FOERFARANDE OCH ANORDNING FOER TILLVERKNING AV EN PERFORERAD ROERFORMING PLASTFILM MED HJAELP AV EN LASERSTRAOLE, EN PERFORERAD ROERFORMIG PLASTFILM SAMT EN AV DYLIK ROERFORMIG PLASTFILM BILDAD PLASTFILM.

摘要

PCT No. PCT/NL89/00049 Sec. 371 Date Nov. 29, 1990 Sec. 102(e) Date Nov. 29, 1990 PCT Filed Jun. 15, 1989 PCT Pub. No. WO89/12540 PCT Pub. Date Dec. 28, 1989.A continuously conveyed tubular plastic foil is perforated by a laser beam which is focused by a mirror or lens on the perforation forming plane, lying at the focal point of the mirror or lens, of a tautly conveyed tubular plastic foil. For taut conveyance of the tubular foil it is guided over a support placed in the tubular foil, or over supporting plates, lying outside the tubular foil and provided with a foil suction device and with laser beam transmission apertures. The slightly tapering perforations with a minimum aperture at the inside of the tubular foil form, on the one hand, a pattern of parallel lines running in the lengthwise direction and, on the other hand, a pattern of parallel lines 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 apparatus for perforation is made up of, in addition to a laser beam source, a lens beam-directing device and a lens or mirror, a support to be placed in a tubular foil, or supporting plates, provided with apertures and with foil suction apertures, for taut conveyance of the tubular foil in a perforation forming plane.