Plastic mold molding classification (2)

(4) Injection molding
Also known as die casting. It is to add plastic raw materials into the preheated feeding chamber, then put the pressure column into the charging chamber to lock the mold, and apply pressure to the plastic through the pressure column. The plastic melts into a flowing state under high temperature and high pressure, and enters the cavity through the pouring system. It gradually solidifies into a plastic part. This molding method is also called transfer molding. Injection molding is suitable for plastics that are lower than solid plastics and can be compression molded in principle, and can also be molded by injection molding. However, it is required that the molding material has good fluidity in the molten state when it is lower than the curing temperature, and has a larger curing rate when it is higher than the curing temperature.

(5) Blow molding
It is to fix the tubular or sheet-like blanks in the plasticized state made by extrusion or injection into the molding die, and immediately introduce compressed air to force the blanks to expand and stick to the wall of the mold cavity. A processing method for obtaining the desired hollow product by demoulding after cooling and shaping. Plastics suitable for hollow molding are high pressure polyethylene, low pressure polyethylene, hard polyvinyl chloride, soft polyvinyl chloride, polystyrene, polypropylene, polycarbonate, etc. According to different parison molding methods, hollow molding is mainly divided into extrusion blow molding and injection blow molding. The advantage of extrusion blow molding is that the structure of the extruder and the extrusion blow mold is simple, and the disadvantage is that the wall thickness of the parison is inconsistent, which is easy to cause uneven wall thickness of plastic products. The advantage of injection blow molding hollow molding is that the wall thickness of the parison is uniform and there is no flash. Since the injection parison has a bottom surface, the bottom of the hollow product will not have joints and seams, which is not only beautiful but also high in strength. The disadvantage is that the molding equipment and molds used are expensive, so this molding method is mostly used in the mass production of small hollow products, and it is not widely used in extrusion blow molding.

(6) Die-casting mold
Die casting molds are also called transfer molding molds. The plastic raw material is added to the preheated feeding chamber, and then pressure is applied to the pressure column. The plastic is melted under high temperature and high pressure, and enters the cavity through the casting system of the mold, and gradually hardens and forms. This molding method is called die casting. The mold used It is called die casting mould. This kind of mold is mostly used for the molding of thermosetting plastics.
In addition, there are foam molding molds, glass fiber reinforced plastic low-pressure molding molds, and so on.