Abstract: The invention relates to an extrusion head and a method with which the thickness distribution of hollow bodies, for example, can be further improved. The extrusion head consists of at least one mandrel (1) and one nozzle (2), which have a rigid geometry and therefore cannot be varied or can also be deformed flexibly in some areas and form a flow channel (3), wherein the positions of the mandrel (1) and the nozzle (2) can be varied relative to one another, so that the geometry of a discharge gap (s) of the flow channel (3) can be varied while a melt is being discharged, wherein each head part has at least one head section with a uniform cross-sectional area in a discharge area (A) of the extrusion head, and wherein at least one head part has at least two head sections (B) and (C), each of which has a predominantly uniform cross-sectional area within the head section (B), (C), which are spaced axially apart from one another and which have mutually different cross-sectional areas.

Abstract: A plastic film is formed by passing a web of extruded thermoplastic material through a slit formed between a pair of smoothing rolls. One of the rolls is biased toward the other roll by a yieldable biasing mechanism to accommodate variations in thickness of the web.