skrueekstruder

A skrueekstruder, or screw extruder, is a machine used in polymer processing and other industries to melt and shape materials. It consists of a barrel, a rotating screw, and a die. The screw is typically helical and rotates within the barrel, which is heated to the melting point of the material. As the material is fed into the barrel, the rotating screw conveys it forward, compresses it, heats it through shear and external heating, and homogenizes it. The molten material is then forced through a die, which has a specific shape, to produce a continuous profile or shape.

The process begins with the raw material, often in pellet or powder form, being introduced into the feed throat of the extruder. The screw's geometry is designed to gradually reduce the volume available for the material as it moves along its length, increasing pressure and facilitating melting. Heating jackets surrounding the barrel control the temperature profile, ensuring proper melting and preventing degradation. At the end of the screw, a screen pack and breaker plate are often used to filter out contaminants and improve melt uniformity before it reaches the die.

The shape of the die determines the final product. Common applications include the production of plastic films, pipes, profiles, filaments for 3D printing, and even food products. Different screw designs exist, optimized for specific materials and processing requirements, such as single-screw, twin-screw, and multi-screw extruders, each offering unique advantages in terms of mixing, venting, and pressure generation.