WHAT IS EXTRUSION? -2
Extrusion produces plastic products such as drainage and irrigation pipe, medical fluid and IV tubing, weather-stripping, fencing, deck railings, vinyl siding, window frames, home décor, and furniture trim, automotive components, appliance trims and seals, filtration parts, drinking straws, the “zip” strip on re-sealable bags, food processing tubing and rails, plastic films and sheeting, thermoplastic coatings, electrical conduit and cable protectors and wire insulation.
Research and development continue to expand the benefits of plastic extruded products for medical devices, aerospace, and recycling.
An advantage of extrusion in manufacturing is that a product can be produced continuously with high output in a conforming shape and then reeled for applications requiring continuous product such as tubing extrusion, pipe extrusion, or film; or parts are cut with high precision to various lengths as needed for a wide variety uses. Secondary operations, such as drilling holes or further shaping, add functionality.
Flexible and rigid plastics can be formed with extrusion. If two or more materials are required to make a product, the co-extrusion process is used.
For example, a coextruded tube could have an internal hardened tube through which a cable can be run along with a flexible outer layer to maintain maneuverability. A white drinking straw that has two colors of stripes, requires a total of three extruders to manufacture. Each extruder feeds a different material or variation of the same material into a central co-extrusion die. Co-extrusion can also reduce costs by using recycled and reground scrap inside virgin material for handrails, fences, and other applications. In fact, one of the first industrial uses of extrusion was in 1820 when Thomas Hancock invented a process to reclaim rubber scraps.