Extruder Screw Design and Repair Process
Published:
2022-10-13 11:50
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,
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,
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Sharing the Economic Factors of Extruder Screw Design
For any technical problem, it is totally wrong to ignore the economy of design. In some cases, the rationality of screw design must be analyzed more comprehensively, that is, from the perspective of economy.
View detail10/13
2022
Functional characteristics of exhaust screw
In the extrusion process, the gas to be discharged from the raw material includes three parts: the air brought in between the raw material particles; Moisture adsorbed on granular materials; Gases or liquids contained in raw materials, such as residual monomers, low molecular volatiles and water, etc.
View detail10/13
2022
Determination of screw groove depth and pump ratio of exhaust screw
Among the parameters of the exhaust screw, the screw groove depth H1 and H2 are the most important, because these two values directly affect the working state of the exhaust screw
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2022
Parameters of extruder screw exhaust section
The exhaust performance of the exhaust screw of the extruder is mainly determined by the parameters of the exhaust section, and there are many factors that affect the exhaust effect. The simulation device shown in Figure 14-2 is used to study the exhaust effect of the exhaust screw of the exhaust extruder. The results show that the length of the exhaust section L, the residence time of the molten material in the exhaust section t, and the shear rate of the molten material in the exhaust section γ, Finally, the filling degree of the plastic in the screw groove of the exhaust section (expressed by the filling coefficient F) is directly related to the exhaust effect
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2022
Surface treatment and service life of injection molding machine screw
We have emphasized many times that the screw barrel is the most critical and soul part of the injection molding machine. During the injection molding process, plastic raw materials enter the barrel of the injection molding machine from the tail. The screw rotates in the barrel, extrudes and pushes the plastic particles and their fillers, blends and plasticizes in the advance, and injects the screw head into the mold cavity. At this time, the barrel and screw bear certain high temperature and high pressure of different plastics, and the working temperature of the screw of the injection molding machine is also different.
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2022
Introduction to the principle of ball screw
Ball screw has been widely used in all electric servo injection molding machine because of its high mechanical efficiency and high compliance performance. The ball screw is a motion pair that uses the ball as the power transmission interface between the screw and the nut to roll. Ball screw is mainly developed for the purpose of machine tool driving device, and its development purpose is to achieve position accuracy and smoothness. Ball screws have been successfully used in precision machinery, automation, various power transmission, semiconductor, medical and aerospace industries.
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