| 摘要 |
A system for precision perforation of moving webs employing a pulsed, fixed focus laser beam wherein the laser pulses are automatically controlled in pulse repetition frequency and in pulse width to provide a desired preset web porosity. Closed loop circuitry responsive to web speed, sensed web porosity, and a porosity preset signal provides the precise system control needed to produce and maintain the preset porosity over a wide range of system variables. The illustrative embodiment described is particularly useful for perforating paper, film, and like materials where a high degree of product uniformity and porosity control is desired. |
