| 摘要 |
<p>Narrow edge margins (16) of a thin metal sheet (10) for a can body cylinder are cleaned of organic lacquer or other coatings, prior to the sheet being bent into a cylinder and the edges adjacent the margins being welded together to form a longitudinal seam. Cleaning is effected by a beam from a lower-power laser (21) which is distorted into a line spanning the width of the narrow edge margin and which sweeps the length of the latter as the sheet is moved in a direction normal to the beam. The beam intensity is enough to destroy the coating but not enough to cause any damage or metallurgical change in the metal of the sheet. Alternatively the beam may be focussed on the margin as a spot and scanned across it in zig-zag fashion.</p> |
