Bottle-Can Screw Part Inspection Using Diagonal Illumination
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Solution Overview
Problem
Existing inspection methods for screw parts of bottle-cans are complex, time-consuming, and struggle to accurately detect deformations like bends, requiring cumbersome processes such as coloring the thread-starting part.
Innovation Solution
The inspection equipment uses diagonally irradiated illumination light to emphasize the lower inclined surface of the screw part, allowing for clear detection of the thread-starting and ending parts, and incorporates a curl portion-illumination device to specify reference positions, enabling precise and rapid inspection by separating reflected lights and preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional inspection methods using outline images are used, then the inspection process can be performed, but the process becomes complex and time-consuming
Solution Approach 1:
The invention extracts and emphasizes only the critical inspection target (screw part) by projecting illumination light specifically onto it, separating it from the background. This allows direct imaging of the screw part without needing to process entire outline images, thereby simplifying the inspection process and reducing time while maintaining accuracy
Solution Approach 2:
The invention changes from two-dimensional outline image processing to three-dimensional surface imaging by projecting light onto the screw part surface and capturing the reflected light patterns. This dimensional transition enables direct observation of screw part geometry including thread depth, ridge lines, and surface defects without complex image processing
2Measurement precision
If conventional illumination methods are used, then the screw part can be imaged, but deformation detection such as bends is difficult
Solution Approach 1:
The invention applies localized illumination specifically to the screw part region rather than uniform illumination of the entire bottle-can. By projecting light at specific angles onto the screw part surface, the method enhances local surface features and defects, making deformations such as bends and thread anomalies clearly visible for precise measurement
Solution Approach 2:
The invention utilizes changes in light reflection patterns (analogous to color changes) on the screw part surface caused by deformations. When the bottle-can rotates, variations in reflected light intensity and pattern reveal surface irregularities, thread depth changes, and geometric deviations, enabling accurate detection of deformations that would be invisible under conventional illumination
3Measurement precision
If the thread-starting part is colored beforehand for detection, then the circumferential position can be specified, but additional processes are required
Solution Approach 1:
The invention enables the screw part itself to serve as the detection marker by utilizing its inherent geometric features (thread ridges, grooves, and surface structure) to reflect illumination light. The thread-starting part position is automatically identified through light reflection patterns without requiring any external marking or coloring processes, thereby simplifying manufacturing while maintaining detection precision
Solution Approach 2:
The invention replaces the mechanical/chemical marking process (coloring the thread-starting part) with an optical detection method. By using structured illumination and analyzing light reflection patterns from the screw part surface, the system automatically identifies the thread-starting position based on geometric features alone, eliminating the need for additional marking processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for quick and accurate detection of the thread-starting part and inspection of the screw part, reducing inspection time and improving precision by emphasizing the inclined surface and using flickering illumination to enhance image clarity.
Implementation Method 1
obtain an inspection image by imaging reflected light of illumination light from the screw part
Data Source
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AI summary
Inspection equipment for screw part of bottle-can which can reliably inspect the screw part of the bottle-can in a short time is provided. Inspection equipment for a screw part 2 of a bottle-can 4 having a mouth section 3 provided with a curl portion 1 in which an opening edge thereof is rolled up outward and the screw part 2 for fitting a cap by threads below the curl portion 1 for attaching the cap with a liner, the inspection equipment inspects a shape of the screw part 2 of the mouth section 3 by imaging an imaging area which is set so as to include a part of the mouth section 3 while rotating the bottle-can 4 around a can-axis X, the inspection equipment including: a rotating device 21 which holds and rotates the bottle-can 4 around the can-axis; a thread-illumination device 22 which irradiates illumination light A toward the screw part 2 of the bottle-can 4 in the imaging area diagonally upward from a radially outside and can-axially lower part; an imaging device 24 which continuously obtains inspection images including reflected light A' of the illumination light A at the imaging area; and an thread-inspection device 25 which inspects the screw part 2 including a thread-starting part by detecting the thread-starting part of the screw part 2 based on an imaging result of the reflected light A'.