JPH0813410B2 - Injection control method for die casting machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection control method for controlling the injection of molten metal in a die casting machine.

(Prior Art) Generally, in a die casting machine, when casting, optimum casting conditions such as injection speed and casting pressure are determined according to the product to be cast, and the die casting machine is operated under these conditions. There is. Such optimum casting conditions are calculated by various calculation expressions from various set values such as the inner diameter of the injection sleeve and the gate cross-sectional area. In order to save the troublesomeness of such calculation, it has been proposed to automatically calculate and display the calculation result on a display (see, for example, Japanese Utility Model Laid-Open No. 2-11657).

(Problems to be Solved by the Invention) However, in the case of the above-mentioned conventional technique, although the casting conditions such as the injection speed can be easily calculated, the operator actually adjusts the die casting machine according to the obtained casting conditions. It was necessary to operate it, and the operability was poor.

Further, even if the optimum casting conditions are obtained, there is a problem that the optimum conditions vary depending on the operating conditions of the die casting machine such as the temperature of the mold and the oil temperature of the hydraulic oil for driving the injection cylinder. It was

For example, taking the temperature of the mold as an example, empirically from the past, when the mold temperature at the start of casting is lower than a predetermined temperature, the molten metal flow in the cavity is poor, resulting in a high defective casting rate. It is known. Then, when continuous casting begins and the mold temperature falls within a predetermined temperature range, the molten metal flow becomes stable and the defective casting rate becomes almost zero. Further, when the mold temperature rises above a predetermined temperature, the molten metal becomes excessive and burrs are generated to increase the defective casting rate.

In view of such a fact, it is the current situation that the defect rate is conventionally reduced by the operator's experience to correct the injection condition according to the operating state of the die casting machine such as the mold temperature.

In this way, since it depends on the experience and intuition of the operator, the operability is poor and it is very difficult to stabilize the quality.

The present invention has been made to solve the above-mentioned problems of the conventional technology, and the purpose thereof is to automatically set the required control unit of the die casting machine which has been manually performed according to the optimum casting conditions. It is intended to improve operability so that it can be performed.

Another object is to stabilize the casting quality by automatically correcting the casting conditions according to the operating conditions of the die casting machine.

(Means for Solving the Problems) In order to achieve the above object, an injection cylinder drive hydraulic pressure provided with an injection speed control valve for controlling the injection speed of the injection cylinder and a time adjusting valve for adjusting the operation timing of the pressure boosting cylinder. In the injection control method of a die casting machine equipped with a circuit and its controller, a theoretical / empirical formula for calculating the optimum injection data and a data table are stored in advance in the optimum injection data storage unit, and when the casting is started, the optimum injection data is stored in the optimum injection data. As the fixed set values to be substituted, the specifications of the die casting machine, the product parameters, the die parameters, and the filling pressure of the hydraulic accumulator serving as the drive source of the die casting machine are input, and the optimum injection data stored in advance in the optimum injection data storage unit is input. And, when the calculation is performed based on the input fixed set value and the provisional casting conditions are output, Together, the opening of the injection speed control valve and the time adjustment valve corresponding to the output is automatically set as an initial setting value for setting the optimum casting conditions according to the operating state of the die casting machine, and the operating state of the die casting machine. Variable set values such as mold temperature, hydraulic oil temperature, and oil pressure that vary depending on
Measured in the continuous casting process, the optimum casting conditions are set by correcting the openings of the injection speed control valve and the time adjustment valve based on the measured values, and the variable set values are corrected by correcting the initial set values. A correction data table for applying a correction corresponding to the measured value is stored in advance in the correction data storage unit for trial casting, and the injection speed control valve and the time adjustment valve are opened based on the correction data table and the measured value. While automatically correcting the degree, perform a predetermined shot of trial casting according to a preset trial casting pattern to raise the mold temperature to an appropriate temperature for main casting, and then automatically shift to the main casting pattern. Is characterized by.

(Operation) According to the injection control method of the die casting machine configured as described above, the operator sets the specifications of the die casting machine, the product parameters, the die parameters, and the hydraulic accumulator filling pressure as the driving source of the die casting machine as the fixed set values. Just by inputting, the temporary casting conditions are calculated and output based on the optimum injection data, and the opening of the injection speed control valve and the time adjustment valve of the injection cylinder drive hydraulic circuit of the die casting machine corresponding to the output is optimal. It is automatically set as an initial setting value for setting casting conditions.

In addition, even if the optimum casting conditions change due to the variable set value that changes according to the operating conditions of the die casting machine, such as the mold temperature, the hydraulic oil temperature of the hydraulic circuit, and the accumulator filling pressure, the variable set value also changes. Since the opening degrees of the injection speed control valve and the time adjustment valve are automatically corrected based on the above, the casting quality is maintained because the casting is always performed under the optimum casting conditions corresponding to the operating state of the die casting machine.

Further, since the initial set value is corrected by the correction data stored in the correction data storage unit in correspondence with the measured value of the variable set value and trial casting is performed, the operator constantly changes depending on the operating state of the die casting machine. It is not necessary to adjust the casting conditions, it is possible to automatically shift from the trial casting pattern to the main casting pattern, and it is possible to smoothly shift to the main casting process.

(Example) Below, this invention is demonstrated based on the Example shown in figure.

FIG. 3 shows an example of an injection process of a die casting machine to which the injection control method of the present invention is applied. Ie 5B
Is an injection sleeve, and the molten metal 3 is placed in this injection sleeve 5B.
The molten metal 3 is pressed by an injection plunger 4 which is driven and controlled by a hydraulic circuit described later to be injected and filled in the cavity 2 of the mold, and pressure casting is performed.

This injection process includes a low-speed injection process, a high-speed injection process,
And a pressure increasing step (not limited to these three steps).

In the low speed injection process, as shown in FIG. 3 (a), the injection sleeve 5B is filled with a predetermined amount of the molten metal 3 and then at a low injection speed V _{L as} shown in FIG. 3 (b).
Stroke the injection plunger 4 until the space between the gate 5C above the left end of the and the injection plunger 4 is filled with the molten metal 3.
Let S _L. In this state, the injection pressure P _L is hardly applied as shown in FIG. 4 (b).

Next, in the high-speed injection process, as shown in FIG. 3C, the injection plunger 4 is pressed at a high injection speed V _h for a predetermined stroke S _h , and the cavity 2 is passed through the gate 5C.
The molten metal 3 is injected inside. Predetermined injection pressure in this process
P _h is added (see FIG. 4 (b)), and the time between them is the filling time T _f .

When the high-speed injection process is completed, the process proceeds to the pressure increasing process, and the filling pressure is increased to the pressure increasing pressure P _i as shown in FIG. 4 (b) so that defects such as cavities do not occur in the cast product.

FIG. 1 is a block diagram of the basic configuration of the injection control method of the present invention. That is, the set value input unit 100 for inputting various setting data such as the inner diameter d of the injection sleeve 5B and the cross-sectional area a of the gate 5C, and the optimum injection data in advance, that is,
Optimal injection data storage unit 101 for storing theoretical / empirical formulas and data tables, and calculation based on the above input values
The hydraulic circuit for driving the injection cylinder 5 such as the injection speed control valve 11 and the boosting rise time adjusting valve 24 according to the optimum casting conditions output by the calculation unit 102 (see FIG. 5). The required control unit 104 of 1) is automatically set and controlled. Further, there is provided a correction unit 103 that corrects the optimum casting conditions output from the calculation unit 102 according to the operating state of the die casting machine. The correction unit 103 is connected to a measuring means 105 for measuring the operating state of the die casting machine such as the temperature of the die and a correction data storage unit 106 for storing various correction data, and the calculation unit 102 calculates and outputs a correction value. To be done.

FIG. 2 is a flowchart of the present invention. Before starting the casting of the die casting machine, enter the fixed set value (STEP1).

The fixed set values are parameters that do not change such as the specifications of the die casting machine and the parameters of products and molds. That is, the injection sleeve inner diameter d, the injection sleeve length l, the die casting machine shape, the product wall thickness t, and the gate cross-sectional area. _These are parameters for determining optimum casting conditions such as a, hot water supply amount w, product weight W, accumulator filling pressure P _ACC .

Next, the theoretical and empirical formulas stored in the optimum injection data,
And a data table (the optimum data storage unit 10 in FIG.
Calculate based on 1) and output optimum casting conditions.

 An example of the theoretical / empirical formula will be described.

1) Filling time T _f T _f = K · t + α (1) K is a coefficient, α is a correction value related to the product shape, and the optimum value is selected from the optimum injection data.

2) High injection speed V _h a: Gate cross-sectional area d: Injection sleeve inner diameter V _g : Gate speed (See Fig. 3, select the optimum value from the optimum injection data based on the flow velocity of the molten metal passing through the gate 5C.) W: Product weight (see Fig. 3 (c), weight excluding biscuits) T _f : Filling time ρ: Specific gravity of molten metal 3) Low-speed injection stroke S _{L SL} = 1 (1-Ψ) (4) l is Injection sleeve length (see Fig. 3 (a)) Ψ is the sleeve filling rate and the volume of the injection sleeve. Of hot water supply (w / ρ) 4) High-speed injection stroke S _h 5) Low speed injection speed V _L Select the optimum value from the optimum injection data.

From the above, the low-speed injection speed ( _VL ), high-speed injection speed ( _Vh ), low-speed injection stroke ( _SL ), high-speed injection stroke ( _Sh ), etc. are determined as temporary casting conditions (STEP
2).

Next, the opening of the injection speed control valve 11 and the opening of the boosting rise time adjusting valve 24 (see FIG. 5) corresponding to V _L , V _h , T _s, etc. are previously stored in the optimum injection data storage unit 101. The valve opening is automatically set / controlled as an initial condition for calculating / outputting based on the stored data table and setting the optimum casting condition according to the operating state of the output die casting machine.

This automatically set initial set value is a set of correction data stored in the correction data storage unit 106 of FIG. Calculation unit 1 based on the table
The microcomputer 02 calculates and outputs the output, and based on the output, the opening of the injection speed control valve 11 and the pressure increase rise time adjustment valve 24
Is automatically corrected (STEP3).

The correction data table of the correction data storage unit 106 includes the mold temperature correction shown in FIG. 9, the correction based on the oil temperature of the injection speed control valve 11 shown in FIG. 10, and the adjustment valve 24 of the boosting rise time T _s shown in FIG. This includes data that has been created and stored in advance as test operation data that corresponds to the shape of the die casting machine and that is corrected by the oil temperature. The details of FIGS. 9, 10, and 11 will be described later.

 Therefore, trial casting is started (STEP4).

The trial casting is performed under the trial casting conditions called a trial casting pattern (described in FIG. 8).

In the trial casting, since the die 1 is cold, the trial casting pattern is executed until the die temperature rises to an appropriate temperature, and the main casting is continued.

An example of the trial casting pattern is shown in FIGS. 8 (a), (b), and (c). The first trial casting pattern of several shots from the first time has a low injection speed V _L and a low injection pressure P. _{At L} , advance all injection strokes and do not increase pressure.

Second試鋳forming pattern several shots from the next of the N times, performs a slow injection speed V _L, the low speed injection stroke S _L, fast injection speed V _h, a high-speed injection stroke S _h, the pressure increase is not executed.

In the third trial casting pattern from the next shot, a pressure is applied to the above conditions and the same conditions as in the main casting are executed.

In the trial casting, the mold temperature sensor 41, the oil temperature sensor
Measure the mold temperature and oil temperature with 43 (see Fig. 6),
The opening degree of the injection speed control valve 11 and the pressure increase rising time adjustment valve 24 is corrected.

Further, the opening degree of the injection speed control valve 11 and the pressure increase rise time adjusting valve 24 are corrected even when the accumulator filling pressure P _ACC changes.

After performing a predetermined shot in the trial casting process, the process automatically shifts to the main casting process to continue continuous casting.

In the continuous casting process, the automatic correction is executed every predetermined shot.

The trial casting pattern is shown in Fig. 8 (a),
The conditions are not limited to (b) and (c), and conditions suitable for main casting startup may be set.

FIG. 5 shows a hydraulic circuit for driving an injection cylinder of a die casting machine for carrying out the injection control method of the present invention.

Reference numeral 1 denotes a mold, which is configured to press the molten metal 3 into the cavity 2 with an injection plunger 4 to inject and fill, and to perform pressure casting.

The injection plunger 4 is attached to a piston rod 5A of a hydraulically operated injection cylinder 5 and operates the injection cylinder 5 to inject molten metal under pressure.

The pressure increasing cylinder 6 is located behind the injection cylinder 5 and supplies pressure increasing oil to the injection cylinder 5. A position sensor 16 for detecting the position of the injection plunger 4 is provided on the side portion of the injection cylinder 5, whereby the timing at which the injection plunger 4 passes each preset point is detected. .

Further, the injection cylinder 5 is provided with a pressure sensor 30 for measuring the hydraulic pressure in the injection cylinder 5.

An accumulator 9 is connected to a hydraulic pressure source 10 and is filled with a constant pressure.

11 is an injection speed control valve which is an injection speed control valve driven by the electric motor M.
A stopper (15A, 1
9A) is adjusted, the amount of oil from the accumulator 9 is controlled, and the speed of the injection plunger 4 is controlled.

A stroke setting mechanism is provided on both sides of the injection speed control valve 11.
15, 19 are provided to adjust the positions of the stoppers (15A, 19A) and set the stroke by the pilot piston 12 and the stroke using the chamber 17 and the port 18 to adjust the opening degree of the valve 11A. This opening degree is detected by the encoder (15B, 19B). The speed of the injection plunger 4 is controlled to a low speed and a high speed by adjusting each opening.

A check valve 13 for increasing pressure is for preventing backflow because the pressure of the injection cylinder 5 becomes higher than the pressure of the first hydraulic circuit 7 in the pressure increasing step. 14 is the valve 13 in the pressure check valve 13.
This is a pilot piston that controls the opening and closing of A.

Reference numeral 24 is a pressure increasing rise time adjusting valve as a time adjusting valve, which adjusts the pressure increasing rise time after completion of filling. The opening degree of the boosting rise time adjustment valve 24 is set by the electric motor 28a and the stroke setting mechanism 28, and this opening degree is detected by the encoder 29.

The pressure sensor 30 meets the A / D converter 39 and the controller 3
It is connected to 1 and the detection signal is input to the controller 31.

Reference numerals 7 and 8 respectively denote a first hydraulic circuit and a second hydraulic circuit that connect the injection speed control valve 11, the pressure increasing check valve 13, the pressure increasing cylinder 6 and the pressure increasing rise time adjusting valve 24. 22 and 23 are sequence valves which operate at a pressure slightly lower than the maximum pressure of the first hydraulic circuit 7. Reference numerals 21 and 27 are solenoid valves for switching the oil passage. 20, 25 and 26 are pilot hydraulic lines, respectively.

FIG. 6 is a schematic diagram illustrating microcomputer control related to injection control. That is, the controller 31 includes an input port 31a to which various data are input, and a central processing unit CP that performs a predetermined calculation based on the input data.
U, an output port 31b that outputs a predetermined signal in accordance with the result of this calculation, and storage devices ROM and RAM that store optimal injection data and the like in advance.

Then, the detection signal of the variable set value and various fixed set values from various sensors that measure the operating state of the die casting machine are input to the input port 31a. As various sensors, in this embodiment, in addition to the pressure sensor 30 and the position sensor 16, a temperature sensor 41 that measures the temperature of the mold, a pressure sensor 42 that measures the filling pressure of the accumulator, and an oil temperature of the hydraulic oil are measured. The oil temperature sensor 43 is used to convert the digital signal through the A / D converter 44 into the input port 31.
connected to a. Also, various fixed set values can be set with the setting input device 33.
Will be entered more.

FIG. 7 is an enlarged view of the temperature sensor mounting portion on the surface of the mold 1, in which the gate 5C of the mold 1 has a non-through hole 41a into which the temperature sensor 41 is inserted while leaving the surface of the mold 1 and the thickness C. Drilled,
A temperature sensor 41 such as a thermocouple for measuring the temperature of the bottom surface of the hole 41a is internally provided. As the temperature sensor 41, various sensors such as a thermo fiber used as a radiation thermometer can be used.

A display device 50 such as a CRT or an alarm device 51 may be connected to the controller 31. Display device 50 has a controller
It is possible to output the optimum casting condition data and the correction data which are automatically processed and calculated in 31.

Here, the correction data table stored in the correction data storage unit 106 will be described. The fixed set values input at the start of casting, theoretical / empirical formulas as optimum injection data, the casting conditions calculated from the data table, and the initial set values of the opening of the injection speed control valve and the time adjustment valve are provisional. However, there is a problem in using these as they are to operate the die casting machine.

That is, in order to perform optimum casting in die casting, it is necessary to optimize casting conditions in accordance with variable set values such as mold temperature, hydraulic oil temperature, and hydraulic pressure, which change every moment depending on the operating state of the die casting machine.

Therefore, the correction data table is used to measure the variation set values such as the mold temperature, hydraulic oil temperature, and hydraulic pressure that change depending on the operating state of the die casting machine from the trial casting process to the main casting / continuous casting process, and based on these measured values. The purpose of this is to correct the opening of the injection speed control valve and the time adjustment valve, reset the optimum casting conditions, and perform proper casting.

Note that the same correction data table can be used for both trial casting and main casting / continuous casting, and it is also possible to use the same casting data table and die casting machine for punching good casting products. The trial casting required for idle-up has a different purpose from the main casting and continuous casting, and the variation of the mold temperature etc. changes greatly.Therefore, a separate correction data table can be used for each die casting machine. It may be arbitrarily performed according to the characteristics.

The opening correction of the injection speed control valve 11 with respect to the mold temperature t _D is
The relationship between the mold temperature t _{D and} the correction coefficient η of the high-speed injection speed V _h is determined according to FIG. 9, and when the mold temperature t _D is within the predetermined temperature range, the correction coefficient η is not corrected to 1.0, and When the mold temperature t _D is t _D1 below the predetermined temperature range, for example, η =
1.2 shows that the high-speed injection speed V _h is increased by 20%.

Therefore, when the mold temperature t _D is low, the high-speed injection speed V _h becomes high, and therefore the filling time must be kept to keep the gate speed V _g at the optimum value.
Perform correction to shorten T _f .

Further, when t _D3 equal to or higher than the predetermined temperature, for example, η = 0.8 indicates that the high-speed injection speed V _h is reduced by 20%.

The data of the correction coefficient η shown in FIG. 9 is stored in the storage unit ROM or the like, and the high-speed injection speed V _h calculated in STEP 2 of the flowchart is multiplied by the correction coefficient η to obtain a corrected high-speed injection speed η · V _h. Determine to V _h . After that the injection speed control valve
It suffices to execute 11 degree of opening control.

Regarding the opening correction of the boosting rise time adjustment valve 24, when the temperature is lower than a predetermined temperature by the mold surface temperature measurement value t _D ,
Shortening the increase圧立uplink time T _s by increasing the opening degree of the increase圧立uplink time adjusting valve 24, in the case of the predetermined temperature range, the pressure increase to return the opening degree of the increase圧立uplink time adjusting valve 24 to the standard value Rise time T _s
It was a standard value, if above a predetermined temperature, in which automatically corrects to increase the increasing圧立uplink time T _s by reducing the opening degree of the increase圧立uplink time adjusting valve 24. Although illustration of the correction of the boosting rise time adjusting valve 24 is omitted, it is assumed that the correction coefficient as shown in FIG. 9 is stored in the ROM or the like of the storage unit.

The opening degree correction of the injection speed control valve 11 corresponding to the oil temperature change is
Create a relational curve between the value E of the encoder indicating the opening degree of the high-speed injection speed V _h and the injection rate control valve 11 when the parameters of the oil temperature, such as FIG. 10 in advance by testing, for example, oil temperature 2
A table of the high-speed injection speed V _h and the opening E of the injection speed control valve at 0, 30, 40, and 50 ° C. is created, and this data is stored in the storage unit ROM or the like.

Then, the data of FIG. 10 is read from the storage device ROM by the oil temperature data input from the oil temperature sensor 43 to the input port 31a through the A / D converter 44, and the injection speed control valve 11 corresponding to the oil temperature change is read. The opening E is output from the output port 31b. Then, the opening control motor M of the injection speed control valve 11 is driven through the amplifier, and the opening E is fed back by the encoder EN. Therefore, when the opening E of the output from the output port 31b matches, the injection speed control is performed. The control of the opening degree of the valve 11 is completed.

Then, the opening correction of the injection speed control valve 11 for the accumulator pressure P _ACC is the curve of FIG. 10 created for 115,125,135,145kgf / cm ² for example the accumulator pressure P _ACC, ROM storage device that data Is stored in the input device 31a from the pressure sensor 42 through the A / D converter 44.
To the injection speed control valve 11 by reading the data from the storage device ROM for the accumulator pressure P _ACC .
Control the opening degree of.

As shown in Fig. 11, the opening correction corresponding to the change in the oil temperature of the boost pressure rise time adjustment valve 24 was made by testing the relationship curve between the encoder value of the opening of the pressure increase valve 24 and the pressure increase rise time T _s at that time. The data may be created and stored in advance in the storage device ROM or the like, and the opening degree control motor 28a may be controlled as in the case of the injection speed control valve 11.

In the above embodiment, the injection speed control valve 11 is provided with the opening control motor 15 and the opening stopper mechanism having the opening encoder E.
Although the control valves of 15A and 19A are used, the present invention is not limited thereto, and the opening may be a servo valve and the spool position of the servo valve may be detected by a linear encoder such as a differential transformer.

(Effects of the Invention) The present invention has the above-described configuration and operation, and calculates and outputs based on the optimal injection data stored in advance, and the output automatically sets and controls the drive hydraulic circuit of the injection cylinder of the die casting machine. As a result, the operator can set the casting conditions only by inputting various fixed set values, and the operation is extremely simple, which can improve the casting quality.

Furthermore, if the casting conditions are corrected and optimized according to the operating conditions of the die casting machine such as the mold temperature, the casting quality can be further stabilized.

Further, it is possible to preset the trial casting pattern and the main casting pattern, and after the predetermined shot of the trial casting pattern, it is possible to automatically shift to the main casting pattern, improving the operability and starting time to the main casting process. Can be shortened.

[Brief description of drawings]

FIG. 1 is a basic control block diagram of a control method of a die casting machine of the present invention, FIG. 2 is a control flowchart of the present invention, and FIGS. 3 (a) to 3 (c) are injection parts for explaining an injection process. 4A is an injection velocity diagram of the main casting process, FIG. 4B is an injection pressure diagram of the main casting process,
FIG. 5 is a drive hydraulic circuit diagram of an injection cylinder to which the injection control method of the die casting machine of the present invention is applied, and FIG.
FIG. 7 is a control block diagram showing the control configuration of the controller of the injection cylinder shown in FIG. 7, FIG. 7 is a cross-sectional view of an essential part showing an example of the temperature sensor of the mold shown in FIG. 6, and FIGS. 8 (a) to 8 (c) are trial castings. Fig. 9 is a graph showing the injection pattern of the process, Fig. 9 is a graph showing the relationship between the mold temperature and the correction coefficient, and Fig. 10 is a graph showing the relationship between the high-speed injection speed and the valve opening as an oil temperature parameter.
FIG. 11 is a graph showing the relationship between the pressure increase rise time and the valve opening, with the oil temperature as a parameter. Explanation of symbols 1 ... Mold, 2 ... Cavity 3 ... Molten metal, 4 ... Injection plunger 5 ... Injection cylinder, 5A ... Piston rod 5B ... Injection sleeve, 5C ... Gate 6 ... Booster cylinder , 7 ...... 1st hydraulic circuit 8 ...... 2nd hydraulic circuit, 9 ...... Accumulator 11 ...... Injection speed control valve 15, 19 ...... Stroke setting mechanism 15A, 19A ...... Stopper 24 ...... Increase pressure rise time adjustment valve 28 …… Stroke setting mechanism 29 …… Encoder 41 …… Temperature sensor, 42 …… Pressure sensor 43 …… Oil temperature sensor

Claims (1)

[Claims] 1. An injection cylinder drive hydraulic circuit having an injection speed control valve for controlling the injection speed of the injection cylinder and a time adjusting valve for adjusting the operation timing of the pressure boosting cylinder, and an injection control of a die casting machine having the controller thereof. In the method, the theoretical and empirical formulas for calculating the optimum injection data and the data table are stored in advance in the optimum injection data storage unit, and the specifications of the die casting machine are set as fixed set values to be substituted into the optimum injection data at the start of casting. , Product parameters, mold parameters, hydraulic accumulator filling pressure as a drive source of the die casting machine is input, and based on the optimum injection data stored in advance in the optimum injection data storage unit and the input fixed set value. The calculation is performed to output the temporary casting conditions, and the injection speed control valve corresponding to the output is output. And the opening of the time adjustment valve is automatically set as the initial setting value for setting the optimum casting conditions according to the operating condition of the die casting machine, and the mold temperature that changes depending on the operating state of the die casting machine,
Optimum casting conditions are measured by measuring variable set values such as hydraulic oil temperature and hydraulic pressure from the trial casting process to the main casting / continuous casting process, and correcting the openings of the injection speed control valve and the time adjustment valve based on these measured values. Is set to correct the initial setting value, and a correction data table for adding correction corresponding to the measured value of the fluctuation setting value is stored in advance in the correction data storage unit and trial casting is performed, And while automatically correcting the opening of the injection speed control valve and the time adjustment valve based on the measured value, a predetermined shot of trial casting is performed according to a preset trial casting pattern, and the die temperature is set to the main casting. An injection control method for a die casting machine, which comprises raising the temperature to an appropriate temperature that can be performed and then automatically shifting to the main casting pattern.