Plastic production line
Issuing time:2021-05-14 16:51
With plastic extruding machine for a host of plastic products production line, has a rigid pipe extrusion line, hose extrusion molding line, in extrusion molding line and rod extrusion line, blown film extrusion molding line, hollow plastic extrusion blow molding production line, sheet extrusion line, flat wire extrusion molding line, monofilament extrusion line, packing belt extrusion production line and plastic mesh, composite extrusion production line, etc.
The mechanical flow of plastic extrusion is calculated as Q= qd-qp-ql, which is equal to the algebraic sum of positive flow Qd, pressure flow Qp and leakage flow Ql. Among them, extruder leakage Ql is a flow along the screw axis to the direction of the hopper in the gap between the screw edge and the barrel, which is caused by the counter pressure of the melt by the head, the splitter plate and the filter screen. Because of the small gap, the leakage flow is much smaller than the positive flow under normal conditions. But you can't ignore it.
The basic mechanism of the extrusion process is simply a screw rotating in the cylinder and pushing the plastic forward. The screw structure is a ramp or ramp wound around a central layer to increase the pressure to overcome greater resistance. As far as extruders are concerned, there are three kinds of resistance to overcome when they work: one is friction, which includes the friction of solid particles (feed) on the wall of the cylinder and the friction between them in the first few turns of the screw (feed area); Second, the adhesive force of melt on the wall of the tube; The third is the logistics resistance when the melt is pushed forward.
Single screw extruder plays an important role in plasticizing granulator and forming machine. In recent years, single screw extruder has made great progress. At present, the single-screw extruder for large-scale granulation is produced in Germany, with the diameter of screw up to 700mm and the output of 36t/h.
Extruders can be divided into single-screw, double-screw and multi-screw extruders according to the number of screws. At present, single screw extruder is widely used and suitable for extrusion processing of general materials. The twin screw extruder has less heat generated by friction, more uniform shearing of materials, larger conveying capacity of screw, more stable extruder, longer residence of materials in the barrel, even mixing.