| 摘要 |
<p>Apparatus is provided for measuring residual thickness of metal beneath a score line (4) provided in a metal can end (6) for facilitating opening of the can. The apparatus comprises a carrier means (14) for supporting the can end and first and second measuring means (18,20) of known distance apart arranged to be on opposite sides of the can end. At least the first measuring means (18) comprises a conoscope adapted to direct a beam of radiation at that surface of the can end (6) provided with the score line (4) at a location of the score line whereby the residual thickness can be determined.</p> |
