| 摘要 |
<p>Prodn of a row of apertures along a strip edge by cutting a row of slits in the strip edge portion parallel to the strip edge and stretching the portions between the slits and the edge in a direction transverse to the strip major surface planes. These latter portions are then flattened and deformed outwardly in the major surface plane so as to open the slits in these planes. Application is to both metal and plastics sheet but esp. prodn of steel angle members.</p> |
