JPH01154858A - Method for controlling injection in die casting machine - Google Patents

Abstract

PURPOSE:To stabilize the quality of a casting by predicting high speed starting position and cast completing position of a plunger tip from actual molten metal supplying quantity found by measuring the molten metal surface height in a ladle just before supplying the molten metal at every casting shots and injecting into an injecting stroke based on the predicted position thereof. CONSTITUTION:At the time of stopping by advancing a ladle 30 to a pouring hole 26 in the injecting sleeve 24 for an injection apparatus 20, the height to the molten metal surface in the ladle 30 is measured and the molten metal quantity in the ladle 30 for actually filling up in the sleeve 24 is grasped. As this molten metal quantity is corresponding to the total weight of cavity, runner and biscuit quantities, the cast completing position of the plunger tip 22 to obtain feeding effect under the optimum condition is predicted and can be decided. Then, by reversedly calculating from this cast completing position, the high speed starting position of the plunger tip 22 is found. In this result, the stroke of the plunger tip 22 is fixed in accordance with the molten metal quantity for actually supplying in the sleeve 24 and always the optimum feeding effect can be obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an injection control method for a die-casting machine, and particularly to an injection control method for a die-casting machine that stabilizes the feeder effect and stabilizes the quality of cast products. Regarding control method.

[Conventional technology]

-In the die casting machine, an injection device is connected to a runner portion leading to a cavity of the mold, and the molten metal supplied from the water heater and filled in the injection sleeve is pushed out by a plunger tip and injected into the cavity. There is. In the injection operation, the plunger tip is initially advanced at a constant low speed from the retraction limit position, and after the molten metal has passed through the injection port, it is moved at high speed, and casting is completed with a slight gap left between the plunger tip and the end face of the injection sleeve. ing.

By the way, what about feeding the injection device? Although 1 hWt is a constant amount for the same cavity, the amount scooped by the ladle that supplies hot water is not strictly constant, so there may be variations in the amount of hot water supplied. Therefore, due to the error in the feed tJIE, the feeder effect of the injection device becomes unstable, and there is a problem in that the quality of the cast product cannot be stabilized. In order to improve such problems, as a conventional technique, the thickness of the molten metal remaining between the shunt end position, which is the runner opening end face of the injection sleeve of the injection device, and the casting completion position of the plunger tip is determined for each shot. In other words, a method has been proposed in which the thickness of the biscuit is detected and the amount of molten metal supplied is adjusted and controlled so that the thickness remains constant (Japanese Patent Publication No. 59
-21262). According to this, there is no possibility that the feeder effect will be lost due to the bisquent part solidifying before the runner part, or the contact surface of the injection sleeve starting to solidify early, increasing the sliding resistance of the plunger tip. You get benefits you don't have.

[Problems to be Solved by the Invention] However, according to the above method, the amount of hot water supplied cannot be increased or decreased in order to keep the value of Biskent thickness (= 1 minute flow element end position - casting completion position 1) within the set range. It is a feedback control that suppresses the amount of hot water, and moreover, grasping the amount of hot water is dependent on the scooping star by the ladle. Therefore, the conventional method essentially requires corrective control after the actual error has occurred.
Therefore, even if the ladle adjusts the amount scooped according to the controlled amount, if a disturbance such as spilling occurs during transport to the ladle before pouring, the actual amount of hot water supplied to the injection sleeve will change. There was a problem where the correct correction was not made. As a result, in the conventional control method, correction control is performed after a biscuit thickness control deviation occurs, and follow-up correction is performed after the influence of the disturbance appears, and the influence of the disturbance is essentially unavoidable. It was something.

The present invention focuses on the above-mentioned conventional problems, and makes it possible to always correctly control the injection stroke by avoiding the effects of disturbances such as hot water spillage, thereby making it possible to stabilize the quality of cast products by making the feeder effect constant. The purpose of this invention is to provide a method for controlling injection of a die casting machine.

(Means for Solving the Problems) In order to achieve the above object, the injection control method for a die casting machine according to the present invention firstly includes the following steps: The actual amount of hot water to be supplied is determined by measuring the height of the internal cold water level, and from this actual amount of hot water, the high-speed rising position of the plunger tip and the casting completion position are predicted, and injection is performed using an injection stroke based on this predicted position. .Secondly,
In the injection control method for die casting machines, the actual amount of hot water supplied is determined by measuring the height of the cold metal liquid level in the ladle immediately before the hot water supply for each casting shot, and from this actual amount of hot water, the high-speed rise position of the plunger tip and the casting completion position are determined. The prediction is made, and the injection is performed using an injection stroke based on this predicted position. At least the casting completion position is measured for each injection stroke, and the measured casting completion position is compared with the predicted casting completion position, and the measured casting completion position is determined. The system is configured to correct the amount of hot water supplied when the predicted casting completion position is outside the set range.

[Effect]

According to the above configuration, when the ladle advances to the pouring port of the injection sleeve of the injection device and stops, the distance to the liquid surface of the molten metal in the ladle is measured, and the distance between the molten metal in the ladle and the injection sleeve is actually filled. It is possible to grasp the amount of melt that will be produced. Since this melting rate corresponds to the sum of the cavity amount, the runner portion amount, and the biscuit f, it is possible to predict and determine the plunger tip casting completion position where the optimum riser effect can be obtained.

Then, by calculating backward from this casting completion position, the high-speed rising position of the plunger tip is determined.

As a result, the stroke of the plunger tip is determined according to the amount of molten metal actually supplied into the injection sleeve, and an optimal feeder effect can always be obtained.

Furthermore, in the second invention, in addition to the predictive control, if an error occurs in the actual injection stroke, it is corrected. Therefore, when the casting completion position of the plunger tip set by predictive control is out of the allowable range in the actual stroke, it acts to correct this.

In other words, if the pouring completion position of the plunger tip is measured and it deviates from the predicted position by exceeding the allowable range, the amount of molten metal scooped by the next ladle is corrected so that the pouring completion position converges to the predicted position. Make it. This results in
It is possible to cope with disturbances caused by both the amount of molten metal and the injection device, and to achieve injection control with a good feeder effect.

〔Example〕

Embodiments of the injection control method for a die-casting machine according to the present invention will be described in detail below with reference to the drawings.

First, as shown in FIG. 2, the die casting machine has a fixed mold 10a fixed to a fixed platen 10 and a movable mold 12a fixed to a movable platen 12, and a cavity 14 is formed on the joint surface of the two. is formed. A runner 16 communicating with the cavity 14 is formed in the fixed mold 10a, and an injection device 20 for injecting and supplying molten metal 18 is connected to the runner 16. The injection device 20 includes an injection sleeve 24 containing a plunger tip 22, and a plunger tip 22 driven by an injection cylinder 28 pushes out the molten metal 18 supplied from a pouring port 26 provided in the injection sleeve 24 into a cavity. 14, injection filling. The operation of the plunger tip 22 is controlled by a control device (not shown), in which it moves forward from the retract limit position, passes through the pouring port 26, and moves at a low speed to a high-speed rise command position, and then moves at a high speed from this high-speed rise command position to a casting completion position. Move to cavity 14
Performs high-speed injection. The casting completion position, which is the forward movement end of the plunger tip 22, is a certain distance from the shunt end position, which is the inner end surface of the injection sleeve 24 where the runner 16 is opened, and this distance is the so-called biscuit It becomes thick.

Here, in the injection operation, the plunger tip 22 is first advanced at a constant low speed from the retraction limit position, and after passing through the molten metal pouring port 26, it is moved at a high speed, and the injection sleeve 24 is poured into the casting leaving a slight gap to the end surface of the injection sleeve 24. is to be completed. Therefore, in the moving range of the plunger tip 22 shown in the upper part of FIG. Casting completion position ξ where the plunger tip 22 stops after filling is completed
, take each position. The position of the rear end surface of the injection sleeve 24 where the runner 16 is opened becomes the shunt end position B.

In such a die-casting machine, as shown in FIG.
In this embodiment, the molten metal 18 is supplied and filled into the ladle 30 immediately before the molten metal 18 is poured into the pouring port 26. The amount of It is detected. For this purpose, a post 32 is provided upright on the side of the injection sleeve 24, and a distance sensor 34 is attached to the post 32 so as to be horizontally movable at a predetermined height position. 30 to the liquid level of the molten metal 18 can be measured. The distance sensor 34 is normally retracted, but the ladle 30 is located at the spout 26 of the injection sleeve 24.
When the robot moves forward to a stop state, the post 32 is rotated and moved to a position directly above the ladle 30 to enable measurement. Further, the distance sensor 34 is composed of an ultrasonic sensor, and the ladle 3
A plurality of sensors are provided in order to simultaneously measure several locations on the liquid level of the molten metal 18 within zero. This is the molten metal 18 in the ladle 30.
This is to deal with the fact that the liquid level is not necessarily flat.

An injection control method according to an embodiment using such a die-casting machine is performed as follows.

FIG. 1 (1) shows a die casting manon injection control method according to an embodiment, in particular feed forward (F - F) in which the positioning of the injection stroke is determined by predicting from the amount of molten metal.
7 is a flowchart showing a control processing procedure.

In FIG. 1(1), step 101 includes the ladle 30
In this step, the rake angle ψ of the ladle 30 is set to a theoretical angle determined by the size of the cavity 14 used. Thereafter, the ladle 30 scoops up the molten metal with the filler angle 1P, moves forward from the scooping position, detects the forward limit position, which is the position of pouring the metal into the pouring port 26 of the injection sleeve 24, using a rimisotosinch or the like, and stops (steel 102). .

With respect to the ladle 30 which has reached the position immediately before pouring into the injection sleeve 24 in step 102, in step 103, the liquid level l of the molten metal 18 in the ladle 30 is measured in order to control the injection position.

Therefore, after the distance sensor 34 detects that the ladle 30 has reached the spout 26, it rotates the post 32 and measures the distance ^U.
Move the sensor 34 to a position directly above the ladle 30. In this case, as shown in FIG. 4, a plurality of distance sensors 34. ．．
34□, 34. is attached to the header 36 and the distance from the surface of the molten metal 18 in the ladle 30 is 11.1 t, l
Measure x. Then, in step 104, the average path H1 to the liquid level is calculated from these measured values using the following equation.

1s-Σp,/n (i=1.2.3)-(1) Furthermore, the distance sensor 34 is located at a constant height, and the ladle 30 is also at a constant height at its forward limit position. As shown in FIG. 4, the distance sensor 34
The distance AML to the bottom of the ladle 3o is a fixed value. Therefore, the height lX from the bottom of the ladle 30 to the liquid level of the molten metal 18 is given as Further, X is the molten metal 18 in the a ladle 30.
The weight of 1w is calculated from the correspondence table. That is, the ladle 30 has a specified size, and there is a certain relationship between the level of the molten metal 18 contained therein and its weight, and once the level is known, the internal molten metal 18 can be determined. The weight is determined. Therefore, by creating a correspondence table in advance and using the calculated f, the molten metal 18
The weight 1w of can be found.

Next, in steps 106 and 107, the biscuit thickness h is calculated from the weight of the molten metal 18. The weight of the molten metal 18 that passes through the gate and fills into the cavity 14 to become a molded product, that is, the weight that passes through the gate, is U, and the weight of the runner portion remaining in the runner 16 at the time of completion of injection is V,
When the amount of hot water supplied is W, the weight itT of the biscuit part is:
T = W −U −V (3) (Step 106). Therefore, the weight of the biscuit remains in the injection sleeve 24 at the position where the plunger tip 22 is completely cast. Therefore, the biscuit thickness h (mm) can be calculated from the following formula.

h=lOT/+(πR2・ρ/4) Xl0−”)...
・(4) In this case, R is the inner diameter (W) of the injection sleeve 24
, ρ is the specific gravity N (g/cJ), and T is the weight expressed in g. In addition, for the gate-passing type iU and runner weight (2), it is sufficient to measure the weight of each product by cutting the corresponding part of the weight of the once-injected product.
Set it as a fixed value.

Biscuit thickness h (m
a) is the distance b to the shunt end position B (backward angle position O
This is the distance ^1f from the position where injection is completed (distance from The distance c to the completion position ξ8 is calculated by stopping c,=b-h (5). This casting completion position ξ
3 is the position at which the plunger tip 22 should stop, which is determined by the actual amount of hot water supplied.

After the distance C1 to the casting completion position ξ5 is calculated, in step 109, the high-speed rising position A
The distance to ff1Ia is calculated. In a die-casting machine, the type of injection device 20 and the cavity 1
4, the type of molten metal, and other reasons, each injection device 20 has a specific high-speed injection distance l, so the distance a to the high-speed rise position A is within the predetermined high-speed injection path of 1 m. As a fixed value, it can be calculated from the second of a=c, -m (6).

In this way, the amount of molten metal in the ladle 30 immediately before it is supplied to the injection sleeve 24 is determined by the distance sensor 34, and from this the distance ^1a to the high-speed rising position HA of the plunger tip 22 and the distance C3 to the casting completion position ξ1 are calculated. After that, the process proceeds to step 110, where the ladle 30 is tilted to start supplying hot water to the injection sleeve 24.

When the injection sleeve 24 is completely filled with the molten metal 18, a shot is started based on the predicted distance Lu a to the high-speed start-up position A, the distance Hc to the casting completion position ξ, and the injection sleeve 24 is filled with the molten metal 18. 14.

By the way, as mentioned above, the distance a to the high speed start-up position A and the distance #c1 to the casting completion position ξ calculated from the actual amount of hot water supplied are determined by the disturbance that occurs before the ladle 30 moves to the hot water supply position. By performing injection with an injection stroke based on this value, a stable feeder effect can be obtained. However, even if the above control alone performs correct position control corresponding to the actual hot water supply amount, if a disturbance occurs in the injection device 20 itself, the actual position of the plunger tip 22 will not match the predicted position. The desired injection effect cannot be obtained. Therefore, in this embodiment, in addition to the above-mentioned F-F control, injection is performed using an injection stroke based on the predicted position, and at least the casting completion position is measured for each injection stroke, and this measured casting completion position and the The predicted casting completion position is compared with the predicted casting completion position, and when the measured casting completion position is outside the setting range of the predicted casting completion position, feedback (F-B) control is performed to correct the amount of hot water supplied.

Specifically, as shown in FIG. 1 (2), the injection device 20 starts a shot based on the result of F.F control.
In contrast, the injection stroke is measured for each shot, and in step 112, the actual casting completion position ξ is measured.

Next, the process proceeds to step 113, where the measured distance C1 to the casting completion position ξ is the predicted casting completion position c.
It is compared and determined whether the setting is between the setting upper limit ξh8 of 1 and the setting lower limit ξ1.1. If the measured casting completion position ξ is outside the set range, the process proceeds to step 114, outputs a defective indication, and after taking out the cast product at the relevant shot,
Activate the sorting device that transports the defective products to the storage area.

If the distance C8 to the measured casting completion position ξ is within the set range, the process proceeds to step 115, where it is determined whether the measured value is within the allowable range. This is the difference (lc
i-C,l) is within the tolerance range ±ε. For example, if the difference is within ±10%, it is determined that it is OK and the process returns to the first step 101 to perform predictive position control of the injection stroke. Let it restart.

However, if the difference (lcr c-l) between the measured pouring completion position ξ and the predicted pouring completion position ξ exceeds the allowable range, control is performed to correct the hot water supply 1 so that the correct pouring completion position ξ3 is reached. I am trying to get them to do this. In this case, the measured value is smaller than the predicted set value (Ci < c,)
Sometimes, as shown in FIG. 5(1), the actual casting completion position ξ is on the retraction limit position side, the biscuit thickness h is thicker than planned, and the high-speed injection path AIm is short. Therefore, in this case, proceed to step 117,
Try to reduce the amount of hot water the next time. On the other hand, when the measured value is larger than the predicted setting value (cr>cs), the actual casting completion position ξ1 is on the side of the shunt end position B and the biscuit thickness h is thinner than planned, and the high-speed injection distance m is longer. In this case, proceed to step 71118 and increase the amount of hot water supplied next time.

Incidentally, the amount of hot water supplied is determined by the angle of inclination of the ladle which determines the amount of molten metal scooped by the ladle 30, and the relationship between these is shown in FIG. 6, as the amount of hot water supplied decreases as the angle of ladle inclination increases. Now, the maximum hot water supply amount (g) is W HA
sW! Minimum ladle inclination angle (degrees) corresponding to IAM
ψKIN, minimum hot water supply! (g) w,! ,, ,W,,
The maximum ladle inclination angle (degrees) corresponding to N is ψ9. X, α
α−(WMAII WMI N ) /(ψMAX
−ψMIN), then salary? The formula for determining the ladle inclination angle ψ from WRW is as follows.

ψ=ψNIN+(~V −W ,, X) X cr
-----(1) From this equation (7), correction corresponding to the difference between the distance C7 (w) to the measurement completion position ξ, including 1 hour measurement, and the distance shearing 1fc, (mm) to the predicted casting completion position ξ8 Ladle correction inclination angle ψ from molten metal weight Wc (g). The formula for calculating the tip diameter of the injection sleeve 24 is R (mm).
, ) If the weight of the upper heel is ρ (g/c4), then we
-l ct C,l XπR” x (10-J
ρ/4X1/10 (8) Therefore, the ladle correction inclination angle ψ. In the middle. −ψH(
It can be determined as H+ (WC-WMAX)

For this reason, in step 117, the molten metal correction type Nwc corresponding to the calculated difference in the casting completion position (l Ci - Cs l) is determined from the above equation (8), and
) is used to calculate the ladle correction angle ψ. and,
The ladle inclination angle ψ is negatively corrected as shown in the seventh UjJ (1), and the ladle corrected inclination angle is determined as ψ-=ψ-min, which is output to step 101 and the ladle inclination angle is corrected. On the other hand, in step 118, conversely, (8)
, the Radtle correction angle is calculated based on equation (9), but
In this case, the ladle inclination angle ψ is plus corrected as shown in FIG. 7 (2), and the ladle inclination angle is ψ,=ψ10. The angle of ladle inclination for the next time can be corrected by calculating the ladle inclination angle and outputting it to step 101.

Note that any known device may be used as the water heater.
It is sufficient to use an apparatus having a general structure in which the amount of molten metal scooped by the angle of inclination of the ladle exhibits characteristics similar to the following linear equation.

As described above, according to this embodiment, the actual weight of the molten metal 18 is determined using the distance sensor 34 immediately before pouring into the injection device 20 of the die-casting machine, and this determines the high-speed rising position A of the plunger tip 22 and the casting position. Since the completion position ξ3 is set, injection control can be performed while eliminating disturbances caused by hot water spilling, etc., and a good feeder effect can be obtained. Further, the drawback that predictive control is open-loop control is suppressed by the subsequent feedback control, and the drawbacks of both are mutually compensated for, allowing extremely excellent injection molding to be performed.

[Effects of the Invention] As explained above, according to the present invention, the stroke setting for each shot can be corrected while suppressing disturbances caused by hot water spilling during feeding to the ladle 1F. The excellent effect is that the occurrence of cavities is constant, the riser effect is stabilized, and the quality of the cast product can be stabilized.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the processing procedure of the injection control method for a die-casting machine according to an embodiment, FIG. 2 is a cross-sectional explanatory diagram of main parts of the injection state of the die-casting machine, and FIG. 3 is an explanation showing the relationship between the ladle and the injection device. Fig. 4 is an explanatory diagram of the measurement state by the distance sensor, Fig. 5 is an explanatory diagram of the stroke of the plunger tip, Fig. 6 is an explanatory diagram of the relationship between the ladle inclination angle and the molten metal rod, and Fig. 7 is an explanatory diagram of the ladle correction angle. FIG. 14... Cavity, 16... Runner, 18... Molten metal, 20... Injection device,
22...Plunger tip, 24...
Injection sleeve, 26...Pouring port, 28...
...Injection cylinder, 30...Ladle, 34...
...Distance sensor, 38...Gate.

Claims (2)

[Claims] (1) In the injection control method for a die casting machine,
For each casting shot, measure the level of the molten metal in the ladle immediately before supplying the metal to determine the actual amount of molten metal supplied. From this actual amount of molten metal, predict the high-speed rise position of the plunger tip and the casting completion position, and perform injection based on this predicted position. An injection control method for a die casting machine, characterized in that injection is performed by a stroke. (2) In the injection control method for a die casting machine,
For each casting shot, measure the level of the molten metal in the ladle immediately before supplying the metal to determine the actual amount of molten metal supplied. From this actual amount of molten metal, predict the high-speed rise position of the plunger tip and the casting completion position, and perform injection based on this predicted position. While injecting with a stroke, at least the casting completion position is measured for each injection stroke, and the measured casting completion position is compared with the predicted casting completion position, and it is determined that the measured casting completion position is outside the setting range of the predicted casting completion position. An injection control method for a die-casting machine, characterized in that the amount of hot water supplied is corrected at a certain time.