| 摘要 |
<p>The method involves partially or completely cutting free or punching out a blank from a web material. The blank is embossed or deformed in several steps so that two curvatures (27,26) and a U-shaped cross section (23) are formed. The U-shaped cross section is comprised of an opening width (W1) of 6 mu or less and extended in a longitudinal direction in both the curvatures. The centre points of two curvatures are configured to lie to the side of a limb of the U-shaped cross section and above or below the opening in the U-shaped cross section respectively.</p> |
