In the plastic extrusion molding equipment, the plastic extruder machine is usually called the main machine, and the supporting equipment plastic extrusion molding machine is called the auxiliary machine. After more than 100 years of development, the plastic extruder has been derived from the original single screw, such as twin screw, multi-screw, and even no screw.
Plastic Extrusion Principle
The extrusion method of a plastic extruder generally refers to melting plastic at a high temperature of about 200 degrees, and the molten plastic is formed into a desired shape when it passes through a mold. Extrusion requires a deep understanding of plastic characteristics and rich experience in mold design. It is a molding method with high technical requirements. Extrusion molding is a method in which materials are continuously passed through a die in a flowing state by heating and pressing in an extruder. It is also called “extrusion”. Compared with other molding methods, it has the advantages of high efficiency and low unit cost.
Extrusion is mainly used for the molding of thermoplastics and can also be used for some thermosetting plastics. Plastic extruder machines for sale are continuous profiles, such as tubes, rods, wires, plates, films, wire and cable coatings, etc. In addition, it can also be used for mixing, plasticizing, granulating, coloring and blending of plastics. Extruded products can be called “profiles”, because the cross-sectional shape is mostly irregular, it is also called “profiles”.
Method of Plastic Extrusion
The principle of screw feeding and discharging. The function of the extruder is to use heat, pressure and shear to transform the solid plastic into a uniform melt and send the melt to the next process. Melt production involves the mixing of additives such as color masterbatches, resin blending and pulverization. The finished melt must be uniform in concentration and temperature. The pressure must be large enough to squeeze out the viscous polymer. The pipe extrusion machine completes all the above processes through a barrel with a screw and a spiral. The plastic pellets enter the barrel through a hopper at one end of the barrel, and then are transferred to the other end of the barrel through a screw.
In order to have enough pressure, the depth of the thread on the screw decreases as the distance to the hopper increases. External heating and internal heat generated by friction between the plastic and the screw cause the plastic to soften and melt. Is a simplified extruder. Different polymers and different applications often have different requirements for the design of the extruder