| 摘要 |
<p>An apparatus for perforating thermoplastic sheet material comprises a platen for supporting the sheet material and means for carrying an array of heated pins (14). The array of heated pins is brought into contact with the sheet material held on the platen whereby to perforate it. The pins are heated electrically, and preferably each needle is individually heated. Temperature is preferably controlled within the range 360 to 410 DEG C in order to obtain a clean perforation.</p> |
