1, further comprising a cooling fluid supply for providing cooling fluid to pass through each of the passages and cooling the mold.   3. The combined high speed molding system of claim 2, further comprising a drainage device used to provide high pressure gas and to eliminate cooling or hot fluid remaining in each of the passages.   2. The composite type according to claim 1, wherein the molding die includes a male die and a female die, which are closed to each other to form a cavity and used to inject liquid resin therein. High speed molding system.   5. The composite high-speed molding system according to claim 4, wherein the passage is penetrated through one of a male mold and a female mold of the molding die.   The combined high-speed molding system according to claim 4, wherein the induction heating coil is moved between the male mold and the female mold to heat the surface of the cavity.   2. The apparatus according to claim 1, further comprising a cooling plate, which is selectively moved to contact the molding die and is moved to cool the molding die or to be detached from the molding die. The combined high-speed molding system described.   The composite high-speed molding system according to claim 7, further comprising a seat, wherein the molding die and the cooling plate are installed on the seat.   9. The composite high-speed molding system according to claim 8, further comprising a mold opening / closing device, which is installed on the seat portion and performs mold closing and mold opening of the molding mold.   The mold includes a male mold and a female mold, the male mold is fixedly installed on the seat, and the mold opening / closing device is coupled to the female mold, and the male mold is moved to move the male mold The composite high-speed molding system according to claim 9, wherein the mold is closed and the mold is closed, or the mold is opened by being detached from the male mold.   The composite high-speed molding system according to claim 8, further comprising a moving device, installed on the seat and used to move the cooling plate.   The composite high-speed molding system according to claim 1, further comprising an actuator, wherein the induction heating coil is moved by the actuator and supported by the molding die.   A complex high-speed molding system, comprising a molding die and an induction heating coil, wherein the molding die is used for molding by injecting and solidifying a liquid resin therein, and the induction heating coil is used as a working current. And a high-speed molding system characterized in that the molding die is provided with a plurality of passages and is used for passing a fluid therethrough .   14. The composite high speed according to claim 13, wherein the molding die includes a male die and a female die, and is used to close a space to form a cavity and to inject a liquid resin therein. Molding system.   The composite high-speed molding system according to claim 14, wherein the passage is penetrated through one of a male mold and a female mold of the molding die.   The combined high-speed molding system according to claim 14, wherein the induction heating coil is moved between the male mold and the female mold to heat the surface of the cavity.   The composite high-speed molding system according to claim 13, further comprising an actuator, wherein the induction heating coil is moved by the actuator and supported by the molding die.

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