The products of plastic extrusion surround us everyday. In fact, the toothbrush that you used this morning was created by large plastic extrusion machines. Not to mention the computer, keyboard and mouse you use on a regular basis were all manufactured by the extrusion process. The utilization of plastic and the variety of forms it can take, has led to a purchasing power of products never before seen in manufacturing.
The first plastic extrusion machines were large hydraulically controlled presses that held together two halves of a steel mold. Through a large cannon like barrel, which is heated hot enough to melt plastic, small bits of granular plastic are pushed by a turning screw. The plastic is streamed into the mold through a nozzle which directs the liquid plastic into the mold. When the plastic cools, the machine opens the molds and out pops the parts.
Plastic extrusion is also employed for placing the insulation over electric wires that conduct electricity in homes. Large spools of bare copper wires are passed between extrusions nozzles of plastic as one long continuous strand. These machines can be a 100 feet long in order to allow the plastic sufficient time to cool so that it can be run onto large spools.
Plastic milk containers and chip bags are also manufactured by the extrusion process. Although not placed in a strict mold, the plastic snack chip bag material is heated and pushed through a long barrel to be forced out the end of a specifically sized long horizontal nozzle. The plastic is then passed through rollers to give the final thin shape and form. Plastic milk containers are blown into molds by high-pressure hot air after the raw material is also passed through the screw and barrel.
The plastic extrusion operation lends itself to the reuse of the plastic material. Large grinding machines are employed to re-size larger materials into pieces that can be used by the screw and barrel extrusion process. This leads to recycling of many plastic products.
As more and more plastic products are finding their way into our lives and homes, we must be conscious of the disposal factor in our own lives. Recycling of the extruded materials can create a large cost benefit not only for the manufacturer and consumer, but as new science facts have come to surface perhaps our own environment as well.
Read more: Definition of Plastic Extrusion | eHow.com