JP3322824B2 - Mold height measurement method for mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the level of molten metal poured into a mold, and more particularly to a method for measuring the level of molten metal without being affected by disturbances such as impurities. It is.

[0002]

2. Description of the Related Art Casting is performed by pouring molten metal such as iron into a mold from a container called a ladle that stores molten metal such as iron. At that time, if the mold level in the mold is low, air will enter the mold and nests will form.If the mold level is high, the casting surface will be roughened and sand will result, and the position of the mold level in the mold will depend on the quality of the casting. Significantly affects improvement. Therefore, at the time of pouring, measure the surface level,
It is necessary to pouring while maintaining the level of the molten metal surface in the mold at a determined height, for example, about 8 minutes as a guide,
An example of the pouring device is shown below with reference to FIG.

In the figure, (1) is a mold, (2) is a ladle,
(3) is a pouring level sensor. The mold (1) consists of a cylindrical cup having an upper opening gate (1a).
The ladle (2) stores the molten metal (4) inside,
a) A container disposed so as to be tiltable up and down obliquely upward, and the pouring spout (2a) is tilted by a tilting operation using a handle or the like, and the molten metal (4) is poured into the mold (1) through the spout (1a). I do. The pouring level sensor (3) is an imaging means such as a CCD camera arranged diagonally above the gate (1a),
The height of the water surface (Ha) by imaging the shape of the water surface from obliquely above
(Hb) ... is measured.

According to the above configuration, when the pouring level sensor (3) captures an image of the molten metal surface obliquely above the gate (1a) and obtains a captured image (F) shown in FIG. The image is binarized by the value to obtain a binarized image (F ′) shown in FIG. Then, a part of the molten metal surface enters the blind spot area (A) of the level sensor (3) by the mold side wall,
Further, the area (A) varies depending on the molten metal level (Ha) (Hb). Therefore, as shown by a straight line (L) shown in FIG.
a) The area of the binarized image (Fa ′) (Fb ′)... of (Fb) is proportional to the level of the molten metal (Ha) (Hb).
a ′) (Fb ′)...
(Hb) ... also increases. The image (Fa ')
(Fb ′)... And the molten metal surface heights (Ha), (Hb)... Are measured, and the molten metal is poured while being stably maintained at a predetermined desired height.

[0005]

The problem to be solved is that, as shown in FIG. 3, the molten metal (4) has a ladle (black impurity in the molten metal) (5) or is contained in the mold (1). When the gas to be ignited and a flame (6) is generated near the gate surface, as shown in FIGS. 4 (b) and 4 (c), the flame image (Fd) and the slow image (Fe) are also captured images (F). Fig. 4 (e)
As shown in (f), those binarized images (Fd ')
(Fe ')... Is a molten metal level (Ha) (H
b) It is no longer proportional to ... and the surface level (Ha) (H
b) cannot be measured. For example, as shown in FIG. 4 (g), when there is a flame (6), the fluctuation of the molten metal level with respect to the area of the binarized image is gentler than the straight line (L) and the curve (C
a), and when there is a slack (5), the curve is steeper than the straight line (L) and becomes a curve (Cb), and the image area is not proportional to the level of the molten metal.

It is an object of the present invention to provide a method for measuring a mold level, which can accurately measure the mold level without being affected by disturbances such as sluggishness and flame.

[0007]

According to the present invention, there is provided a process for automatically pouring a molten metal into a mold whose width is expanded from a bottom to a spout having an upward opening so as to vary the surface area of the molten metal according to the level of the molten metal. A step of two-dimensionally capturing the entire area of the sprue from a position directly above the sprue by a spout height measuring sensor to obtain a spout image, and excluding the flame when a disturbance flame is captured in the spout image. Soup gate
Apply a circular window that captures only the inside of the opening edge to the hot water image
Measuring the image area in the circular window after the image processing, and, when impurities in the molten metal due to disturbance are captured in the molten metal surface image, the center of gravity of the image obtained by removing impurities from the molten metal surface image Is calculated
And the average pixel in the XY direction of the hot water image centered on the center of gravity
Drawing a few minutes in the X and Y directions and converting to a circumscribed rectangle having the same center of gravity to calculate the image area of the circumscribed rectangle; and determining the degree of conformity to the target value of the molten metal level from each of the image areas by fuzzy inference. And measuring the level of the molten metal.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for measuring a mold surface level of a mold according to the present invention will be described below with reference to FIGS. First, FIG. 2 shows a partial cross-sectional side view of the automatic pouring device used in the present invention, where (2) is a ladle for storing molten metal as in the prior art, (7) is a mold, and (8) is a height measurement. It is a sensor. The mold (7) is a gate (7a) having an upper opening.
And a sloped side wall (7b) and a trumpet-shaped cup body whose width is increased upward from the bottom. Then, when the molten metal (4) is automatically poured into the mold (7) from the ladle (2) through the gate (7a) by tilting, the cup width becomes equal to the surface height (Ha).
(Hb) ... because it changes in proportion to the molten metal surface height (Ha)
The molten metal surface area (fa) changes in proportion to (Hb). The height measurement sensor (8) is arranged almost directly above the gate (7a), and is an imaging means such as a CCD camera that covers the entire area of the gate (7a). An image is obtained by taking an image.

Here, as shown in FIGS. 2 and 3, the molten metal (4) has a slag (black impurity in the molten metal) (5), or the gas contained in the mold (7) ignites and the gate is ignited. When the flame (6) occurs near the surface, the influence of the flame (6) does not accurately reflect the surface area (fa) of the molten metal according to the molten metal height (Ha) (Hb). Becomes difficult. Therefore, one height measuring sensor (8) is switched to take in images of a normal, hot, and sluggish surface, or a dedicated camera is arranged depending on whether or not there is disturbance. For example, a normal hot surface, a hot hot surface, and a hot hot surface may be imaged with three cameras, respectively, or one of the two images may be switched and imaged.

The operation of the present invention based on the above configuration will now be described. First, the height measurement sensor (8) captures an image of the molten metal surface shape over the entire gate surface, and the molten metal surface image (P) shown in FIG.
Assume that a) is obtained. Then, the gate (7a) is imaged in a two-dimensional plane, and the waving of the surface is averaged, and a waving image such as a wave height does not appear in the surface image (Pa), and a stable captured image is obtained. Moreover, the surface area (fa) of the molten metal varies in proportion to the height (Ha) of the molten metal, and the surface area decreases as the molten metal surface goes down to the bottom, and increases as the metal surface goes up. Then, from the image area (Sa) of the bath surface image (Pa) by the height measurement sensor (8), the bath surface height (Ha) ...
Can be measured accurately.

Here, as described above, when there is a ladle (5) in the molten metal (4) or when a flame (6) is generated near the surface of the gate, the molten metal (4) is affected by the influence of the molten metal (4) and the height of the molten metal (Ha) is affected. ) Does not accurately reflect the surface area (fa) of the molten metal surface, making it difficult to measure the molten metal surface height. Therefore, for example, as shown in FIGS. 1B and 1C, when a hot water image (Pb) including a flame image (Pd) and a hot water image (Pc) including a slow image (Pe) are obtained,
Image processing of each surface image (Pb) (Pc) (5)
Exactly the height of the molten metal surface (Ha) by eliminating the effect of heat and flame (6) ...
Is measured.

That is, first, when there is a flame (6), FIG.
As shown in (d), after a circular window (W) that captures only the inside of the gate opening edge is subjected to image processing over the molten metal surface image (Pb), the image area (Sb) in the circular window (W) is measured, and the opening is measured. The surrounding flame image (Pd) is not captured as a captured image. Next, when there is a slack (5), as shown in FIG. 1 (e), the center of gravity of the image obtained by removing the filtered image (Pe) from the hot water image (Pc) is calculated, and the center of gravity is calculated. First, the image area (Sc) of the circumscribed rectangle (Ps) is calculated by drawing a line in the XY direction by the average number of pixels in the XY direction of the hot water surface image (Pc) and converting it to a circumscribed rectangle (Ps) having the same center of gravity.

Next, the image area (Sa) (Sb) (S
From c), the molten metal level (Ha) is determined by fuzzy inference. The fuzzy inference is performed by a probability-based determination means. First, a membership function (M) for fuzzy surface level shown in FIG. 1 (f) is created. The membership function (M) is calculated based on the image area (Sa) (Sb) (S
The probability distribution of the surface level for c) is drawn, and (N
a) (Nb) (Nc) (Nd) are normal images (P
a), Slow image (Pc), Flame image (Pb)
Each of the fuzzy sets of images having abnormalities such as hot water spills and the like, the horizontal axis represents the measurement area (S), and the vertical axis represents the degree of conformity (h) to the target value of the molten metal level.

For example, if (Sm) is measured as the measurement area (S), the fuzzy sets (Na) (Nb) (N
c) Each fitness (H) in (Nd) is (ha), 0,
(Hc), 0, and ha> hc, so that the molten metal surface image approaches the target molten metal surface height of the normal image. Also, the measurement area (S)
If (Sn) is measured as fuzzy set (N
a) Each fitness (h) in (Nb) (Nc) (Nd)
Is 0, 0, 1, 0, and the hot water level image matches the target hot water level of the image having a flame.

[0015] This makes it possible to calculate the level of the molten metal, and to simultaneously discriminate between obstructive factors such as sluggishness and flame and abnormalities.

[0016]

According to the present invention, when measuring the surface level of a mold in an automatic pouring apparatus for casting, a molten metal is automatically poured into a mold whose diameter has been increased upward, and the entire area of the gate from almost directly above. excluding the disturbance such as impurities or flame from a two-dimensional manner bath level image captured
The height of the molten metal is measured without the influence of disturbance, and the accuracy of measuring the molten metal is greatly improved. Casting quality can be ensured.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are images of a normal hot surface, a hot hot surface, and a hot hot surface taken by a height measuring sensor according to the present invention. (D) and (e) are processed images of a hot and cold lane image. (F) is a graph of the membership function of fuzzy inference according to the present invention.

FIG. 2 is a partial cross-sectional side view of an automatic pouring apparatus showing an embodiment of a method for measuring a mold surface level of a mold according to the present invention.

FIG. 3 is a partial sectional side view showing an example of a conventional automatic pouring apparatus.

4 (a), (b) and (c) show a normal molten metal surface image, a hot molten metal surface image captured by a conventional pouring level sensor,
Smooth bath surface image. (D), (e), and (f) show a binarized image of a normal molten metal surface, a binarized image of a hot molten metal surface, and a two-dimensional image of a lazy molten metal surface of an image captured by a conventional pouring level sensor. Valued image. (G) is a graph showing a change in the level of the molten metal with respect to each of the binarized image areas of the conventional normal, flaming, and lazy metal surfaces.

[Explanation of symbols]

 Reference Signs List 4 molten metal 7 mold 7a gate 8 level measuring sensor fa level surface area Ha level height

Continuation of the front page (56) References JP-A-52-114533 (JP, A) JP-A-4-327360 (JP, A) JP-A-7-68370 (JP, A) JP-A-7-332661 (JP) , A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B22D 37/00

Claims (1)

(57) [Claims] 1. A step of automatically pouring a molten metal into a mold having a width expanded from a bottom to a gate opening upward to vary the surface area of the molten metal according to the level of the level of the molten metal. A step of two-dimensionally capturing the entire gate area by the metal level measuring sensor to obtain a metal level image, and when a disturbance flame is captured in the metal level image, only the inside of the gate opening edge is removed to remove the flame. Circle to capture
After processing the window over the hot water image,
A step of measuring an image area of the window, the molten metal surface when the molten metal in the impurity disturbance is captured in the image, calculates the center of gravity of the image excluding the non <br/> pure product from the molten metal surface image, the center of gravity Hot water around
Draw in the XY direction by the average number of pixels in the XY direction of the plane image
Then, a step of calculating the image area of the circumscribed rectangle by converting to a circumscribed rectangle having the same center of gravity, and determining the degree of conformity to the target value of the molten metal level from each of the image areas by fuzzy inference to determine the molten metal level A method for measuring the mold surface height of the mold, comprising: