Sheet extruder | Plastic sheet extruder | Mixing sheet extruder

Sheet Extruder Plastic Sheet Extruder
The main parameters of the screw The main parameters of the screw are diameter aspect ratio compression ratio pitch screw groove width screw groove depth helix angle the gap between the screw and the barrel, etc. These Parameters have a great influence on the extrusion process and performance.
Screw diameter
Types of screws In order to meet the needs of different plastic processing, there are many types of screws. The common ones are the following: gradual type, equal distance and unequal depth, gradual type, equal depth and unequal distance, mutation type , torpedo head type, etc. Selection of screw The selection of screw type is mainly determined based on the physical properties of the plastic and the production technical specifications of the extruder.
The softening of amorphous polymers is completed within a relatively wide temperature range, and equidistant gradient screws are generally used. The melting temperature range of crystalline polymers is relatively narrow, and equidistant mutation screws are generally used. On a small extruder, for example, the screw of the extruder adopts a full thread type with equal distances and different depths. The length and diameter of the screw are relatively small. It is mainly used to extrude the insulation layer and sheath layer of small cross-section, and the extrusion speed is relatively high. quick. The screw diameter is the outer diameter of the thread. The production capacity of the extruder is approximately proportional to the square of the screw diameter. When other conditions are the same, a slight increase in the screw diameter will cause a significant increase in the extrusion volume, and its impact is even It has a greater impact on the extrusion volume than the increase in screw rotation speed.
The advantage of the two-stage method is that the two phases are dispersed more evenly.
Medium-sized screws adopt a full-thread type with equal spacing and gradual thread depth. Its length-to-diameter ratio is larger than that of small screws. The pitch of the threads is equal, from shallow to deep from the root. The thread at the end of the thread is deeper and the thread at the root is shallower, so that more plastic can be extruded without affecting the strength of the screw. The extrusion speed is fast and the plastic is well plasticized. It is suitable for the production of insulation layers and protective shields for general small and medium-sized extruders. Ideal screw for jacketing.
The diameter of large screws is generally above 1, such as in extruders. There are two types of large screws. One is equidistant and unequal depth, such as an extruder. The second is the screw is divided into three sections, namely equidistant and unequal depth, equidistant and unequal depth, such as an extruder. Compression ratio In between, the aspect ratio is around, and it is mainly used to produce large-section wire and cable insulation layers and sheath layers. The driving force for mechanical blending comes from the mechanical stirring and shearing effects provided. Mechanical blending is a system homogenization process under the action of mechanical force. It is generally believed that the homogenization process includes the physical mixing and dispersion of each component of the system. However, in fact, the mechanical force in the mechanical blending process is not only the mixing and dispersion of the components. In addition to providing energy through dispersion, it also triggers mechanochemical reactions between components, which has an important impact on the combined performance of rubber and plastics.
Rubber and plastic blending equipment mainly includes high-temperature open mill mixers, screw extruders and continuous mixers. The continuous mixer is divided into two types: internal mixing and extrusion combined type and rotor screw combined type. High-temperature open mills and internal mixers are intermittent mixing equipment, while screw extruders and continuous mixers are continuous mixing equipment. The continuous mixer combines the advantages of an internal mixer and a screw extruder with high production efficiency and will become the most important blending equipment in the future. Other considerations for rubber and plastic blending
Although we understand the miscibility principle of rubber and plastic and the method of rubber and plastic blending, according to people's practice in the field of blending for many years, the following needs to be considered in rubber and plastic blending Factor
Solubility parameter. Each polymer material has a solubility parameter that reflects its intermolecular force. When blending two polymers, the difference in solubility parameter should be as small as possible, but larger than that, because the smaller the difference, the better the blending effect, and the smaller the difference. If it is reached, there will be no two phases, and the meaning of blending will be lost.
Polarity. When choosing to use rubber and plastic together, the traditional approach is to give priority to polymers with similar polarities and avoid using two polymers with widely different polarities. However, with the emergence of compatibilization technology, this consideration can be alleviated.
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