JP2003010960A - Control method for low pressure casting machine and control system for low pressure casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store a required casting condition for a using mold in a control panel without manual inputting of a operator, and control the casting operation based on the casting condition without making the state, where a molten metal in a holding furnace is full, a standard. SOLUTION: In the vicinity of a gate of a mold 11 used in a low pressure casting machine 10, a molten metal passing through detection sensor 13 for detecting when the molten metal passing through is provided. In a host computer 30 constituted so as to enable data communication with a control panel 20 of the low pressure casting machine 10, a casting condition data including a pressure control pattern, which controls by at least using a detection signal of the molten metal passing through detection sensor 13, is stored. When the mold 11 is mounted to the low pressure casting machine 10, the control panel 20 downloads from the host computer 30 the casting condition data inherent in the mold 11 to control the casting operation of the low pressure casting machine 10 according to the casting condition data downloaded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure casting machine control method and a low pressure casting machine control system.

[0002]

2. Description of the Related Art Generally, in the low pressure casting method, the surface of a molten metal in a closed holding furnace is pressurized with a compressed gas to raise the molten metal through a stalk, and the molten metal is poured into a mold cavity installed above the holding furnace. Then, after solidification up to the gate after a certain time has elapsed, the pressurization is terminated, the molten metal in the stalk is returned to the holding furnace, and the casting in the mold is taken out. Here, the mold means a mold or a sand mold.

The low-pressure casting machine used in such a low-pressure casting method is provided with a control board, and the control board has a pressurization control pattern in the holding furnace, a mold temperature control pattern, etc. No control is performed.), And it is necessary to store the necessary casting conditions for the die used. Further, when using a plurality of low-pressure casting machines, it is necessary to store the necessary casting conditions for the mold used for each control panel provided in each low-pressure casting machine.

Conventionally, such a casting condition is manually input by the operator according to the type of the mold and stored in the control panel. For example, regarding the pressurization control pattern, the pressurization for the mold to be used is applied. The control target pattern was manually input and stored in the pressure controller of the control panel. Then, when the casting process is executed, the pressurization controller of the control panel reads out the target pattern and controls the pressurization by the compressed gas according to the pressurization control pattern.

Further, the low-pressure casting machine is provided with a full-level sensor for measuring the amount of molten metal in the holding furnace, and this full-level sensor is provided when the molten metal is stored up to a predetermined full level in the holding furnace. While the molten metal is detected and turned on, it is turned off when the molten metal in the holding furnace is less than the full level.

Conventionally, even when manually inputting a target pattern of pressurization control for a die to be used, pressure data is input with reference to a state where the molten metal in the holding furnace is full. Then, when the casting process is performed, the casting process is performed using the ON / OFF signal of the full level sensor.

[0007]

However, in such a conventional type, since the operator manually stores the necessary casting conditions for the die to be used in the control panel, the die must be exchanged. When the casting conditions are changed, manual input work for storing new casting conditions such as the pressurization control pattern in the holding furnace and the mold temperature control pattern in the control panel is required, which is troublesome. Moreover, when using multiple low-pressure casting machines, each time the casting conditions of each low-pressure casting machine are changed, new control conditions such as the pressurization control pattern in the holding furnace and the mold temperature control pattern are stored in each control panel. Not only is it cumbersome and time-consuming, since it requires manual input work.
Problems such as typos occur easily.

Further, in the conventional one, since the pressure data is inputted with reference to the state where the molten metal in the holding furnace is full,
There are the following problems. That is, the height from the molten metal level surface to the gate at the time of fullness varies depending on the low-pressure casting machine, and the pressurization data is converted by this height (converted value Pk:
(See FIG. 6) It is necessary to input.

Further, when the casting operation is repeated continuously, the molten metal level decrease due to the reduction of the molten metal in the holding furnace is calculated for each shot based on the total casting weight of the product and the plan, and the pressure target is set. In addition, it is necessary to correct it, but this calculation of the amount to be added is calculated by starting from the time when the full level sensor for checking the amount of molten metal in the holding furnace is turned off,
In order to add to the target value, it is necessary to first add the molten metal in the holding furnace in an amount equal to or more than the amount at which the full level sensor is turned on. However, in an actual casting operation, for example, it may be necessary to start the operation in a state where the melting amount is small, and in such a case, correction based on the calculation starting with the off signal of the full level sensor cannot be performed.

An object of the present invention is to eliminate the problems of the above-mentioned conventional ones, to allow a control panel to store necessary casting conditions for a die to be used, without manual input by an operator. A control method for a low-pressure casting machine and a control system for a low-pressure casting machine that can control the casting operation based on the casting conditions without reference to the full state of the molten metal in the holding furnace.

[0011]

The present invention is to solve the above-mentioned problems, and the invention according to claim 1 is a control method for controlling at least one low-pressure casting machine equipped with a control panel. A step of storing casting condition data peculiar to a mold used in the low pressure casting machine in a host computer configured to be capable of data communication with the control panel, and when the mold is attached to the low pressure casting machine, Control panel downloads casting condition data specific to the corresponding mold from the host computer; and the control panel controls the casting operation of the low pressure casting machine according to the downloaded casting condition data specific to the mold. It is a control method of a low pressure casting machine including and.

According to a second aspect of the present invention, in the invention according to the first aspect, the casting condition data peculiar to the mold indicates that the molten metal is present in an appropriate portion of the molten metal flow path of the mold due to pressurization in the holding furnace. It is a control method for a low pressure casting machine that includes at least a pressurization control pattern that is controlled by using a detection signal of a sensor that detects passage.

According to a third aspect of the present invention, in the first aspect of the present invention, the control panel causes the molten metal to pass through an appropriate portion of the molten metal flow path of the attached mold in accordance with pressurization in the holding furnace. Is a control method of a low pressure casting machine including a step of calculating the amount of molten metal in the holding furnace based on the detected pressure in the holding furnace at that time when a detection signal of a sensor for detecting is received.

According to a fourth aspect of the present invention, in the first aspect of the invention, the control panel causes the molten metal to pass through an appropriate portion of the molten metal flow passage of the attached mold in accordance with pressurization in the holding furnace. Is a control method of a low pressure casting machine including a step of performing a predetermined process by determining an abnormality when a detected temperature above the location rises above a set temperature even if a detection signal of a sensor for detecting is not accepted. .

According to a fifth aspect of the present invention, there is provided a control system for controlling a plurality of low-pressure casting machines, each of which is provided with a control board, and the control system is provided in each of a plurality of molds used in each of the low-pressure casting machines. A molten metal passage detection sensor that detects when molten metal passes through an appropriate portion of the molten metal flow path of the mold, and is configured to be capable of data communication with each of the control panels, and for each mold used in each of the low pressure casting machines. As a unique casting condition, there is provided a host computer storing casting condition data including at least a pressurizing control pattern which is controlled by using a detection signal of the molten metal passage detection sensor, and each control panel includes each of the low pressure casting machines. When each mold is attached to
A control system for a low pressure casting machine configured to download the casting condition data specific to a corresponding mold from the host computer and control the casting operation of each of the low pressure casting machines according to the downloaded casting condition data.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, at least two molten metal passage detection sensors are provided near the gate of each mold, and at least two control boards are provided. The control system of the low-pressure casting machine confirms that the molten metal passage detection sensor is normal by comparing the detection values of the molten metal passage detection sensor.

The invention according to claim 7 is the invention according to claim 5, further comprising a pressure sensor for detecting the pressure in the holding furnace, wherein each of the control panels receives a detection signal from the molten metal passage detection sensor. , While calculating the molten metal amount in the holding furnace based on the pressure detected by the pressure sensor at that time,
The control system of the low-pressure casting machine generates a molten metal replenishment request signal when the pressure detected by the pressure sensor at the time point rises above a set pressure.

The invention according to claim 8 is the invention according to claim 5, further comprising a temperature sensor for detecting a temperature above the molten metal passage detecting sensor, wherein each of the control boards is a detection signal of the molten metal passage detecting sensor. However, when the temperature detected by the temperature sensor rises above the set temperature, the control system of the low-pressure casting machine stops the casting operation at a predetermined timing while determining an abnormality and issuing an alarm.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a control system for a low-pressure casting machine according to the present invention. The control system 1 for this low-pressure casting machine comprises a plurality of (for example, four) low-pressure casting machines 10a, 10b, 10c. , 10d for controlling the low pressure casting machines 10a, 10b, 1
0c and 10d are control boards 20a, 20b, 20c and 20
all control boards 20a, 20b, 2
0c and 20d are configured to be capable of data communication with the host computer 30. That is, the control boards 20a, 20
Each of b, 20c, and 20d is composed of a PLC (programmable logic controller), for example, and has a computer function capable of data communication with the host computer 30. And these four low pressure casting machines 1
0a, 10b, 10c and 10d are substantially similar to each other, and the four control boards 20a, 20b, 20c,
Since 20d are also substantially similar to each other, in the following description, four low pressure casting machines 10 and a control panel 20 are represented as a representative.

FIG. 2 is a schematic block diagram showing the mutual exchange of data and control among the low-pressure casting machine 10, the control panel 20, and the host computer 30.

The low-pressure casting machine 10 is equipped with a die 11 and a holding furnace 15. As shown schematically in FIG. 5, the surface of the molten metal 16 stored in the closed holding furnace 15 is heated by compressed gas. By pressing, the molten metal 1 is passed through the stalk 17 connected to the gate of the mold 11 installed above the holding furnace 15.
6 is poured into the cavity 12 of the mold 11, and after a certain period of time has been solidified to the sprue, pressurization is terminated and the molten metal in the stalk 17 is returned to the holding furnace 15, and then the mold 1
The casting in 1 is taken out.

Therefore, the control panel 20 is the low pressure casting machine 10
From the mold 11 of No. 1, mold number, sprue temperature T1, mold temperature T2
Various data such as, and based on these data, through the mold temperature control valve unit 21, the mold 1
While controlling required objects such as 1 cooling water and air,
From the holding furnace 15 of the low-pressure casting machine 10, various data such as the molten metal temperature Tm, the ambient temperature Tf, the full level signal L, and the abnormal signal are received, and based on these data, via the pressurization control valve unit 25, the holding furnace A desired object such as 15 pressurized air is controlled.

Further, the host computer 30 receives various data such as mold number, production information, molten metal request, etc. from the control panel 20, and based on these data, casting conditions specific to the mold corresponding to the mold number. Control data such as is downloaded to the control panel 20.

That is, the control system 1 for this low-pressure casting machine uses the host computer 30 to set the casting conditions (pressurization control pattern, mold temperature control pattern, etc.) specific to the die 11 used in the low-pressure casting machine 10. By storing the data, and when the die 11 is attached to the low-pressure casting machine 10, the control panel 20 downloads casting condition data specific to the die 11 from the host computer 30,
The control board 20 is configured to control the casting operation of the low pressure casting machine 10 in accordance with the downloaded casting condition data unique to the mold 11.

The control system 1 for this low-pressure casting machine
Is to separate the casting conditions unique to the mold 11 stored in the host computer 30 from the casting conditions unique to the low-pressure casting machine 10 other than the mold 11, and to establish the casting conditions truly unique to the mold 11. In addition, the following configuration is provided. That is, the mold 1 used in each low pressure casting machine 10
Each of the molds 1 is provided with a molten metal passage detection sensor 13 that detects when the molten metal passes through an appropriate portion (for example, near the gate) of the molten metal flow path of each mold 11.

As the molten metal passage detection sensor 13, for example, a method of directly embedding an electrode in the mold 11, a method of embedding a temperature sensor, or a method of installing a coil around the outer periphery of the molten metal and detecting passage of the molten metal by a change in magnetic field. However, if it is not desired to increase the control parameters, it is preferable to also use the temperature sensor embedded in the mold 11. In operation, sensors such as a temperature sensor embedded in the mold 11 are required to have durability and stable function that do not break even when heated to 200 ° C. or more during coating. Therefore, a thermometer embedded and used for temperature control of the mold 11 is used as the molten metal passage detection sensor 13 to generate a confirmation signal of molten metal passage when the temperature rises above a set temperature. Is realistic.

Moreover, such a molten metal passage detection sensor 1
At least two units 3 are provided in the vicinity of the gate of each mold 11 as a countermeasure against a sensor failure. The two units are configured as an OR circuit, and each control panel 20 detects the detection values of the two molten metal passage detection sensors 13. By comparing the above, it is confirmed that the molten metal passage detection sensor 13 is normal.

At least the detection signal of the molten metal passage detection sensor 13 is set as the die-specific casting conditions stored in the host computer 30, that is, the casting conditions unique to each die 11 used in each low-pressure casting machine 10. The casting condition data including the pressurization control pattern controlled by using is stored.

Further, the control system 1 of this low pressure casting machine
Is provided with a pressure sensor 19 for detecting the pressure in the holding furnace 15 in addition to the full level sensor 18 in each holding furnace 15, and when each control panel 20 receives the detection signal of the molten metal passage detection sensor 13, The amount of molten metal in the holding furnace 15 is calculated on the basis of the pressure detected by the pressure sensor 19, and a molten metal replenishment request signal is generated when the pressure detected by the pressure sensor 19 at that time rises above the set pressure. It has become.

Furthermore, the control system 1 of this low pressure casting machine
Is equipped with a temperature sensor 14 that detects a temperature above the molten metal passage detection sensor 13, and each control panel 20 does not accept the detection signal of the molten metal passage detection sensor 13, but the temperature sensor 1
When the detected temperature of 4 rises above the set temperature, it is judged to be abnormal and an alarm is issued, and the casting operation is stopped at a predetermined timing (for example, after completion of the one cycle).

Next, the operation of the above embodiment will be described.
This will be described with reference to the flowcharts shown in FIGS.

As shown in FIG. 3, in the mold setup process prior to the casting operation, first, the mold 1 is placed at a predetermined position of the low pressure casting machine 10.
1 is attached (step S11).

Next, the die number of the die 11 is input (step S12), the host computer 30 is accessed (step S13), and die data A including casting condition data unique to the die 11 is entered. Is downloaded (step S14).

Then, the downloaded mold data A is written in the storage device provided in the control panel 20 of the low-pressure casting machine 10 (step S15), thereby completing the casting preparation (step S16).

As shown in FIG. 4, in the casting process, first, it is judged whether or not the pressurizing condition is a predetermined pressurizing condition [1] (step S21), and the predetermined pressurizing condition [1] is determined. If there is (YES in step S21), the pressurizing condition [1]
The pressure is boosted at the boosting speed determined in step S22. On the other hand, if the predetermined pressurizing condition [1] is not satisfied (NO in step S21), the process is stopped (step S3).
2).

The molten metal 16 passes through the measuring point P1 (see FIG. 5) in accordance with the pressurization under the pressurizing condition [1], and the molten metal passage detection sensor 13 (either of the two constituting the OR circuit). Generates a molten metal passage detection signal (step S
23), triggered by the reception of the molten metal passage detection signal, the pressurization control / mold cooling operation is started in accordance with the mold data A previously downloaded (step S2).
4).

Then, the solidification time is calculated using the mold temperature T1, the spout temperature T0, the molten metal temperature Tf, the casting conditions, and the furnace pressure Pf as parameters (step S25), and the pressure is maintained while waiting for solidification (step S26). ), The mold is cooled (step S27).

When the pressure release condition is satisfied (YES in step S28), the pressurization is completed (step S2).
9) On the other hand, the mold 11 executes the mold opening process (step S30), while the control board 20 performs necessary correction for the next shot (step S31).

FIG. 5 is an explanatory view showing the pressurization curve (change curve of the pressing force with the passage of time) in the control system 1 of the low-pressure casting machine, together with the outline of the low-pressure casting machine 10, and FIG. The following can be seen by comparing with a similar pressurization curve in the conventional one.

That is, the conventional pressurization curve shown in FIG.
While the pressing force is increased at a constant speed from the rise to the target value, the control system 1 of the low pressure casting machine shown in FIG.
The pressurization curve of No. 1 increases the pressing force from the rising until the molten metal 16 reaches the measurement point P1 regardless of the mold 11, but the molten metal 16 passes the measurement point P1 and the molten metal passage detection sensor 13 detects the molten metal passage. When the signal is generated, thereafter, the pressing force is increased to the target value according to the casting conditions (pressure control pattern, mold temperature control pattern, etc.) specific to the mold 11. Therefore, separate the pre-process from the start of pressurization until the molten metal 16 reaches the measurement point P1 (preparation process for casting) and the post-process after the molten metal 16 has passed the measurement point P1 (true casting process). And as a result, the holding furnace 15
Even if the height from the inner surface to the gate of the mold 11 varies depending on each low-pressure casting machine 10, only the pre-process (preparing process for casting) is affected by it, and the post-process ( The true casting process) will not be affected at all.

In the above embodiment, the low pressure casting method using four low pressure casting machines 10a, 10b, 10c and 10d is applied, but the present invention is not limited to this. For example, one low pressure casting machine is used. It is also possible to apply to a low pressure casting method using only a table.

[0042]

As described above, according to the present invention, the casting condition data unique to the mold used in the low pressure casting machine is stored in the host computer configured to be capable of data communication with the control panel of the low pressure casting machine. When a die is mounted on the low-pressure casting machine, the control panel downloads the casting condition data specific to the relevant mold from the host computer, and controls the casting operation of the low-pressure casting machine according to the downloaded casting condition data specific to the mold. With this configuration, the operator can store the necessary casting conditions for the die to be used in the control panel without manual input.

Therefore, even if the casting conditions such as the die replacement are changed, new casting conditions such as the pressurization control pattern in the holding furnace and the die temperature control pattern are stored in the control panel, which is a troublesome manual input work. Is unnecessary, especially when using multiple low-pressure casting machines, each time the casting conditions of each low-pressure casting machine are changed, new control patterns such as the pressurization control pattern in the holding furnace and the mold temperature control pattern are added to each control panel. There is no need to perform a complicated and time-consuming manual input operation of storing various casting conditions, and it is possible to prevent an input error from occurring.

The present invention further includes a molten metal passage detection sensor which is provided in each of a plurality of molds used in each low-pressure casting machine and which detects when the molten metal has passed through an appropriate portion of the molten metal flow passage of the mold. Casting condition data including a pressurization control pattern controlled at least by using the detection signal of the molten metal passage detection sensor as the casting condition peculiar to each mold used in each low pressure casting machine, which is configured to be capable of data communication with the control panel. Each control panel is equipped with a host computer storing
When each die is attached to each low pressure casting machine, the casting condition data specific to the corresponding die is downloaded from the host computer, and the casting operation of each low pressure casting machine is controlled according to the downloaded casting condition data. Therefore, it is possible not only for the operator to store the necessary casting conditions for the die to be used in the control panel without manual input, but also for the molten metal in the holding furnace not to be the basis for the casting conditions. The casting operation can be controlled.

Therefore, it is not necessary to convert the height from the molten metal level surface at the time of fullness to the gate, which is different for each low-pressure casting machine, and it is necessary to perform manual input work to input pressurization data to the control panel in the first place. Moreover, there is an effect that a normal casting operation can be performed without any trouble even if the molten metal is not first put in the holding furnace in an amount larger than that at which the full-level sensor is turned on.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a control system for a low pressure casting machine.

FIG. 2 is a schematic configuration diagram showing a mutual relationship among a low pressure casting machine, a control panel, and a host computer.

FIG. 3 is a flow chart showing the operation of the mold setup process of the one shown in FIGS.

FIG. 4 is a flow chart showing the operation of the casting process of the one shown in FIGS.

FIG. 5 is an explanatory view showing the pressurization curves of FIGS. 1 and 2 together with the outline of a low pressure casting machine.

FIG. 6 is an explanatory view showing a pressure curve of a conventional one together with an outline of a low pressure casting machine.

[Explanation of symbols]

1 Low pressure casting machine control system 10a, 10b, 10c, 10d Low pressure casting machine 11 mold 12 cavities 13 Molten metal passage detection sensor 14 Temperature sensor 15 Holding furnace 16 molten metal 17 Stoke 18 Full level sensor 19 Pressure sensor 20a, 20b, 20c, 20d control panel 21 Mold temperature control valve unit 25 Pressurization control valve unit 30 host computer

Claims (8)

[Claims] 1. A control method for controlling at least one low pressure casting machine equipped with a control panel, comprising: a host computer configured to be capable of data communication with the control panel; and a mold used in the low pressure casting machine. Storing unique casting condition data, when a mold is attached to the low-pressure casting machine, the control panel downloading casting condition data unique to the mold from the host computer, the control panel Controlling the casting operation of the low pressure casting machine in accordance with the casting condition data specific to the downloaded mold, the method of controlling a low pressure casting machine. 2. The casting condition data peculiar to the mold is controlled by using a detection signal of a sensor that detects that the molten metal has passed through an appropriate portion of the molten metal flow path of the mold with pressurization in a holding furnace. The control method of the low-pressure casting machine according to claim 1, further comprising at least a pressurization control pattern. 3. The point of time when the control panel receives a detection signal of a sensor that detects that the molten metal has passed through an appropriate portion of the molten metal flow path of the attached mold due to pressurization in the holding furnace. 2. The method for controlling a low pressure casting machine according to claim 1, further comprising the step of calculating the amount of molten metal in the holding furnace based on the pressure detected in the holding furnace. 4. The control panel does not accept a detection signal of a sensor that detects that the molten metal has passed through an appropriate portion of the molten metal flow path of the attached mold due to pressurization in the holding furnace. 2. The control method for a low pressure casting machine according to claim 1, further comprising a step of determining an abnormality and performing a predetermined process when the detected temperature above the location rises above a set temperature. 5. A control system for controlling a plurality of low-pressure casting machines, each of which is provided with a control board individually, each of which is provided in each of a plurality of molds used in each of the low-pressure casting machines and has a melt flow path of the mold. A molten metal passage detection sensor that detects it when the molten metal passes through an appropriate portion of the control panel, is configured to be capable of data communication with each of the control panels, and as casting conditions unique to each mold used in each of the low pressure casting machines, And a host computer storing casting condition data including a pressurization control pattern controlled by using a detection signal of at least the molten metal passage detection sensor, wherein each control panel is attached to each low pressure casting machine by each die. At that time, the casting condition data unique to the corresponding mold is downloaded from the host computer, and the low-pressure casting is performed according to the downloaded casting condition data. A control system for a low-pressure casting machine, which is configured to control a casting operation of a molding machine. 6. The molten metal passage detection sensor is provided at least two near the gate of each mold, and each control panel compares the detected values of the at least two provided molten metal passage detection sensors, The control system of the low-pressure casting machine according to claim 5, wherein it is confirmed that the molten metal passage detection sensor is normal. 7. A pressure sensor for detecting the pressure in the holding furnace is provided, and when each control panel receives a detection signal of the molten metal passage detection sensor, the control panel holds the pressure based on the pressure detected by the pressure sensor at that time. 6. The low-pressure casting machine according to claim 5, wherein the molten metal amount in the furnace is calculated, and when the pressure detected by the pressure sensor at the time point exceeds a set pressure, a molten metal replenishment request signal is generated. Control system. 8. A temperature sensor for detecting a temperature above the molten metal passage detection sensor is provided, and the temperature detected by the temperature sensor is set even though each of the control boards does not receive a detection signal of the molten metal passage detection sensor. The control system for the low-pressure casting machine according to claim 5, wherein when the temperature rises above the temperature, it is determined to be abnormal, an alarm is issued, and the casting operation is stopped at a predetermined timing.