Plastic injection molding is the process of making plastics of various forms (powders, pellets, solutions and dispersions) into articles or blanks of the desired shape. Forming up to thirty kinds of methods.
The choice of plastic injection molding depends on the type of plastic (thermoplastic or thermosetting), the initial form and the shape and size of the product. Processing of thermoplastics commonly used methods are extrusion, plastic injection molding, rolling, blow molding and thermoforming, Plastic Injection Molding processing thermosetting plastics generally use molding, transfer molding, but also with plastic injection molding. Plastic injection molding is the process of making plastics of various forms (powders, pellets, solutions and dispersions) into articles or blanks of the desired shape. Forming up to thirty kinds of methods. Lamination, molding and thermoforming are shaping the plastic on a flat surface. The above plastic processing methods, can be used for rubber processing. In addition, Plastic Injection Molding there are liquid monomer or polymer as raw materials such as casting. In these methods, extrusion and plastic injection molding with the most, but also the most basic molding method.
Plastic injection molding process is one of the most important technical processes in plastic processing. For PET plastic bottles, in most cases, plastic packaging plants will be made by blow molding, but plastic injection molding process is particularly unique processing advantages
Plastic injection molding is mainly used to enhance the molding of PET. Usually using screw-type injection machine. Screws are generally required to be hardened to avoid abrasion after prolonged use. Plastic Injection Molding The length of the injection nozzle hole should be as short as possible, its diameter should be controlled at about 3mm. Enhance the melting point of PET up to 260 ℃, Plastic Injection Molding in order to prevent nozzle clogging, should install a larger power heater. In addition, the tip of the nozzle hole is preferably machined into an inverted cone type as shown in Fig. 1, so that the molten material in the flow path and the nozzle can be easily cut off.
Plastic injection molding is mainly used to enhance the molding of PET. PET under normal circumstances can only use screw-type injection molding machine. It is best to use a mutant screw with a reverse ring at its top, with a high surface hardness and wear resistance. The aspect ratio is less than L / D = (15 ~ 20): 1 The compression ratio is about 3: 1. L / D too much material in the barrel to stay too long, excessive heat easily lead to degradation, Plastic Injection Molding affecting product performance. Compression ratio is too small shear heat less, easy to plastic poor, poor product performance. The glass fiber will be more broken, mechanical properties decline. Processing of glass fiber reinforced PET, the barrel wall wear more powerful, the use of wear-resistant materials, the use of wear-resistant materials or lining with wear-resistant materials. The nozzle is short as well, Plastic Injection Molding the inner wall requires polished, the aperture is as large as possible. It is better to use hydraulic brake valve type nozzle. The nozzle must be kept warm and the temperature is controlled to ensure that the nozzle does not freeze. But the nozzle temperature can not be too high, otherwise cause salivation. Before the start of molding must use low-pressure PP material, the barrel clean.