Extruded plastics can be made into window profiles, building siding and trim, gutters and channels, sealing sections, hoses, curtain rods, tubes, pipes, drinking straws and many other common products.
Extruded plastic sheets are used in packaging and are often thermoformed into consumer products and packaging. The extrusion process is highly customizable and is capable of high volume production as well as short runs, making plastic extrusion one of the most versatile and economical methods of plastic fabrication.
Plastic rods and thick gauge sheets are machined by automotive, aerospace and construction industries into parts for close tolerance applications. Since the extrusion process uses a continuous output of smooth, thoroughly heated and mixed material, extruded plastics seldom have bubbles or inconsistencies, and they are therefore valued for their structural integrity and consistent profiles.
HDPE, LDPE, PETG, PVC, butyrate, vinyl, polypropylene and polystyrene are all plastics that are commonly extruded. The extrusion process begins with raw plastic pellets or flakes being fed into a hopper placed atop a closed extruding channel.
Gravity feeds the raw plastic material down into the extruding channel. Running through the length of the channel is a screw conveyor that moves the raw plastic toward the opposite end, shearing and heating the plastic through friction.
The plastic pellets plasticize, or melt, as they move through the conveyor, and on the end of the conveyor channel a die is secured that forms the molten plastic into a specific profile as it is pushed through. The newly formed plastic profile is cooled and pulled through by a series of conveyors and cut to appropriate lengths.
In this way plastic profiles, channels and tubing are manufactured quickly and in high volumes. Plastic sheeting is extruded in a similar way, except the molten plastic is pushed through flat or semicircular dies and then stretched into flat sheets, cooled through a series of rolling calendars and wound around spools.