In this process, conical needles pierce the web (e.g., paper, thin metal foils, PE films). The grooves of the counter roller match exactly with the needle pattern. The needles create funnel-shaped holes. This causes, for example, in paper increased water permeability and in PE films air permeability.
|Funnel Shaped Holes||The needles create funnel-shaped holes. This causes for example, in paper increased water permeability and in PE films air permeability.|
|No Material is removed||In this method, no material is removed. Therefore, the holes may partially close again when pressure is applied to the web.|