PETpla.net Insider 03 / 2021

Inspection 44 PETplanet Insider Vol. 22 No. 03/21 www.petpla.net Agr helps beverage brand owners manufacturing PET containers A journey into the unknown In many beverage plants, the decision to self-manufacture PET bottles is a journey not just into the unknown, but the unknown unknown. Agr’s Process Performance Optimization Group (PPOG) consultants help processors navigate this unfamiliar terrain. The new millennium has seen tremendous advances in PET bottle blowing technology, from block or integrated blow-fill machines to the breakthrough Process Pilot auto- mated blowmoulder control system introduced by Agr International. At the same time, there’s been an absence of demand growth for carbonated bev- erages, a consequence of the increas- ing consumer appetite for a healthier diet as evidenced by tremendous demand growth for bottled water. Sev- eral big-name converters have con- solidated, changed focus, or exited the business. Not surprisingly, the industry saw a wave of retirements among plastics engineers. All this was unfolding against the backdrop of mounting environmental concerns that prompted fillers to rethink the need to ship empty bottles hundreds of miles to their plants. The beverage industry responded with a logical solution: bring blow- moulding in-house. The numbers pencil out, and it makes sense from the sustainability perspective. Making bottles on demand at the point of filling also offers the advantages of increased flexibility and closer control. According to Paul DiZinno, Manager of Agr’s Process Performance Opti- mization Group, brand owners have invested in hundreds of blowmould- ing lines over the past decade. The seismic shift to self-manufacturing has spread far beyond the U.S. to bever- age operations around the globe. But as one major CSD processor in Ger- many found out, there’s a lot to learn about the blowmoulding process. Labeller trouble Opening in 2018, the German plant was designed and equipped for efficiency and productivity, with the Agr Process Pilot installed inside the 20-mould KHS blow-fill machine. Prior to installation of Agr’s Process Pilot system, container handling issues were observed on the high-speed line producing 42,000 bph. Sometimes, the bottles seemed to wobble in the label- ler, as though they weren’t sitting well in the cup. Further downstream, labels would pop off as the containers were going into pallets. New to blowmoulding, plant per- sonnel didn’t know how to track down the cause of the skewed labels. Nor did they suspect that it was the symp- tom of a much more significant prob- lem. As a long-term supplier of critical measuring instruments and produc- tivity tools to the plastic packaging industry, Agr was keenly aware of the industry shift to self-manufacturing - and its pitfalls. PET bottle making is extremely sensitive to a host of variables. Dynamics like tempera- ture, humidity, preform composition, machine condition, or even operator skill can impact material distribution, the key factor in bottle performance. Process Pilot takes and analyses real- time measurements of the thickness of the sidewall of every single bottle, then adjusts the blowmoulder control parameters if material distribution starts trending out of spec. The result is an optimised blowing process that ensures consistent container quality and performance. PPOG supplements Agr’s Process Pilot by providing plants with fundamen- tal process knowledge. Brand owners have discovered a shortage of knowl- edgeable plastics personnel in the job market. The PPOG engineers, veterans with a long history in bottle manufactur- ing operations, have deep expertise in the blowmoulding process. They also take a holistic view of the vast chain of interrelationships throughout the pro- duction cycle. All these elements must be coordinated to achieve sustainable improvements in stability, uniformity, and productivity. Turn down the heat The issue of the wobbling bottles came up when PPOG Process Engi- neer Consultant Damon Choate was in the German plant for phased commis- sioning of the Process Pilot. Without on-site equipment to do qualitative bottle testing, Choate sent samples to the Agr service depot in Italy for analysis. There, bottle volume expansion and maximum burst pressure data, provided by Agr’s PPT3000 Packaging Pressure Tester, revealed that the bottles were subject to frequent base stress crack failures. “Half the sample bottles burst in the base just a few seconds into the test,” Choate relates. “The ones that didn’t fail had over 40 per cent volume expan- sion. The resin wasn’t being distrib- uted properly, which is why the bottles wobbled and didn’t fit in the label cup.” “Agr is well known for our ability to test volume expansion,” DiZinno observes. “We were the first to do the 13-second expansion test. This is the number-one parameter PPOG engineers look at. Even if the weights are exactly centered, we can tell whether the problem resides with the material, the process, or the design.” With the PPT results indicating room for improvement in the process, the engineers reviewed the bottle recipe, or blowmoulder settings. It was clear to them that too many oven lamps were The Process Pilot interface is a window into blowmoulder operation, translat- ing realtime data into an easy-to-under- stand visual format.