PETpla.net Insider 03 / 2015

PREFORM PRODUCTION 42 PET planet insider Vol. 16 No. 03/15 www.petpla.net Injection parameters, part 18 Practical Guide to Injection Molding of Preforms PETplanet insider is publishing extracts from successive chapters of Ottmar Brandau’s “Bottles, Preforms and Clo- sures”, which was first published by hbmedia. A newly revised version is reissued under the Elsevier imprint. 3.2.8 Postmold Cooling Devices The outside skin of preforms must be cooled to about 50 °C (122 °F) before they can fall onto a conveyor belt. Higher temperatures lead to unsightly blemishes or even deformi- ties. Preforms can however be taken out of the preform tooling at much higher temperatures, up to 100 °C (212 °F). At temperatures above this value, preforms may buckle during ejection. Postmold cooling devices with three or up to six stations take the ejected preforms and cool the outsides with water-cooled take-out tubes. In a typical three-stage robot machine,