| 摘要 |
<p>A cementitious tile (54) is perforated using a punch (10) of elongate section having a leading face (16) with a saw tooth profile along its length. The punch (10) may also be used to produce indentations (A) which look like perforations when in situ. Circular punches (10) also having a saw tooth profile may be used. The tooth depth is preferable less than 2 mm and the included angle of the tooth profile between 90° and 150°. The punches (10) produce exceptionally clean edges in the tile (54).</p> |
