Principles of plastics extrusion equipment

Plastic extrusion equipment is widely used for pipe, bar, single wire, sheet, film, wire and cable coating, profiles and other processing.
The principle of plastic extruder is that solid plastic melts and plasticizes under the conditions of heating and rotating pressure of the screw of extruder, and then makes continuous plastic products with the same cross-section and die shape through a specific die shape. Its main manufacturing materials are carbon structural steel, alloy tools, and some extrusion dies in the need for wear-resistant parts will be inlaid with diamond and other wear-resistant materials. Extrusion process is usually only suitable for the production of thermoplastic products, and its structure is obviously different from injection mold and compression mold.
Principles of plastics extrusion equipment
Foaming extrusion: thermoplastic elastomer TPV can be bubbly by chemical and mechanical means. For chemical foaming, blowing agents such as heavy salt and salt can be used. The percentage of foam density reached 0.97 (typical non foaming TPV) to 0.70. Lower density is influenced by patents. Foaming agents deteriorate between 180 and 190 degrees Celsius, because most TPV is based on 195 to 215 degrees Celsius.
Multilayer extrusion: Co-extrusion is a technology that combines two materials into one part in a single extrusion process. The two extruders are connected in series to provide the base die and to coextrude the respective polymer materials along the corresponding channel to obtain the extrusion glue for the two materials. Homogeneous materials, such as TPV and polypropylene, can be integrated together. Multilayer extrusion is a good way to mix hard and soft materials. Typically, high hardness sections, such as thermoplastic elastomer tpv, are used as support structures for 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 flattened to achieve good sealing effect. In the process of equilibrium flow field, it is easier to replace polypropylene with high hardness thermoplastic elastomer TPV as rigid material.
Welded joints: hot welding is a popular method for joining extruded glue made of TPV. Heat is introduced to the joint surface, causing the surface to melt, then bonding the surface together, and applying a slight pressure to ensure that no gas enters the contact surface. After cooling, the bonding strength is almost the same as that of the component itself. Another way to engage extrusion parts is to use adhesive systems.