Hot needle perforation

Hot Needle Perforation or hot pin perforation refers to the placement of holes or apatures in a material using a hot or heated needle or pin. Packaging films are often microperforated in order for the packaged contents to breathe. Other applications include medical to allow wounds to breathe, sound and vapor barriers and other applications.

Process

The primary tool in a hot needle perforation system is of course the pinned roller or pinned punch [http://upload.wikimedia.org/wikipedia/en/3/36/3rollers.gif] .These high precision tools can be integrated into an existing line of machinery, or built as a stand alone unit. The needles or pins can he heated by a number of methods.
# Natural gas jet or natural gas burner externally can be inserted in a web with needles, pins,
# Electrically externally by radiant heater or infra red
# Electrically internal heating by cartridge heater
# Steam / hot water internally
# Hot oil internallyor a combination of these.

Hot needle perforation melts a hole in the material being perforated. This can be essential in thin films, as the molten material creates a re-enforced ring around the hole, or in thick films where surface tension is an issue. In more brittle films, cold perforation can cause slitting rather than creating a round hole, which can jepordize the materials integrity under pressure. Hot needle perforation also assists when high density pin patterns are utilized, as the heat aids the perforation of the material. Pinned perforation rollers can be manufactured to house up to 1250 pins per square inch, with hole sizes down to 70 micrometres or so. Pinned sleeves can be interchanged to achieve different perforations.

Manufacturers

There are few companies in the world that manufacture such high caliber rotary and punch hot needle microperforation tooling, one example is Stewarts of America, Inc. in the USA [http://www.stewartsofamerica.com] .

Laser perforation

The alternative to hot needle perforation is Laser perforation. Laser perforation is a much more expensive version of perforation. Laser perforation simply burns a hole in the material being processed. One laser system offers flexible hole sizes and patterns.

References

ee also

*Microperforation
*Perforation