Plastic molding is an operation in which the molten polymer material is poured into a special mold, where it hardens and takes the required form. Plastic molding is performed using special equipment – injection molding machines. They heat the workpiece, the material is poured into a preset shape and cooled finished product. Construction equipment used in injection molding, has a close relationship with the properties of polymers used. Injection molding capabilities to meet the indicators such substance used as the temperature of its processing, the transition to a plastic condition, viscosity of the solution, particularly freezing. In injection molding is extremely important to consider all these features, as well as other parameters characterizing the polymer. For example, the range of melting temperatures should be such that to ensure uniform melting and casting quality plastic, but it does not have a devastating effect on the structure of matter.

In addition, molding plastics should consider how the transition occurs in liquid state. For example, polystyrene is characterized by a smooth transition, and polyamide and polypropylene, by contrast, change their properties dramatically, abruptly. One of the items of equipment, construction of which depends on the properties of a substance used in injection molding – a screw. He is responsible for plasticizing the polymer and provides the starting material in the form below. For the correct casting plastic is necessary that its design is taken into account nature of the transition of matter in the fluid state, its thermal stability, sensitivity to shear stresses.

Knowing the temperature at which the molding of plastic, it is necessary to calculate the level of heating cylinder. It is important to note that what is already a range of melting temperatures, the more accurate should be calculated, because in this case, even a slight deviation from the established regime violates molding plastics. On features transition in a plastic condition depends on the depth of the channel metering, particularly the nozzle and the tip of the screw. Many of the design parameters are determined by thermal stability of the polymer used in molding plastics.