JP2975198B2 - Die casting machine injection control method and monitor screen display method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection control method for a die casting machine and a monitor screen display method for displaying injection conditions on a monitor screen.

[0002]

2. Description of the Related Art A conventional injection control method for a die-casing machine of this type will be described with reference to FIG. First, a predetermined amount V of molten metal 104 is measured and supplied to the injection sleeve 101 with the ladle 115, and the injection plunger 102 is advanced (leftward in the figure) with the retreat limit of the injection cylinder (not shown) as the origin A to perform injection at a low speed. Start. The low-speed injection stroke SL is set by a limit switch 116 and a dog 117 provided on the injection plunger 102.
A high-speed injection is controlled by controlling a hydraulic valve (not shown) in accordance with a switching signal from the controller, and the cavity 103 is rapidly filled with the molten metal 104. In this high-speed injection, filling is completed with a predetermined high-speed injection stroke Sh.
2 decelerates rapidly.

The above is a generally known die casting machine.

In order to monitor the injection state of the die casting machine, an injection speed diagram and an injection pressure diagram as shown in FIG. 9 are displayed on a CRT screen of a monitor.

[0005] In the injection speed and injection pressure diagram, the horizontal axis indicates time, and the vertical axis indicates injection speed and injection pressure. In the figure, t1 and t2 are the time from the start of injection to the origin, the limit switch 116 of FIG. 8 is operated, the hydraulic valve is operated, and the injection plunger 102 is switched from the low injection speed VL to the high injection speed VH. The time when the molten metal 104 is filled into the cavity 103 at the high injection speed VH, the speed is rapidly reduced upon completion of filling, and the speed drops to a predetermined speed or less, that is, the time until the completion of filling.

The injection conditions of the die casting machine are such that the low-speed injection time t1 is on the order of several seconds, while the high-speed injection time t2 is on the order of 0.02 to 0.1 seconds. As shown in the figure, a command is issued to enlarge the portion after t3 from the origin to make it easier to see.

[0007] However, there is a problem that the command for enlarging the screen after t3 only causes an inconvenience on the monitor screen after the next shot, and the high-speed injection area shown in FIG. 10 deviates from the CRT screen. Even if the low-speed injection stroke SL is determined, the time (t1-β) from when the injection plunger 102 moves forward with the injection start point to the origin A and the limit switch 116 is switched by the dog 117 (t1-β) is the variation in the low-speed injection speed VL. This is because it fluctuates greatly. Here, β is an electrical and hydraulic delay time from when the limit switch 116 transmits the high-speed injection switching signal to when the hydraulic valve operates and the injection plunger 102 moves to high-speed injection.

Therefore, conventionally, as in the state C or D1 in FIG. 10, a point at which the speed rapidly increases or decreases is obtained by data processing, and the point is determined by the CRT.
Complex data processing has been performed such as shifting to a predetermined position on the screen, for example, to the center of the screen.

In FIG. 8, the gas vent valve 118 in the cavity 103 is opened and closed by an actuator (not shown), and the opening and closing is performed by opening and closing a solenoid valve (not shown) at a predetermined timing by setting a limit switch 119. .

[0010]

However, in the above-described conventional injection control method, the injection start point of the injection plunger 102 is set to the origin A and the high-speed injection switching position is set by the limit switch 116. Is ΔV fluctuating, the filling completion stroke Sf becomes ΔSf = 4
-ΔV / πD ² (where D is the inner diameter of the injection sleeve 101 and ΔV is the amount of change in the hot water supply amount (volume)).

[0011] Therefore, casting conditions for injection into the cavity 103 fluctuate, which has an unstable factor with respect to casting quality stability.

Also, the closing timing of the gas vent valve 118 depends on the setting of the limit switch 119, and has the same unstable factor as described above.

Further, as for the monitor screen display, since the injection speed and the injection pressure are displayed on the monitor screen with the injection start point as the origin A, as described above, the data of the injection speed diagram can be obtained from the data of FIG. Complicated computer processing, such as searching for a point at which the injection speed suddenly changes to a high injection speed or a point at which the injection speed suddenly decelerates, such as D1, and shifting that point to a predetermined position on the CRT screen, has been required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to enable a high-speed injection switching position to be automatically corrected to an optimum position suitable for a hot water supply amount. Another object of the present invention is to stabilize casting quality by making an injection monitor screen for managing injection conditions easy to see.

[0015]

In order to achieve the above object, in the injection control method for a die casting machine according to the present invention, a filling completion time stroke of an injection plunger is measured and the position of the filling completion time stroke is determined. A high-speed injection switching position is calculated based on the origin and a high-speed injection stroke predetermined according to the product volume, and the injection speed of the injection plunger is changed from low to high at the calculated high-speed injection switching position. Switching control is performed.

The average stroke of the stroke at the time of filling completion of the previous shot is always calculated, the newly calculated origin is replaced with the previous origin, and the high-speed injection switching position after the next shot is automatically determined based on the new origin. It is preferable to correct.

Further, it is preferable to calculate the high-speed injection switching position by measuring the filling completion stroke through the trial casting shot and the main casting shot.

It is effective to set the high-speed injection switching signal transmission position ahead of the high-speed injection switching position by a predetermined stroke in consideration of electrical and hydraulic delays.

Further, the blockage signal transmission position of the gas release valve for releasing gas from the cavity is automatically corrected by a preset correction value based on the gas release valve closing time with reference to the origin. .

Further, the present invention is characterized in that the pressure increase start signal transmission position of the pressure increase control is automatically corrected to a position of a predetermined stroke with reference to the origin.

When the high-speed injection switching position in which the correction signal of the predetermined amount of hot water supplied to the injection sleeve is automatically corrected based on the origin exceeds a predetermined allowable value, the automatic correction amount and the correction are corrected. It is characterized in that the sign of the amount is calculated / determined and used as a correction signal for the predetermined amount of hot water supply.

On the other hand, a monitor screen display method for displaying and managing injection conditions on a monitor screen measures a stroke at the time of filling completion of the injection plunger, sets the position of the stroke at the time of filling completion as an origin, and sets the origin of the stroke at the horizontal axis of the monitor screen. The injection condition is displayed on a monitor screen by setting the origin at a predetermined position.

Further, the present invention is characterized in that the injection stroke is taken as the horizontal axis of the region from the origin to the start of injection, and time is taken as the horizontal axis of the region after the origin.

[0024]

According to the injection control method for a die casting machine having the above-described structure, the high-speed injection stroke is uniquely determined in advance according to the product volume. Even in this case, the high-speed injection switching position can be set to an optimum position suitable for the hot water supply amount.

Further, if the average stroke of the filling completion strokes of several shots is calculated, and the newly calculated origin is replaced with the previous origin and used as the origin for injection control after the next shot, each shot can be obtained. The influence of the variation is reduced, and the high-speed injection switching position can be set to a more optimal position.

Further, if the high-speed injection switching signal transmission position corresponding to the high-speed injection switching position is corrected in consideration of electrical and hydraulic delays in addition to the high-speed injection stroke predetermined from the product volume, the optimum timing is obtained. Can be operated with

Further, the position at which the closing signal of the vent valve is transmitted is automatically corrected with a preset correction value based on the closing time of the vent valve based on the origin, so that the closing operation of the vent valve is optimally performed. Can be operated with

It is also effective to automatically correct the pressure increase start signal transmission position from the origin to a position of a predetermined stroke. Further, a predetermined amount of hot water supplied to the injection sleeve can be automatically corrected.

On the other hand, according to the monitor screen display method of the present invention, the injection condition at the time of high-speed injection can be set even if there is variation in low-speed injection speed by using the position of the stroke at the time of completion of filling of the injection plunger as the origin. Can be displayed at a predetermined position on the monitor screen.

By taking the injection stroke on the horizontal axis of the region from the origin to the start of injection,
Injection conditions such as injection speed and injection pressure can be enlarged and displayed.

Further, by taking the time on the horizontal axis of the area after the origin, it is possible to enlarge and display the change in the injection pressure such as the pressure increase start state.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 shows a basic configuration of a die casting machine to which the injection control method of the present invention is applied. This die casting machine comprises a cavity 1 filled with molten metal and a cavity 1 through a gate 2.
And an injection plunger 5 for pressing a molten metal 4 poured into the injection sleeve 3. The injection plunger 5 is driven by an injection cylinder 6. A hydraulic pressure is supplied to the injection cylinder 6 from a hydraulic source 8 having an accumulator 7, and the supply of the hydraulic pressure is controlled by a control valve 9. The control valve 9 is controlled by a control panel 10 on which a microcomputer is mounted. A control signal output from the control panel 10 is amplified by an amplifier 11 and input to the control valve 9.

An input device 12 for inputting initial data and the like and a stroke detection sensor 13 for detecting a stroke of the injection plunger 5 are connected to the control panel 10. A display device 14 for monitoring is connected.

On the other hand, a degassing valve 15 is connected to the cavity 1.

Next, the steps of the injection control method of the present invention will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG.

The injection control of this die-casting machine is a method in which the speed of the injection plunger 5 is initially reduced and then increased in the middle. In the present invention, the high-speed switching position is particularly controlled to the optimum position.

First, from the input device 12 of the control panel 10, a low-speed injection stroke SL and a high-speed injection stroke S
h, the correction stroke α, the number of shots N for calculating the average stroke, the filling completion time Vf, and other various setting values are input and the control program is executed (step 1,
2).

The high-speed injection stroke Sh is uniquely determined from the product volume. The casting product weight w and its specific gravity ρ,
This is a stroke that can be calculated from the sectional area E of the inner diameter D of the injection sleeve 1.

That is, it can be easily obtained by calculating Sh = w / ρ.E.

The above formula is put into the control program of the flowchart, and the product weight w, specific gravity ρ,
The sectional area E (or inner diameter D) of the injection sleeve 3 may be input.

At the start of the injection, the injection speed, the injection stroke, and the injection pressure are measured. This initial origin is the retreat limit of the injection cylinder 6, that is, the time when the injection of the injection plunger 5 starts.

The stroke of the injection plunger 5 is formed as a magnetic scale by forming a magnetic or non-magnetic stripe pattern of equal pitch on the surface of the piston rod 16 of the injection cylinder 6 shown in FIG. Sensor 13
Is used as a magnetic sensor to generate a pulse in accordance with the stroke, and a control panel 10 having a microcomputer performs arithmetic processing to measure the stroke and speed of the piston rod 16. These measurement systems are known and will not be described in detail.

Next, when the injection stroke of the injection plunger 5 reaches (SL-α), a high-speed injection switching signal is transmitted, and a drive current flows from the control panel 10 via the amplifier 11 to the exciting coil of the control valve 9. Then, the control valve 9 is rapidly opened to supply a large amount of pressurized oil from the hydraulic source 8 having the accumulator 7 to the injection cylinder 6, and the molten metal 4 is rapidly injected into the cavity 1 at high speed (steps 3 and 4). This high-speed injection switching position may be calculated as (Sh + α).

The correction stroke α is the difference between the high-speed injection switching signal transmission position and the actually measured position that has been switched at high speed.
This is a stroke difference caused by electrical and hydraulic delays. Assuming that the delay time is td and the low-speed injection speed at that time is VL, α = VL · td. td is a value determined by the control valve 9 and its control circuit, and can be determined in advance by an operation test of the die casting machine.

Further, instead of inputting α, td may be input as a set value, and VL may be set as a set value or an actually measured value, and an arithmetic expression may be programmed and operated.

In a state where the high-speed injection switching position is controlled to the optimum position, it is preferable that the tip 4a is located inside the gate 2 as shown in FIG.

When the filling of the molten metal 4 into the cavity 1 is completed (see FIG. 1 (b)), the injection plunger 5 is rapidly decelerated, and for example, 0.1 times the high-speed injection speed Vh is set as the filling completion point speed Vf. (Vf = 0.1 Vh), the stroke of the injection plunger 5 at the moment when the speed is reduced to the filling completion time Vf or less is measured as the filling completion time stroke Sf, and stored in the microcomputer of the control panel 10 (steps 5 and 6). ).

Further, if the above-described calculation of Vf = 0.1 Vh is performed in the program, it is not necessary to input the speed Vf at the time of filling completion first. The coefficient 0.1 is not limited, and is in the range of 0.1 to 0.3.

In this way, the N-shot casting is performed, and the average value (Sf bar) of the stroke Sf at the time of completion of filling is calculated (steps 7 and 8).

Hereinafter, as for the notation of the average value throughout this specification, as in the above-mentioned (Sf bar), the symbol (bar) is added after the symbol.

Next, the position of the average filling completion time stroke (Sf bar) is set as the origin position, and the origin is converted (step 9).

Then, {(SL bar) = (Sf bar) -Sh} is calculated based on the origin, and the low speed injection stroke SL corresponding to the high speed injection switching position is replaced with (SL bar). To the shot (step 10).

As described above, the first few shots are injected with the injection start point of the injection plugger 2 as the origin A in the same manner as in the prior art, and the filling completion time stroke Sf is measured to find the average stroke (Sf bar). Is converted to its average stroke (Sf bar) position. Then, the low-speed injection stroke (SL bar) corresponding to the high-speed injection switching position of the subsequent shot is represented by (SL bar) = ｛(Sf bar) −S
Calculate from h｝, replace the high-speed injection switching position with (SL bar), automatically correct it, and cast several shots under these conditions. Further, the average value (Sf bar) of the stroke Sf at the completion of filling of several shots at this time is obtained, and the origin is again set to (Sf bar).
f bar). As described above, since the origin is corrected every N shots and the origin is floated, the calculated origin is referred to as a floating origin X. By setting the floating origin X, the high-speed injection switching position can be changed. Automatic correction is performed every N shots.

FIG. 3 is a flowchart relating to claim 7. In step 1, SL, Sh, V in FIG.
Input Z and D in addition to h, Vf, α and N.

Z is the difference between the high-speed injection switching position (SL bar) automatically corrected based on the origin and the preset high-speed switching position SL, that is, the maximum allowable value of ΔSL = (SL bar) −SL. , Are called preset tolerance values (see FIG. 4).

D is the inner diameter of the injection sleeve 3.

Steps 2 to 10 are the same as those in FIG. 2 and will not be described.

In the above steps, the high-speed injection switching position is automatically corrected to (SL bar) based on the origin.

Next, ΔSL = (SL bar) −SL is calculated and stored (step 11).

Next, it is determined whether or not the absolute value of the automatic correction amount ΔSL exceeds the preset allowable value Z, and the hot water supply amount V for the automatic correction amount ΔSL is determined.
The correction amount ^{ΔV, ΔV = πD 2/4} · | ΔS L | computed from (step 12, 13).

Next, it is determined whether the automatic correction amount ΔSL is positive or negative. If the automatic correction amount ΔSL is positive, it means that the hot water supply amount V is insufficient.
If the value is negative, the hot water supply amount is excessive, and a hot water supply amount correction signal of + ΔV and −ΔV is issued to adjust a hot water supply device (not shown) (steps 14 and 15). The hot water supply device is not limited to the ladle type, but can be applied to an electromagnetic pump hot water type and others.

FIG. 4 shows a state in which the high-speed injection switching position has been automatically corrected, and the tip 4 a has reached the inside of the gate 2. SL, (SL bar), + ΔSL, −ΔS
The positions of symbols such as L and Z are explained.

FIGS. 5 and 6 show monitor display screens for displaying the injection speed and the injection pressure as the injection control conditions in the injection control step.

In this display screen, the injection stroke is plotted on the horizontal axis in the region from the floating origin X to the injection start position (left side of the floating origin X in the figure) with reference to the floating origin X at the time of filling completion. In the area after the floating origin X (on the right side of the floating origin X in the figure), the time is displayed on the horizontal axis.

By always setting the floating origin X at a predetermined position on the display screen, for example, at the center position, when the injection conditions of a plurality of shots are overwritten, a completely overlapped diagram is obtained, and abnormalities in the casting conditions are detected. If it occurs, it can be found immediately.

The control of the vent valve 18 will be described as another embodiment.

FIG. 7 shows only a procedure that is added to the flowchart of FIG. 2 when the gas vent valve 15 is controlled. That is, the injection is started and the injection plunger 5 is started.
When the stroke reaches (SL-G), the vent valve 1
A signal to block 5 is transmitted. (SL-G) is replaced by (SL +
G). Thereby, the closing timing of the vent valve 15 is automatically corrected to the optimal position, and the quality of the cast product can be stabilized.

Here, G is inputted from the input device 12 as a correction value set in advance based on the valve closing time of the vent valve from FIG.

The timing of the pressure increase control is also
As shown in FIG. 6, the pressure increase control can be performed with the position of the predetermined stroke F based on the floating origin X as the pressure increase transmission signal transmission position.

[0071]

As described above, according to the present invention,
Since the high-speed injection switching position is calculated and controlled using the stroke position at the time of filling completion as the origin, it is possible to set the high-speed injection switching position to an optimum position suitable for the hot water supply amount even if the hot water supply amount varies. In addition, the high-speed injection area is always set to a constant injection condition, which is effective in stabilizing the quality of the cast product.

In addition, even when the gas release valve is used, it can be operated at the optimum timing, and in the pressure increase control, the pressure increase start signal transmission position can be automatically corrected and operated at the optimum timing. .

Furthermore, by setting the origin at a predetermined position on the monitor screen, the injection conditions of the high-speed injection area can be displayed at a predetermined position on the monitor screen without performing complicated data processing.

Further, by taking an injection stroke in the area from the origin to the start of injection, the screen of the high-speed injection area can be enlarged and viewed, and in the area after the origin, time is taken on the horizontal axis. It is possible to enlarge the change of the injection pressure such as the pressure increase state, and the control condition can be easily managed.

Further, if the injection conditions for several shots are superimposed and displayed on the injection monitor screen, a completely overlapped diagram is obtained, and it is extremely easy to find an abnormality in the casting conditions.

[Brief description of the drawings]

FIG. 1A is a schematic diagram showing an example of a control structure of a die casting machine to which an injection control method and a monitor screen display method of the die casting machine according to the present invention are applied, and FIG.
FIG. 3A is a main part configuration diagram showing a position of an injection plunger at the time of completion of filling in FIG.

FIG. 2 is a flowchart showing a control procedure of the die casting machine of FIG.

FIG. 3 is a flowchart according to claim 7;

FIG. 4 is a diagram showing the position of an injection plunger at the time of high-speed injection switching.

FIG. 5 is a view showing a monitor screen for displaying an injection speed and an injection pressure of the die casting machine of FIG. 1;

FIG. 6 is an enlarged view of a main part of FIG. 5;

FIG. 7 shows another embodiment of the present invention.
FIG. 6 is a diagram showing a flowchart for adding to a.

FIG. 8 is a schematic diagram showing a control configuration of a die casting machine to which a conventional method of controlling a die casting machine is applied.

FIG. 9 is a diagram showing an injection speed and an injection pressure.

FIG. 10 is an enlarged diagram showing a high-speed emission area in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cavity 3 Injection sleeve 4 Melt 5 Injection plunger 6 Injection cylinder 8 Hydraulic power source 9 Control valve 10 Control panel 12 Input device 14 Display device 15 Gas release valve Sf Filling completion time point Sh High speed injection stroke SL Low speed injection stroke X Floating origin

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22D 17/32

Claims (9)

(57) [Claims] 1. A filling completion time stroke of an injection plunger is measured, and a filling completion time is set as an origin, and a high-speed injection switching position is calculated based on the origin and a high-speed injection stroke predetermined according to a product volume. And controlling the injection speed of the injection plunger from a low speed to a high speed at the calculated high-speed injection switching position. 2. A high-speed injection switching position after the next shot, based on the new stroke, always calculating the average stroke of the stroke at the time of filling completion of the previous shot, replacing the newly calculated origin with the previous origin. Claim 1 which automatically corrects
3. The injection control method for a die casting machine according to claim 1. 3. The injection control method of a die casting machine according to claim 1, wherein a stroke at a time of completion of filling is measured through a trial casting shot and a main casting shot to calculate a high-speed injection switching position. 4. A high-speed injection switching signal transmission position,
4. The injection control method for a die-casting machine according to claim 1, 2 or 3, wherein the injection stroke is advanced by a predetermined stroke from the high-speed injection switching position in consideration of hydraulic delay. 5. The method according to claim 1, further comprising automatically correcting a blockage signal transmission position of the degassing valve for discharging gas from the cavity with a correction value set in advance based on the degassing valve closing time based on the origin. Item 5. The injection control method for a die casting machine according to any one of Items 1, 2, 3, and 4. 6. The die casting machine according to claim 1, wherein the pressure increase start signal transmission position of the pressure increase control is automatically corrected to a position of a predetermined stroke with reference to the origin. Injection control method. 7. A high-speed injection switching position in which a correction signal of a predetermined amount of hot water supplied to the injection sleeve is automatically corrected based on the origin, and when the high-speed injection switching position exceeds a preset allowable value, the automatic correction amount and the correction are corrected. 2. The method according to claim 1, wherein the positive / negative of the amount is calculated and determined to obtain a correction signal for the predetermined amount of hot water supply.
5. The injection control method for a die casting machine according to 2, 3, or 4. 8. A monitor screen display method for displaying and managing injection conditions on a monitor screen, wherein a stroke at the time of completion of filling of the injection plunger is measured, a position of the stroke at the time of completion of filling is set as an origin, and a horizontal axis of the monitor screen is displayed. A monitor screen display method, wherein the origin is set at a predetermined position and injection conditions are displayed on a monitor screen. 9. The monitor screen display method according to claim 8, wherein an injection stroke is set on a horizontal axis of a region from the origin to the start of injection, and a time is set on a horizontal axis of a region after the origin.