KR20170087173A - Temperature control system for molds - Google Patents

Abstract

The present invention relates to a mold temperature control system capable of controlling the temperature of a mold by using a high frequency induction heating method.
The present invention relates to a mold temperature control system for controlling the temperature of a mold, which is capable of heating a molding part in which injection molding is performed through a high frequency induction heating method at a heating position between a movable mold and a stationary mold upon mold release of the injection mold And a high-frequency heating means through which a high-frequency current flows.
Wherein the high frequency heating means includes a high frequency electrode portion through which a high frequency current flows and an electrode transfer portion through which the high frequency electrode portion is caused to enter and exit the heating position in accordance with the mold and mold separation of the movable mold and the stationary mold, It is preferable that the cooling water can be moved inside to prevent the temperature from rising due to the radiant heat.

Description

[0001] TEMPERATURE CONTROL SYSTEM FOR MOLDS [0002]

Mold technology

In the plastic injection molding process, the mold is repeatedly heated and cooled. Whether the target temperature has been reached quickly and whether the target temperature has been achieved uniformly throughout the molding surface has a decisive influence on the productivity and merchantability of the product Temperature control of the mold is very important.

A temperature control device for a mold is disclosed for easy temperature control of the mold.

The temperature regulating device includes a supply distributor to which an outlet line of the temperature regulator is connected, a plurality of supply refrigerant lines connected to the supply distributor and the mold, a discharge refrigerant line and an outlet distributor, And heating means for adjusting the temperature to another temperature.

The conventional temperature control apparatus for a mold has a problem that it is not easy to rapidly heat the mold to a predetermined temperature because the mold is heated and cooled through the heating medium of the refrigerant line inserted into the mold.

In addition, since it is not easy to uniformly form the temperature distribution on the surface of the cavity in which the product is manufactured, the temperature control device for adjusting the temperature of the mold through the conventional cooling line is cooled There is a problem that productivity is deteriorated and product quality is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method and a device for manufacturing a mold, in which the temperature of a mold is quickly raised and lowered to an appropriate temperature for injection molding by using a high frequency induction heating method, Temperature state, that is, a thermal equilibrium state.

The present invention relates to a mold temperature control system for controlling the temperature of an injection mold, in which a molding part for performing injection molding through a high frequency induction heating method at a heating position between a movable mold and a stationary mold at the time of mold- A high-frequency heating means through which a high-frequency current flows.

Wherein the high frequency heating means includes a high frequency electrode portion through which a high frequency current flows and an electrode transfer portion through which the high frequency electrode portion is caused to enter and exit the heating position in accordance with the mold and mold separation of the movable mold and the stationary mold, It is preferable that the cooling water can be moved inside to prevent the temperature from rising due to the radiant heat.

And heat is transferred from the injection portion through the mold so that the thermal equilibrium state can be quickly reached over the entire molding surface of the injection portion while being heated by the high frequency heating means The heat conduction preventing means includes a cooling line having a flow path through which a cooling fluid can move, and the cooling conduit through which the cooling fluid passes Preferably, the fluid is a gas and a turbulence inducing member is provided in the inner flow path of the cooling line to induce turbulent flow of gas.

The mold temperature control system according to the present invention can quickly heat the mold temperature to an appropriate temperature during injection molding and shorten the time required for reaching the thermal equilibrium state of the entire molding surface so that the quality of the molded product can be improved have. In addition, since the injection molding time of the product is shortened, the productivity can be improved accordingly.

The mold temperature control system according to the present invention uses a high-

The mold is heated to raise the temperature of the injection part at the time of injection molding to an appropriate temperature for molding.

The injection mold includes a stationary mold and a movable mold. The movable mold moves in accordance with the movement of the movable mold, and a mold cavity is formed through the engagement of the injection port.

The fixed plate and the movable plate, which support the fixed mold and the movable mold, respectively, are connected to each other by a guide rod for guiding the moving direction during the molding and demolding, and the movable mold is moved by an actuator of the injection molding machine.

In injection molding, the control of the molding temperature in the mold is very important for preventing appearance defects such as weld lines, deformations, sinking marks,

In order to prevent rapid cooling of the molten resin during injection into the cavity to prevent the molten resin from cooling before being completely filled in the cavity to cause defects on the surface of the product, It is preferable to heat the mold.

The mold temperature control system includes high-frequency heating means for heating an injection portion which is combined to form a cavity, and heat conduction preventing means.

The high frequency heating means includes a high frequency electrode portion through which induction heating is generated in the injection portion through the high frequency current to induce the temperature of the injection portion to rise so that a high frequency current flows therethrough and the high frequency electrode portion is connected to the fixed mold The electrode to be fed into and out of the heating position between the molds includes a feeding portion.

When a high-frequency current of 10 to 500 kHz is applied from the oscillator to the high-frequency electrode portion, an eddy current is induced in the injection portion through the oscillator, and the temperature of the injection portion is raised by the electric resistance due to the eddy current.

In particular, the eddy current induced by the high-frequency current has a very high current density at the surface of the injection part, so that there is a skin effect that mainly generates heat on the surface. Therefore, since the heat is mainly generated on the surface of the injection part into which the molten resin is injected, Can reach.

The oscillator may be a vacuum tube type, an MG set, or a semiconductor type. Preferably, a semiconductor oscillator excellent in power efficiency, light weight, miniaturization, and stability is used.

The high-frequency electrode unit is formed to have a flow path through which cooling water can flow.

When a high-frequency current is applied to the high-frequency electrode portion and the surface of the irradiation portion is heated, the temperature of the high-frequency electrode portion may rise due to radiant heat transmitted from the irradiation portion. Since the high-frequency electrode portion is formed of copper material, when the temperature rises excessively, deformation of the shape may occur, and the resistance increases due to a rise in temperature, resulting in deterioration of current flow.

Therefore, in order to minimize the temperature rise of the high-frequency electrode portion, a channel through which the cooling water can move is formed in the high-frequency electrode portion, and the temperature of the high-frequency electrode portion is prevented from rising by the cooling water flowing through the channel.

The electrode feeding portion moves the high frequency electrode portion so that the high frequency electrode portion enters and exits to the heating position according to the molding and die separation of the metal mold. The high frequency electrode portion is moved forward and backward by the hydraulic or pneumatic actuator. Of course, the electrode may include a motor having a screw member extending a predetermined length to the rear of the high-frequency electrode unit, and a motor including a worm and a worm wheel for advancing and retracting the screw member.

The heat conduction preventing means is for preventing the heat generated in the injection portion from being transmitted to the rear side of the mold through the mold when the injection portion is heated by the high frequency heating means.

As described above, since heating of the injection portion is for preventing rapid cooling of the molten resin filled into the cavity when the injection mold is molded, it is preferable to heat only the molding surface of the injection portion in contact with the molten resin.

Therefore, the heat conduction preventing means prevents the heat from being conducted to the rear side of the mold, so that the heat generated is used for heating the injection portion, thereby shortening the heating time of the injection portion.

The heat conduction preventing means of the present embodiment is constituted by a cooling line through which a cooling fluid moves. A flow path through which a cooling fluid can flow is formed inside the cooling line, and an injection surface of the injection portion heated by the high- So as to prevent the heat from moving to the rear of the mold.

Since the heat generated by the injection part is not conducted to the rear side of the mold by the heat conduction preventing means and is used to raise the temperature of the injection part, the temperature of the injection part can quickly rise to a proper temperature for molding, It quickly reaches the thermal equilibrium state during injection molding, thereby minimizing the probability of occurrence of surface defects due to the temperature difference of the contact surface inside the cavity.

A gas was used as the cooling fluid passing through the interior of the cooling line.

Since the gas has lower thermal conductivity than the liquid, if the gas is filled in the cooling line, the heat conduction at the point where the cooling line is formed can not be smoothly performed, so that the heat conduction to the rear of the mold can be minimized.

Further, when the cooling fluid is used as the base, it is possible to make the diameter of the cooling line smaller as compared with the case where the liquid is used as the cooling fluid, and the interval between the respective lines can be narrowed more narrowly, The thermal barrier effect can be further enhanced.

The cooling line used as the heat conduction preventing means can also be utilized as a cooling means for increasing the cooling rate of the molten resin.

The cooling rate of the molten resin is increased because the cooling gas flows through the inside of the cooling line. As described above, since the thermal conductivity of the substrate is lower than that of the liquid, heat exchange for cooling the resin is actively performed A spiral spring type turbulence inducing member is installed inside the cooling line.

The turbulence inducing member induces a turbulent flow of the gas passing through the cooling line. When the number of collisions with the pipe wall of the cooling line increases while the gas is flowing in a turbulent flow, the heat exchange between the cooling fluid and the mold becomes more active It is possible to increase the cooling rate of the resin after filling the molten resin.

The turbulence inducing member is formed integrally with the cooling line so as to protrude from the inner wall of the cooling line toward the flow path to induce turbulence, .

The cooling line is formed in an inclined slit shape. Therefore, the thickness of the thermal barrier in the cooling line becomes thick,

It is possible to more effectively block the heat conduction to the rear side.

Particularly, when the cold gas line is formed in a slit shape, it is more preferable to use the low temperature gas as the refrigerant because it is more difficult to use the liquid state refrigerant.

Claims (1)

A mold temperature control system for controlling a temperature of an injection mold,
Further comprising a high-frequency heating means through which a high-frequency current flows so as to heat a forming portion, which is injection-molded through a high-frequency induction heating method, at a heating position between the movable mold and the stationary mold upon mold release of the injection mold. system.
Claim 2
The high frequency heating device according to claim 1, wherein the high frequency heating means comprises a high frequency electrode portion through which a high frequency current flows,
And an electrode transferring portion for transferring the high frequency electrode portion to a heating position in accordance with the mold-molding and separation of the movable mold and the stationary mold.
Claim 3
3. The mold temperature control system according to claim 2, wherein the high-frequency electrode unit is formed so that cooling water can move inside to prevent the temperature from rising due to radiant heat from the heated mold.
Claim 4
2. The method according to claim 1, further comprising the steps of: providing heat inside the movable mold or the stationary mold so that heat can be quickly reached over the entire molding surface of the injection section while being heated by the high- And
Further comprising heat conduction preventing means for preventing conduction in the direction of the mold temperature.
Claim 5
5. The mold temperature control system according to claim 4, wherein the heat conduction preventing means comprises a cooling line having a flow path through which a cooling fluid can move.
Claim 6
6. The mold temperature control system according to claim 5, wherein the cooling fluid passing through the inside of the cooling line is a gas, and a turbulence inducing member is provided in an internal flow path of the cooling line to induce a turbulent flow of the gas. .