JPH10314926A - Method for measuring molten metal surface height in mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a molten metal surface height can not be precisely measured because a picture area is not proportional to the molten metal surface height by fetching the following causes into the pick-up picture in the case a black impurity exists in the molten metal or flame is developed near the sprue surface in a mold, at the time of pouring the molten metal into the mold. SOLUTION: A molten metal surface height measuring method is provided with a process for differing in the molten metal surface area fa... according to the molten metal surface height Ha... by automatically pouring the molten metal 4 into the mold 7 enlarging the width from the bottom part to the sprue 7a of the upper opening part, a process for obtaining the molten metal picture by two-dimensionally picking up the whole range of the sprue 7a from almost just above the sprue with a molten metal surface height measuring sensor 8, a process for measuring the picture area in wind by blasting the wind to the molten metal surface picture so as to remove flame in the case of picking up the picture of the flame as the disturbance, a process for calculating the picture area of a circumscribed rectangular shape after converting the molten metal picture into the circumscribed rectangular shape having the same center of gravity as the picture removing the impurity in the case of picking up the impurity in the molten metal surface as the disturbance and a process for measuring the molten metal surface height by discriminating an adaptability to a target value of the molten metal surface height from each picture area with a fazzy inference.

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 level of the molten metal in the mold is low, air mixes into the mold and nests are generated.If the level is high, the casting surface is roughened and sand is caused, and the position of the molten metal in the mold depends 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]

SUMMARY OF THE INVENTION The present invention comprises a step of automatically pouring a molten metal into a mold whose width is expanded from the bottom to the upper opening of a sprue 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. Measuring the image area in the window by applying a window to the molten metal surface image, and when impurities in the molten metal of the disturbance are imaged in the molten metal surface image, the same center of gravity as the image obtained by removing the impurities from the molten metal surface image is used. A step of calculating the image area of the circumscribed rectangle by converting the circumscribed rectangle to have, and a step of measuring the level of the molten metal by determining the degree of conformity to the target value of the molten metal level from each of the image areas by fuzzy inference. It is characterized by having.

[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 molten metal (4) and the molten metal (H) ) 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
This is a plot of the probability distribution of the surface level for c), where (N
a) (Nb), (Nc) and (Nd) are normal images (P
a), slow image (Pc), flame image (Pb)
Each fuzzy set of images having abnormalities such as hot water spills and the like, the horizontal axis represents the measured area (S), and the vertical axis represents the degree of conformity (h) to the target value of the level of the molten metal.

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. Is two-dimensionally imaged, and image processing is performed on the image of the molten metal surface with disturbances such as impurities and flames, and the height of the molten metal surface is determined by fuzzy inference. Height measurement accuracy is greatly improved, and casting quality during pouring 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

Claims (1)

[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 imaging the entire gate area by the molten metal level measuring sensor to obtain a molten metal surface image, and, when a disturbance flame is captured in the molten metal surface image, a window is formed in the molten metal surface image so as to remove the flame. Multiplying the image area in the window by multiplying the molten metal surface image by capturing the impurities in the molten metal, and converting the molten metal surface image into a circumscribed rectangle having the same center of gravity as the image excluding the impurities. A mold having a step of calculating a rectangular image area, and a step of measuring the level of the molten metal by determining the degree of conformity to the target value of the molten metal level from each of the image areas by fuzzy inference. Method of measuring the height of the hot water level.