Crash-Safety Auto Airbag Igniter Inspection
Gauging the status of a hair-thin wire in 0.5 seconds.
The challenge was to accurately check for the presence and integrity of a .003 in. (.08mm) thick bridge wire that is spot welded across a glass insulator at the bottom of a .125 in. (3.2mm) diameter steel cup. Difficulties included sufficiently lighting the interior of the cup while allowing the camera a proper view and to do so at a constant assembly line speed.
Newton engineers developed a custom, miniature on-axial illuminator using beam-splitters that enabled the camera and illumination to share the same light path. The light source emitted polarized light which reduced reflections and glare from the image. The camera and lighting system was assembled into a dark-shrouded machine that was capable of processing two lines of parts for verification at a throughput of 24 parts per minute and with a stable inspection time of approximately half a second.