Chain saw chain dead knot defect detection method

Abstract

The invention discloses a chain saw chain dead knot defect detection method. A chain saw chain dead knot detection mechanism is adopted for detection. When the chain saw chain moves to a dead knot detection station, an industrial camera is adopted for image collection, a PLC sends out a signal at each movement interval, and the camera is triggered to take a picture; the system adopts a stack mode to detect each picture collected by the camera, discriminates the collected pictures, and judges the dead knot defect in a mode of detecting the area of a blank area by calculating the images; when a dead knot defect is detected, data information is sent to the PLC, the system adopts a multi-thread mode to display a judgment result in real time on a picture shot by the camera and a defect picture, and if the dead knot defect exists, a worker can conveniently see the shape of the saw chain defect, and meanwhile, the position of the image of the dead knot defect is displayed on a display interface to display NG. According to the invention, the speed and precision of saw chain defect identification are effectively improved, the omission ratio and production cost of manual detection are reduced, and a dead knot defect chain is effectively prevented from flowing into the market.

Description

Technical Field

[0001] The invention relates to a method for detecting defects of dead joints in a chain saw chain. Background Art

[0002] As the basic component of mechanical transmission, chainsaw chains have the advantages of high transmission rate, high efficiency and long life, and are widely used in various engineering machinery fields. The "dead joint" defect of chainsaw chains (saw chains) refers to the inability of some links on the chain to rotate freely, causing the chainsaw chain to become stuck and not smooth during operation, thus affecting work efficiency and safety. At present, there are four types of detection methods for chainsaw chains. The first type is manual detection. Most domestic chain manufacturers still use manual detection to detect chain knot problems after chain components are assembled. The dead knot defects of chainsaw chains need to be detected by the eyes and hands of inspectors. The second type is mechanical contact detection. This detection method relies on the lever structure between the chainsaw chain and the mechanical components to enable the sensor to obtain the corresponding detection results. The detection speed is slow and the reliability is low. In addition, the probe wears more during the measurement process, and the structure is complicated and easy to damage. The third type is non-contact detection. During the detection, the measuring component does not need to be in direct contact with the chainsaw chain to obtain the detection result. The common method is to use image sensors to detect dead knot defects in chainsaw chains. This is also the most widely used method in automatic chain detection. The fourth type is digital imaging detection. The principle is to use industrial cameras, image detection software and PLC programs to perform real-time detection on each section of the assembled chainsaw chain.

[0003] In the production process of saw chains, due to the limitation of production level, chain saw chain dead knot defects will occur, which have a great impact on the working strength of the tool and the safety of the operator. Therefore, it is urgent to develop a saw chain dead knot defect detection method with fast detection speed and high accuracy to solve the personnel safety accidents caused by improper production. Summary of the invention

[0004] The purpose of the present invention is to provide a chain saw chain dead knot defect detection method that can quickly and effectively detect chain saw chains with dead knot defects, greatly improve production efficiency, reduce the labor intensity of operators, and effectively prevent chain saw chains with dead knot defects from entering the market.

[0005] The technical solution of the present invention is: A method for detecting a chain saw chain dead joint defect, characterized in that: a chain saw chain dead joint detection mechanism is used for detection; the chain saw chain dead joint detection mechanism includes a workbench, a dead joint guide plate assembly is arranged on the workbench, a triangular detection area is formed between the chain saw chain to be detected and the dead joint guide plate assembly, an industrial camera installed on the workbench through a camera bracket is arranged above the triangular detection area, the lens of the industrial camera faces the triangular detection area, an opening is provided on the workbench, and a background light assembly is provided below the table at the opening; the background light assembly includes a dead joint background light source, a backlight source bracket, an acrylic plate, a material receiving tray, and mounting screws, the background light source is fixedly installed on the backlight source bracket by screws, and a transparent acrylic plate is provided below the workbench. The board is fixed on the backlight source by screws at an angle. The inclined installation allows the components dropped on the table to slide through the inclined surface into the receiving tray without affecting the field of view. The acrylic board is transparent to ensure that the light is not blocked. The overall background light component is installed below the table. The opening of the work table is directly below the industrial camera lens to ensure that the overall background light component is directly below the industrial camera lens. The background light source penetrates the dead knot guide plate assembly through the opening of the work table. The blocked position of the chain saw chain and the guide plate under the camera appears as a black area on the image. The unblocked position between the chain saw chain and the guide plate appears as a white blank area on the image, thus ensuring that the dead knot detection station has sufficient black and white contrast. When the chainsaw chain moves to the dead knot detection station, an industrial camera is used to collect images. The PLC sends a signal at each movement interval to trigger the camera to take pictures. The system uses a stacking method to detect each picture collected by the camera, identify the collected pictures, and determine the dead knot defect by calculating the area of ​​the blank area of ​​the image. When a dead knot defect is detected, data information is sent to the PLC. The system uses a multi-threaded method to display the judgment results of the pictures taken by the camera and the defect pictures in real time. If there is a dead knot defect, it is convenient for workers to see the shape of the saw chain defect and NG is displayed on the display interface at the position of the image of the dead knot defect.

[0006] Dead knot defect judgment logic: When the detection chain passes through the dead knot detection structure, the white blank area in the yellow triangle area is calculated within the triangular detection area formed between the chain and the dead knot guide assembly under the backlight assembly structure; if the white area exceeds the set threshold, it is judged as a dead knot defect; if the white area is within the set value range, it is judged as a qualified chain.

[0007] The dead joint guide plate assembly includes an upper guide plate, a middle guide plate, and a lower guide plate; guide plates of different sizes are designed according to different chain sizes, and chains of different specifications and models are suitable by adjusting the dead joint guide plate sharp angle size R1; the above three layers of guide plates are connected into a whole by fixing screws and fixed on the workbench with screws, the lower guide plate supports the transmission plate and supports the sharp angle of the transmission plate, the upper guide plate limits the upper connecting plate of the oil saw chain, and the lower guide plate limits the lower connecting plate of the oil saw chain. The guide plate assembly causes the connecting plate of the oil saw chain to be stressed, and the transmission plate of the oil saw chain is embedded between the upper and lower guide plates.

[0008] The present invention adopts digital imaging detection. Digital imaging has the advantages of non-contact detection and can accurately and intuitively obtain relevant information of chainsaw chain defects, which can greatly improve the detection efficiency, achieve a higher degree of industrial automation, ensure product quality, effectively improve the detection efficiency and detection quality of chainsaw chain dead knots, and greatly reduce the labor intensity of operators.

[0009] The present invention will effectively improve the speed and accuracy of saw chain defect identification, reduce the missed detection rate and production cost of manual detection, meet the requirements of the manufacturing industry to develop in the direction of intelligence and automation, and will bring good economic and social benefits. It will effectively prevent the dead knot defect chain from entering the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0011] Figure 1 It is a structural schematic diagram of a chain saw chain dead joint detection mechanism.

[0012] Figure 2 It is a structural diagram of the background light component.

[0013] Figure 3 It is a structural schematic diagram of the dead joint guide assembly.

[0014] Figure 4 , Figure 5 , Figure 6 , Figure 7 It is a schematic diagram of different states of the system display interface. DETAILED DESCRIPTION

[0015] A method for detecting a chain saw chain dead joint defect, which adopts a chain saw chain dead joint detection mechanism for detection; the chain saw chain dead joint detection mechanism comprises a workbench 1, a dead joint guide plate assembly 2 is arranged on the workbench, a triangular detection area is formed between the chain saw chain to be detected and the dead joint guide plate assembly, an industrial camera 4 is arranged above the triangular detection area and mounted on the workbench through a camera bracket 3, a lens 5 of the industrial camera faces the triangular detection area, an opening is arranged on the workbench, and a background light assembly 6 is arranged below the table at the opening; the background light assembly comprises a dead joint background light source 16, a backlight bracket 7, an acrylic plate 8, a material receiving tray 9, and mounting screws 10, the background light source is fixedly mounted on the backlight bracket by screws, and a transparent The acrylic plate is fixed on the backlight source at an angle by screws. The inclined installation can make the components dropped on the table slide into the receiving tray through the inclined surface without affecting the field of view. The acrylic plate is transparent to ensure that the light is not blocked. The overall background light component is installed below the table. The opening position of the work table is directly below the industrial camera lens, ensuring that the overall background light component is directly below the industrial camera lens. The background light source penetrates through the opening of the workbench to the dead knot guide plate assembly. The blocked position of the chain saw chain and the guide plate under the camera appears as a black area on the image, and the unblocked position between the chain saw chain and the guide plate appears as a white blank area on the image. Therefore, ensure that the dead knot detection station has sufficient black and white contrast, such as Figure 4-Figure 7 As shown; When the chain saw chain 14 moves to the dead knot detection station, an industrial camera is used to collect images. The PLC sends a signal at each movement interval to trigger the camera to take pictures. The system uses a stacking method to detect each picture collected by the camera, identify the collected pictures, and determine the dead knot defect by calculating the area of ​​the blank area of ​​the image. Figure 4 The triangular area is the divided detection area; when a dead knot defect is detected, data information is sent to the PLC. The system uses a multi-threaded method to display the judgment results in real time using the pictures taken by the camera and the defect pictures. If there is a dead knot defect, it is convenient for workers to see the shape of the saw chain defect and the position of the dead knot defect image is displayed on the display interface. NG is displayed, such as Figure 6 , Figure 7 shown.

[0016] Dead knot defect judgment logic: When the detection chain passes through the dead knot detection structure, the white blank area in the yellow triangle area is calculated within the triangular detection area formed between the chain and the dead knot guide assembly under the backlight assembly structure; if the white area exceeds the set threshold, it is judged as a dead knot defect; if the white area is within the set value range, it is judged as a qualified chain.

[0017] The dead joint guide plate assembly includes an upper guide plate 11, a middle guide plate 12, and a lower guide plate 13; guide plates of different sizes are designed according to different chain sizes, and chains of different specifications and models are suitable by adjusting the dead joint guide plate sharp angle size R1; the above three layers of guide plates are connected into a whole by fixing screws 15, and then fixed on the workbench with screws, the lower guide plate supports the transmission plate and the sharp angle of the transmission plate, the upper guide plate limits the upper connecting plate of the oil saw chain, and the lower guide plate limits the lower connecting plate of the oil saw chain. The guide plate assembly makes the connecting plate of the oil saw chain bear force, and the transmission plate of the oil saw chain is embedded between the upper and lower guide plates. In this way, it can be ensured that the chain does not tip over during the dead joint station inspection, and the chain with dead joint defects has a good defect highlighting effect in the triangular detection area. According to the blank area of ​​the collected image, the system determines whether there is a dead joint defect, and can collect pictures of the dead joint defect, so that the dead joint defect can be guaranteed to be detected without omission and error.

Claims

1. A method for detecting a chain saw chain dead joint defect, characterized in that: A chain saw chain dead joint detection mechanism is used for detection; the chain saw chain dead joint detection mechanism includes a workbench, a dead joint guide plate assembly is arranged on the workbench, a triangular detection area is formed between the chain saw chain to be detected and the dead joint guide plate assembly, an industrial camera installed on the workbench through a camera bracket is arranged above the triangular detection area, the lens of the industrial camera is facing the triangular detection area, an opening is opened on the workbench, and a background light assembly is arranged below the table at the opening; the background light assembly includes a dead joint background light source, a backlight source bracket, an acrylic plate, a material receiving tray, and mounting screws, the background light source is fixedly installed on the backlight source bracket by screws, and the transparent acrylic plate is fixed obliquely by screws Installed on the backlight source, the inclined installation can make the components dropped on the table slide down to the receiving tray through the inclined surface without affecting the field of view. The acrylic plate is transparent and can ensure that the light is not blocked. The overall background light component is installed below the table. The opening position of the work table is directly below the industrial camera lens, ensuring that the overall background light component is directly below the industrial camera lens. The background light source penetrates the dead knot guide plate assembly through the opening of the workbench. The blocked position of the chain saw chain and the guide plate under the camera appears as a black area on the image. The unblocked position between the chain saw chain and the guide plate appears as a white blank area on the image, thus ensuring that the dead knot detection station has sufficient black and white contrast; When the chainsaw chain moves to the dead knot detection station, an industrial camera is used to collect images. The PLC sends a signal at each movement interval to trigger the camera to take pictures. The system uses a stacking method to detect each picture collected by the camera, identify the collected pictures, and determine the dead knot defect by calculating the area of ​​the blank area of ​​the image. When a dead knot defect is detected, data information is sent to the PLC. The system uses a multi-threaded method to display the judgment results of the pictures taken by the camera and the defect pictures in real time. If there is a dead knot defect, it is convenient for workers to see the shape of the saw chain defect and NG is displayed on the display interface at the position of the image of the dead knot defect.

2. The method for detecting a chain saw chain dead joint defect according to claim 1, characterized in that: Dead knot defect judgment logic: When the detection chain passes through the dead knot detection structure, the white blank area in the yellow triangle area is calculated within the triangular detection area formed between the chain and the dead knot guide assembly under the backlight assembly structure; if the white area exceeds the set threshold, it is judged as a dead knot defect; if the white area is within the set value range, it is judged as a qualified chain.

3. The method for detecting a chain saw chain dead joint defect according to claim 1 or 2, characterized in that: The dead joint guide plate assembly includes an upper guide plate, a middle guide plate, and a lower guide plate; guide plates of different sizes are designed according to different chain sizes, and chains of different specifications and models are suitable by adjusting the dead joint guide plate sharp angle size R1; the above three layers of guide plates are connected into a whole by fixing screws and fixed on the workbench with screws, the lower guide plate supports the transmission plate and supports the sharp angle of the transmission plate, the upper guide plate limits the upper connecting plate of the oil saw chain, and the lower guide plate limits the lower connecting plate of the oil saw chain. The guide plate assembly causes the connecting plate of the oil saw chain to be stressed, and the transmission plate of the oil saw chain is embedded between the upper and lower guide plates.

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