| 摘要 |
A method and apparatus for perforating sheet material wherein the resulting perforations are in a predetermined pattern which avoids imparting structural weakness to the perforated sheet material. The predetermined pattern includes spaced perforations along linear paths which are spaced along one linear dimension of the sheet material and each of which paths is disposed at an acute angle relative to another linear dimension of the sheet material. The predetermined pattern avoids straight paths of perforations along the longer linear dimension of the sheet material and thereby avoids imparting structural weakness to the material. Preferably the predetermined pattern is a series of herringbone patterns along the longitudinal dimension of the sheet with the rows of herringbone patterns and peaks thereof extending laterally of the sheet material. The pattern is formed by moving the sheet material in a first direction and scanning the material in a second direction with a pulsed laser beam. The perforated sheet material can be used as a conveyor belt in a vacuum/suction hold-down conveyor.
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