PETpla.net Insider 07+08 / 2021

BOTTLE MAKING 26 PETplanet Insider Vol. 22 No. 07+08/21 www.petpla.net Quality control, fast-track material development and bottle prototyping Optimising bottle production Blowscan was developed to provide users with the capability to quantify the effects of blowing behaviour and understand variations in preform quality and material performance. It was born out of an EPSRC €1M collaborative partnership involving BMT, Queen’s University Belfast, Sidel, Logoplaste, Procter and Gamble, Husky and Pack 3.0. The machine has been designed to flexibly interchange between free- blow and mould-blow modes. This unique dual functionality is intended to provide a low-cost, efficient approach to troubleshoot preform manufacturing and bottle blowing problems, whilst at the same time enabling pre- production prototyping capability for new bottle development projects. How does it work? Blowscan has been developed as a lab-based stretch-blow machine that features bespoke instrumentation to investigate the complexities of the preform-to-bottle process. It utilises a pre-loaded batch feed system, as opposed to a continuous preform feed. This removes the need for ancil- lary equipment, such as conveyors, hoppers and unscramblers, consider- ably reducing the footprint. Oil bath or industrial-standard near-infrared (IR) heating are available as means of heating. The purpose of two heating methods is to isolate and assess the most influential properties of the pre- form, that being the mechanical and the optical properties. Oil bath heating disregards the colour of the preform and provides a consistent and reliable temperature profile that reveals the pure mechanical properties. The IR heating can be regarded as a more standard, industrial approach that provides a realistic temperature profile with the knowledge that it is influ- enced by preform colour. The desired blowing method can be selected prior to testing, with Blowscan offering free-blow and mould blow capabili- ties using a modular ‘roll-in, roll-out’ subassembly. With either set-up, the bottle is ejected from the blowing sta- tion and is deposited into a collection drawer for the user to retrieve and inspect. When the mould is removed, and the preform is allowed to deform freely, a considerable amount of detail can be extracted regarding the pre- form quality and material behaviour. During the free-blow process, the pre- form temperature, inflation pressure and blowing geometry can all be com- pared against a reference preform. To identify any changes in preform quality within a batch, evaluating the difference in blowing behaviour with BOTTLE MAKING Blowscan operational flow With growing environmental awareness, there is an increased uptake of sustainable materials by the bottle indus- try, such as recycled PET, bio-materials and additives. Their different compositions, when compared to typical polymers (e.g. virgin PET), means that there is a need to better monitor their influence on the blowing behav- iour of the preform during stretch blow moulding (SBM) to ensure the quality of the final bottle. The latest state of the art instrument from Blow Moulding Technologies (BMT), Blowscan, has been specifi- cally designed with this in mind. The technology became a valuable tool for BMT’s partners Logoplaste and PepsiCo for providing confidence for successful bottle production.