PROCESS AND INSTALLATION OF MANUFACTURING A PERFORATED TUBULAR PLASTIC FOIL BY ACTION OF A LASER BEAM, PERFORATED TUBULAR PLASTIC FOIL AND PLASTIC BAG FORMED FROM SUCH A TUBULAR PLASTIC FOIL

摘要

A continuously conveyed tubular plastic foil (1) is perforated by a laser beam which is focused by means of a mirror or lens (12) on the perforation forming plane (13, 13'), lying at the focal point of the mirror or lens (12), of a tautly conveyed tubular plastic foil. For taut conveyance of the tubular foil (1) it is guided over a support (14) placed in the tubular foil, or over supporting plates (15, 15a) lying outside the tubular foil and provided with foil suction means (17) and with laser beam transmission apertures (16). The slightly tapering perforations (2) with a minimum aperture at the inside of the tubular foil (1) form, on the one hand, a pattern of parallel lines (A) running in the lengthwise direction and, on the other hand, a patterm of parallel lines (B) which run at an angle relative to the longitudinal axis of the flattened tubular foil. A bag can be formed from the tubular foil. An installation for perforation comprises, in addition to a laser beam source (11), lens beam-directing means (18) and a lens or mirror (12), a support (14) to be placed in a tubular foil, or supporting plates (15, 15a) provided with apertures (16) and with foil suction apertures (17), for taut conveyance of the tubular foil in a perforation forming plane (13, 13').