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Plastic Extruders What is an extruder? A Plastic Extruder is a machine for producing more or less continuous lengths of plastic sections. Its essential elements are a tubular barrel, usually electrically heated; a revolving screw, ram or plunger within the barrel; a hopper at one end from which the material to be extruded is fed to the screw, ram or plunger; and a die at the opposite end for shaping the extruded mass.Plastic extruders melt plastic granules and transform them various products. Plastic extruders are but one component of a complete system which is composed of several pieces of equipment and designed to make a particular end product. Plastic Extruders are divided into two general types: Single Screw and Twin Screw Design The family of single-screw Plastic Extruders includes units with various diameters of a single screw. These extruders are designed for the manufacture of pipes, profiles, films and other goods from thermoplastics. They offer different gear rations, engine powers and torques and several speeds, which enables an optional selection of an extruder, suited to a particular application and plastic. A single screw Plastic Extruder is typically more harsh in its handling of plastics and may result in more degradation than a twin screw machine 2.) Twin-ScrewA twin screw extruder features most of the properties of the single-screw described above. However, as the name indicates, there are two screws that operate simultaneously to melt, mix, and convey the material. The screws are parallel and side by side in the barrel. They can either co-rotate, ie. turn in the same direction, or counter-rotate, turn in opposite directions. Co-rotating twin-screw machines offer the highest torque-per-free-volume and the highest screw speed of any commercial available compounding extruder. They are available in sizes ranging from 37 to 175 millimeters. Counter-rotating, machines (non-intermeshing systems) enhance feed acceptance, provide superior distributive mixing, and enable multistage feeding, to produces optimum venting of gases contained in the material(s).
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