JPH0557769A - Mold temperature-regulating device of injection molding machine - Google Patents

Abstract

PURPOSE:To obtain the mold temperature-regulating device of an injection molding machine capable of easily regulating mold temperature at prescribed value. CONSTITUTION:The medium path is formed which feeds the medium for heating and cooling to the mold 10 of an injection molding machine. While a medium- circulating path 11 is connected to said medium path, the high frequency induction heating device 12 having the construction member of the medium-heating path and the cooling device 13 cooling the medium, are connected to said medium-circulating path 11, thereby controlling the temperature of the mold 10 of the injection molding machine. The program-controlling device 14 capable of regulating the high frequency heating energy fed to the high frequency induction heating device 12 in the heating and temperature-keeping process of the mold 10 is provided.

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 an injection molding machine, which can adjust the temperature of a mold of an injection molding machine to a target value.

[0002]

2. Description of the Related Art Generally, in an injection molding machine, a molten resin injected into a mold is fluidized and solidified while being cooled by the mold. In this case, a linear stripe, a so-called weld mark, occurs at the confluence of the molten resins. This weld mark is
When the molten resin merges, the mold surface corresponding to the confluence point of the molten resin can be eliminated by heating with a heating means. However, this purpose alone is not very practical, and considering the purpose of shortening the molding cycle together, after the surfaces where the molten resin merges become the same layer,
Immediate cooling and solidification is required.

Conventionally, as an example of an injection molding machine satisfying such a demand, there is one disclosed in Japanese Patent Laid-Open No. 1-269515. This is to form a medium passage for passing a heating / cooling medium in a mold of an injection molding machine, connect a medium circulation passage to the medium passage, and have a medium heating passage constitution member in the medium circulation passage. A high frequency induction heating device and a cooling device for cooling the medium are connected. With such a configuration, it is possible to perform control according to the molding cycle. That is, in general, the mold is heated until the molten resin reaches the confluence (up to the filling step), and then the mold is cooled to eliminate the weld mark and shorten the molding cycle. It is possible to improve the efficiency of the molding work.

[0004]

However, as shown in FIG. 6, the conventional injection molding machine simply overheats / cools by turning on and off in accordance with the operation of the molding machine cycle. In the molding cycle of mold clamping, injection, cooling and metering, there is a problem that the temperature control cannot be performed momentarily as the molten resin flows in the mold, and the desired temperature control cannot always be performed.

FIG. 5 is a block diagram showing a schematic structure of a mold temperature control device of a conventional injection molding machine, in which the temperature of the heating coil 2 of the high frequency power generator 1 is detected by a temperature detector 3. When the detected temperature value is input to the temperature controller 4 and there is a deviation between it and the set temperature value, an ON command is given to the high frequency power generator 1, and a deviation is detected between the detected temperature value and the set temperature value. When there is no signal, the high frequency power generator 1 is configured to give an off command. In this case, the power (fixed) set by the power setting device 5 is supplied from the power source 6 to the high frequency power generation device 1 only when the high frequency power generation device 1 is given an ON command, so that the target temperature is set. Difficult to control (adjust).

In the example of FIG. 5, in order to adjust to the target temperature, specifically, in the heating step, as shown in FIG. 7A, high frequency energy (high frequency power) is adjusted, or As shown in FIG. 7b, the time during which high-frequency energy is applied is limited, and further, a and b in FIG.
Since it is performed simultaneously, it is difficult to adjust to the target temperature.

In such a control method, in order to keep the target temperature constant, when the high frequency energy is small as shown by the curve d in FIG. 8, the temperature change per unit time is shown by the temperature curve dt. On the other hand, on the other hand, it takes a long time to reach the target temperature during heating. Further, as the high frequency energy is larger as shown by the curve of FIG. 8C, the temperature change per unit time is larger as shown by the temperature curve ct.
The time to reach the target temperature during heating is short. Therefore, it is an object of the present invention to provide a mold temperature adjusting device for an injection molding machine, which can be easily adjusted to a desired temperature.

[0008]

According to the present invention, in order to achieve the above object, a medium passage for passing a heating / cooling medium is formed in a mold of an injection molding machine, and a medium circulation passage is provided in the medium passage. Along with connecting, a high-frequency induction heating device having a medium heating flow path forming member and a cooling device for cooling the medium are connected to the medium circulation path, and in which the temperature of the mold of the injection molding machine is controlled,

A program control device is provided which is capable of adjusting the high frequency heating energy supplied to the high frequency induction heating device in multiple steps or in steps during the heating and heat retaining process of the mold.

[0010]

According to the present invention, since the program control device is provided, it is possible to freely set the electric power at the time of heating and the time thereof, and thus it is possible to easily adjust to the target temperature.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic structure of the present invention. A mold 10 of an injection molding machine is provided with a medium passage (not shown) for passing a medium for heating / cooling, for example, a synthetic organic heat medium oil. A medium circulation passage 11 having a pump 15 is connected to the medium passage, and a high-frequency induction heating device 12 having a medium heating passage constituent member such as an iron pipe (not shown) and a medium such as insulating oil are cooled in the medium circulation passage 11. The cooling device 13 is connected. The high frequency induction heating device 12 is provided with a program control device 14 capable of adjusting the high frequency heating energy supplied to the high frequency induction heating device 12 in multiple steps or infinitely during the heating and heat retaining steps of the mold 10. There is.

FIG. 2 shows a specific configuration of the program control device 14 shown in FIG. 1. A relay R having normally open contacts Ra1, Ra2 and a normally closed contact Rb, and normally open contacts T1a1, T1.
a2 and a normally closed contact T1b, and a timer T1 of a time-delaying type that operates after a first set time, for example, 10 seconds, normally open contacts T2a1, T2a2 and a normally closed contact T2b, and a second setting A time-delaying timer T2 that operates after a time of 15 seconds, a time-delaying timer T3 that has normally open contacts T3a1, T3a2 and a normally-closed contact T3b, and that operates after a third set time of 29 seconds, A timer T4 having a normally closed contact T4b and operating after a fourth set time, for example, 15 seconds, and 100%, 70%,
60%, 30% power, eg 20KW, 14KW, 12
Power setting devices P1, P2 for setting power of kW and 6 kW
P3, P4 and heating coil 1 of the high frequency induction heating device 12
The thermostat TS for detecting the abnormal temperature of 2b and the operation signal of this thermostat TS are input to the heating coil 1
Normally closed contact T that opens when 2b overheat is detected
It is composed of an overheat detector TX having Xb and terminals A and B to which a command (heating operation external command) is input from a control unit of an injection molding machine (not shown).

The operation of the mold temperature controller of the injection molding machine thus configured will be described below with reference to FIG. Now, when a command is input to the terminals A and B from the control unit of the injection molding machine (not shown), the normally closed contact T is applied to the relay R.
The voltage of the control buses P and N is applied via Xb. Then, the relay R is energized and the normally open contacts Ra1 and Ra2 are closed,
The timer T1 operates for 10 seconds. While the timer T1 is operating, the normally closed contact T1b remains closed and the normally open contact T1a is closed.
1, T1a2 is still open, and when timer T1 times out, normally closed contact T1b opens and normally open contact T
1a1 and T1a2 are closed. In this way, while the normally closed contact T1b is closed, that is, 10 times after the relay R is energized.
For a second, a power command of 20 KW from the power setting device P1 is applied to the high frequency power generator 12a, and accordingly, the heating coil 12b is supplied with power of 20 KW from the power supply 12c.

When the normally closed contacts T1a1 and T1a2 are closed, the timer T2 operates for 15 seconds, during which the normally closed contact T2b and the normally open contact T2a do not operate. Until 15 seconds elapse after the timer T2 is activated, the high-frequency power generator 12a is supplied with a power command of 14 KW from the power setting device P2, which causes the heating coil 12b to receive 1 power from the power supply 12c.
4 KW of power is applied for 15 seconds.

When 15 seconds have passed since the timer T2 was energized, the normally closed contact T2b opens and the normally open contacts T2a1 and T2a2 close, so that the timer T3 operates for 29 seconds. T3a1 and T3a2 do not operate. Until 29 seconds have passed since the timer T3 was activated,
The high frequency power generator 12a has 1
A power command of 2 kW is given, which allows heating coil 1
Power of 12 kW is applied to 2b from the power supply 12c for 15 seconds.

When 29 seconds have passed after the timer T3 was energized, the normally closed contact T3b opens and the normally open contacts T3a1, T3.
Since a2 is closed, the timer T4 operates for 15 seconds, and during this period, the high-frequency power generator 12a is given a 6 KW power command from the power setting device P4, which causes the heating coil 1 to operate.
Power of 6 kW is applied to 2b from the power supply 12c for 15 seconds. After that, the voltage applied to the terminals A and B, that is, the heating operation signal is not supplied. It is needless to say that in FIG. 2, when the thermostat TS operates and the overheat detector TX operates, the program control device 14 does not operate when the normally closed contact TXb opens. The actual outlet temperature characteristic of the high-frequency induction heating device when controlled in this way is as shown by the broken line in FIG.

The power setting devices P1 to P4 of the above-described embodiment
By setting the value of and the time-delay operating time of the timers T1 to T4 as shown by the solid line (1) -1 or (2) -1 in FIG. 4, the actual outlet temperature characteristic of the high frequency induction heating device is 4 is indicated by a broken line (1) -2 or (2) -2. As described above, since the electric power at the time of heating and the heating time can be freely set, the mold temperature of the injection molding machine can be easily adjusted to a target value.

As an example of the program control device 14 of the above-mentioned embodiment, a combination of the relay R and the timers T1 to T4 has been given, but the invention is not limited to this, and a plurality of amplifiers, slide resistors, a controller or a recording device. Any combination of a meter, a combination of a microcomputer and a temperature setter, or the like can be used as long as it can arbitrarily control high-frequency heating energy such as electric power supplied to the high-frequency induction heating device.

[0019]

According to the present invention, it is possible to provide a mold temperature adjusting device for an injection molding machine, which can easily adjust the temperature to a desired temperature.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a mold temperature controller of an injection molding machine according to the present invention.

FIG. 2 is a circuit diagram showing a specific example of the program control device shown in FIG.

FIG. 3 is a diagram for explaining the operation of FIGS. 1 and 2.

FIG. 4 is a diagram for explaining the operation of FIGS. 1 and 2.

FIG. 5 is a block diagram showing a schematic configuration of a mold temperature adjusting device of a conventional injection molding machine.

FIG. 6 is a diagram showing operation steps of a conventional injection molding machine.

FIG. 7 is a diagram for explaining the operation of FIG.

FIG. 8 is a diagram for explaining the operation of FIG.

[Explanation of symbols]

10 ... Mold, 11 ... Medium circulation path, 12 ... High frequency induction heating device, 13 ... Cooling device, 14 ... Program control device, 1
5 ... Pump.

Claims (1)

[Claims] 1. A medium passage for passing a heating / cooling medium is formed in a mold of an injection molding machine, a medium circulation passage is connected to the medium passage, and a medium heating passage constituting member is connected to the medium circulation passage. Which controls the temperature of the mold of the injection molding machine by connecting a high-frequency induction heating device and a cooling device for cooling the medium, wherein the high-frequency induction heating device is supplied during the heating and heat-retaining steps of the mold. A mold temperature controller for an injection molding machine, which is equipped with a program controller capable of adjusting the high-frequency heating energy in multiple steps or steplessly.