Braided wire inspection: catching 54 μm broken strands on a 1.8 m wide line running at 2 m/s
From a colour-recognition test to an in-line inspection plan: chromaticity separates green and yellow braids, and two 33K line-scan cameras in a staggered layout cover the 1,800 mm line width.
Braided wire lines are fast and wide, and defects such as broken or misrouted strands are only a fraction of the wire diameter — far too small and fast for manual checks. Shin Shou first validated the principle on samples, then proposed an in-line inspection plan for the whole line.
Step 1: colour recognition
Imaging with a 5 MP colour camera at about 20 μm under bar lights and converting to a chromaticity map clearly separated green and yellow braids, proving colour conversion is a workable way to check braid colour.
Step 2: in-line inspection plan
- Line width 1,800 mm, production speed 2 m/s
- Wire diameter 0.272–1.0 mm; a defect is 20% of the diameter, so the smallest is about 54.4 μm
- Monochrome line-scan cameras: 33.98K, 28 μm pixels, 84 μm minimum detection, 950 mm field of view, 80 kHz line rate
- Two cameras staggered to cover the full width, with two PCs computing in parallel
Why line scan
For wide products in continuous motion, a line-scan camera builds the image line by line without the stitching boundaries of area cameras, which makes it the best fit for high-speed lines. During installation, working distance and fixtures are adapted to the available space.
