JPH01196310A - Heat medium flow rate control device for mold temperature controller - Google Patents

Abstract

PURPOSE:To maintain automatically the proper mold temperature at all times by providing a heat medium temperature sensor on the mold outlet side of branching pipes and controlling the opening degree of flow rate regulating valve of the branching pipes by means of signals of respective sensors. CONSTITUTION:Temperature sensors S1, S2 and S3 are provided on the mold outlet side of respective branching pipes 11, 12 and 13 to sense the temperature of heat mediums after heat exchange in a mold 2. When the temperatures T1, T2 and T3 of respective heat mediums are sensed and the average value Tm is computed, the opening degree of a flow rate regulating valve 41 is regulated by a controller 7 so that T1 is equal to Tm. Similarly, flow rate valves 42 and 43 are regulated so that T1 and T3 are also equal to Tm. When the heat medium temperatures T1, T2 and T3 on the mold outlet side are maintained equal to Tm, a number of heat mediums flow in a high temperature section in the mold 2 to uniform the temperature distribution of the whole mold and to enhance molding quality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a heat medium flow rate control device for a mold temperature controller that maintains a resin molding mold at an appropriate temperature.

(Prior Art) A heat medium circuit diagram of a conventional mold temperature controller is shown in FIG. This mold temperature controller has a circulation circuit composed of three branch pipes 11, 12, and 13 that pass through a main pipe 1 and a mold 2, and includes a main vibe 1, a pump P1, a heater 3, a cooler 4, A solenoid valve 21.22°23.31.32.33 is installed in each branch vibrator 11.12.13. In addition, water or brine is used as a heat medium, 5 is a header that branches the main vibe 1, and 6 is a branch vibe 11.
．． This is a header that merges 12.13.

Therefore, when the mold temperature controller operates, the pump P and heater 3 are activated, and the heated heat medium circulates in the direction of the arrow in the circuit, heating the mold 2 to the appropriate molding temperature, that is, warming up the mold. be done. Next, when the molding process starts, the temperature of the mold 2 rises due to the molten resin, so the cooler 4
The mold 2 is cooled by circulating the cooled heat medium.

However, as can be seen from Fig. 2, the passage lengths and hole diameters of the branch vibes 11, 12, and 13 passing through the mold 2 are not necessarily the same, so even if the heat medium of the same temperature flows in from the inlet, the amount of heat exchanged will vary. are not the same, and the temperature distribution of the mold 2 becomes uneven, causing molding defects.

For this reason, recently, flow rate adjustment valves 41, 42, 43 are installed in the branch vibrators 11, 12, 13, and workers can manually adjust the heat medium flow rate of each branch vibrator 11, 12, 13. Efforts are being made to equalize mold temperature.

(Problem to be solved by the invention) However, in the conventional flow rate control device, it takes a considerable amount of effort to adjust each flow rate regulating valve 41, 42, 43, and the molding cycle time increases accordingly. There are drawbacks. Also, depending on the type of resin material and the shape of the molded resin,
It is necessary to change the temperature of a predetermined portion within the mold 2 from that of other portions, and controlling the flow rate in this case is extremely difficult with conventional devices.

The present invention has been made in view of the above circumstances, and its purpose is to provide a mold temperature controller that can maintain the mold temperature at an appropriate level at all times by automatically adjusting the flow rate of the heat medium flowing through each branch vibe. An object of the present invention is to provide a heat medium flow rate control device.

(Means for Solving the Problem) In order to achieve the above object, in the invention of claim (1), the mold is properly molded by flowing a heated or cooled heat medium through a plurality of branch vibes passing through the mold. In the heat medium flow control device of the mold temperature regulator that maintains the temperature, a flow rate adjustment valve is installed in each branch vibrator, and a temperature sensor for detecting the heat medium temperature is installed on the mold outlet side of the branch vibe, and each temperature is A control means is provided which calculates an average value of the heat medium temperature from the detection signal of the sensor and controls the opening degree of the flow rate regulating valve so that each heat medium temperature on the mold outlet side coincides with this average value.

Further, in the invention of claim (2), the opening degree of at least one flow rate regulating valve is controlled so that the heat medium temperature of the corresponding branching vibe becomes a set value, and the remaining flow rate regulating valves are controlled in the invention as claimed in claim (1).
) is provided with a control means for controlling the same.

(Function) According to the configuration of claim (1), when the cooling operation of the mold temperature controller is started, the temperature of each heat medium after passing through the mold is detected by the temperature sensor, and these detection signals are sent to the control means. sent to.

The control means calculates an average value of the heat medium temperature from each detection signal, then compares each heat medium temperature with the average value, and sequentially controls the opening degree of the flow rate regulating valve in a direction in which the difference decreases. When the temperature of the heat medium on the mold outlet side is controlled to an average value, the flow rate of the heat medium becomes larger in the hotter parts of the mold, the amount of cooling increases, and the temperature distribution throughout the mold becomes uniform.

In the flow rate control device of claim (2), first, the mold exit temperature of the heating medium in a predetermined branch vibe is preset to a temperature suitable for molding. When the mold temperature controller is in cooling operation,
The temperature of the heat medium is detected by each temperature sensor, and the flow rate regulating valve is controlled so that the temperature of the heat medium in the branch vibrator whose temperature has been set coincides with the above-mentioned set value. Next, an average value is calculated from the other heat medium temperatures, and the opening degree of each flow rate regulating valve is controlled so that each heat medium temperature matches this average value.

(Example) Fig. 1 shows a circuit diagram of a mold temperature controller to which the flow rate control device of the present invention is applied, where solid line arrows indicate the flow of heat medium and dotted line arrows indicate the flow of electrical signals. It shows. Furthermore, each configuration of the mold temperature controller itself is the same as that shown in FIG. 2, so the explanation will be omitted.

This flow rate control circuit is composed of temperature sensors St, S2°S3, a controller 7, and flow rate regulating valves 41, 42°43.

Temperature sensors Sl, S2. S3 is each branch vibe 11.1
2.13 is installed on the mold outlet side, and detects the temperature of the heat medium, such as water or brine, after heat exchange in the mold 2. Moreover, these temperature sensors St, S2. S3 allows individual temperature settings to be made manually.

The flow rate adjustment valves 41, 42, 43 are connected to the branch vibrator 11°12.
The amount of heating or cooling of the mold 2 is adjusted by changing the flow rate of the heat medium flowing into each part of the mold. In this embodiment, an electric valve is used to automatically adjust the valve opening degree.

The controller 7 has a built-in control program as shown in the flowchart of FIG. 3 or 4, and controls temperature sensors Sl, S2 . The flow regulating valves 41, 42, 43 are individually controlled based on the detection signal from S3. The controller 7 also controls the pump P according to an operation switch (not shown).
In addition to operating the electromagnetic valves 21 to 23 and 31 to 33, the heater 3 and cooler 4 are also controlled according to the mold temperature.

FIG. 3 is a flowchart of control for maintaining uniform temperatures of each heat medium coming out of the mold 2 during cooling operation, and FIG.
This is a flowchart for controlling one heat medium temperature to a certain set value and the other heat medium temperatures to their average value.
The order of each operation will be explained below.

First, when the mold temperature controller operates, the heat medium is circulated by the pump P in the direction of the arrow in Fig. 1, and if the mold 2 is cold at this time, the heater 3 is activated to perform so-called warm-up. . Next, when the mold 2 starts molding, the temperature of the mold 2 rises due to the heat of the molten resin, so the cooler 4 is activated, and the cooled heat medium is distributed to the main vibe 1 and the branch pipes 11, 12, 13. The mold 2 is cooled through. still,
The control steps of the heater 3 and cooler 4 by the controller 7 and the temperature sensor of the mold 2 are not shown because they are the same as those of the conventional product.

At this point, the flow rate control shown in Fig. 3 is started, and first the temperature sensor S
l, S2. The temperature Tl, T2 . of each heat medium is determined by S3. T
3 was detected (R1), Tl.

T2. The average value TI of T3 is calculated (R2).

It is then determined whether T1 is lower than T11 (R3
), when the temperature is low, the process proceeds to step R4, and when it is high, the cooling is insufficient, so the opening degree of the flow rate regulating valve 41 is increased to increase the flow rate of the heat medium (R5).

In step R4, it is determined whether T1 is equal to Tm. If they are equal, the process proceeds to step R7. If they are not equal, the opening degree of the flow rate regulating valve 41 is reduced (R8) since it is too cold. Hereinafter, in R7...R8, 72. T
The flow rate regulating valves 42 and 43 are also controlled in the same manner as described above so that 3 coincides with TI.

Heat medium temperature Tl, T2 on the mold outlet side. Maintaining T3 at T1 means that more heat medium flows in the hotter parts of the mold 2, making the temperature distribution uniform throughout the mold, which leads to improved molding quality. .

On the other hand, if it is necessary to partially change the temperature of the mold 2 depending on the resin material, the control process shown in the flowchart of FIG. 4 is used. In the flowchart of FIG. 4, Tl is controlled to a required temperature Ts, and other T2. T3 is the average value TI
This is an example of controlling.

In this case, first, the temperature of the heat medium of the branch vibrator 11 is set to a temperature Ts suitable for molding by the controller 7 side. When the cooling operation of the mold 2 is started in this state, the temperature sensor S
l, S2. T1 by SS. T2. T3 was detected (
rl), it is determined whether only T1 is lower than the set value Ts (T2). If Tl is lower than Ts, the process proceeds to step r3, and if T1 is higher than Ts, the opening degree of the flow rate regulating valve 41 is increased to increase the flow rate of the heat medium (
T4).

Next, in step r3, it is determined whether T1 matches Ts, and if they do not match, it is too cold, so the opening degree of the flow rate adjustment valve 41 is narrowed to reduce the heat medium flow rate (r5
), if they match, the opening degree is maintained as it is and the process proceeds to step r6.

In step r6, the temperature T2. of the heat medium flowing through the other branch pipes 12.13. The average value Tm is calculated from T3, and then T2. T
Each flow regulating valve 42, 43 is controlled so that 3 coincides with T■.

By this control, a specific part of the mold 2 is maintained at a set temperature, and the remaining parts are maintained at an average temperature.

Of course, T2. It is also possible to control T3 to a set temperature Ts.

(Effects of the Invention) As detailed above, according to the heat medium flow rate control device of claim (1), the mold outlet temperature of the heat medium flowing through each branch pipe is uniform, in other words, the temperature inside the mold is high. Since more heat medium flows through the parts, there is an effect that the temperature distribution in the mold can be made uniform at all times without requiring any effort.

Further, according to the heat medium flow rate control device of claim (2), it is possible to maintain a specific part of the mold at a set temperature and other parts at an average temperature, and it is possible to cope with various resin moldings. can.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a mold temperature controller to which the heat medium flow rate control device of the present invention is applied, Fig. 2 is a circuit diagram of the conventional product, Fig. 3 is a flowchart of the first invention, and Fig. 4 is It is a flowchart of the second invention. 1... Main pipe, 2... Mold, 7... Controller, 11.12.13... Branch pipe, 41.4
2゜43...Flow rate adjustment valve, SL, S2. S3...Temperature sensor. Patent Applicant Sanden Co., Ltd. Agent Patent Attorney Yoshi 1) Takashi Sei Figure 3

Claims (2)

[Claims] (1) In a heat medium flow control device for a mold temperature controller that maintains a mold at an appropriate molding temperature by flowing heated or cooled heat medium through a plurality of branch pipes passing through the mold, each of the branch pipes A flow rate adjustment valve is installed at the mold outlet side of the branch pipe, and a temperature sensor for detecting the heat medium temperature is installed on the mold outlet side of the branch pipe.The average value of the heat medium temperature is calculated from the detection signal of each temperature sensor. A heat medium flow rate control device for a mold temperature regulator, characterized in that a control means is provided for controlling the opening degree of the flow rate regulating valve so that the medium temperature matches this average value. (2) In a heat medium flow control device for a mold temperature controller that maintains a mold at an appropriate molding temperature by flowing heated or cooled heat medium through a plurality of branch pipes passing through the mold, each of the branch pipes A flow rate adjustment valve is installed on the mold outlet side of the branch pipe, and a temperature sensor that detects the heat medium temperature is installed on the mold outlet side of the branch pipe, and the opening degree of at least one flow rate adjustment valve is set so that the heat medium temperature of the corresponding branch pipe becomes the set value. control means that calculates the average value of the heat medium temperature from the detection signals of other temperature sensors, and controls the opening degrees of other flow rate regulating valves so that these heat medium temperatures match this average value. A heat medium flow control device for a mold temperature controller, characterized in that it is provided with: