How Plastic Extrusion Process Carried out with Extrusion Machinery
Plastic extrusion is the process to define new plastic products of required size and shape through extrusion machinery. You can manufacture various plastic products like piping, wire insulation, plastic sheet, adhesive tape, window frames etc. Plastic granules are melted and reform again by this machinery in required shape and design. In such process plastic granules or plastic raw materials are added to extruder cavity through hopper. In extruder the plastic material needs to be mixed with colorants or UV inhibitors to make them mix and stimulate the melting process. In plastic extruder cavity the temperature is so high that the raw materials molted and generated in liquid form. The temperature in heated extruder cavity is so high upto 400F. Sometimes the temperature goes above the normal required level which can evaporate the liquid. To stop vaporization, it requires to cool down the head to maintain required temperate in heated extruder. Cooling fans are used to cool down and maintain the temperature level. After attaining the required temperature for certain time for liquidation, the extruder screw enhances the pressure to move liquid plastic to the die through proper channel. This die is a frame where it store the liquid plastic material, came out of extruder with pressure. Now liquid plastic has been moved to the die for further looking in sealed water bath to solidify plastic material to form a plastic product. Sometimes dies are passed through special cooling rolls instead of water baths to make the die and product cool fast at required temperature.
There are various types of extrusion machineries having different extrusion process to form plastic like extrusion coating lamination plant in which Extrusion coating is used a blown or cast film process to coat an additional layer onto an existing roll stock of paper, foil or film. For example, this process can be used to improve the characteristics of paper by coating it with polyethylene to make it more resistant to water. Blown film plant is used for blow film extrusion process which is the same as a regular extrusion process up until the die. The die is an upright cylinder with a circular opening similar to a pipe die. The diameter can be a few centimeters to more than three meters across. The molten plastic is pulled upwards from the die by a pair of nip rolls high above the die. There are different types of blown film plants are used in extrusion process like mono layer blown film plant, two layer blown film plant and multilayer blown film plant.