Plastic Manufacturing

Plastic Manufacturing

All plastics can be placed into one of two categories: thermosets and thermoplastics. Thermosets are petrochemical derivatives that, once formed by heat forming processes, cannot be melted down and reformed. Thermoplastics are the opposite; when subject to heat and pressure, thermoplastics can be formed into almost any shape. Both kinds of plastic are popular throughout industry, commerce and in consumer products contexts. Plastic is less expensive and more versatile than metal, glass and wood in many applications; it is long lasting, temperature resistant and will not shatter if dropped on a hard surface. It also fares well when exposed to moisture or abrasive chemicals. Common plastics used for manufacturing products include acrylic, nylon, polyester, polycarbonate, polystyrene, polyvinyl chloride, polyethylene and acrylonitrile butadiene styrene, all of which have different properties, limitations and benefits. Products manufactured from plastic come in most conceivable shapes and sizes, including flat, spherical, hollow and other complex shapes. Most plastics are fabricated with the use of heat and automated machinery that is controlled by computer software, which eliminates the risk of human error. These machines are called CNC or CAD/CAM systems. They are fast, produce high volumes of products and have a high degree of repeatability.

Plastic can be bent, stamped, cut, welded together, extruded, molded, engraved, milled, drilled or turned. These are divided into two main fabrication categories: molding and forming. Molding involves heating the plastic resin until it is soft or molten and either injecting it or placing it on a mold in the shape of the desired product. This method is mainly used for hollow or complex plastic products. Thermoforming, extruding and injection molding are all plastic manufacturing processes that work with molten plastic and a mold. Sometimes pre-fabricated plastic shapes like sheets or tubes need further shaping and forming. They may be stamped by a ram with great force, bent, cut with lasers or a saw or engraved with text or design. Many plastic products require assembly. This is most likely done by welding multiple flat pieces of plastic together for designs too complicated to mold. Plastic tanks, tubing systems, containers and objects that form a 90º angle are often welded together with the use of heat, pressure and sometimes extra plastic material to help join the two separate pieces of plastic into one.