PD_Packaging Digest

Packaging Digest, April 2014

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30 NEW TECHNOLOGY // APRIL 2014 www.PackagingDigest.com Modeling optimizes blow-molded PET bottles Engineers at Queen's University model the injection stretch blow molding process for PET bottles TO IMPROVE BOTTLE PRODUCTION AND PERFORMANCE—and to cut costs. Rick Lingle, Technical Editor If something can be modeled, it can be studied, optimized and tested as needed via simulation without trial-and-error methodologies. T is speeds development time and cuts costs. For more than two decades, engineers in the Advanced Materials and Processing group based in the School of Mechanical and Aerospace Engineering at Queen's University , Belfast, Northern Ireland, have explored almost everything that happens when a plastic bottle is created—and identif ed which parameters are most critical in ensuring that the end result is an optimized bottle. As Packaging Digest readers know, there are ongoing pressures to use less material, produce stronger containers and redesign plastic bottles according to customer demand and consumer desires. As a result, the university's specialized skillset remains in demand by leading multinational companies around the globe. "T e challenge our industrial partners face is to make a bottle with as little material as possible, yet still have the proper end-service performance requirements," explains Dr. Gary Menary, senior lecturer, School of Mechanical and Aerospace Engineering. "T e problem is that the process continues to rely to some extent on trial and error. Even now, we hear of engineers who come up with a new bottle idea and bring it down to the shop f oor to manufacture dif erent shapes while guessing the proper design and production conditions. It's still a bit of a black art all around." Beginning in 1991, the group received funding from the U.K. Research Council with the objective of removing all the trial and error from the injection stretch blow molding (ISBM) process. "T is started as a three-year project, but 20 years later we're still working on it, though with a far more sophisticated toolset," Menary points out. "As we get ever closer to numerically describing and predicting the blowing process from start to f nish, we are beginning to be able to optimize the design, and even the manufacture, of just about any product conf guration." T e primary simulation tool for Queen's all along has been Abaqus Finite Element Analysis (FEA) software from Dassault Systèmes Simulia . As the group's analyses of the ISBM process grew increasingly sophisticated over the years, so did the software's capabilities. Menary's vision is to link everything together with simulation, from bottle and preform design and process conditions, to thickness distribution and mechanical properties. Menary reports that their group typically interfaces with senior engineers from companies' research and development teams who are responsible for computer-aided engineering (CAE) within their organization. Besides optimizing new bottle designs, their tools are also used for troubleshooting. Here are more responses from Menary and his team. What do you of er that can't be found elsewhere? Queen's University: We have unique expertise and testing equipment in characterizing materials, and the process. Using this information, we can develop and validate our simulations. T ere is no other company in the world of ering the type of services we provide. What main factors inf uence modeling? Queen's University: T e ISBM process is a complex process that depends on many process parameters and is why I believe simulation is a vital tool. T e major parameters for the process are the preform design, the material (the behavior of which is highly dependent on temperature and time), the stretch Experiment on an instrumented, marked PET bottle prototype allowed a perfect synchronization between force, displacement and pressure measurements of the stretching and blowing stages of the bottle-making process. Above are results from image capture using a high-sampling rate video camera and the corresponding predictions from the Abaqus FEA simulation. Contours are of axial strain. Queen's Belfast University ISBM TARGET MARKETS: PET containers (of any size) used as Fast-Moving Consumer Goods (FMCG) STATUS: Available for industrial applied research and commercial products LEAD TIME: 12 weeks Tech at a glance ES413471_PD1404_030.pgs 03.27.2014 23:03 UBM black yellow magenta cyan

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