At last month’s PETnology Europe 2016 show in Germany, Sacmi of Italy (U.S. office in Des Moines, Iowa) presented what it says is “the first complete ‘one-step’ preform production, stretch-blow molding, and filling platform.” This “fully integrated” system is not a true one-stage injection-stretch-blow molding (ISBM) system, in that it involves close synchronization of separate preform and bottle production systems--rather than both functions in one machine--with the aid of Sacmi CPB Link, an automatic buffer system that intervenes only as necessary, to make up for the different “average efficiency” of the two processes. It maintains the preforms in an “ultra-clean environment,” Sacmi says. Eliminating the preform storage unit typical of two-stage processes reportedly also eliminates preform cleaning and heating-cooling costs, allowing bottlers to cut average bottle costs by 5-15% while keeping total energy consumption for the complete system below 1 kWh/kg of processed PET. Risk of moisture regain during preform storage is also avoided.
This new “heroPET 4.0” system does not use injection molding for preform production; rather, it uses Sacmi’s proprietary continuous compression molding process. It allows use of high-viscosity PET that can’t be used for injection molded preforms, which provides higher-strength preforms that can be lightweighted by 0.2-0.4 g, about 4%. Lower temperatures and pressures in compression molding also reduce acetaldehyde formation, and the absence of a gate allows production of flat-bottomed preforms.