ekstrudere

Ekstrudering is a manufacturing process in which material is pushed or drawn through a die to form objects with a fixed cross‑section. The verb ekstrudere means to extrude. It is used for polymers, metals, and foods to produce profiles, pipes, sheets, and films.

Process overview: Material is fed into a heated barrel and conveyed by a screw. It is heated or softened, then forced through a die to shape the cross‑section. The extrudate is cooled and cut or wound. Key variables include temperature, screw speed, pressure, and residence time.

Equipment and variants: The common form is a single‑screw extruder; twin‑screw designs provide better mixing for compounding. Ram extrusion uses a piston. In metals, hot and cold extrusion push metal through a die to produce billets or profiles.

Materials and applications: Plastics such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene are extruded for pipes, films, sheets, and profiles. Aluminum and other metals are extruded for structural parts. Food products include pasta and snacks; ceramics and concrete can be extruded for continuous profiles.

Quality considerations: Die design, temperature control, and downstream handling affect surface quality and tolerances. Common defects include melt fracture, die lines, air entrapment, and orientation effects.

History: The extrusion concept emerged in the late 19th and early 20th centuries, with major development in polymer processing during the 20th century. Modern extrusion benefits from advances in screw designs and process control.