The manufacturer of power cable extruder introduces that extruder is a type of plastic machinery that originated in the 18th century. The extruder can be divided into right angle molds and oblique angle molds based on the material flow direction of the mold and the angle between the screw centerline.
The manufacturer of the power cable extruder stated that the screw extruder generates pressure and shear force from the rotation of the screw, which can fully plasticize the material, mix it evenly, and then form it through a mold. [2] Plastic extruders can be basically divided into twin screw extruders, single screw extruders, rare multi screw extruders, and non screw extruders.
Power cable extruder manufacturer introduces the principle of single screw extruder:
The manufacturer of the power cable extruder stated that a single screw is generally divided into three sections in terms of effective length, and the effective length of the three sections is determined based on the diameter of the screw and the depth of the pitch, usually one-third each.
The last thread of the material outlet is called the conveying section: the material requirements here are not plasticization, but preheating and pressure compaction. Previously, the old extrusion theory believed that the material here was loose, but later it was proven that the material movement here was similar to a solid piston, so as long as the conveying task was completed, its function was to complete it.
The second part is called the compression part. At this point, the volume of the screw groove gradually decreases from large to small, and the temperature needs to reach the level of material plasticization. The compression generated here comes from the conveying section 3, where it is compressed into one. This is called the compression ratio of the screw -3:1. Some machines also have changes, and the plasticized material enters the third stage.
The third section is the metering section, where the material is kept at the plasticizing temperature, and only the melt material is accurately and quantitatively transported like a metering pump to the machine head. At this point, the temperature should not be lower than the plasticizing temperature, generally slightly higher.
The energy-saving of the extruder can be divided into two parts: one is the power part, and the other is the heating part.
Part of energy-saving: mainly using frequency converters. The energy-saving method is to save the excess energy consumption of the motor. For example, the actual power of a motor is 50Hz, but you only need 30Hz to generate enough power in production. Those excess energy consumption will be wasted. The frequency converter changes the power output of the motor to achieve energy-saving effects.
Heating energy-saving: Heating energy-saving is mostly achieved through electromagnetic heaters, with an energy-saving rate of about 30% to 70% of that of old-fashioned resistance coils.
Workflow:
The manufacturer of the power cable extruder stated that plastic enters the extruder from the hopper and is transported forward under the drive of the screw. During the forward movement, the material melts through the heating of the barrel, shear and compression brought by the screw, thereby achieving changes in three states: glass state, high elastic state, and viscous state.
Under pressure, the material in a viscous state passes through a mold with a certain shape, and then becomes a continuum with similar cross-section and mold pattern according to the mold. Then, it is cooled and formed into a glass state to obtain the product to be processed.