Bringing inspection into the light: automated fluorescent dye inspection of mass-produced metal parts

Abstract

We report further on a fully automated fluorescent dye inspection system which can also be used under normal lighting/ daylight conditions and can detect every single relevant indication on millions of parts without affecting production throughput rates. Currently, the dark-room conditions and enclosed inspection cells required for dye penetrant inspection of cast components increase manpower, reduce floorspace and are the cause of severe production bottlenecks and low throughput rates at inline inspection points. Moreover, reliance on human inspection, attention span and skill levels are approaching their limit. The variation between human inspectors often results in quality standard inconsistencies and the failure to detect defects altogether. We present examples from the aerospace, automotive industries of an automated NDT inspection system that: ‐ <ul> <li>Removes the production bottleneck problem by enabling inspection of parts to be performed under bright light conditions.</li> <li>Reduces reliance on human inspectors with fully automated software solution that characterise indications as either relevant or non-relevant by applying criteria based on indication size, geometric shape, and brightness.</li> <li>Generates a full report, including () the initial raw data image, () photographic image of the part with the relevant indications overlaid on top, () fully annotated with measurements/comments and () the option to overlay indication information on top of a 3-D surface in an STL file.</li> <li>Scans a part at least 10 X faster than a human inspector and can find every defect on millions of inspected components to provide full 100% Quality Audit and which reduces inspection costs by 90%.</li> <li>Permanently stores all captured images (pass or fail) for traceability of parts even after they have entered service. </li> <li>Repeatedly achieves measurement tolerances that are better than 5 thousandths of an inch. (We present detailed results from extensive characterisation and Gauge R&R trials with several large aerospace castings manufacturers in the United States).</li> </ul>