PREFORM DEVICE

摘要

The invention concerns the production of preforms from polyethylene terephthalate (PET) for the production of bottles by stretch-blow moulding. The deformation zone (1) of the preform, located under the retaining flange (2), is provided with several longitudinal ridges (3) of which the flanks (4) determine an increase in the surface area of the deformable zone, by a certain value relative to the surface area represented by the same external diameter of a cylindrical preform without ridges, for a same length of this zone. This increase in the surface area makes it possible to reduce, to the same proportion, the thickness of material in the deformable zone (1). The tops (6) and the bottoms (7) of said ridges (3) are radiated depending on the thickness of material in order to keep said thickness (8) constant in each section of the deformable zone (1), of which the ends (5) of the ridges are radiated in order to ensure the centring of the preform in the feed guide of the stretch-blow moulding machine. Reducing the thickness of the preform makes it possible to reduce the cooling cycle during the injection and to increase production rates.