JPS5921262B2 - How to control hot water supply amount for die casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the amount of hot water supplied to a die-casting machine, and in particular, it automatically controls the biscuit thickness corresponding to the amount of hot water supplied to always be within a set range, thereby making the feeder effect constant and improving the quality of cast products. This invention relates to a method for controlling the amount of hot water supplied to a die-casting machine for the purpose of stabilizing quality.

In conventional die casting machines, each casting shot is supplied with a constant volume by a preset water supply device.

However, most of the water heaters are constructed of a ring mechanism including a swinging drive arm to which a ladle is attached, and the trajectory of the ladle is not accurate (especially at top dead center and bottom dead center). Moreover, since the ladle scoops up hot water that is placed in a crucible and whose water level is not always constant, the amount of hot water supplied is not strictly constant but varies by at least a factor of ±2.

Such variations in the amount of hot water supplied are not limited to those using a link mechanism, and similar phenomena can be observed in other known water heaters as well.

Therefore, such an error in the amount of hot water supplied does not make it possible to stabilize the feed water effect, making it difficult to stabilize the quality of cast products.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
An object of the present invention is to provide a method for controlling the amount of hot water supplied to a die-casting machine, which can stabilize the quality of cast products by automatically making the feeder effect constant.

FIG. 1 is a diagram illustrating the feeder effect of a die-cast product.

In FIG. 1, the molten metal supplied from the water heater into the shot sleeve 12 from the arrow A is transferred to the shot cylinder 14.
The shot plunger 16 is actuated to the left in the figure to eject the shot.

This injection force is the biscuit 1 at the tip of the short sleeve.
Runner 22 and feeder 2 formed in mold 20 from 8
4 and is transmitted to the casting 28 through the gate 26.

Among these, the dimensions and shapes of the runner 22, feeder 24, gate 26, and cast product 28 are uniquely determined by mold manufacturing, but the thickness L of the 75ζ biscuit 18 varies depending on the amount of hot water supplied during each casting shot.

However, if the thickness L of the biscuit 18 is too small, the biscuit portion will solidify before the runner 22 and feeder 24 portions, and the casting effect of the cast product 28 will be lost.

On the other hand, if the thickness L of the biscuit 18 is too large, the solidified area of the portion in contact with the inner surface of the shot sleeve 12 will increase, and the sliding resistance of the plunger due to the solidification will increase.
Again, the feeder effect of the cast product 28 is reduced.

At the same time, a problem arises in that the coagulation time becomes longer and the end stop is lowered.

Therefore, in order to make the feeder effect constant and stabilize the quality of the cast product, it is necessary to always keep the thickness of the biscuit 18 constant.

The present invention has been made with attention to this point, and detects the biscuit thickness for each shot, compares this with the thickness setting value, and when the difference with the set value exceeds the allowable range, the water heater The present invention provides a hot water supply amount control method that automatically corrects the hot water supply amount to keep it within a set range, thereby making the hot water supply effect constant.

The control method of the present invention is suitable for being executed by a control system such as a microcomputer.

Hereinafter, one embodiment of the hot water supply amount control method of the present invention will be specifically described with reference to FIGS. 1 to 3.

In FIG. 1, the shot sleeve 12 is fixed through a fixed plate 30, and the fixed side of the mold 20 (fixed mold) is attached to the fixed plate.

On the other hand, the movable side of the mold 20 (movable mold) is attached to the movable plate 32, and during casting, the fixed mold and the movable mold are clamped together to form a mold for the cast product 28.

From the structure shown in FIG. 1, the thickness L of the biscuit 18 can be calculated as follows.

Now, Pl is the front end position of the shot plunger 16 at the start of the double yawning, P2: the front end position of the fixed plate 30, P3 is the front end position of the shot plunger 16 when the double yacht is completed, P4 is the front end position of the double yacht sleeve 12, Dl: P
Distance between l and P2, D2: Distance between Pl and P4, S: Distance between PI and P3, or shot stroke, L: Distance, or biscuit thickness, between P3 and P4. For example, the thickness L of the biscuit 18 is L=D1+D2-8.

Since DI and D2 are unique values for each die-casting machine, the thickness L of the biscuit 18 can be calculated by measuring the shot stroke S for each shot.

This calculation can be performed using a microcomputer or the like.

The actual shot stroke S is measured by providing a known position detecting device such as a rotary encoder 34 that operates in conjunction with the shot plunger 16, and inputting its detection signal to the microcomputer.

FIG. 2 is a flowchart showing the processing procedure of an embodiment of the hot water supply amount control method of the present invention.

In FIG. 2, step 101 is the shot sleeve 1
After the hot water supply is completed, the shot cylinder 14 is operated in step 102 to start a shot.

As the shot starts, the shot stroke S is measured in step 103.

Next, in step 104, the thickness L of the biscuit 18 is calculated.

Next, the process proceeds to step 105, where the calculated biscuit thickness L is set as the upper limit LH and lower limit LL of the biscuit thickness.
A comparison is made to determine whether or not it is within the set range.

This comparison is usually made between the biscuit thickness L and the set value Lo.
This is done by comparing the difference between the two and determining whether the difference is within an acceptable range.

For example, compare the thickness calculation value with the set value Lo by ±15%.
If it is within ±15, it is OK, and if it is outside ±15, it is N.
A determination of G is made.

In addition, the set value of biscuit thickness. Although it differs depending on the model, it is set to, for example, 25 degrees.

The above process is performed for each shot, and each time the result of the determination in step 1050 is NG, a defective display is performed in step 105A, and a sorting device is activated to take out the cast product of that shot and transport it to a defective product storage area.

On the other hand, the NG signal from step 105 is
Here, it is determined whether NG has occurred N times (predetermined number of times) consecutively.

If NG occurs N times in a row, the process proceeds to step 101, where the average value LM of N consecutive biscuit thickness measurements is calculated.

In step 108, this average value LM is compared with the set value LO, and it is determined whether the difference is within a tolerance range (for example, ±15 factors).

If it is outside the allowable range, an NG signal, ie, a hot water supply amount correction signal, is transmitted to step 109, where the hot water supply amount of the water heater is corrected.

In addition, in the example shown in FIG. 2, the amount of hot water supply was corrected based on the average value for N shots of biscuit thickness L; however,
In some cases, this N can be set to 1 and the hot water supply amount can be corrected for each shot in which there is an NG.

In that case, the NG signal from step 105 may be transmitted to step 109 as a hot water supply amount correction signal.

After the hot water supply amount is corrected in step 109, the process returns to step 101 again and hot water is supplied.

If the result of the determination in step 106 is that NG is not consecutive N times, the process returns directly to step 101, and hot water for the next shot is supplied without modifying the amount of hot water supplied.

Further, as a result of the determination in step 105, if the detected value of the biscuit thickness is within the set range, the process returns directly to step 101 to supply hot water for the next shot.

Furthermore, even if the average value LM of the biscuit thickness is within the set range as a result of the determination in step 108, the process returns directly to step 101 from here to supply hot water for the next shot without performing hot water supply correction.

In addition, the amount of correction when correcting the hot water supply is, for example, ±1 rrr or ±2 rrr when considering the thickness L of the biscuit 18! One of n is selected.

Further, in the embodiment shown in FIG. 2, the biscuit thickness L for each shot calculated in step 104 can be displayed in step 104A.

FIG. 3 is a diagram showing an embodiment of the hot water supply amount correction device.

In FIG. 3, the ladle rotation motor 42 is connected to a belt 44.
The worm 46 can be rotationally driven via the worm 46.

The worm is engaged with a gear 50 on the shaft 48,
A sprocket 52 is fixed to one end of the shaft.

The sprocket 520 rotations are chain 54, 56.58
is transmitted to the ladle 60 via the rotor so that the ladle can be rotated about an axis 62.

The angle of inclination of the ladle is an angle θ with respect to the illustrated horizontal line, which varies, for example, from 30 degrees to 60 degrees.

As the angle θ increases, the amount of hot water supplied decreases, and as the angle θ decreases, the amount of hot water supplied increases.

On the other hand, a lever 64 is attached to the other end of the shaft 48, and rotates as the shaft rotates, and when it comes into contact with a stopper 66, a limit switch 68 stops the ladle rotation motor 42. ing.

The position of the stopper 66 is adjustable, and the adjustment is performed by rotating the threaded rod 10 engaged with the stopper.

The rotation of this threaded rod can also be done manually by operating the ladle 12, but the stopper adjustment motor 14 is rotated by a predetermined amount according to the amount of correction in response to a hot water supply amount correction signal from a control system such as a microcomputer. This is done by rotating the threaded rod 10 via the bevel gear 16.

When the amount of hot water to be supplied is corrected by the stopper adjustment motor γ4, an electrical pulse is generated by the proximity switch γ8 and the dog 80 as the motor rotates, and this pulse is sent to a microcomputer or the like.

Therefore, the number of electrical pulses corresponding to 1 mm of biscuit thickness is determined based on the relationship between the size of the ladle 60 and the diameter of the shot sleeve 12 (Fig. 1) of the die-casting machine, so the electrical pulses are counted. When the stopper adjustment motor γ4 is stopped when the predetermined number of pulses is reached, the stopper 66 is set at a position corresponding to the amount of correction, and the inclination angle θ of the ladle 60 by the ladle rotation motor 42 is corrected to adjust the amount of hot water supplied. Can be fixed.

For example, in the case of a 3Kv ladle and a shot sleeve with a diameter of 65 mm, 16 electric pulses will reduce the thickness of the biscuit by 1.
It is set to correspond to the cabinet.

In this way, the amount of biscuit thickness correction (for example, 11rrI
n or 21rr! It is possible to complete the hot water supply amount correction corresponding to n).

As is clear from the above explanation, according to the method for controlling the amount of hot water supplied to a die casting machine of the present invention, the thickness of the biscuit is kept constant by automatically correcting the amount of hot water supplied for each shot, thereby stabilizing the feed water effect. It is possible to achieve stable quality of cast products.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main parts of a die-casting machine showing the relationship between the feeder effect and biscuit thickness (shot stroke), FIG. FIG. 3 is an explanatory diagram showing an example of a hot water supply amount correction mechanism of the hot water supply device. 12... Shot sleeve, 16...
Shot plunger, 18...Biscuit, 2
0... Mold, 28... Casting product, 42.
...Motor for rotating the ladle, 60...Ladle, 66...Stopper, 68...Limit switch, T4...Motor for adjusting the stopper, A...Hot water supply section to the shot sleeve, L...
...Biscuit thickness (measured value), LM...
Average value (measured value) of biscuit thickness, L□・・・・・・
Biscuit thickness setting value, LH... Upper biscuit thickness setting, LL... Lower limit of biscuit thickness setting, S... Shot stroke, θ...
Ladle inclination angle.

Claims (1)

[Claims] 1. In a method for controlling the amount of hot water supplied to a die-casting machine, the biscuit thickness is detected by measuring the shot stroke for each casting shot, and the detected value is compared with a set biscuit thickness value, and the biscuit thickness is determined by measuring the shot stroke for each casting shot. A method for controlling the amount of hot water supplied to a die-casting machine, characterized in that the amount of hot water supplied from a water heater is automatically corrected when the amount of hot water is outside a set range. 2. In the method for controlling the hot water supply rate IJ of a die-casting machine as set forth in claim 1, when the detected value of biscuit thickness is continuously outside the set range over a predetermined number of shots, the average value of the detected biscuit thickness is A method for controlling the amount of hot water supplied to a die-casting machine, characterized in that the average value is compared with a set value, and the amount of hot water for the next shot is automatically corrected when the average value is outside the set range.