PETpla.net Insider 07+08 / 2021

BOTTLE MAKING 34 PETplanet Insider Vol. 22 No. 07+08/21 www.petpla.net Bottle design and bottle making From the seed to success Italian company Sipa says that it deploys an array of tools in supporting PET bottle makers create attention-catching designs that can be produced quickly, economically and sus- tainably. Prototypes are developed with 3D printing as well as more traditional laboratory machines; software simulation is used to anticipate thermal profile, thickness distribution, cooling optimisation, and final bottle performance. Knowledge of legal aspects These technical capabilities are complemented by understand- ing of, and adherence to, current and upcoming regulations relating to consumer packaging, especially single-use plastics. In the immediate future, EU legislation will impact the PET bottle sector with the require- ment for tethered caps, which will affect all bottles up to 3 l in volume. By 2024, new solutions will need to be in place, which means there will be significant changes to production lines. Sipa is already testing new cap and neck designs. The EU is also requiring higher PET recycled percentage on new bot- tles, along with higher waste collec- tion rates. … and technical Sipa is already proposing new lightweight versions of some of the most widely used neck finishes in the market for waters, CSDs, edible oils and hot-fill liquids. The aim is to achieve material savings without any loss of performance, using the same closures and without any changes to handling on the production line. A new neck ring is the only change needed by preform producers in order to switch to the new designs. Five steps to design heaven The company’s design and engi- neering experts consider not only the look of a container but also how the look fits with the identity of the pack- aged product, how the container feels and behaves, how easy it is to produce, how it performs on the filling line, in storage, and in transport; and – last but not least – how much it will cost. A typical design project can be separated into five steps, starting with the marketing brief from the client, using a proprietary Sipa interactive document to share ideas, inspirations and expec- tations. Step two covers sketches, concept ideas, and computer-generated 3D proposals. Step three is production of prototypes, for which Sipa has been using 3D printing for several years. The company maintains that this technology delivers a look and feel very close to that of the final product. Sipa employs various printing technologies to create prototypes in sizes from 10ml all the way up to 4l. Stereolithography (SLA), enables the use of a clear, almost water-white, photopolymer in creation of hollow parts. Engineering aspects Step four tackles the feasibility of the product, including preform develop- ment, technical specifications, stretch ratio calculations and shelf simulation. The mechanical performance of the bottle is assessed with the help of Finite Element Analysis (FEA). In Step five, technical drawings are finalised. Preform and bottle production can be tried and moulded products put through rigorous laboratory testing, to confirm computer predictions. Once this has been carried out to the customer’s satisfaction, full production can begin. Use of rPET The use of post-consumer recy- cled PET (rPET) in bottle design and process technologies requires appropri- ate expertise. Sipa’s designs take into account differences and variations in BOTTLE MAKING rPET bottle design