PETpla.net Insider 06 / 2011

BOTTLE MAKING 16 PET planet insider Vol. 12 No. 06/11 www.petpla.net Single stage conversion - How does it fit in? Single stage or two stage Single stage feature- part 1 by Wolfgang von Schroeter It is estimated that 80% of PET resin converted into bottles is processed in two stage technology and 20% in single stage technology. PETplanet Insider decided to take a closer look at the 20%! and Netstal for injection moulding, Sidel and Krones for blow moulding. The single stage market remained a domain of the Japanese, until Sipa joined in the late 1980s with mas- sive, big size, high output single stage machinery of American origin. Single stage PET processing PET processing in principle is the same in single-stage and two- stage: PET resin is plasticised, then injected into the preform mould and afterwards blown to make the bottle. The machinery involved: two separate machines for injecting and blowing in two-stage compared to the one single compact machine that does it all in one single stage. Typically, the single stage process will produce 5,000 to 10,000 bph, whilst the two-stage production can give - typically and economically - 30,000 to 50,000bhp - naturally there are exceptions, but generally these figures are accurate in most cases. It is estimated that 80% of PET resin converted into bottles is processed in two stage technology and 20% in single stage technology. Typical single stage application are bottles for food, cosmetics including perfumes, pharmaceutical and detergents. Variable formats in small and medium sized volume emerging markets. Engi- neering challenge: variable formats, flexible shapes and design, integrated caps, handles and grips. Typical two stage application are bottles for beverages, standard bottle formats, high volume and developed markets. Engineering is challenged today for better performance, higher thoughput, increased productivity, which boils down to more cavitations, shorter working cycles. The high volume beverage markets drive the two stage process. Certainly there are overlaps, i.e. applications, where both systems are used. Gino Duca, Business Develop- ment Manager of Sipa, should know, since Sipa develops, produces and sells both single stage and two stage machinery as well, when he says: “The right solution is driven by eco- nomics and depends on the specific circumstances. There are a lot of cri- teria in decision making: Geography, logistics, annual volumes and require- ments, culture, issues involving ser- vice, buyer’s preferences and seller’s persuasiveness.” Markets Despite its dominant position two stage applications are reaching saturation point in developed markets. Machine suppliers have turned their attention to emerging markets – par- ticularly on BRIC countries – Brazil, Russia, India and China. It is realistic to assume that requirements in BRIC states will eventually also reach satu- ration. The beginning The single stage or stage process of moulding PET bottles from PET resin was developed simultaneously together with processing PET in two stages - in the mid-1970s . At that time, when companies such as Cincinatti Milacron (injection moulding) and Husky (mould making) and Krupp Corpoplast (blow moulding) were experimenting with PET bottle processing in two stages with two separate moulding machines, - at the same time the first single stage conver- sion – i.e. injection stretch blow mould- ing in one machine - was developed in Japan by Aoki Technical Laboratories under the umbrella of Nissei Plastics, the latter being high volume manufac- turer of injection moulding machines for general purpose application. Nissei ASB – sister company of Aoki, also under the umbrella of Nissei Plas- tics – was responsible for sales and marketing of what was developed and produced by Aoki Technical Laborato- ries at the time. The markets of single stage and two stage machines developed sepa- rately and in parallel. In subsequent years pioneering big players entered the two stage markets such as Husky