Extruder Screw Design and Repair Process

10/13

2022

Boronizing treatment of steel screw barrel surface

Screw and barrel are mostly scrapped due to large gap caused by wear, which can not be extruded and injected normally. Few of them fail due to insufficient strength. Especially, in addition to strength, more consideration should be given to structural commonweal and thermal inertia in the design of barrel, and the wall thickness determined by the latter two factors should be far greater than the calculated value of strength conditions

10/13

2022

Extruder Screw Design and Repair Process

The extrusion system consists of screw and barrel, which is the "heart" of extrusion work. The screw completes the continuous conveying, plasticizing, homogenizing, constant pressure and quantitative extrusion of plastics in the barrel. The types of screws are: constant pitch gradual change screw, constant pitch depth abrupt change screw, variable depth variable pitch screw, etc. The structure of constant pitch progressive screw is studied as an example. Its main features: the thread pitch of the screw thread is equal, while the depth of the thread groove remains unchanged in the feeding section and homogenizing section, while the depth of the thread groove in the plasticizing section gradually becomes shallow from the depth, which is suitable for extrusion plasticization of various plastics. The progressive screw divides the working length of the screw into three basic functional segments,

10/13

2022

How to judge the output of extruder screw?

The output is a main index to evaluate the performance of extruder screw. However, it is not significant to only emphasize the percentage increase in the output of the improved screw compared with the original screw, because the benchmark for comparison is not clear. From the theory of fluid dynamics, we know that the output will be greatly improved if the worn screw is replaced by the screw with smaller screw clearance. In order to accurately reflect the performance of the screw, the following four aspects can be compared.

10/13

2022

Share standards for extruder screw performance

Extrusion process is a complex process, which involves many factors. Facts show that it is one-sided to evaluate the performance of extruder screw only according to the productivity. As we all know, if the colleague with high output has high capacity consumption, the screw is not desirable. For another example, if the extrudate has a high temperature rise at the same time of high output, the cooling burden of the main and auxiliary engines will increase. In fact, such screws cannot be used at high speed, and their performance is not much better than that of ordinary screws at low speed.