JP2022040686A - Mold temperature control system - Google Patents

Abstract

To provide a mold temperature control system capable of correctly managing a temperature even in a mold having a many number of lines.SOLUTION: A mold temperature control system 1 controls the temperature of a mold 3 in a die casting machine 2, and comprises: a temperature sensor 6 detecting the temperature of each part of the mold 3; a flow controller 17 controlling the instantaneous flow rate of cooling water cooling each part of the mold 3; and a control device 7 acquiring the mold temperatures by the temperature sensor 6, calculating deviations between target mold temperatures and the present mold temperatures per period of a production cycle, converting the deviations into flow rate value, and transferring the same to the flow controller 17, in which the flow rate of the cooling water controlled at a fixed flow rate upon production is changed within one shot.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mold temperature control system that controls the temperature of a mold of a die casting machine.

In a die casting machine that casts aluminum die casting products, it is important to control the temperature by cooling because the aluminum hot water enters the center of the mold for each shot. In particular, when the size of the mold becomes large, temperature unevenness is likely to occur in each part, and in order to eliminate this temperature unevenness, it is necessary to exhaust heat to an appropriate part with an appropriate amount of cooling water, and the amount of cooling water should be reduced for each part. Need to change. However, since the large mold has an extremely large number of parts, the management method is complicated and it is difficult to manage by a normal method.

Looking at the literature on conventional management methods, for example, there are the mold temperature control device of Patent Document 1 and the mold temperature control system of Patent Document 2, but the effect is that the amount of cooling water is simply adjusted according to the mold temperature. It is a management method of a variable level that can be divided into 2 to 3 zones at most, just by describing. There are many cases of temperature control methods including other literature, but the current situation is that there are almost no management methods for molds with a large number of systems.

Actually, there are many mold cooling holes in the 4-cylinder engine block, and there are 120 systems, and the heat input differs between the fixed type and the movable type. Further, since the size of the mold is as large as 2 to 3 m square, it is not possible to determine which part of the temperature should be controlled for each system. Furthermore, if each part of the 120 system is individually controlled so that the mold temperature of each system becomes constant, it cannot be controlled as expected due to mutual interference with the adjacent system, and the temperature can be controlled as expected. There was a problem that it wasn't there.

Japanese Unexamined Patent Publication No. 11-47883 Japanese Unexamined Patent Publication No. 10-109343

Therefore, the present invention has been made in view of such a problem, and an object thereof is to provide a mold temperature control system capable of accurately controlling the temperature even in a large mold having a large number of systems. To do.

In order to solve the above problems, the present invention has the following features.

The mold temperature control system according to claim 1 is a system that controls the temperature of the mold of a die casting machine, and comprises a temperature sensor that detects the temperature of each part of the mold and each part of the mold. The flow controller that controls the instantaneous flow rate of the cooling water to be cooled and the mold temperature detected by the temperature sensor are acquired, and the deviation between the target mold temperature and the current mold temperature is calculated for each production cycle cycle. However, it is characterized by being provided with a control device that converts it into a flow rate value and transfers it to the flow controller.

The mold temperature control system according to claim 2 is the system according to claim 1, wherein the control device compares a representative mold temperature at each part of the mold with a current mold temperature and deviates from the current mold temperature. Is calculated, and the correction value of the flow rate is determined from the deviation.

The mold temperature control system according to claim 3 has the same correction value for each part of the mold in the system according to claim 2, and adjusts the entire flow rate value by a certain amount. It is characterized by that.

In the mold temperature control system according to claim 4, in the system according to claim 2, the correction value is a value different for each part of the mold, and the value at the time of the previous production cycle is set to 100%. It is characterized in that the flow rate value is adjusted by the ratio of each part from the value.

The mold temperature control system according to claim 5 is the system according to claim 3 or 4, wherein the control device is preset with a flow rate program in which the flow rate during the production cycle is variable. It is characterized in that the correction value is added without changing the waveform of the flow rate program.

The mold temperature control system according to claim 6 is the system according to claim 1, wherein the control device divides one cycle of the production cycle into three time zones in the order of T1, T2, and T3 by a timer. The flow rate of T1 and T3 is a predetermined flow rate value, and the flow rate of T2 is characterized by acquiring the mold temperature after the end of the production cycle and calculating and correcting the flow rate value of the next production cycle. And.

The mold temperature control system according to claim 7 is characterized in that, in the system according to claim 6, the correction is performed by increasing or decreasing the flow rate value of T2.

The mold temperature control system according to claim 8 is the system according to claim 6, wherein the correction is the time of T2 within the time specified by T4 when one cycle of the production cycle is T4. It is characterized in that it is performed by increasing or decreasing.

According to the present invention, by using the flow controller that controls the instantaneous flow rate of the cooling water, there is an effect that the installation space and cost can be suppressed and the mold temperature control of many cooling systems can be realized. Further, by changing the flow rate of the cooling water controlled at a constant flow rate at the time of production within one shot, there is an effect that the solidification rate can be changed and the characteristics of the product can be improved. Further, it becomes possible to adjust the height of the temperature fluctuation within one shot at the time of production, and there is an effect that the quality and yield of the product are improved when manufacturing a product having a thin wall or a complicated shape.

It is a conceptual diagram which shows the whole structure of the mold temperature control system which concerns on this invention. It is a partial cross-sectional view which shows the structure of the flow rate control unit in this system. It is sectional drawing which shows the internal structure of the flow controller in this system. It is a flowchart which shows the control method by this system. It is explanatory drawing which shows an example of the mold temperature characteristic data. It is a graph which shows the relationship between the mold temperature and the cooling water flow rate in a production cycle. It is a block diagram which shows the detail of arithmetic processing. It is a table diagram which shows the relationship between a reference temperature and a reference flow rate. It is a graph which shows the example of the correction value of the flow rate. It is a graph which shows the example which adds the correction value to the waveform of a flow rate program. It is a graph which shows the correction example which increases the flow rate value of T2 in a production cycle. It is a graph which shows the correction example which increases the time of T2 within the predetermined time of T4 in a production cycle.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

As shown in FIG. 1, in the mold temperature control system 1 of the present embodiment, in a die casting machine 2 for producing (casting) an aluminum die casting product, the flow rate of cooling water controlled at a constant flow rate at the time of production is changed. This is a system for controlling the temperature of the mold 3. The mold 3 constitutes a part of the die casting machine 2, and is composed of a fixed mold 4 provided in the injection device and a movable mold 5 provided in the mold clamping device.

A temperature sensor 6 (to 6n) made of a thermocouple or a resistance temperature detector is attached to each part of the mold 3 (fixed mold 4 and movable mold 5). The temperature sensor 6 detects the maximum temperature, the minimum temperature, the average temperature, and the current temperature of the mold 3 in the production cycle in real time. The detected temperature information of the mold 3 is converted into an electric signal and output to a control device 7 that performs arithmetic processing described later.

A cooling water circulation device 8 for circulating cooling water is provided outside the die casting machine 2 as a means for adjusting the temperature of the mold 3. The cooling water circulation device 8 includes a cooling tower 9, a heat exchanger 10, a tank 11, and a pump 12. The water in the tank 11 is cooled by the cooling tower 9 via the heat exchanger 10. The cooling water is supplied by the pump 12 to the cooling water holes provided at each portion of the mold 3 through the water supply pipe 13, and circulates to the tank 11 through the return pipe 14.

A flow rate control unit 15 is attached to each of the molds 3 (fixed mold 4 and movable mold 5). As shown in FIG. 2, the flow rate control unit 15 includes a manifold 16 connected to the water supply pipe 13 and an aggregate of a plurality of flow controllers 17 (to 17n) connected to the manifold 16. Cooling water from the water supply pipe 13 is introduced into the cavity 18 via a strainer (not shown) in the manifold 16, and is branched at a plurality of ports 19 (to 19n) to be branched into individual flow controllers 17 (to 17n). ) Is supplied.

The flow controller 17 is a flow control device that controls the instantaneous flow rate of the cooling water that cools each part of the mold 3 (fixed mold 4 and movable mold 5). As shown in FIG. 3, the flow controller 17 includes a flow rate control valve 20, a flow rate measuring unit 21, and a control unit 22, and is configured via two joint adapters 23 and 23 that are alternately connected. It is connected to the port 19 of the manifold 16.

The flow rate control valve 20 employs a ball valve mechanism in this embodiment. This ball valve mechanism has a valve body 25 connected to the rotation shaft of the motor actuator 24, and a ball portion 26 provided at the tip of the valve body 25 and capable of adjusting the valve opening degree.

The flow rate measuring unit 21 employs an impeller type flow meter in this embodiment. This impeller type flow meter has an impeller 27 rotatably supported in the flow path and a sensor unit 28 for measuring the rotation speed of the impeller 27. The sensor unit 28 includes a sensor substrate 29, a GMR sensor 30, and a bias magnet 31, measures the rotation speed of the impeller 27 detected by the GMR sensor 30, and outputs a pulse signal (rotation speed signal) according to the measurement result. Output to the control unit 22.

The control unit 22 is a microcomputer. The control unit 22 controls the motor actuator 24 based on the rotation speed signal output from the flow rate measurement unit 21, and feedback-controls (PID control) the opening degree of the flow rate control valve 20.

The above is the configuration of the mold temperature control system 1 of the present embodiment. Next, the control method will be described with reference to FIG.

<STEP401>
First, the control device 7 starts the system.

<STEP402>
Before performing temperature control, mold temperature characteristic data is created from the parameters of the amount of cooling water according to the appropriate mold temperature distribution. For the mold temperature characteristic data, first, the cooling water is adjusted so that the mold temperature distribution is appropriate, and the temperature at this time is set as the target temperature (SV) at the time of control. Further, the amount of cooling water is recorded, and the flow rate value at this time is set as the reference flow rate (StFWn).

Next, as shown in FIG. 5, the cooling water is grouped for each part of the mold 3. In the grouping, the part (cooling No.) to be the reference position is determined. The reference position is preferably a portion close to the center when the temperature of each portion is adjusted, and a portion where a change is likely to appear and a temperature sensor 6 can be easily attached. If the mold temperature characteristic data has already been created, the existing data is read.

<STEP403>
When the discard casting by the die casting machine 2 is completed and the production is started, the mold temperature is controlled.

<STEP404>
Mold temperature control (calculation processing) is started by the process trigger signal.

<STEP405>
Time is measured with the production cycle interval between process trigger signals. This time measurement result is set in the calculation cycle and adjusted so that the actual production cycle and the calculation cycle match.

<STEP406>
The mold temperature is detected by the temperature sensor 6. As shown in FIG. 6, as the mold temperature, the maximum temperature (MAX), the minimum temperature (MIN), the average temperature (AVE), and the current temperature (DIR) in the production cycle are acquired and held, and any one of them is acquired and held. The temperature of is set to the mold temperature (PV) at the time of performing arithmetic processing.

<STEP407>
Monitor the calculation cycle.

<STEP408>
The target temperature (SV) and the mold temperature (PV), and the current temperature (DIR) in the present embodiment are monitored for each cycle, the two temperatures are compared, the SV-PV deviation is calculated, and the PID calculation is executed.

<STEP409>
The PID calculation is performed, and the flow rate value conversion process of converting the obtained result into the flow rate value of the flow controller 17 is performed.

<STEP410>
The flow rate value obtained by the flow rate value conversion process is transferred from the control device 7 to the flow controller 17.

<STEP411>
The production cycle in the casting process may be delayed in time due to the product take-out process or the like, and the production cycle and the arithmetic process may be different from each other in the preset arithmetic cycle. Therefore, the input interval of the process trigger is measured as the production cycle interval, and the calculation cycle is corrected.

<STEP412>
After the end of production, the system will be stopped.

As described above, the arithmetic processing is performed after the arithmetic cycle (time-up), and the arithmetic processing is periodically performed from the start of production to the end of production. It should be noted that this arithmetic processing is performed only for the reference points of the grouped cooling water groups.

Here, to explain the calculation process in more detail, as shown in FIG. 7, the set flow rate value of the reference point converts the PID-calculated value into the flow rate value as it is. The set flow rate value other than the reference point is converted into the set flow rate value by using the increase / decrease rate (IDr) between the current set flow rate value (SvFWn) and the reference flow rate (StFWn) of the reference point.

As shown in FIG. 8, for example, the reference temperature (SV) of the reference point (cooling No. C002) is 122 ° C., the reference flow rate (StFW002) is 1.7 L / min, and the cooling Nos. of the same group. It is assumed that the reference flow rate (StFW003) of C003 is 2.5 L / min. At this time, when the temperature of the reference point (cooling No. C002) at a certain time point is 145 ° C. and the set flow rate value (SvFW002) is 2.3 L / min as a calculation result, the cooling No. of the same group. The set flow rate value of C003 is calculated as follows.

IDr = SvFW002 / StFW002
= 2.3 / 1.7
≒ 1.35
SvFW003 = StFW003 * IDr
= 2.5 * 1.35
≒ 3.38L / min

Next, the correction of the flow rate value will be described. The flow rate of each part determined based on the mold temperature characteristic data is the optimum distribution according to the current environment, and the temperature of the aluminum hot water, the outside air temperature, and the cooling water temperature from the cooling tower 9 differ depending on the season and morning and noon. Therefore, even if a predetermined flow rate is applied, the mold temperature changes with time due to this disturbance. In order to correct the disturbance, it is necessary to adjust the flow rate of the cooling water, but it should be noted that the waste heat distribution should not be changed. If this distribution is changed, the overall temperature distribution will be disrupted, so care must be taken, and it is important to increase or decrease the flow rate and control the temperature so as not to change the distribution.

In this embodiment, after supplying cooling water at a flow rate determined based on the mold temperature characteristic data to each part of the mold 3, the deviation is calculated by comparing the representative mold temperature with the current mold temperature. Then, the correction value of the flow rate is determined from the deviation. This correction value is only the correction value of the whole, and the correction value is set as the rate of change (%), and this rate of change is given to the current flow rate of each system (the first time is a predetermined flow rate), and the flow rate is increased or decreased. The temperature of the mold 3 is controlled.

Here, as shown in FIG. 9A, the correction value can be set to the same value for each part (system) of the mold 3, and the overall flow rate value can be adjusted by a certain amount. Further, as shown in FIG. 9B, the correction value may be set to a different value for each part (system) of the mold 3, and the ratio may be adjusted for each part (system). For example, the value at the time of the previous production cycle is set to 100%, and the flow rate value can be adjusted by the ratio for each part (system) from that value.

In this case, the flow rate within one shot of the production cycle may be constant for each molding shot. As a result, the mold temperature can be detected with only one representative value (reference point), and the correction value is also one. Therefore, even if the number of systems increases, the management method does not change, and the size of the mold 3 is large. However, the temperature can be easily controlled. As for the number of temperature sensors 6, a plurality (2 to 3) may be attached and set to one value by a weighted average. Regarding the calculation of the correction value, the PID calculation is used, but a method of calculating from another data table (step control) may also be used. Since the fixed mold 4 and the movable mold 5 are independent of each other, the representative temperature of the mold 3 is 2 in total, so that the temperatures of the individual fixed mold 4 and the movable mold 5 are constant. Actually, it is desirable to control and operate at each representative temperature.

Further, by varying the flow rate during the production cycle in a more complicated manner, it becomes possible to provide a product of better quality in a short cycle time. For example, as shown in FIG. 10, a flow rate program in which the flow rate during the production cycle is variable is set in the control device in advance, and a correction value is added to increase or decrease the flow rate without changing the waveform of the flow rate program as it is. The adjustment allowance may have the same correction value as shown in FIG. 9A, or may differ depending on the ratio as shown in FIG. 9B.

Further, in the embodiment described below, the flow rate of the cooling water is changed by using three timers. As shown in FIG. 11, one cycle of the production cycle is divided into three time zones in the order of T1, T2, and T3 by three timers. Then, the flow rates of T1 and T3 are set to predetermined flow rates, the mold temperature after the end of the production cycle is acquired for the flow rate of T2, and the flow rate value to be passed to T2 in the next production cycle is calculated by PID calculation. To correct.

Since it is difficult to manage when the number of systems is large in a large mold, the temperature distribution of the mold is imaged in advance with an infrared thermography camera (not shown), etc., so that the optimum mold temperature distribution can be obtained for each system. The amount of cooling water is determined in advance. Further, the temperature sensor 6 is also installed at a typical part, and the flow rate of T2 is corrected for each system so that the temperature becomes constant, so that the mold temperature can be easily controlled and the temperature waveform can be adjusted. can.

In this embodiment, three timers T1, T2, and T3 are used, but instead, the flow rate of the cooling water is changed only by two timers T1 and T2 or T2 and T3. Is also good. Further, the correction is also performed by increasing or decreasing the flow rate value of T2, but as shown in FIG. 12, when one cycle of the production cycle is T4, the time of T2 is within the specified time of T4. It may be corrected by increasing or decreasing only.

In the above embodiment, the waveform curve of the mold temperature in the production cycle is adjusted. By adjusting the waveform curve in this way, it is possible to adjust the finished state of the product (hot water wrinkles, sink marks, etc. due to solidification). Therefore, not only the yield of the product is improved, but also the shot time of one cycle is finally shortened. Especially in the case of thin-walled products, these controls are essential.

1: Mold temperature control system 2: Die caster 3: Mold 4: Fixed mold 5: Movable type 6: Temperature sensor 7: Control device 8: Cooling water circulation device 9: Cooling tower 10: Heat exchanger 11: Tank 12: Pump 13: Water supply pipe 14: Return pipe 15: Flow control unit 16: Manifold 17: Flow controller 18: Cavity 19: Port 20: Flow control valve 21: Flow measurement unit 22: Control unit 23: Joint adapter 24: Motor actuator 25: Valve body 26: Ball part 27: Impeller 28: Sensor unit 29: Sensor board 30: GMR sensor 31: Bias magnet

Claims (8)

It is a system that controls the temperature of the die casting machine.
A temperature sensor that detects the temperature of each part of the mold, and
A flow controller that controls the instantaneous flow rate of cooling water that cools each part of the mold,
The mold temperature detected by the temperature sensor is acquired, the deviation between the target mold temperature and the current mold temperature is calculated for each production cycle cycle, converted into a flow value, and transferred to the flow controller. A mold temperature control system characterized by being equipped with a control device. In the system according to claim 1, the control device calculates a deviation by comparing the representative mold temperature at each part of the mold with the current mold temperature, and determines the correction value of the flow rate from the deviation. Mold temperature control system characterized by The mold temperature control system according to claim 2, wherein the correction value is the same for each part of the mold, and the total flow rate value is adjusted by a certain amount. In the system according to claim 2, the correction value is a value different for each part of the mold, the value at the time of the previous production cycle is set to 100%, and the flow rate value is adjusted by the ratio for each part from that value. A mold temperature control system characterized by being a thing. In the system according to claim 3 or 4, the control device is preset with a flow rate program in which the flow rate during the production cycle is variable, and the correction value is set without changing the waveform of the flow rate program. Mold temperature control system characterized by addition. In the system according to claim 1, the control device divides one cycle of the production cycle into three time zones in the order of T1, T2, and T3 by a timer, and the flow rate of T1 and T3 is predetermined. A mold temperature control system characterized in that the flow rate of T2 is used as a flow rate value, the mold temperature after the end of the production cycle is acquired, and the flow rate value of the next production cycle is calculated and corrected. The mold temperature control system according to claim 6, wherein the correction is performed by increasing or decreasing the flow rate value of the T2. In the system according to claim 6, the amendment is performed by increasing or decreasing the time of T2 within a predetermined time of T4, where one cycle of the production cycle is T4. Type temperature control system.

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