JP2000036046A - Method and device for evaluating thixo-molding state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively evaluate a molding state at a high speed and to effectively utilize it for molding process research and development and process adjustment by detecting a solid phase area by picking up the image of the cross section of a thixo- molding article and calculating a feature amount expressing the state of each solid phase. SOLUTION: A cross section 3 for observation of a molding article 2 is illuminated, the image is picked up by a video camera 6 and the image signal is inputted to an A/D converting circuit 9 of an image processing part 7. Image data outputted from the A/D converting circuit 9 are inputted to a processing area setting circuit 11 and a range to be processed is set as a processing area. In a solid phase candidate area detecting circuit 12, image data higher than prescribed luminance are detected as a solid phase candidate area out of the image data inside the processing area. The areas of the respective solid phase areas are added and the total area of the solid phase areas is measured. Then, the ratio of the total area of the solid phase areas and the area of the processing area is calculated by a solid phase rate calculating circuit 14 and the solid phase rate is obtained. Further, the size of each solid phase area and the distribution of number of the solid phase area are calculated by a solid phase area distribution detecting circuit 15 and the distribution data are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thixomold molding state evaluation method and apparatus for evaluating the molding state of a thixomold molded article.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a thixomolding method (molding using the properties of thixotropy) from the viewpoint of reducing the size and weight of a molded article, improving strength, or recycling. In the thixomolding method, an alloy material (for example, an alloy of aluminum and magnesium) in which a solid phase and a liquid phase are mixed at a predetermined temperature is injected into a mold by an injection molding machine. The thixomolded product made by this is
Solid metal particles are mixed in the molten metal that was liquid at the time of injection. Thixomolded products are higher in strength than molded products formed by the die casting method or the like using the same alloy material.Thus, by using a metal having a small specific gravity, for example, aluminum or magnesium, a lightweight and high-strength product is used. A molded article can be obtained. The thixomolding method is under development and research and development are being actively conducted. In such a situation, it is important to evaluate the molding state of the thixomolded article, but the evaluation method has not been established yet, and the development of an apparatus for quantitatively and quickly evaluating the molded article is desired. Hereinafter, an example of a conventional method for evaluating a molding state will be described with reference to the drawings.

FIG. 6 is a configuration diagram of a conventional molding state evaluation apparatus by visual observation. The cross section 23 to be observed is formed by partially shaving the surface of the object 22 to be evaluated placed on the positioning table 21 shown in FIG. A microscope 24 and an illuminating device 25 are installed to observe the cross section 23, and a camera 26 is attached to the microscope 24 to take a photograph of the cross section. A diagram schematically showing the photographed micrograph 27 shown in FIG. 6B will be described. First, Photo 2
Measure the overall weight of the. Next, a portion that was solid at the time of molding, that is, a portion of the solid-phase region 28, which was photographed as a white or black region in the photograph 27, is cut out with scissors or a knife.
Then, the total weight of a large number of cut small pieces shown in FIG. 6C is measured. Finally, the ratio of the weight of the photograph 27 to the total weight of the small pieces is determined, and the solid phase ratio, which is the ratio of the solid phase region to the entire region, is calculated from the weight ratio.

[0004]

However, in the method for evaluating the molding state for obtaining the solid fraction as described above, since the manual cutting operation is used, the accuracy of the evaluation is lacking, and the evaluation operation takes time. There was a problem.
SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and performs a thixotropic evaluation of a molding state quantitatively and quickly using video image processing, which can be used for research and development of a molding method and adjustment of a process. An object of the present invention is to provide a molding state evaluation device.

[0005]

In order to achieve this object, a method and an apparatus for evaluating the state of thixomold molding according to the present invention use an image input means for simulating a cross section of a thixomold molded article (hereinafter abbreviated as molded article). And image input means;
The solid phase region of the molded article is extracted from the image input by the image input means. It is characterized in that a characteristic quantity such as a solid phase ratio that quantitatively represents a molding state is calculated based on each solid phase region.
The solid phase region in the video of the input image and the other regions have different brightness. The total area of the solid phase region is determined based on the difference in brightness, and the solid phase ratio is determined from the ratio of the total area to the total area of the solid phase region.

The thixomolding state evaluation apparatus of the present invention is characterized by further comprising means for measuring the size and distribution of each solid phase region. The size and distribution of the solid phase region are measured based on the difference in brightness between the solid phase region and the other regions in the image of the input image. This allows a more detailed evaluation of the molding state.

[0007] The thixomold molding state evaluation apparatus of the present invention creates a cross section for observation of a molded article at a plurality of places such as a place near or far from the injection part at the time of injection molding, and comprehensively evaluates observation results at a plurality of places. I do. As a result, it is possible to evaluate the overall molding state without bias to a part of the molded article.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a thixomolded state evaluation apparatus according to an embodiment of the present invention. The molding 2 of the object to be evaluated, which is placed on a positioning table 1, has an observation section 3 with a partially cut surface. An illumination device 4 is provided above the molded product 2 to illuminate the observation section 3. The illuminating device 4 irradiates light substantially perpendicularly to the observation section 3 by using, for example, an incandescent lamp as a light source. Since the solid phase region has a higher light reflectance than the other portions, the luminous intensity of the reflected light in the solid phase region is higher than the other portions. A television camera 6 having a microscope lens supported by a movable support 5 is provided opposite to the observation section 3, whereby the observation section 3 is provided.
Is imaged. The TV camera 6 is a TV camera control circuit 8
Is controlled by The video signal output from the television camera 6 is input to an analog / digital conversion (hereinafter, referred to as A / D conversion) circuit 9 of an image processing unit 7 connected via a television camera control circuit 8 to reduce the brightness of the image. Depending on,
For example, the image data is converted into image data of 0 to 255 (256 gradations) and is digitized.

The image processing unit 7 further includes a CPU 10 as judgment control means to which command signals 30 and 31 for starting the operation of the evaluation device and the like are given from an external main controller or an operation panel (not shown). The CPU 10 includes a processing area setting circuit 11 for specifying a processing area for image processing, a solid phase candidate area detecting circuit 12 for determining a threshold value and detecting a solid phase candidate area, and a size of the area of the detected solid phase candidate area. A solid phase region determination circuit 13 for determining a solid phase region using feature amounts such as a solid phase ratio; a solid phase ratio calculation circuit 14 for calculating a solid phase ratio (= total solid phase region area / processing area area); Is connected to a solid-phase region distribution detecting circuit 15 for detecting a distribution state according to the size of the solid-phase region.

The operation of the thixomolded state evaluation apparatus constructed as described above will be described with reference to the flowchart of FIG. The observation section 3 of the molded article 2 to be inspected placed on the positioning table 1 is illuminated by the illuminating device 4, imaged by the television camera 6, and the output image signal is processed through the television camera control circuit 8 for image processing. A / D of part 7
The data is input to the conversion circuit 9 (step 1 in the flowchart of FIG. 2). Since the light reflectance of the solid phase region is higher than that of the other portions, the brightness of the solid phase region in the image signal is higher than the brightness of the other portions. The image data output from the A / D conversion circuit 9 is A
The data is input to the processing area setting circuit 11 connected to the output terminal of the / D conversion circuit 9, and the processing range is set as the processing area (step 2).

The image data in the processing area set by the processing area setting circuit 11 is input to a solid phase candidate area detection circuit 12. The solid-phase candidate area detection circuit 12 detects an image data in the processing area having a luminance higher than a predetermined luminance as a solid-phase candidate area (step 3). FIG.
(A) shows the solid-phase candidate regions 19A, 19B, and 19C. Since the solid-phase candidate regions are detected based on the threshold value of luminance, all solid-phase candidate regions are detected if they have high luminance. For example, a small flaw or adherence on the observation section 3 may be detected as the solid phase candidate region 19A. Further, when the observation section 3 is formed by cutting, a wide surface having a high reflectivity is formed depending on the cutting state, and these may be detected as the solid phase candidate region 19B. Therefore, in order to select only a true solid phase region from the solid phase candidate regions 19A, 19B, and 19C, a predetermined area range is set, and a predetermined area range within the solid phase candidate regions 19A, 19B, and 19C is set. Is determined to be a true solid phase region. In the example of FIG. 3A, the area range is set so that the solid-phase candidate regions 19A and 19B are excluded. As a result, the solid phase candidate region 19C is determined as a solid phase region (step 4).

An example of a specific processing method of step 4 will be described below. The duration when image data of the solid phase candidate region having high brightness continuously occurs is measured, and if it is equal to or longer than a predetermined upper limit time, the solid phase candidate region is determined to be equal to or larger than the predetermined upper limit area. I do. Similarly, if the duration is equal to or shorter than the predetermined lower limit time, it is determined that the solid phase candidate region is equal to or smaller than the predetermined lower limit area. FIG. 3B shows an example of the processing area 19 in which only the solid phase region 20 selected by the above processing exists. Next, the total area of the solid phase regions is measured by adding the areas of the individual solid phase regions (step 5). The measurement of the area in step 5 can be performed by accumulating the time during which image data having high luminance occurs during the processing time of the processing area 19. The ratio of the total area of the solid phase region to the area of the processing area is calculated by a solid phase ratio calculation circuit 14
Is calculated to obtain the solid fraction (step 6). Further, the distribution of the size of each solid phase region and the number of the solid phase regions is calculated by the solid phase region distribution detection circuit 15 to obtain distribution data shown in the graph of FIG. 4 (step 7).

As shown in FIG. 5, the molded article 2 may be provided with a plurality of cross sections 35 and 36 for observation. In this case, a plurality of portions such as a cross section 35 of the molded product near the protrusion 34 formed by the injection hole and a cross section 36 far from the protrusion 34 formed by the injection hole when the molding material is injected into the mold are cut to obtain a plurality of observation objects. A cross section may be provided. By performing the above-described steps 1 to 7 on each of a plurality of observation sections, the solid phase ratio and distribution of the solid phase region of the entire molded article can be detected, and more accurate evaluation can be performed.

The thixomolding state evaluation device can be connected to an injection molding machine, and the detection result of the solid phase ratio can be input to the injection molding machine online for control. For example, when the solid fraction is low, automatic adjustment and control of the injection molding machine can be performed, such as lowering the temperature at the time of injection.

[0015]

According to the present invention, the cross section for observation of the molded article is imaged by the television camera, and the solid phase region is detected based on the obtained video signal. It is possible to accurately evaluate the molding state with a small amount.

[Brief description of the drawings]

FIG. 1 is a block diagram of a thixomold forming state evaluation apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart of the operation of the embodiment.

FIG. 3A is a diagram showing an example of a solid-phase candidate region in a processing area. (B) is a diagram showing an example of a solid phase region in a processing area.

FIG. 4 is a graph showing the size and the number of solid phase regions.

FIG. 5 is a layout view of a cross section for observation of a molded product.

FIGS. 6A to 6C are configuration diagrams of a conventional thixomolded state evaluation apparatus.

[Explanation of symbols]

 Reference Signs List 1 Table 2 Molded product 3 Observation section 4 Illumination device 5 Movable support unit 6 TV camera 7 Image processing unit 8 TV camera control circuit 9 Analog / digital conversion circuit 10 CPU 11 Processing area setting circuit 12 Solid phase candidate area detection circuit 13 Solid phase Area determination circuit 14 Solid phase ratio calculation circuit 15 Solid phase area distribution detection circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G051 AA90 AB20 BA20 CA03 CA04 CB01 DA07 EA12 EB01 EB02 2G059 AA03 AA05 BB08 BB15 CC20 EE02 FF01 GG10 JJ11 KK04 MM01 MM09 5B057 AA17 CC03 CE09 DA01 DB02 DC04

Claims (5)

[Claims] 1. An apparatus for analyzing and evaluating a molding state of a thixomold molded product, comprising: an image capturing means for capturing a cross section of the thixomold molded product; and an image signal output from the image capturing means. A thixomolding state evaluation device, comprising: means for detecting a solid phase region in a cross section; and means for calculating a characteristic quantity representing a state of a solid phase in each solid phase region. 2. The thixomold forming state evaluation apparatus according to claim 1, further comprising means for measuring the size and distribution of each solid phase region. 3. The solid-phase region detecting means detects the solid-phase region based on a difference between a solid-phase region and another region of a luminance signal included in the image signal. The thixomold forming state evaluation device according to claim 1. 4. The apparatus according to claim 1, wherein the means for calculating the characteristic amount synthesizes a measurement result of a cross section at a position close to the injection unit and a cross section at a position away from the injection unit of the molding apparatus for a thixomolded product. Item 3. The thixomold molding state evaluation device according to Item 1. 5. A method for analyzing and evaluating a molding state of a thixomold molded product, comprising: a step of imaging a cross section of the thixomold molded product by image capturing means; A step of detecting a solid phase region of the cross section on the basis of the solid phase region, and a step of calculating a characteristic amount representing a state of a solid phase in each solid phase region.