| 摘要 |
A method for the extrusion of preforms ( 1 ), which exit from a die gap of an extrusion head ( 4 ) delimited by a mandrel ( 2 ) and a die ring ( 3 ), and are widened in a blow mold ( 5 ). The width of the die gap is changed during the extrusion of the preforms, by means of a setting movement of the mandrel and/or of the die ring. The cross-sectional geometry of an elastically deformable sleeve ( 9 ) disposed on the extrusion head ( 4 ) and delimiting the die gap on the circumference side is also changed during the extrusion of the preforms. By means of setting movements of an additional element ( 10 ) that is controlled or regulated separately, the melt distribution on the circumference side is changed at least in that section of the preforms ( 1 ) that is widened to form an upper barrel end in the blow mold ( 5 ). In this connection, the deformation of the sleeve ( 9 ) and the setting movements of the additional element ( 10 ) are coordinated with one another in such a manner that the upper region of the barrels widened in the blow mold has no deviations in thickness from default values in the circumference direction.
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