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What are the applications of Meltblown Extruder Screw Barrel?

Update:19-08-2022
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Cold feed screw extruder The cold feed screw extruder f […]

Cold feed screw extruder
The cold feed screw extruder from Meltblown is an excellent choice for the manufacture of plastics. The screw design enables it to process a wide range of materials. The barrel structure and screw shape can be customized for the specific process requirements. The screw and barrel can be designed for various applications including plasticization, granulation, blending, and homogeneity. Other applications include the production of masterbatch, powder coatings, and engineering polymers.

The extruder consists of three parts: screw, barrel, and head. A screw extruder is also equipped with a temperature control system. It must be fed with a material that is either hot or cold tempered. The material being extruded undergoes a series of chemical processes, including mixing, shearing, and pumping. The twin screw extruder allows a greater level of melting and conveying.

Special screws for high-flow polymers
The use of special screws for the extrusion of high-flow polymers is crucial for efficient manufacturing. The screw's design must consider both the flow and melting temperature of the polymer. Generally, a screw designed for a high-flow application has a diameter of approximately 3mm and a length-to-diameter ratio of 10. The extrudate must be processed at a linear velocity of 30 m/s, which is controlled with a laser micrometer. Then the screw must be equipped with a high-flow polymer pump and metering system to ensure a consistent and efficient flow of the material.

Spunbond layer
The spinning and deposition processes require a precise integration of the two steps. Polymer spinning begins with the feeding of the polymer through the feed pipe and ends with the filament drawing process, which typically involves the use of venturi tubes. This is done in order to ensure an even distribution of polymer throughout the entire die. This process is critical for the successful application of spunbond technology.

The extruder is equipped with a feed, transition, and metering zone. The feed zone pre-heats the polymer pellets within the deep channel of the extruder. The transition zone is shallower, compressing the polymer. This step is required to prevent the material from cooling below the melting point, preventing it from forming a ring.

Pressurized zone
The Pressurized Zone (PZ) on a Meltblown Extruder Screw Barrel is an important aspect of the melting process. The PZ is the height of the channel in the feeding zone, which is generally very small (3.9 mm on average). The granules are compressed and heated as they pass through the feeding zone. The temperature profile of the barrel is also important because the early section of the screw is very hot.

The Model 3D is in good agreement with measured data, and it considers the three-dimensional shape of the screw channel and the shear-thinning flow behavior of the polymer melt. This approach accurately represents the pressure-consuming conveying behavior under all processing conditions. The Model 2D without shape factors underestimates the experimental pressure drop, and the two-dimensional approach ignores the rate-reducing influence of the screw flights. Moreover, the model 2D overestimates the amount of drag flow and underestimates the pressure drop observed experimentally.

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