JPH0724929B2 - Die casting machine Hot water supply control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for controlling the amount of hot water supplied by a die casting machine, and in particular, the amount of hot water supplied by a die casting machine that is capable of stabilizing the effect of the feeder and preventing the formation of burrs. Regarding control method.

[Conventional technology]

Generally, in a die casting machine, an injection device is connected to a runner portion that communicates with a cavity of a mold, and molten metal supplied from a hot water supply device and filling a shot sleeve is pushed out by a plunger and injected into the cavity. In the injection operation, the plunger is moved forward from the retreat limit position at a constant low speed, is moved at a high speed after passing through the molten metal injection port, and the casting is completed with a slight gap to the end surface of the shot sleeve. .

By the way, the amount of hot water supplied to the injection device is constant for the same cavity, but the scooping amount of the ladle for hot water supply is not strictly constant, and therefore the amount of hot water supplied may vary. For this reason, there is a problem in that the effect of the feeder by the injection device becomes unstable due to an error in the amount of hot water supplied, and it becomes impossible to stabilize the quality of the cast product. In order to improve such a problem, as a conventional technique, a shunt end position which is a runner opening end face in the shot sleeve of the injection device for each shot, and the molten metal thickness remaining between the casting completion position of the plunger, That is, 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 is constant (Japanese Patent Publication No. 59-21262).
According to this, the biscuit portion does not solidify before the runner portion, the sliding resistance of the plunger increases due to the start of solidification of the shot sleeve contact surface, and the feeder effect is not lost. Benefits are obtained.

[Problems to be solved by the invention]

However, according to the method as described above, the value of the biscuit thickness (= | shunt end position−casting completion position |) is suppressed by increasing / decreasing the hot water supply amount so that it falls within the set range. The adjustment of the amount causes a variation of the pouring completion position at the same time. As a result, there is a problem in that the distance between the casting completion position and the high-speed movement start command position of the plunger changes, and in particular when the high-speed injection section becomes long, cavities occur in the cast product. This is because the residual gas of the product increases due to the lengthening of the high-speed injection section, which causes the formation of cavities. Therefore, in order to cast die-cast products with few cavities, it is clear that it is better to shorten the high-speed injection section, but with the above-mentioned conventional method, although the feeder effect can be obtained, the quality of the cavities on the surface The above problem still remained.

The present invention focuses on the above conventional problems, and an object of the present invention is to provide a die casting machine hot water supply amount control method capable of improving the quality of a cast product by simultaneously satisfying the feeder effect and the prevention of generation of burrs. And

[Means for solving problems]

In order to achieve the above object, the method for controlling the amount of hot water supplied by the die casting machine according to the present invention measures the pouring completion position for each casting shot, and transfers this position and the high-speed rising position for each shot onto one axis of the two-dimensional coordinate. Along with, calculate the angle formed by the pouring completion position and the high-speed rising position with respect to the fixed point on the orthogonal axis passing through the high-speed rising position as the pouring completion angle, and between the pouring completion angle and the preset pouring completion setting angle. When the angle difference exceeds the allowable value, the amount of oil supply is corrected according to the angle difference to make the high-speed injection section constant.

Specifically, the casting completion angle corresponding to the high-speed injection section is introduced and set, this angle is detected for each shot, and the detected value is compared with the angle set as an appropriate value in advance,
When the difference from the set value exceeds the allowable range, the hot water supply amount of the hot water supply device is automatically corrected and kept within the set range, and the high-speed injection section is thus made constant. .

[Operation] According to the above configuration, the high-speed injection section for each casting shot matches the stroke amount of the shot plunger from the high-speed rising position to the casting completion position. There is an error in the scooping amount of the ladle. Therefore, when the hot water supply amount changes, the retracting limit position of the plunger is constant and the shot sleeve capacity is also constant, so the pouring completion position changes. Such a change in the pouring completion position appears as a change in the distance between the high-speed rising position on the axis of the two-dimensional coordinate, and the angle formed by the line connecting the fixed point on the orthogonal axis passing through the high-speed rising position and each position. Corresponding to these. This angle is used as the pouring completion angle, and is compared with the pouring completion setting angle that is set in advance for the optimum high-speed injection section, and if the angle difference exceeds the allowable range, the hot water supply ladle is corrected. Adjust the inclination angle of to correct the amount of hot water supplied. As a result, in the next shot, the high-speed injection section falls within the set range, the formation of cavities in the product is prevented, and a dense pressure-resistant cast product is obtained.

〔principle〕

The principle of the present invention that causes the above-described operation is as follows.

That is, the die casting machine, as shown in FIG.
A fixed mold 10a fixed to the fixed plate 10 and a movable mold 12a fixed to the movable plate 12 are provided, and a cavity 14 is formed on the joint surface between them.
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 the molten metal 18 is connected to the runner 16. The injection device 20 includes a shot sleeve 24 having a piston 22a at the tip of a plunger 22 and a piston driven by a drive device (shot cylinder) 28 to supply the molten metal 18 supplied from an injection port 26 provided in the shot sleeve 24. It is extruded by 22a, and the cavity 14 is injected and filled. The operation of the piston 22a moves forward from the backward limit position by the controller (not shown), moves through the injection port 26 at a low speed to the high-speed rising command position, and moves from the high-speed rising command position to the pouring completion position at high speed to move the cavity. Make a fast injection to 14. The casting completion position, which is the forward movement end of the piston 22a, is a position with a certain distance from the shunt end position, which is the deep end face of the shot sleeve 24 in which the runner 16 is opened, and this distance is the so-called biscuit thickness. It becomes

Here, in order to grasp the high-speed injection section, a pouring completion position is measured, and based on this, a pouring completion position and a high-speed rising position are transferred onto one axis of two-dimensional coordinates as shown in FIG. To create. That is, X
The origin (0, 0) of the −Y coordinate is set as the retract limit position of the piston 22a, for example, and the high speed rising position A and the shunt end position B are plotted on the X axis, and the measured pouring completion position ξ is plotted on this. Then, fixed points D and C having a length of L = | B−A | are set on an orthogonal axis passing through the high-speed rising position A and the shunt end position B to complete the rectangle ABCD. When the fixed point D on the orthogonal axis passing through the high speed rising position A and the pouring completion position ξ are connected, ∠ADξ corresponds to the high speed injection section.

Now, assuming that this angle is the casting completion angle θ, the following equation is established.

θ = tan ⁻¹ | ξ−A | / L (1) Therefore, the casting completion angle θi corresponding to the casting completion position ξi measured for each shot can be calculated based on the above diagram. The magnitude of the pouring completion angle θi serves as an index of the stroke amount in the high-speed injection section, and a smaller value indicates a shorter high-speed rising section, and a larger value indicates a longer stroke. Therefore, by comparing θi with the preset pouring completion setting angle θs corresponding to the preset pouring completion setting position ξs, the variation amount in the high-speed injection section can be grasped. In this case, θ
When i is smaller than θs, there is no problem because the high-speed injection section is short, but when i is large, the high-speed injection section becomes long,
There is a risk of nest formation due to gas entrapment in the product. Therefore, from the viewpoint of preventing the formation of nests, the hot water supply amount may be controlled for the case where θi is larger than θs.

By the way, the amount of hot water supply is determined by the inclination angle of the ladle, and as shown in FIG. 4, a linear linear equation in which the amount of hot water supply decreases as the inclination angle of the ladle increases is approximately established. Now, the maximum hot water supply amount (g) is W _MAX , the minimum ladle inclination angle (degree) corresponding to W _MAX is Ψ _MIN , and the minimum hot water supply amount (g) is W
Ψ _{MAX is} the maximum ladle inclination angle (degree) corresponding to _MIN and W _MIN .
If α is α = (W _MAX −W _MIN ) / (Ψ _MAX −Ψ _MIN ),
The formula for obtaining the ladle inclination angle Ψ from the hot water supply amount W is as follows.

Ψ = Ψ _MIN + (W−W _MAX ) × α (2) From this equation (2), the weight of the molten metal corresponding to the difference between the pouring completion position ξi (mm) and the pouring completion setting position ξs (mm).
Wc = | ξi−ξs | ×, where R (cm) is the tip diameter of the shot sleeve 24 and ρ (g / cm ³ ) is the specific weight of the molten metal. Since π R ² ρ / 4 × 1/10 (3), the Laddle corrected tilt angle Ψc can be obtained as Ψc = Ψ _MIN + (Wc−W _MAX ) × α (4).

Then, in order to calculate the ladle tilt angle from the casting completion angle θi, the above equation (3) is expressed as Wc = L | tan θi−tan
θs | · πR ² ρ / 400 because it is ... (5), by substituting the equation (5) to _{(4), Ψc = Ψ MIN + (L} | tanθi-tanθs | · πRRρ / 400 -W MAX ) × α (6), which is the amount of correction of the tilt angle of the ladle according to the amount of correction of the hot water supply. Therefore, as shown in FIG. 5, when the pouring completion position ξi fluctuates and the pouring completion angle θi becomes larger than the set angle θs and exceeds the allowable range, the previous ladle tilt angle is calculated based on the equation (6). By adding the correction angle by the equation (6) to reduce the hot water supply amount, the increased high-speed injection section is corrected so as to be short, and it is possible to prevent the formation of cavities due to gas entrainment.

〔Example〕

Hereinafter, an embodiment of a hot water supply amount control method for a die casting machine according to the present invention will be described in detail with reference to FIG.

FIG. 1 is a flowchart showing a processing procedure of a hot water supply amount control method for a die casting machine according to an embodiment.

In this figure, step 101 shows the hot water supply to the shot sleeve 24, and after the hot water supply is completed, the shot cylinder 28 is operated in step 102 to start the shot.

As the shot starts, in step 103 the pouring completion position ξ
Measure i.

Next, at step 104, the pouring completion angle θi corresponding to the pouring completion position ξi is calculated. This may be done based on the above formula (1). In this case, since the high-speed rising position A and the shunt end position B are set as fixed points, the pouring completion angle θi can be easily calculated only by detecting the variable ξi.

Then, in step 105, determines comparison between set upper limit theta _H IgH complete set angle θs that computed casting completion angle θi is cast and the set lower limit theta _L ow, i.e. whether it is within the set range . This comparison determination is usually performed by comparing the pouring completion angle θi and the pouring completion setting angle θs and determining whether or not the difference is within the allowable range ± ε. For example, the pouring completion angle θi is compared with the pouring completion setting angle θs, and if the difference is within ± 10%, it is determined as OK, and if it is other than ± 10%, it is determined as NG.

The above processing is performed for each shot, the determination result of step 105, if OK determination, returns to step 101 to continuously perform casting work, and if NG determination, outputs a defect display in step 106, After taking out the cast product in the shot, a sorting device for transporting the cast product to the defective product storage is operated. Further, the NG signal from step 105 is output to step 107, and the hot water supply amount correction operation is started.

In step 107, the front-rear relationship between the pouring completion position ξi and the pouring completion setting position ξs is made to correspond to θ, and judgment is made by comparing the pouring completion angle θi and the pouring completion setting angle θs. That is, θs <θi, or θs
> Θi is determined. In this case, θs> θ
When i indicates that the high-speed injection section is shorter than the set range, there is no possibility of gas entrainment during injection, and therefore the process returns to step 101 and the hot water supply operation is re-executed. However, θ
On the contrary, when s <θi, there is a risk of gas entrapment, and in such a case, the routine proceeds to step 108, where the hot water supply amount is corrected. This is calculated based on the equation (6), the tilt angle ψc of the ladle is obtained, and the hot water supply device outputs a correction command so as to decrease the tilt angle by an amount corresponding to this angle and increase the hot water supply amount. To be executed.

As the hot water supply device, a known device may be used, and a device having a general structure in which the scooping amount of the molten metal exhibits the characteristics shown in FIG. 4 depending on the inclination angle of the ladle may be used.

In the embodiment as described above, in particular, the determination of the magnitude relationship between the biscuit thickness and the high-speed injection section can be processed by a simple angle element. Moreover, the angle range of the casting completion angle is 0 to 45 degrees, and the range of the ladle tilt angle is 20 to 60 degrees.
Compared with the degree, it is possible to process the ladle tilt angle by the sum of the casting completion angle and the angle constant.

〔The invention's effect〕

As described above, according to the present invention, the concept of the casting completion angle is introduced as the variation of the casting completion position with respect to the high-speed rising position, and in comparison with the casting completion setting angle corresponding to the significant minimum high-speed injection section, the high speed Since the amount of hot water supplied is adjusted so that the injection section becomes the significant minimum high-speed injection section, it is possible to mold a dense cast product that does not have a riser effect and cavities by simple control.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing procedure of a hot water supply amount control method for a die casting machine according to an embodiment, FIG. 2 is a sectional view for explaining the operation of the die casting machine, FIG. 3 is a diagram showing a pouring completion angle, and FIG. FIG. 5 is a characteristic diagram showing the relationship between the ladle tilt angle and the amount of hot water supplied, and FIG. 5 is an explanatory diagram showing the relationship between the ladle tilt angle and the pouring completion angle. 20 …… Injection device, 22 …… Plunger, 24 …… Shot sleeve.

Claims (1)

[Claims] 1. A hot water supply amount control method for a die casting machine, wherein a pouring completion position for each casting shot is measured, and this position and the high speed rising position for each shot are transferred onto one axis of two-dimensional coordinates, and the high speed rising is performed. The angle between the pouring completion position and the high-speed rising position with respect to the fixed point on the orthogonal axis passing through the position is calculated as the pouring completion angle, and the angle difference between the pouring completion angle and the preset pouring completion setting angle has an allowable value. A hot water supply amount control method for a die casting machine, characterized in that, when it exceeds, the hot water supply amount is corrected according to the angle difference to make the high-speed injection section constant.