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Sheet extruder extruding process

Sheet-extrusion extrusion process! Is generally based on the type of polymer and the shapes of products or semi-finished products, selected the extruder, die and die, as well as forming and haul off ancillary devices, such as, and then determine the extrusion processes such as screw speed, head pressure, temperature and set temperature, speed, etc. In the extrusion process, material must go through plastic chain, but different shaping methods. For example, extruded plastics often needs cooling, curing, extrusion of rubber semi-finished goods, require further curing. With different extrusion equipment and processes, different products can be obtained.
1, granular material: polymer when mixed with various additives, melting into the extruder, and mix. Through a porous die, forming multiple Strip, then cut them into pellets. Grain and cold cut off there is a keen cutting points. Former Strip after leaving the die, using air or water cooling, with rotating knives cut off immediately. Which is to strip all cooling, then dice into the cutter.
2, pipe: material through the die and mould consisting of ring-shaped gap formed tubes, then shaped and cooled by, receive accurate surface finish, size and shape of the pipe. Outer diameter of the setting method is the use of stereotypes, extrusion tubes via a bore and outside diameter of the same shaped sleeve, using tube close to the inner wall of stereotypes, so as to get accurate pipe outside diameter. In order to create pressure, to the tube into the compressed air can also cause negative pressure in the tube.
3, sheet and film: where the thickness 0.25mm, length is much larger than the width of the sheet of flat products; thickness is less than 0.25mm film. Flat die film-like object by a very smooth surface cooling cooling drum can be made flat, this method is also known as out of the casting method. This is the common method of manufacture polypropylene film. If proceeds of the film into the stretching machine, vertical and horizontal stretching 4~10 times (also longitudinal tensile and transverse tensile), biaxial oriented film can be prepared. Because of the tension and molecular orientation, high film strength, permeability, permeability decreased. Commonly used in the manufacture of polypropylene and polyester film. Materials adding foaming agents and using a special screw and die, low foam plastic sheets can be prepared.
4, covered lines: when metal wires is a t-shaped die, molten plastic around the bare wire to form the coating, coated wire is cooled after winding, namely all kinds of wire and cable products. (Play cups of extruder filter effects on plastic extrusion! )

 

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