How to protect the Extruder screw barrel?
The design of the extruder screw barrel and the structure of the screw and barrel are very important when extruding thermoplastic composites. If you think about these issues ahead of time. The thermoplastic composites can be processed satisfactorily. Generally speaking, the design of extruder screw barrel for thermoplastic composite materials mainly involves two different aspects, one is the mixture of materials; The second is the processing of thermoplastic composites. This article focuses on the latter. But many of the practical issues discussed are directly related to both.
The good extruder screw barrel design
Most of the main functions of screws used for thermoplastic resin extrusion are: feed, plasticize and extrude. Typically, the feed section of the screw is used to transport solid resins and fillers. The feed section of thermoplastic composite screw is very different from that of thermoplastic polymer screw without filler in structure, which is mainly affected by the relative friction coefficient of solid particles. Generally speaking, the friction generated in the feed stage comes from three aspects, namely the friction between particles and cylinder wall, the friction between particles and screw, and the friction between particles and particles. In the case of no filler, the feed performance of pure resin is better, but with the addition of foundation, the friction coefficient changes greatly, which has a great influence on the feed efficiency of screw. For example, when mica is added, the friction coefficient is significantly reduced and the feed section of the screw should be lengthened and kept at a constant depth. Ensure that the material receives sufficient feeding force (stable pressure) before entering the plasticized section of the screw (including the conveying section and the retaining section).
Similarly, to improve particle transport efficiency, it is necessary to change the temperature environment, which can be increased by increasing the temperature of the first section of the high quality extruder screw barrel to increase the friction coefficient between the particle and the barrel wall, so that the polymer adheres to the barrel and is transported forward. Often, erratic or inefficient feeding processes lead directly to reduced yields and adversely affect processing.
