PETpla.net Insider 09 / 2016

CAPPING / CLOSURES 47 PET planet insider Vol. 17 Please order your copy at the PETplanet insider book shop: https://www.petpla.net/books Bottles, Preforms and Closures - A Design Guide for PET Packaging Second Edition by Ottmar Brandau € 115,00 180 pages © Copyright Elsevier 2012 * This article was published in Bottles, Preforms and Closures, Ottmar Brandau, Chapter 4.5 and 4.6 Copyright Elsevier 2012 sports caps and other complicated configurations can be manufactured. Moveable inserts allow the creation of undercuts such as those necessary to slit tamper-evident bands right inside the mould instead of having them punched in a secondary operation. IM closure tools are sophisticated moulds that often cost more than the injection machine they are running on. To get the extremely low cycle times modern tools allow, water channels must be close to the plastic even in moving parts. This leads to significant manu- facturing challenges that are costly to overcome. These tools also require a stringent maintenance programme especially when moving mould inserts are involved. A pressure difference of 5 bar (72 psi) between the supply and return water channels is also recommended to accomplish good turbulent flow that is able to extract heat quickly. Process control during injection and hold is most crucial for highest qual- ity. Closed-loop controls on high-performance machines are recom- mended. Cycle times as low as 3.2s are possible, but other tool/machine combinations may run as slow as 14s.