Die extrusion moulding
Is to make the plastic in the flow state, at high temperature and under pressure, through a die with a specific profile, and then at a lower temperature, setting the required cross section shape of a molding method of continuous profiles. Extrusion molding production process is the preparation of moulding material, extrusion molding, cooling, extrusion product handling, traction and cutting (quenched and tempered or heat treatment). Extrusion molding process, attention to the adjust the extruder barrel heated die and die temperature, screw speed, speed and other parameters in order to obtain qualified extruded profiles. Special attention to adjust head die extrusion of polymer melt rates. Because when the melt extrusion rate is low, the extruded section has a smooth surface, uniform shape; but when the melted material extrusion speed reaches a certain limit, the extrusion of surfaces can become rough, dull, sharkskin, Tangerine Skin, shape distortion occurs, and so on. When the extrusion rate further increased, the extruded surface distortion, even fragmentation and fracture into molten debris or cylinder. Extrusion speed control is important.