Abstract
A new method and optical system have been developed to detect crack initiation during bending and hemming, and to characterize the surface quality on the bent/hemmed region. To detect the initiation of cracking during hemming, the cumulative lengths of micro-cracks are plotted against the total numbers of micro-cracks. The maximum number of micro-cracks is used to detect the initiation of cracking as the micro-cracks merge to form macro-cracks. The average length of the micro-cracks from each captured image of the hemline surface is used as an index for surface quality evaluation. Experimental results on the hemmed surface of an AA6111-T4 sheet demonstrate the validity of the proposed method. Furthermore, the average lengths of micro-cracks corresponding to cracking are found to be nearly constant, regardless of hemming process conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 49-55 |
| Number of pages | 7 |
| Journal | Transactions of the North American Manufacturing Research Institute of SME |
| Volume | 33 |
| Publication status | Published - 2005 |
| Externally published | Yes |
| Event | North American Manufacturing Research Conference, NAMRC 33 - New York, NY, United States Duration: 24 May 2005 → 27 May 2005 |
Keywords
- Average length
- Cumulative length
- Hemming
- Image processing
- Surface crack