PETpla.net Insider 11 / 2011

BOTTLE MAKING 27 PET planet insider Vol. 12 No. 11/11 ments. Next came testing to confirm the optimum Process Pilot settings. The third stage, over a longer term, compared bottles produced on the KHS Blomax with Process Pilot ON and OFF to quantify the benefits derived from its use. Accuracy validation Because the Process Pilot control software relies on precise thickness data to operate successfully, the first step in the evaluation program was to validate the PETWall Profiler’s measurement capabilities. Suntory conducted multiple tests to compare the accu- racy of the on-line measure- ment system with traditional off-line measurements, which are typically thought to gener- ate a higher degree of accu- racy. Several sets of bottle samples were taken during production runs, and on-line measurements were recorded for individual bottles in each set. The same bottles were subsequently measured by a high accuracy laboratory device. After thorough analysis of both sets of data, Suntory concluded that the PETWall Profiler possessed the highly accurate measurement func- tionality necessary for its light- weighting initiative. Blowmoulder control The second stage of test- ing evaluated the Process Pilot’s ability to actually control the blowmoulder to maintain desired bottle thickness distribu- tion consistently over a period of time. This series of tests included varying oven settings, pre-blow pressure and timing, preform temperature, and oven ventilation with the Process Pilot system enabled to prove its ability to control and stabi- lise the process, regardless of changes in environmental conditions. Results showed that the Process Pilot system quickly responded to the various control input changes and maintained the process with little variation. Suntory then moved into more extensive production testing. Multiple production runs were conducted, each with a different set of Process Pilot configuration settings, incrementally tightening the tolerances. From these, the ideal configuration was determined, resulting in an extremely stable process with little variation. Confirming Process Pilot value Utilising the blowmolder configura- tion developed during the earlier tests, the third phase of tests analysed bottles produced with and without Pro- cess Pilot control to assess the effects on bottle quality and performance. Over several weeks, the physical bottle parameters - thickness distri- bution at critical locations, topload, and volume - were documented for bottles produced with Process Pilot turned OFF and ON. Bottles produced with the system showed a marked improvement in the form of reduced standard deviation of sidewall thick- ness, increased topload strength, and greater consistency in brimful volume (see figures 1 and 2). The