Blown film screw, screw feed section, compression section, metering section, length to diameter ratio at least 1:25 to 1:32 as required for PE plasticization, screw length and diameter ratio of 1:28 or more good.
(A) Output The so-called output refers to the output or output of a given machine head under the premise of guaranteeing the quality of plasticization. As mentioned earlier, the output is usually expressed in kg/hour or kg/rev. A good screw should have high plasticizing ability. (Production capacity) It should be pointed out that low-temperature extrusion is a current development trend, it can improve the quality of extruded products (such as reducing internal stress, etc.), prevent thermal decomposition of heat-sensitive materials, reduce energy consumption, and reduce the main auxiliary cooling system Burden, increase productivity.
(B) Plasticizing Quality A screw must first be able to produce products that meet quality requirements. The so-called quality requirements mean that the products produced should meet the requirements of the following aspects: 1. Have various properties that meet the requirements. Has consistent physical, chemical, mechanical and electrical properties; 2. Appreciable apparent quality. If you can achieve the user's requirements for bubbles, crystals, dyeing uniformity. 3. The plasticizing quality of the screw that meets the requirements: 1) whether the melt temperature extruded by the screw is even, axial fluctuation, and radial temperature difference. 2) Is there a minimum melt temperature to be formed? 3) Whether the extruded melt has pressure fluctuations. Whether the dispersion of dyeing and other additives is even.
(C) Unit consumption Unit consumption refers to the energy consumed for each kilogram of plastic (rubber) extruded, which is generally expressed as N. Where N is power (kW) and Q is output (kg/hour). The larger the value, the more energy required to plasticize the plastic (rubber) of the same weight, which means that the more heating power is consumed, the more the mechanical work done by the motor enters the material through the form of shear and frictional heat. many. vice versa. With a good screw, the unit consumption should be as low as possible under the premise of ensuring the quality of plasticization
(D) Adaptability The so-called adaptability of the screw refers to the ability of the screw to process different plastics, match different heads and different products. In general, the stronger the adaptability, the lower the plasticization efficiency. Therefore, we always hope that a good screw has both adaptability and high plasticization efficiency.
(E) Difficulties in manufacturing A good screw must also be easy to manufacture and cost-effective.