JPH0768366A - Method and equipment of vacuum die casting - Google Patents

Abstract

PURPOSE:To provide a cast product of high quality without porosity by interlocking the timing of opening/closing a vacuum valve with the position of a plunger to control the degree of the vacuum in a cavity and to prevent the inclusion of the air in injecting the molten metal into the cavity. CONSTITUTION:When an injection plunger 13 is advanced to the first position SV0, a vacuum valve 3 is opened to start the evacuation of the gas in the cavity, and when the injection plunger 13 reaches the second position SVC, the vacuum valve 3 is clossed to stop the evacuation of the gas in the cavity 2, and at the same time, the degree of the vacuum of the vacuum system when the injection plunger reaches the second position is compared with the preset value. When the degree of the vacuum at the second position is higher, the first position is changed by the prescribed distance toward the die side. On the other hand, when the degree of the vacuum at the second position is lower, the first position is changed by the prescribed distance toward the counter die side, and in the following cycle, the timing to open the vacuum valve 3 at this changed position is adjusted to execute the injection process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention In a vacuum die casting, the present invention controls the degree of vacuum of the cavity within a predetermined range to prevent the formation of cavities due to the entrainment of gas when the molten metal is injected into the cavity. TECHNICAL FIELD The present invention relates to a vacuum die casting method and an apparatus thereof that contribute to stabilization of quality.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a structure of a vacuum control system in a vacuum die casting machine. A cavity 2 is formed by the fixed die 1a and the movable die 1b which form the die 1, and the cavity 2 is connected to a vacuum device 5 via a vacuum pipe 4 in which a vacuum valve 3 is incorporated. The vacuum device 5 is composed of a vacuum tank, 6 and a vacuum pump 7. The vacuum pump 7 is operated to maintain a state in which the vacuum degree of the vacuum tank 6 is increased, and the vacuum valve 3 is opened.
The cavity 2 is instantly depressurized. The vacuum pipe 4 has a filter 8 downstream of the vacuum valve 3.
And a vacuum gauge 9 are provided, and the degree of vacuum can be visually controlled by this vacuum gauge 9.

On the other hand, the injection sleeve 11 for pressurizing and filling the molten metal 10 into the cavity 2 has a pouring port 1 at a predetermined position.
2 is provided, and an injection plunger 13 that pressurizes the molten metal 10 is slidably fitted. In this case, the rod 14 of the injection blanker 13 is connected to an injection cylinder (not shown), and the molten metal 10 is applied by the pressure of the injection cylinder.
Pressurize. In order to interlock the opening and closing of the vacuum valve 3 with the operation of the injection plunger 13, the rod 14
Is a set of limit switches 15a, 15b at a predetermined position.
Is provided with a dog portion 16 that comes into contact with the contactor. The limit switches 15a and 15b are connected to a relay 18 that controls opening / closing of the vacuum valve 3. In the die casting machine as described above, first, when the molten metal is poured from the pouring port 12 by the unillustrated ladle, the injection plunger 13 advances by Svo from the initial position and closes the pouring port 12 as shown in the figure. In the first position, the dog portion 16 hits the contact of the limit switch 15a and the limit switch 1
5a is turned on. Based on this position detection signal, the contact of the relay 18 is turned on and the solenoid valve (not shown) of the vacuum valve 3 is energized to open the vacuum valve 3. Therefore, since the cavity 2 and the vacuum tank 6 communicate with each other via the vacuum valve 3, the pressure reduction of the cavity 2 is started, and the molten metal 10 starts to be filled in the cavity 2 as the injection plunger 13 advances.

When the injection plunger 13 further advances and reaches the injection stroke Svc, the dog portion 16 kicks the contact of the limit switch 15b to turn off the relay 18 at the second position. As a result, the vacuum valve 3 is closed immediately before the filling of the molten metal 10 into the cavity 2 is completed. In this way, the molten metal 10 is rapidly filled with the cavity 2 sufficiently depressurized.

[0005]

However, in the above-mentioned prior art, the opening / closing timing of the vacuum valve 3 is
Since it is independent of the control of the degree of vacuum, there is a problem that the gas is sucked into the cavity 2 while being entrained together with the molten metal 10. That is, when the injection plunger 13 is located in front of the hot water supply hole 12, or as shown in FIG. 5, the level of the molten metal 10 in the injection sleeve 11 is further below the center line of the injection sleeve 11. When the vacuum valve 3 is opened at some time, the molten metal 10 is sucked into the cavity 2 while entraining gas. Such a phenomenon causes a cavity in the cast product to deteriorate the quality. The timing for opening and closing the vacuum valve 3 is set only by the positional relationship between the limit switches 15a and 15b and the dog portion 16, and the time required for the high-speed injection stroke of the injection plunger 13 is extremely short. Since there is no great difference from the operation delay time of the solenoid valve for activating, the adjustment of the opening / closing timing of the vacuum valve 3 was very difficult. As a technique for adjusting the operation timing of the vacuum valve 3, the present applicant has proposed USP 5,022,457.
Control system of Die cast Machine described in
Is proposed. In addition to controlling the timing of opening and closing the vacuum valve 3 described above, controlling the degree of vacuum is also an important factor in preventing the formation of cavities and stabilizing the quality of the cast product. That is, it is known that filling the cavity with the molten metal while keeping the degree of vacuum constant is effective from the viewpoint of generating cavities. However, since the molten metal amount is not always constant, various factors such as the error of the sensor that detects the vacuum degree are involved, and the injection cycle time is a very short time interval of several seconds, the detected value of the vacuum degree is It was difficult to control the degree of vacuum by feedback. Therefore, conventionally, the degree of vacuum is currently controlled by visual control using the vacuum gauge 9. Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional technology,
By controlling the vacuum degree in the cavity by interlocking the opening and closing timing of the vacuum valve with the position of the plunger, it prevents the entrainment of air when injecting the molten metal into the cavity, and is a high-quality cast product with no cavities. Is to get.

[0006]

In order to achieve the above object, the vacuum degree control method according to the present invention is provided in a vacuum system connected to the cavity while measuring the degree of vacuum of the cavity in the mold. In a vacuum die casting method in which a vacuum valve is opened and closed, and molten metal is pressure-molded while sucking a vacuum in the cavity, the vacuum valve is opened when the injection plunger is advanced to the first position. To start sucking gas in the cavity, and when the injection plunger reaches the second position, close the vacuum valve to stop sucking gas in the cavity,
The degree of vacuum of the vacuum system at the time of reaching the second position is compared with a preset degree of vacuum, and when the degree of vacuum at the second position is high, the first position is moved to the mold side by a predetermined distance. When the degree of vacuum is low, the first position is moved to the side opposite to the mold for a predetermined distance to change the opening / closing timing of the vacuum valve, and the correction is performed in the next injection step. The first position and the second position are linked to the opening and closing of the vacuum valve to perform pressure molding while maintaining the degree of vacuum of the cavity of the mold at a predetermined value.

In the above method, the second position of the injection plunger is set in advance, the vacuum degree data is measured along the time axis from the start of the injection process, and the vacuum degree at the second position of the injection plunger is measured. And the set value are compared, and the difference in vacuum degree is time-converted based on the vacuum degree data. This time-converted value is converted into a correction value for the injection plunger position, and the first value of the injection plunger in the next injection step is converted.
Is updated so that the position of the injection plunger in the injection process and the opening / closing timing of the vacuum valve are interlocked.

Further, according to the present invention, a vacuum sensor for measuring the degree of vacuum of a cavity in a mold, a vacuum valve for opening and closing a vacuum system connected to the cavity, and the vacuum system for vacuuming the cavity are provided. In a vacuum die casting apparatus equipped with a vacuum device for sucking through, a vacuum degree detecting means for detecting a vacuum degree of the vacuum system, a position detecting means for detecting a position of the injection plunger, and a unit time from the start of the injection process. A means for storing the detected vacuum degree data, a vacuum degree comparing means for comparing the vacuum degree at the time when the vacuum valve is closed, and a preset vacuum degree, and a vacuum degree detected based on the vacuum degree data. Is higher than the set vacuum degree, the first position of the injection plunger that opens the vacuum valve in the next injection step is corrected to move to the mold side by a predetermined distance, A vacuum valve open position correction means is provided for performing a correction for moving the first position to a side opposite to the mold by a predetermined distance when the generated vacuum level is lower than the set vacuum level. .

In the above vacuum die casting apparatus, a closing limit detector for detecting that the vacuum valve is completely closed is provided, and the degree of vacuum after detection of the closing limit of the vacuum valve is set based on the output of the closing limit. It is characterized by comparing with the degree of vacuum.

In the above vacuum die casting apparatus, when the detected vacuum degree is lower than a predetermined vacuum degree limit, an alarm signal generating means for generating an alarm signal or a die cast machine stop signal, and an alarm signal are received. And an alarm device for issuing an alarm.

Further, in the above vacuum die casting apparatus, the vacuum degree data stored in the storage means and the temporal change of the vacuum degree based on the output data of the position detector, the speed of the injection plunger, and the injection rate. A computing means for computing a parameter representing a cycle condition; a vacuum degree curve representing a temporal change in vacuum degree according to an output of the computing means; and an injection speed curve representing a temporal change in the speed of the injection plunger, and A display device may be provided for displaying the parameters.

[0012]

When the detected degree of vacuum is higher than the set value, the first position of the injection plunger at which the vacuum valve opens is corrected to a position further advanced by a predetermined value, so that the vacuum valve is opened and the cavity is opened. It is controlled so that the timing of starting the depressurization is delayed.

On the other hand, when the degree of vacuum is lowered due to a cause such as clogging of the filter, the position of the injection plunger for opening the vacuum valve is corrected to the front, so that the vacuum valve is opened earlier. Controlled as. Therefore, since the pressure reduction of the cavity is started earlier, the degree of vacuum of the cavity can be automatically maintained within a predetermined constant range.

When the degree of vacuum is much lower than the set value, this is detected and an alarm is automatically issued. Furthermore, the status of the injection cycle is displayed in real time by displaying the degree of vacuum curve and the injection speed curve. It is configured so that the status of the injection cycle can be monitored.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vacuum degree control method and apparatus for vacuum die casting according to the present invention will be described below with reference to the accompanying drawings. In FIG. 1 showing the configuration of one embodiment of the present invention, the same components as those of the prior art of FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment, the cavity 2 in the mold 1 and the vacuum pipe 4 connected to the vacuum tank 6 are connected via a vacuum valve 3, and the suction and the suction of the cavity 2 are started and stopped by the vacuum valve 3. It is designed to be opened and closed. The vacuum sensor 20 detects the degree of vacuum of the vacuum system via the passage drawn from the cavity.

The vacuum valve 3 is a valve that switches the position of the spool 32 by a two-way electromagnetic directional control valve 36 and opens and closes a valve element 33 connected to the spool 32. The electromagnetic direction switching valve 36 is controlled by the control device 23, which will be described later, and supplies the working fluid from the fluid pressure source 38 to the cylinder 39 in which the spool 32 is housed to switch the position of the spool 32. Further, in this vacuum valve 3, in order to reliably detect the open / closed state of the valve body 33, a rod interlocking with the spool 32 is projected to the outside, and a dog 34 attached to the tip of this rod turns ON / OFF.
Limit switches 35a and 35b that are turned off are provided at positions corresponding to the open / close positions.

When such a vacuum valve 3 is opened, the cavity 2 and the vacuum pipe 4 communicate with each other through the outlet port 40, so that the cavity 2 can be depressurized.

On the other hand, as means for detecting the position of the injection plunger 13, a magnetic scale 22a attached to the rod 14 of the injection plunger 13 and the magnetic scale 2
2a and a displacement sensor 22b for detecting the displacement of the injection plunger 13, and the displacement sensor 22b outputs a pulse signal proportional to the displacement of the injection plunger 13. These vacuum sensors 2
0, limit switches 35a, 35b, displacement sensor 22
The output of b is configured to be introduced into the control device 23.

The control unit 23 includes a central processing unit 25 equipped with a microprocessor, a main storage unit 26 including a ROM storing a program and a RAM storing input data and processing data, an input port 24 and And an output port 27. Central processing unit 25
Is connected to an input device such as a vacuum sensor 20, a limit switch 21, a position sensor 22 and a keyboard 28 for inputting required setting data necessary for vacuum control via an input port 24. On the other hand, the output port 27
Is a CRT 29 that displays various state curves described later,
Output devices such as an alarm device 30 and an alarm lamp 31 are connected. Next, the operation of this embodiment will be described in relation to the injection process. Here, FIG. 2 is a time chart in which the degree of vacuum, the injection speed of the molten metal, and the like are associated with the position of the injection plunger 13 in the casting cycle of the automatic operation of the die casting machine.

In FIG. 2, a curve A represents the injection speed which is the speed of the injection plunger 13, and a curve B represents the degree of vacuum. In this case, the degree of vacuum is represented by a diagram in which the atmospheric pressure is zero and the degree of vacuum is reversed so that the degree of vacuum increases as it goes downward. Further, Svo is an injection plunger 13 when outputting a signal for opening the vacuum valve 3.
Of the injection plunger 13 when outputting a signal to close the vacuum valve 3 is shown.
Shows the position of.

Therefore, first, in order to initialize the casting cycle in the die casting machine, the setting data such as Svo, Svc, and the set vacuum degree H0 are input from the keyboard 28.

The control unit 2 will be described below with reference to the flow chart of FIG.
The operation of No. 3 will be described. When the cycle begins,
The position S of the injection plunger 13 is given to the central processing unit 25 via the displacement sensor 22b, and when the injection plunger 13 advances by Svo, the first position of this plunger is detected (step S1). . Next, the central processing unit 25 outputs a signal for exciting the solenoid 37a of the directional control valve 36 to a drive circuit (not shown) to open the vacuum valve 3 (step S2). Ascend and vacuum valve 3
As a result, the cavity 2 and the vacuum tank 6 are communicated with each other, and the inside of the cavity is decompressed, and the degree of vacuum thereof gradually increases as shown by the curve B. At the same time, the measurement of the degree of vacuum is subsequently started based on the output of the vacuum sensor 20 (step S3). The degree-of-vacuum data is measured every unit time and stored in the main storage device 26 of the control device 23 as a table.

The injection plunger 13 advances further, and the second
When the position Svc is reached (step S4), the central processing unit 25 closes the vacuum valve 3 and the directional control valve 36
A signal for exciting the solenoid 37b is output (step S5), whereby the spool 32 of the vacuum valve 3 descends and the opening degree of the vacuum valve 3 decreases. The limit switch 35b indicates that the vacuum valve 3 is completely closed.
When the closing limit signal is detected (step S6), the process proceeds to the next step S7. In FIG. 2, the degree of vacuum H at this time C is compared with a preset value H0 of the degree of vacuum, and the injection plunger 13 corresponding to the position where the vacuum valve 3 is opened according to the result of the comparison.
The processing for correcting the first position Svo of is executed.

That is, first, when the set value H0 of the degree of vacuum and the detected value H are equal as a result of the comparison including the allowable range α (Yes in step S8), the correction is not performed and the process proceeds to the next cycle. (Step S18).

On the other hand, when the detected degree of vacuum H is higher than the set value H0 in consideration of the predetermined allowable range α (YES in step S9), the vacuum valve 3 is turned on in the next injection cycle. In order to delay the opening timing, a predetermined correction amount ΔS is added to the position Svo of the injection plunger 13 at which the vacuum valve 3 is opened, and Sv0 + ΔS which is shifted by ΔS to the mold side is set as the position where the vacuum valve 3 is opened in the next cycle. (Step S10).

The first position Sv0 of this injection plunger 13
2 is performed based on the vacuum degree data stored along the time axis as represented by the vacuum degree curve B in FIG. In this case, when the degree of vacuum H at the time point C when the vacuum valve 3 is completely closed is higher than the set value H0, the difference in the degree of vacuum can be converted into a time difference Δt. Assuming that this time-converted Δt corresponds to the correction amount ΔS of the position of the injection plunger 13, by shifting the first position Sv0 by ΔS to the mold side, the vacuum degree in the next injection cycle will be increased. Since it is expected to follow the change in the degree of vacuum as shown by the curve B1, the degree of vacuum at the time point C when the vacuum valve 3 is closed can be controlled to the set value H0. On the other hand, when the detected value of the degree of vacuum H is lower than the set value H0 (No in step S9), conversely, in the next cycle, the correction for sending the timing of opening the vacuum valve 3 is performed. FIG. 3 is a diagram showing a vacuum degree curve B when the vacuum degree H is low.

That is, in step S11, the limit value Z of the degree of vacuum and the detected value H of the degree of vacuum, which are set beforehand based on the specifications of the die casting machine and the casting conditions, are compared as an abnormal value in which the degree of vacuum is too low. Yes (step S1
1). If it is lower than the limit value Z, for example, it is determined that the filter 8 is clogged, and a signal for displaying an alarm is output to the alarm device 30 and the CRT 29 (step S12), and the operation of the die casting machine is stopped. A signal is output (step S13).

On the other hand, if the degree of vacuum H has not decreased to the control value Z, but is lower than the set value H0 in consideration of the allowable range α (Yes in step S14), the vacuum is reversed. In order to accelerate the timing of opening the valve 3, the value of Svo is corrected to the value obtained by subtracting ΔS from the value in the previous step (step S15).

The first position Sv0 of the injection plunger 13
As in the case of FIG. 2, the correction of is based on the vacuum degree data that can be represented by the vacuum degree curve B, and the time depending on the difference between the vacuum degree H at the time C when the vacuum valve 3 is completely closed and the set value H0 Deviation Δt is converted into a correction amount ΔS of the position of the injection plunger 13. Then, the first position Sv0 of the injection plunger 13 is changed to a position displaced by ΔS to the side opposite to the mold, and the next injection cycle is performed. As a result, in the next injection cycle, the degree of vacuum is predicted to change as shown by the degree-of-vacuum curve B2, so that the degree of vacuum can be controlled to the set value H0.

Since this stroke Svo must be larger than a certain value E in relation to the position of the hot water supply hole 12, in the subsequent step S16, the corrected stroke Svo is used.
Is compared with the limit value E, and if the correction stroke Svo is equal to or less than the limit value E, an alarm signal is output to the alarm device 30 (step S16).

In this way, for some reason,
If the degree of vacuum detected by the vacuum sensor 20 is high and the casting cycle is continued with the timing of opening the vacuum valve 3 set to the initial setting, the depressurization of the cavity 2 progresses quickly, so that gas is entrained in the molten metal. However, according to the embodiment, since the vacuum degree is controlled by interlocking the position of the injection plunger 13 and the opening / closing timing of the vacuum valve 3, the injection plunger 13 which opens the vacuum valve 3 is controlled.
The position of is corrected to a position further advanced to the mold side by a predetermined value and is shifted. Therefore, by delaying the timing when the vacuum valve opens and the pressure reduction of the cavity 2 is started, It is possible to eliminate factors that cause nests.

On the contrary, when the vacuum degree of the vacuum pipe 4 is lowered due to the clogging of the filter 8 or the like,
The timing of opening the vacuum valve 3 can be advanced by correcting and shifting the position of the injection plunger 13 that opens the vacuum valve 3 toward the backward direction. Therefore, since the pressure reduction of the cavity 2 is started earlier, the degree of vacuum of the cavity 2 can be automatically maintained within a predetermined constant range.

Next, the vacuum degree curves as shown in FIG. 2 and FIG.
It is displayed on the CRT 29 during the injection cycle, along with other data such as: In the figure, a curve A represents an injection speed curve that represents a temporal change in the speed of the injection plunger 13. The vacuum degree curve BZ is a curve indicating the limit of the control range of the vacuum degree. When the vacuum degree H at the time when the vacuum valve 3 is closed becomes lower than the limit value Z, the die casting machine is stopped as described above. Therefore, by simultaneously displaying the actually measured vacuum degree curve B and, as a result of the correction, the vacuum degree curves B1 and B2 expected in the next injection cycle, the state of the vacuum degree can be visually grasped in real time. Has become. Further, the central processing unit 25 detects the time when the vacuum valve 3 is actually opened by calculating the inflection point Q of the vacuum curve B, and the inflection point Q and the vacuum valve 3 are provided. The time interval R with the reception time point C of the closing signal given from the limit switch 35b is calculated. On the other hand, for the injection speed curve A, the central processing unit 25 calculates the pulse signal output from the position sensor 22 to obtain a change point P at which the injection speed rises from a low speed to a high speed, and the degree of vacuum at this change point P. Calculate X. If the degree of vacuum X is too high, the molten metal may be so strongly injected into the cavity 2 that the vacuum valve 3 may be blocked by the molten metal. Therefore, the degree of vacuum X is the degree of vacuum H at the time C when the vacuum valve 3 is closed. If it is higher than that, an alarm is issued. As illustrated in FIG. 3, C
RT29 includes the above-mentioned vacuum degree curves B, B2, and injection speed curve A, as well as the time interval R from opening to closing of the vacuum valve 3 at a predetermined parameter display position D on the monitor, and the injection speed rising time. Various parameters necessary for monitoring the condition of the injection cycle, such as the degree of vacuum X and the degree of vacuum H when the vacuum valve is closed, are displayed. In addition,
When the degree of vacuum H is lower than the limit value Z, an NG comment indicating defective product is displayed.

[0034]

As is apparent from the above description, according to the present invention, in order to control the degree of vacuum in the cavity to be constant, the position of the injection plunger and the opening / closing operation of the vacuum valve are interlocked with each other to achieve a vacuum. The degree of vacuum inside the cavity is controlled to be constant by changing the position of the injection plunger that opens the vacuum valve in the next injection process according to the difference with the set value of the degree, so that the molten metal entrains gas. It is possible to prevent the generation of cavities due to the above and to stabilize the quality of the cast product.

Further, when a value lower than the set value is detected, an alarm is automatically issued, and the status of the injection cycle can be monitored by the vacuum degree curve and the injection speed curve displayed in real time. Therefore, a stable automatic process of vacuum die casting can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of a vacuum controller according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a monitor screen that displays a vacuum degree curve and an injection speed curve when the degree of vacuum is higher than a set value during an injection cycle.

FIG. 3 is an explanatory diagram showing an example of a monitor screen displaying a vacuum degree curve and an injection speed curve when the degree of vacuum is lower than a set value during an injection cycle.

FIG. 4 is a flowchart showing the operation of the control device according to the present invention.

FIG. 5 is a configuration diagram showing a conventional control device in vacuum die casting.

[Explanation of symbols]

 1 Mold 2 Cavity 3 Vacuum Valve 4 Vacuum Piping 5 Vacuum Device 6 Vacuum Tank 10 Molten Metal 11 Injection Sleeve 12 Injection Plunger 20 Vacuum Degree Sensor 21 Limit Switch 22 Position Sensor 23 Control Device 30 Alarm Device

Claims (6)

[Claims] 1. A vacuum valve provided in a vacuum system connected to the cavity is opened / closed while measuring the degree of vacuum of the cavity in the mold, and molten metal is added while suctioning the inside of the cavity to a vacuum. In the vacuum die casting method of pressure forming, when the injection plunger has advanced to the first position, the vacuum valve is opened to start sucking gas in the cavity, and the injection plunger reaches the second position. Then, the vacuum valve is closed to stop sucking the gas in the cavity, and the degree of vacuum of the vacuum system at the time when the second position is reached is compared with the preset degree of vacuum.
When the degree of vacuum at the position is high, the first position is moved to the mold side by a predetermined distance to change it, and when the degree of vacuum is low, the first position is moved to the anti-mold side by a predetermined distance. The opening and closing timing of the vacuum valve is adjusted by changing the opening and closing timing of the vacuum valve, and in the next injection process, the corrected first position and second position are linked with the opening and closing of the vacuum valve to adjust the vacuum degree of the mold cavity. Is maintained at a predetermined value and pressure molding is performed. 2. The second position of the injection plunger is preset, the vacuum degree data is measured along the time axis from the start of the injection process, and the vacuum degree and the set value at the second position of the injection plunger are set. And the difference in vacuum degree is converted into time based on the vacuum degree data, and this time converted value is converted into a correction value for the position of the injection plunger to update the first position of the injection plunger in the next injection process. 2. The vacuum die casting method according to claim 1, wherein the position of the injection plunger and the opening / closing timing of the vacuum valve are linked in the injection process. 3. A vacuum sensor for measuring the degree of vacuum of a cavity in a mold, a vacuum valve for opening and closing a vacuum system connected to the cavity, and a vacuum for sucking the inside of the cavity through the vacuum system. In a vacuum die casting apparatus equipped with a vacuum device, a vacuum degree detecting means for detecting a vacuum degree of the vacuum system, a position detecting means for detecting a position of the injection plunger, and a vacuum detected every unit time from the start of the injection process. Means for storing degree data, a degree-of-vacuum comparison means for comparing the degree of vacuum at the time when the vacuum valve is closed and a preset degree of vacuum, and the degree of vacuum detected based on the degree-of-vacuum data is the set degree of vacuum. If it is higher than the degree, the vacuum detected by correcting the first position of the injection plunger that opens the vacuum valve in the next injection process to the mold side by a predetermined distance There vacuum die casting apparatus characterized by comprising a vacuum valve open position correcting means for correcting for moving the first position by a predetermined distance Hankin type side is lower than the set degree of vacuum. 4. The vacuum die casting apparatus according to claim 3, further comprising a closing limit detector for detecting that the vacuum valve is completely closed, and detecting the closing limit of the vacuum valve based on the output of the closing limit. A vacuum die-casting device, characterized in that the degree of vacuum of the above is compared with the set degree of vacuum. 5. The vacuum die casting apparatus according to claim 3 or 4, further comprising an alarm signal generating means for generating an alarm signal or a die casting machine stop signal when the detected vacuum level is lower than a predetermined vacuum level limit. And a warning device which receives a warning signal and gives a warning, and a vacuum die-casting device. 6. The vacuum die casting apparatus according to any one of claims 3 to 5, wherein the vacuum degree data stored in said storage means and the temporal change of the vacuum degree based on the output data of said position detector, and said injection. Computing means for computing parameters representing the speed of the plunger and the condition of the injection cycle;
A vacuum degree curve showing a temporal change of the vacuum degree according to the output of the arithmetic means, an injection speed curve showing a temporal change of the speed of the injection plunger, and a display device for displaying the parameter are provided. Vacuum die casting equipment.