JPS63274808A - Method for inspecting sectional shape of can seaming part - Google Patents

Abstract

PURPOSE:To perform the safe, speedy, and easy inspection and measurement of respective points of a seaming part which are enough to obtain a reliable inspection result by using X-ray transmission information on the section of the seaming part. CONSTITUTION:An X-ray is projected on the seaming part 4 of a can 1 in its tangential direction and the X-ray which is transmitted through the seaming part 4 is inputted to an X-ray camera 11 as X-ray fluoroscopic information on the section of the seam parting 4. The camera 11 converts the input X-ray fluoroscopic information into an electric signal and outputs it to an image processor 12. The image processor 12 emphasizes a part having contrast larger than a constant reference to extract an image of the regular section 4a of the seaming part 4. The extracted sectional image of the seam parting 4 is displayed on a display 13. Consequently, an inspector inspects the sectional shape of the can seaming part 4 visually according to the sectional image on the display 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for inspecting the cross-sectional shape of a seamed portion of a metal can used as a container for canned food or the like. [Prior Art] Metal cans used as containers for canned foods, etc. are made up of a can body, nine can lids, and a can bottom. In the case of so-called three-piece cans, the can body has a can lid and a can bottom. In the case of a two-piece can in which the can body and can bottom are integrated, it is constructed by wrapping the can lid around one can body.
Efforts are being made to keep canned goods sealed. The seaming part of this can body and can M (hereinafter referred to as one can lid including the can bottom) is connected to a podium hook (B H ) and a cover hook (CH) formed on the outer periphery of the can lid are engaged and crimped. The quality of this seaming part has a great effect on maintaining the quality of the contents filled in the can. That is, Podehook (B
Cans with defects in the seaming part, such as because the overlapping part (OL) between H) and cover hook (CH) is not long enough, will cause problems such as spoilage of the contents due to poor sealing. For this reason, it is necessary to periodically inspect the cross-sectional shape of the seamed portion of cans that have undergone the seaming process to control the process to prevent the occurrence of poorly seamed cans. The conventional method for inspecting the cross-sectional shape of the seamed part of a can is to cut the seamed part in the axial direction using a scroll saw to make the cross section inside the seamed part visible. It was for measuring dimensions. In addition, such inspections and measurements are usually performed at only three locations around the entire circumference of the seaming portion, since cutting with a scroll saw requires time and effort. [Problems to be Solved] As mentioned in L, the conventional method for inspecting the cross-sectional shape of the seaming part of a can is to set three inspection and measurement points by cutting the seaming part using a scroll saw. I was doing it. However, this cutting operation is troublesome and involves the risk of cutting fingers. In addition, there is a pode hook (BH) in the seaming part. The tip of the cover hook (CH) often has irregular undulations at short intervals due to seaming. Therefore, the quality of the entire circumference of the seaming part is judged based on inspection and measurement at about three locations. Conventional methods also had the problem of lack of reliability.6 The present invention was made to solve these problems, and it uses fluoroscopic information, especially fine focus X-rays, on the seaming part. The present invention provides a method for inspecting the cross-sectional shape of a seamed portion of a can that uses information to safely, quickly and easily inspect and measure each point of the seamed portion sufficient to obtain reliable inspection results. purpose. [Means for Solving the Problems] In order to achieve the above object, the method for inspecting the cross-sectional shape of a seamed portion of a can of the present invention projects X-rays in a tangential direction to the seamed portion of a can to be inspected, and X-rays transmitted through the seaming part
X-ray fluoroscopic information of the cross section of the seaming part is obtained by inputting it to the ray camera, and this X-ray fluoroscopy information is further image-processed to obtain a cross-sectional image of the seaming part, and based on this image, the cross section of the can seaming part is This is a method for inspecting the shape. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings. First, an example of an apparatus for carrying out the method of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an example of the device, and FIG. 2 is a cross-sectional view of the tightening section every spring. In FIG. 1, reference numeral 1 denotes a can to be inspected, and a seaming portion 4 for connecting the can 1→2 and a can lid 3 is formed at the end in the axial direction. As shown in FIG.
H) and a cover hook (C
H) are formed by firmly interlocking with each other in a crimped state. In order to judge the quality of this seaming part 4, for example, the podium hook (BH), the cover hook (CH), their overlapping part (OL), and the upper clearance (UC)
, condition of lower clearance (LC) etc. 818! A dormitory will be required. 10 is an X-ray tube as an X-ray source. The X-ray energy emitted by the X-ray tube 10 is desirably set to a value as shown in the table below, depending on the materials of the can 142 and the can lid 3. Reference numeral 11 denotes an X-ray camera, into which X-ray fluoroscopic information regarding the seaming portion 4 is input. That is, the X-ray tube 10 and the X-ray camera 1
1, the winding of the can 1 and the tightening section 4 are arranged, and the X-rays transmitted through the tightening section 4 are inputted as X-ray fluoroscopic information regarding the tightening section 4. Here, the can 1 is arranged such that the tangent to the seaming portion 4 is along the line of the X-ray 10a. The X-ray 10a
transmits through the area shown by hatching in FIG. Therefore, the X-ray fluoroscopic information manually input to the X-ray camera 1 is a combination of the cross-sectional fluoroscopic information of all the parts indicated by the hatching above, and is not information obtained only from the cross-section 4a of the seaming part 4. Therefore, the image In the process of processing, it is necessary to extract a cross-sectional image of the seaming portion from the xMA fluoroscopic information. 12 is an image processing device that performs image processing to extract a cross-sectional image of the seaming portion from X-ray fluoroscopic information; By using a certain level of contrast as a standard and emphasizing the parts with contrast that exceeds that standard and cutting out the parts that are below the standard, it is possible to extract an image that approximates the true cross-sectional image of the seaming part. . Note that all of this image processing is performed using a computer or the like, and the cross-sectional image of the seamed portion 4 obtained in this way is displayed on the display 13. Next, a method of inspecting the cross-sectional shape of a can seaming portion using the above-mentioned device will be described. X-rays are projected from the tangential direction onto the seam portion 4 of the can 1, and the X-rays that have passed through the seam portion 4 are input to the X-ray camera 11 as X-ray fluoroscopic information of the cross section of the seam portion. X-ray camera 11
converts this input X-ray fluoroscopy information into an electrical signal,
Output to the image processing device 12. In image processing technology 12,
An image of the normal cross section 4a of the seaming portion 4 is extracted by emphasizing a portion having a contrast exceeding a certain standard. The cross-sectional image of the seaming portion 4 extracted in this way is displayed on the display 13, so the inspector can visually inspect the cross-sectional shape of the can seaming portion 4 based on the cross-sectional image on the display 13. Can be done. The cross-sectional image of the seaming portion 4 displayed on the display 13 has a shape substantially similar to the cross-sectional shape of the seaming portion 4 shown in FIG. 2 in the case of a normal seaming portion 4. That is,
The pod hook (BH), cover hook (CH), and their overlapping portion (OL) are shaped to maintain sufficient length. On the other hand, if the seaming part 4 is defective, any or all of the above parts are short and the engagement is incomplete. Therefore, if these judgments are made based on the cross-sectional image of the seaming portion 4 displayed on the display, it is possible to easily and quickly detect cans that are poorly seamed. By performing such an inspection by rotating the can l relative to the X-rays, the entire circumference of the seamed portion can be inspected. Next, FIGS. 3(a) and 3(b) are diagrams showing an example of an apparatus equipped with means for preventing halation occurring at the periphery of the cross-sectional image of the seaming portion. The cross-sectional image of the seaming portion 4 displayed on the display 13 is
Halation occurs at the periphery due to the diffraction phenomenon of X-rays, which may make the outline of the periphery unclear. Therefore, in order to prevent this halation, as shown in the figure (a),
In this case, the holder 21 is placed close to or in contact with the circumferential edge of the winding portion 4 at least on the X-ray line. Thereby, the difference in brightness between the seaming portion 4 and its outer periphery is reduced, and halation can be prevented. In addition, in the same figure (b),
A wedge-shaped filter 22 is inserted on the X-ray line to similarly reduce the difference in brightness between the wrapped portion 4 and its outer periphery, thereby preventing halation. Here, the reason for the wedge shape is to adjust the four amounts that block the X-rays according to the difference in the thickness of the seamed portion through which the X-rays pass. By intervening such anti-halation means. By obtaining X-ray fluoroscopic information, it is possible to eliminate dimensional errors in various parts caused by halation in the cross-sectional image of the seamed portion, and it is possible to inspect the cross-sectional shape of the can-sealed portion with higher accuracy. Note that the present invention is not limited to the embodiments described above, and includes, for example, the following modifications. ■Based on the cross-sectional image of the tightening part each spring, the dimensions of each part of the can tightening part, such as podium hook (BH), cover hook (C
H), the total length of these overlapping parts (OL) and seaming parts (W)
A method for inspecting the cross-sectional shape of a can-sealed part by measuring the ■A method for inspecting the cross-sectional shape of a can-sealed portion using various known image processing techniques as image processing means for X-ray fluoroscopic information. A method for inspecting the cross-sectional shape of can seaming parts other than displays using a cross-sectional image of the zero seaming part. <4) A cross-sectional shape inspection dimension of a can-sealed portion that automatically determines whether the cross-sectional shape of a can-sealed portion is good or bad based on the obtained cross-sectional image of the seam-sealed portion. [Effects of the Invention] As described below, according to the present invention, by using X-ray fluoroscopic information of the cross section of the seamed portion, inspection and measurement of each point sufficient to obtain reliable inspection results can be safely performed. Moreover, it has the advantage of being quick and easy to carry out.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an example of an apparatus for carrying out the method of the present invention, Fig. 2 is a cross-sectional view of a can seaming part, and Fig. 3 (
FIGS. 3A and 3B are configuration diagrams each showing an example of a device equipped with an anti-halation IF means.

Claims (2)

[Claims] (1) X-ray fluoroscopic information of the cross-section of the seam is obtained by projecting X-rays tangentially to the seam of the can to be inspected, and inputting the X-rays that have passed through the seam into the X-ray camera. The cross-sectional shape inspection of the can-sealed portion is characterized in that the X-ray fluoroscopic information is further image-processed to obtain a cross-sectional image of the seared portion, and the cross-sectional shape of the can-sealed portion is inspected based on this image. Method. (2) Inspection of the cross-sectional shape of a can-sealed portion according to claim 1, characterized in that X-rays are input into an X-ray camera through a means for preventing halation occurring at the periphery of a cross-sectional image of the seam-sealed portion. Method.