JPH05131455A - Control device of mold temperature - Google Patents

Abstract

PURPOSE:To perform temperature control of a fluid for control of a mold temperature without mixing cooling water into the fluid for the control of the mold temperature. CONSTITUTION:A heater superheating a fluid for control of a mold temperature, which flows out through a mold 4 is provided on a tank 2. The fluid for control of the mold temperature within the tank 2 is supplied to the mold 4 by a pump 5 through a temperature control pipe 8. The temperature control pipe 8 is inserted within a heat exchanger 7. An air blow-off pipe 11 blowing a refrigerant against the temperature control pipe 8 is provided within the heat exchanger 7. The air blow-off pipe 11 is joined to a compressor 10 through a solenoid valve 9. An opening or closing of the solenoid valve 9 is performed by a temperature control device 13 and the temperature control device 13 is joined electrically to a temperature sensor 14 measuring a temperature of the fluid for the control of the mold temperature flowing out through the heat exchanger 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold temperature controller for controlling the temperature of a mold used in plastic injection molding.

[0002]

2. Description of the Related Art Generally, when a thermoplastic material is injection-molded, a fluid is supplied to a fluid passage provided inside the mold to cool the mold, and the injection-molded product is cooled through the cooled mold. There is. However, if the cooling rate of the injection molded product is not properly controlled, defective products will occur.Therefore, the temperature of the fluid supplied to the mold should be optimized according to the size of the plastic material used for injection molding and the injection molded product. It is necessary to control the temperature. Conventionally, the temperature of the fluid supplied to the mold is adjusted by heating the fluid with a heating means such as an electric heater, while supplying cooling water to the fluid to cool it. For example, JP-A-1-157807.
It is disclosed in the mold temperature controller of the publication.

In the conventional mold temperature controller described above, a tank is provided in the middle of a pipe line for circulating and supplying temperature water to the mold. The pipe for returning the temperature-controlled water from the mold to the inside of the tank is arranged so that the inside of the tank is agitated by the returned temperature-controlled water. A supply pipeline for supplying cooling water into the tank and a discharge pipeline for discharging the temperature-controlled water in the tank from the tank are connected to the tank, and the water distribution pipeline is provided with an automatic temperature control valve. A heater and a temperature sensor for heating the temperature-controlled water returned from the mold are provided in the tank. In the mold temperature controller, the cooling water supplied into the tank is agitated by the temperature control water returned from the mold into the tank, so that the temperature control water and the cooling water are uniformly mixed. The temperature of the mold is controlled by setting the temperature-controlled water newly supplied to the mold to a desired temperature. That is, the temperature of the temperature-controlled water in the tank is detected by the temperature sensor.When the temperature of the temperature-controlled water is higher than the desired temperature, cooling water is supplied to the tank and is overheated via the automatic temperature control valve. The temperature controlled water is discharged outside the tank to control the temperature. Conversely, when the temperature of the temperature-controlled water in the tank is lower than the desired temperature, the supply of cooling water is stopped, the temperature automatic control valve is closed, and the temperature-controlled water is heated by the heater in the tank to control the temperature. ing.

[0004]

However, in the above conventional mold temperature controller, when the temperature of the temperature-controlled water is lowered in the tank, cooling water is supplied and the temperature-controlled water is drained to obtain the desired temperature. Since the temperature is set to, the temperature control was very delicate and difficult. As a result, the temperature of the temperature-controlled water is difficult to stabilize, and it takes time to stabilize it.Therefore, the mold temperature is not stable, and it takes a very long time to stabilize it, resulting in defective products. It was The present invention has been made in view of the above-mentioned conventional problems, and the temperature control water is controlled to a desired temperature without mixing the temperature control water and the cooling water, and the mold temperature can be accurately controlled. It is an object to provide a mold temperature control device.

[0005]

In order to achieve the above object, a mold temperature controller of the present invention comprises a tank provided with a heater for heating a mold temperature controlling fluid flowing out from a molding mold,
Heat exchanger that controls the temperature of the mold temperature control fluid heated in the tank, temperature control means that controls the temperature of the mold temperature control fluid that has flowed into the heat exchanger without mixing cooling water, and outflow from the heat exchanger A sensor for detecting the temperature of the mold temperature control fluid, a temperature control unit electrically connected to the temperature sensor for controlling the temperature adjusting means, and a mold temperature control fluid for the tank, heat exchanger and molding die. It was decided to consist of a pump that circulates into the.

[0006]

The mold temperature control device constructed as described above is
The mold temperature control fluid heated by the heater provided in the tank is circulated by the pump in the order of the tank, the heat exchanger, the mold, and the tank. The temperature sensor measures the temperature of the mold temperature control fluid flowing out from the heat exchanger, and sends the measured value to the temperature control unit. The temperature control unit controls the temperature adjusting means so as to bring the mold temperature adjusting fluid to a desired temperature based on the measured value. That is, when there is a large difference between the desired temperature of the mold temperature control fluid and the measured value,
Increase the heating amount or cooling amount by the temperature adjusting means.
On the contrary, when the desired temperature of the mold temperature control fluid and the measured value are small, the heating amount or cooling amount is reduced. At this time,
When the mold temperature control fluid is overheated, the temperature adjusting means is controlled so that it does not exceed the desired temperature and is not overcooled, and when it is overcooled, it does not exceed the desired temperature and is not overheated.

[0007]

[Embodiment 1] FIG. 1 is a sectional view showing a mold temperature control apparatus of Embodiment 1 of the present invention with a part cut away. The mold temperature control device 1 surrounded by the broken line of the present embodiment is provided with a tank 2 having a built-in heater (not shown) for heating the mold temperature control fluid. The tank 2 is provided with an inlet and an outlet for the mold temperature control fluid, the inlet is connected to a fluid passage (not shown) in the mold 4 via the inflow pipe 3, and the outlet is discharged. It is connected to a pump 6 via a pipe 5. The pump 6 is connected to one end of a temperature control tube 8 that is piped in the heat exchanger 7, and the other end of the temperature control tube 8 is connected to the fluid passage of the mold 4.

The heat exchanger 7 is provided with an air jet pipe 11 connected to a compressor 10 via an electromagnetic valve 9. The tip portion 11a of the air ejection pipe 11 is arranged in the heat exchanger 7, and the tip portion 11a is provided with a plurality of air ejection holes 12 facing the temperature control pipe 8. In addition, 7a is an air discharge hole. The electromagnetic valve 9 is electrically connected to a temperature control device 13 that gives an opening / closing command to the electromagnetic valve 9, and the temperature control device 13 is electrically connected to a temperature sensor 14. The temperature sensor 14 is a temperature control tube 8 near the outside of the heat exchanger 7.
It is provided so that the temperature of the mold temperature control fluid flowing therein can be measured, and the measurement result can be electrically sent to the temperature control device 13.

Next, the operation of the mold temperature novel apparatus 1 of this embodiment will be described. The mold temperature control fluid heated in the tank 2 flows in the temperature control pipe 8 by the operation of the pump 6, passes through the heat exchanger 7 and enters the mold 4, and then flows through the inflow pipe 3 into the mold 4 Return from inside to tank 2. At this time, the temperature sensor 14 measures the temperature of the mold temperature control fluid at a position exiting the heat exchanger 7,
The measurement result is sent to the temperature control device 13. If the measured temperature is different from the desired temperature, the temperature control device 13 determines the temperature and sends a signal to the electromagnetic valve 9 to control the opening / closing of the electromagnetic valve 9. At this time, when the temperature of the mold temperature control fluid is higher than the desired temperature, the electromagnetic valve 9 is intermittently opened and the compressed air from the compressor 10 is blown from the ejection pipe 11 to the temperature control pipe 8 so that the mold temperature is controlled. Lower the temperature of the preparation fluid. Here, when the temperature difference is large, the electromagnetic valve 9 is greatly opened so that the cooling can be performed with high efficiency, and at the same time, the open state is lengthened when the electromagnetic valve 9 is opened and closed intermittently. Alternatively, it is cooled in one state. On the other hand, when the temperature difference is small, the electromagnetic valve 9 is opened small so that it can be cooled with low efficiency so as not to be overcooled, and at the same time, the open state in which it is intermittently opened and closed is shortened. Alternatively, it is cooled in one state. On the contrary, when the temperature of the mold temperature control fluid is lower than the desired temperature, the electromagnetic valve 9 is closed and the heater of the tank 2 heats it.

According to this embodiment, based on the temperature measured by the temperature sensor 14, when the temperature of the mold temperature controlling fluid is high, the mold temperature controlling fluid is cooled by compressed air having a low heat exchange efficiency. Supercooling does not occur, and heat exchange can be controlled easily and accurately. Further, even when the temperature of the mold temperature control fluid is low, the heat exchange can be controlled easily and accurately by the heater.

[0011]

[Embodiment 2] FIG. 2 is a sectional view showing a mold temperature adjusting apparatus of Embodiment 2 of the present invention with a part thereof cut away. The heat exchanger 16 of the mold temperature control device 15 surrounded by the broken line of the present embodiment is vertically divided into two parts in a state where the inside thereof is partially communicated by the partition plate 17.
The temperature control pipe 8 is divided into the upper chamber 16a and the lower chamber 16b.
Are arranged. A cooling water supply pipe 18 for supplying cooling water into the heat exchanger 16 is connected to the upper chamber 16a,
The band heater 1 is provided near the heat exchanger 16 of the cooling supply pipe 18.
9 is wound. The band heater 19 is electrically connected to the temperature control device 13 so that the cooling water can be overheated by a command from the temperature control device 13 based on the measurement result of the temperature sensor 14. On the other hand, the lower chamber 16b is connected to a cooling water drain pipe 20 that discharges the cooling water supplied from the cooling water supply pipe 18 and flowing from the upper chamber 16b toward the lower chamber 17b to the outside of the heat exchanger 16. Other configurations are similar to those of the first embodiment.

Next, the operation of the mold temperature controller 15 of this embodiment will be described. Similar to the first embodiment, the temperature of the mold temperature control fluid is measured at the position where the heat exchanger 16 exits. At this time, if the measured temperature is significantly higher than the desired temperature, a signal is sent to the band heater 19 at the judgment of the temperature control device 13 so as not to heat the cooling water supplied from the cooling water supply pipe 18 to the upper chamber 16a. Pass through and quench the mold temperature control fluid.
Then, when the temperature of the mold temperature control fluid approaches a desired temperature, a signal from the temperature sensor 14 is received, and a signal is sent to the band heater 19 at the judgment of the temperature control device 13 to heat the cooling water to heat the metal. Control so that the temperature of the mold temperature control fluid does not drop too much. If the measured temperature is close to the desired temperature from the beginning, a signal is sent to the band heater 19 by the judgment of the temperature control device 13 to heat the cooling water to supercool the temperature of the mold temperature control fluid in the same manner as above. Cooling is controlled so that it is not done. On the other hand, if the temperature of the mold temperature control fluid is lower than the desired temperature,
A signal is sent to the band heater 19 at the judgment of the temperature control device,
The cooling water is heated to help raise the temperature of the mold temperature control fluid. Further, the partition plate 17 prevents the cooling water from directly flowing from the cooling water supply pipe 18 to the cooling water discharge pipe 20, lengthens the contact time between the cooling water and the temperature control pipe 8, and efficiently performs heat exchange. I can do it.

According to this embodiment, the temperature of the cooling water for controlling the temperature of the mold temperature controlling fluid can be controlled by the hand heater 19, so that the control of heat exchange of the mold temperature controlling fluid is simple and accurate. The temperature can be controlled.

[0014]

Third Embodiment FIG. 3 is a sectional view showing a mold temperature adjusting device of a third embodiment of the present invention with a part thereof cut away, and FIG. 4 is an enlarged sectional view of a main part of the third embodiment. Two heat insulating pipes 23 and 24 are slidably provided in the heat exchanger 22 of the mold temperature control device 21 surrounded by the broken line of the present embodiment, and both heat insulating pipes 23 and 24 are connected to each other. A through hole having an inner diameter substantially equal to the outer diameter of the temperature control tube 8 is provided in the length direction. The temperature control pipe 8 on the pump 6 side is inserted into the heat insulating pipe 23, and the temperature control pipe 8 on the mold 4 side is inserted into the heat insulating pipe 24. Further, both ends of the adiabatic pipes 23 and 24 are connected so that one ends of the adiabatic pipes 23 and 24 project toward the mold 4 outside the heat exchanger 22. Further, the heat insulating pipe sliding mechanism 25 is adjacent to the heat exchanger 22 on the protruding side of both heat insulating pipes 23 and 24.

The heat insulating pipe sliding mechanism 25 is provided with a box-shaped frame 26 so as not to move relative to the heat exchanger 22. The heat insulating pipes 23 and 24 are slidably mounted on the side surface of the frame 26 on the heat exchanger 22 side, and the connecting portion 27 of the heat insulating pipes 23 and 24 is connected to the frame 26.
It is located inside. An electric motor 28 is fixed to a side surface of the frame 26 opposite to the heat exchanger 22 side, and a screw rod 29 is connected to a rotating shaft of the electric motor 28. The electric motor 28 is electrically connected to the temperature control device. The tip of the screw rod 29 is the frame 2 on the side of the heat exchanger 22.
A screw rod retainer 30 is fixed to the tip of the screw rod 29. The screw rod 29 is rotatably provided with respect to the frame 26, and the screw portion of the screw rod 29 and the connecting portion 27 of the heat insulating pipes 23 and 24 are screwed in the frame 26. In the figure, 31 is an O-ring provided at the fitting portion of the heat exchanger 22 and the cross-section pipes 23 and 24, which prevents the cooling water from leaking from the fitting portion.

Next, the operation of the mold temperature controller 21 of this embodiment will be described. In the present embodiment, the temperature of the mold temperature control fluid is measured at the position where it exits the heat insulating pipe sliding mechanism 25. At this time, if the measured temperature is significantly higher than the desired temperature, a command is sent to the electric motor 28 at the judgment of the temperature control device 13, the electric motor 28 rotates, and the heat insulating pipes 23, 24 are passed through the screw rod 29. Is moved toward the inside of the frame 26 of the heat insulating pipe sliding mechanism 25 to bring the temperature control pipe 8 of the heat exchanger 22 into direct contact with the cooling water over a large area. This rapidly cools the mold temperature control fluid. When the temperature of the mold temperature controlling fluid approaches the desired temperature, the temperature sensor 1
4 sends a command to the electric motor 28 at the judgment of the temperature control device 13 to move the heat insulating pipes 23 and 24 to reduce the area where the cooling water and the temperature control pipe 8 directly contact with each other, and the die. Control so that the temperature of the temperature control fluid does not drop too low. If the measured temperature is close to the desired temperature from the beginning, a command is sent to the electric motor 28 based on the judgment of the temperature control device 13 to slightly move the heat insulating pipe in accordance with the temperature difference, and the cooling water and the temperature control pipe 8 are moved. Cooling is controlled so that the temperature of the mold temperature control fluid is not overcooled by adjusting the contact area with the. On the other hand, when the temperature of the mold temperature control fluid is lower than the desired temperature, the temperature control device 13 sends a command to the electric motor 28 to rotate the electric motor 28 to move the heat insulation pipes 23 and 24, thereby cooling water. The temperature control tube 8 is surrounded by adiabatic pipes 23 and 24 so that the temperature control tube 8 does not come into direct contact with the temperature control tube 8 and is heated by the heater of the tank 2.

According to the present embodiment, by covering the temperature control pipe 8 with the heat insulating pipes 23 and 24 in the heat exchanger 22, the contact area between the temperature control pipe 8 and the cooling water is adjusted to improve the heat exchange efficiency. Therefore, the temperature of the mold temperature control fluid can be accurately controlled in a short time.

[0018]

As described above, according to the mold temperature controller of the present invention, the temperature of the mold temperature controlling fluid can be controlled without mixing the cooling water with the mold temperature controlling fluid. Therefore, it is not necessary to discharge the mold temperature control fluid to the outside of the tank and simultaneously supply the cooling water into the tank, and the temperature control of the mold temperature control fluid can be performed easily and accurately. Therefore, when the mold temperature control fluid is overheated, the temperature can be controlled to such an extent that it does not exceed the desired temperature and does not overheat, and when it is overcooled, the temperature can be controlled so that it does not exceed the desired temperature and does not overheat. The temperature of the mold temperature control fluid can be stabilized in a short time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mold temperature adjusting device according to a first embodiment of the present invention with a part thereof cut away.

FIG. 2 is a sectional view showing a mold temperature adjusting device of a second embodiment of the present invention with a part thereof cut away.

FIG. 3 is a cross-sectional view showing a mold temperature adjusting device of a third embodiment of the present invention with a part thereof cut away.

FIG. 4 is a sectional view showing a main part of a mold temperature adjusting device according to a third embodiment of the present invention.

[Explanation of symbols]

 1,15,21 Mold temperature control device 2 Tank 4 Mold 6 Pump 7,16,22 Heat exchanger 8 Temperature control tube 9 Electromagnetic valve 10 Compressor 11 Air ejection hole 13 Temperature control device 14 Temperature sensor 18 Cooling water supply pipe 19 band heater 20 cooling water drain pipe 23, 24 heat insulation pipe 25 heat insulation pipe sliding member 28 electric motor 29 screw rod

Claims (1)

[Claims] 1. A tank provided with a heater for heating a mold temperature control fluid flowing out of a molding die, a heat exchanger for controlling the temperature of a mold temperature control fluid heated in the tank, and a heat exchanger which flowed into the heat exchanger. Temperature adjusting means for adjusting the temperature of the mold temperature control fluid without mixing cooling water, a temperature sensor for detecting the temperature of the mold temperature control fluid flowing out of the heat exchanger, and electrically connected to the temperature sensor. A mold temperature controller comprising a temperature controller for controlling a temperature controller and a pump for circulating a mold temperature control fluid to the tank, a heat exchanger and a molding mold.