Extrusion is a continuous process, in which finished products are obtained by forcing molten material through the forming tool (die, die head, holes, etc.). The material used in the extrusion process are characterized by high viscosity, and the products are thus obtained with the desired cross-sectional shape. Extrusion, in other words, is as complex a physico-chemical process as any – one that takes place under the influence of mechanical stress, high temperature and moisture. The variable parameters of the extrusion process includes the humidity and the composition of the material being processed, as well as pressure, temperature, intensity and duration of exposure to the feed.
The basic methods of extrusion include cold forming, heat treatment and the method of “hot extrusion” (molding). Extrusion methods, as well as injection molding, refers to one of the most popular methods for the production of plastic products. Processing may be subject to almost all major types of polymers, thermoplastics, elastomers, and thermosets. Extrusion is actually used in the food industry for the manufacture of various types of pasta and noodles.
The field of polymeric extrusion procession is popular in the production of pipes, films, membranes for cable elements of optical systems, rubber compounds, plastics, ferrite products, etc. In addition, this technology is widely used for the production of thermal insulating materials. Polystyrene material, which is obtained by extrusion, is applied to isolate concrete railway foundations. Using this type of insulation reduces the possibility of changing the surface of the soil due to freezing temperatures.
Molding is carried out on extrusion lines, the most common type of equipment for plastics processing. A line usually includes several extruders, which are special extrusion tools, and a number of additional devices. The main types of equipment used in the processing of polymeric materials include single screw, twin screw, pistons and disk extruders. There is also a blow-type extruder, which has been part of similar installations.
Extrusion training is a sought out type of training many employers in the industrial sector are looking for. Even though it may seem that the need for this type of work is miniscule, the professionalism needed with this job is needed much more. For more information, on extrusion training contact your local extrusion expert.