Principle of Plastic Extrusion Machine


PPR Pipe Making Machine

Plastic extrusion machine is widely used in the processing of pipes, rods, monofilaments, plates, films, wire and cable coatings, profiles and so on.

The principle of the plastic extruder machine is that the solid plastic is melted and plasticized under the conditions of heating and screw rotation of the extruder, and a continuous plastic product having the same cross-section and shape as the die is formed by a die of a specific shape. The manufacturing materials mainly include carbon structural steel, alloy tools, etc. Some extrusion dies are also embedded with wear-resistant materials such as diamond on parts that require wear resistance. The extrusion process is usually only applicable to the production of thermoplastic products, which are structurally distinct from injection molds and compression molds.

Principle of Plastic Extrusion Machine:
Foam extrusion: The thermoplastic elastomer tpv can be foamed by chemical and mechanical methods. For chemical foaming, a blowing agent such as a heavy hydrochloride salt can be used. The foam density specific gravity that can be achieved is 0.97 (typically unfoamed tpv) to 0.70. Lower density is affected by patents. The blowing agent degrades at 180 ° C to 190 ° C because most of the tpv is based on 195 to 215 ° C.

Multi-layer extrusion: Co-extrusion is a technique in which two materials are combined into one part in one extrusion process. Two extruders are connected in series to provide a bottom mold and to cause the respective polymeric materials to be coextruded together along the corresponding channels to obtain an extruded glue of the two materials. Uniform materials such as tpv and polypropylene can be fused together. Multi-layer extrusion is a good way to mix hard and soft materials. Typically, high hardness sections, such as thermoplastic elastomers tpv, are generally used as support structures for the components, while low hardness materials provide flexibility. This is common in sealing applications because the sealing area is soft and the soft material can be crushed for good sealing. In the process of balancing the flow field, it is simpler to use the thermoplastic elastomer tpv with higher hardness as the rigid material instead of polypropylene.

Welded joints: Thermal soldering is a popular method for joining extruded gels made with tpv. Heat is introduced to the joining surface, causing the surface to melt, then bonding the surfaces together and applying slight pressure to ensure that no gas enters the interface. After cooling, the joint is almost the same strength as the part itself. Another method of joining the extruded parts is to use a gluing system.