The Design And Construction Principle Of Screw In Plastic Sheet Production Line
Plastic Sheet Production Line Feeding area: fixed screw groove of the groove deep, its function is responsible for preheating and plastic solid conveying and pushing. It must be ensured that the plastic begins to melt at the end of the feed section - that is, to preheat to the melting point. (PA, POM, PE, PP, CA) of about 48 ~ 58% L, plus glassy nature of about 45 ~ 55% of the non-crystalline (AS, ABS, ps) L.
Plastic Sheet Production Line Compression zone: tapered screw screw groove deep, its function for the plastic raw material melting, mixing, shear compression and pressurized exhaust. Plastic in this paragraph will be completely dissolved, the volume will be reduced, so the degree of compression design is very important. (PA, POM, PE, PP, CA) of about 22 ~ 32% L, plus about 28 ~ 40% L of glass, , Heat sensitivity (PVC) 100% L.
The main function of mixing, melt transfer, measurement, but also must provide sufficient pressure to maintain the uniform temperature of molten rubber and stable flow of molten plastic. (PA, POM, PE, PP, CA, etc.) of about 48 ~ 58% L, plus about 45 ~ 55% glass, L.
Although the plastic Sheet Production Line screw can be divided according to functional or geometric shape, but the actual plasticization process, the overlapping function of each section, it is difficult to distinguish between the interval. The study of plastic screw, nothing more than want to: improve the role of shear mixing, improved even mixing, improve the plasticizing capacity, improve the melt temperature uniformity. When the depth of the feed section deepened the greater the amount of deep, but the screw required greater torque; feed section of the tooth depth is too shallow, the amount of delivery is not enough, compression ratio is insufficient. When the measurement section is too deep, the compression ratio is insufficient, the required feeding power is large; too shallow when too easy to burn and burn. The average tooth depth is about 0.03 to 0.07 times the screw diameter. Therefore, plastic plastic screw has the function of conveying, melting, kneading, compressing and measuring, and plays a very important role in plasticizing quality.
The main components of Plastic Sheet Production Line are screw screw barrels, which play an important role in the plasticization, extrusion and molding of plastics. Therefore, rational selection of screw structure and parameters is an important part of obtaining the ideal product quality and yield. In order to meet the needs of different plastic processing, there are many kinds of screw structure, there are three common: gradient type (isometric), gradient type (isometric), mutant, torpedo and so on.
The selection of the screw structure of the Plastic Sheet Production Line is based on the physical properties of the plastic and the technical specifications of the extruder.
(1) the softening of non-crystalline polymer is completed in a relatively wide temperature, the general use of equidistant gradient screw. Crystalline polymer melting temperature range is relatively narrow, generally use equidistant mutant screw.
(2) in the small Plastic Sheet Production Line, such as φ45 extruder screw is used in the isometric contours of the full thread type, the length of the screw is relatively small, mainly for the extrusion of small sections of the insulation and sheath Layer, extrusion speed faster.
Plastic Sheet Production Line These two important parts, one is an elongated threaded rod, one is a smaller diameter and a long hole, their mechanical processing and heat treatment process are more complex, the accuracy of the Guarantee are more difficult. So, after the wear of these two parts is to repair or replace the new pieces, we must from the economic point of view a comprehensive analysis. If the cost of repair is lower than that of the new screw, it is not necessarily the right choice. The comparison between the repair cost and the update cost is only one aspect. Also depends on the cost of repair and repair the use of screw time and update costs and update the screw to use the ratio of time. The use of small ratio of the program was economical, is the right choice.
Manufacture of plastic sheet Production Line screw and barrel, the current domestic commonly used materials are 45,40Cr and 38CrMoAlA. Imported extruder screw and barrel manufacturing materials, commonly used alloy steel has 34CrAINi7 and CrMoV9. The yield strength of this material is about 900MPa. After nitriding treatment, the hardness of 1000HV or more, both wear-resistant and good corrosion resistance.