Case histories

01/04/2011

SONOCO TEAMS UP WITH SIPA to slash weight of salad dressing bottle

American packaging giant Sonoco has partnered with SIPA in the development of a two-stage PET bottle blow molding operation making a new salad dressing bottle significantly lighter than its predecessor. Last October, it took delivery of two SIPA 300 tons preform production machines and three SFL 6 linear blow molding machines dedicated to the project. At the same time, Sipa also delivered two single-step systems - an ECS HS 12 and an ECS FX 20. The injection molding and reheat blow molding machines will be used to produce a 16-oz (0.47-L) lightweight oval container, at a rate of 7500 bottles/h. A 20% weight reduction. The installation of the equipment came at the end of a year-long development project, during which Sipa and Sonoco worked together to cut the weight of the salad dressing bottle from an original 39 g down to just 30 g – that’s a reduction of over twenty percent! The development project involved carrying out a finite element analysis (FEA) of the new design in order to verify its technical performance, followed by Unit Cavity Development to produce physical prototypes of the container. Further studies were then carried out to optimize its mechanical properties. “We then worked closely with Sonoco throughout production start up to optimize the process,” says Marco Bottecchia, SIPA North America Managing Director. “The main point was optimize the design of the preform to obtain the best possible balance of performance and weight in the final container,” says Bottecchia. The same concept was also developed for two other containers, with volumes of 8 oz and 24 oz. A flexible blowing platform for multiple type of packaging. Sipa’s SFL linear blow moulding machine provides great flexibility in the production of a wide range of different types of containers. The platform can produce standard and personalized bottles for standard filling, for hot filling, oval containers with oriented neck finish and multilayer bottles, lightweight bottles, small containers for the pharmaceutical industry as well as large containers up to 30 liters at high production rates. The machine’s fully electrical operation, the non-lubricated oven chain, the blow clamp equipped with self-lubricating graphite bearings and the electrical stretching are all elements which contribute towards keeping the inside of the machine clean. This results in limited maintenance requirements, energy savings and a high quality of the containers. The SFL range has a compact layout and a small overall dimension. Its size make the SFL suitable even for installation in very small rooms. All models of the range may be shipped complete in a single container and they may be easily positioned on site by means of a crane or a forklift truck. This enables quick positioning and start up. The PPS preform production range includes three models: two high-speed hydraulic injection systems the PPS 96 and the PPS 72 - and a toggle press, the PPS 300. Each model displays characteristics that suit even the most specific production needs: from heavy preform production, to standard or light preforms. PPS machines are also extremely versatile in terms of their productivity: there are variants suited for medium-low productivity as well as for particular applications, such as for the production of heavy and long preforms (up to 450 g in weight and 272 mm in length), with neck diameters up to 65 mm or machines with higher number of cavities for higher output. PPS injection systems can process a variety of materials for a wide range of applications: preforms in virgin PET resin as well as recycled PET and polypropylene (PP), light and special preforms for hot-fill containers, heavy preforms and wide neck preforms for jars or for containers up to 20 liters. SIPA's Preform Systems: flexible production and maintenance reduction. The core of the PPS machine, the injection mold, has a layered structure made up of the adaptor plate, the base plate, the hot runner system, the nozzle plate, the cavity plate and the cores plate. It features individual cooling circuits and self-lubricating bushings and wear plates, allowing for a reduction in cost and time for maintenance. The production of high quality and clean preform is ensured by a special cooling robot. The robot configuration provides for long cooling time (preventing scratching and any possible ovalization of the neck) without interfering with the cycle time and hence with the productivity of the machine. The innovative preform take-out plate does not require cooled air jets or any further cooling devices inside the perform. Sonoco is a multi-billion dollar global manufacturer of consumer and industrial packaging, as well as a provider of packaging services. It has been in business for more than 110 years. From its headquarters in Hartsville, South Carolina and in more than 300 operations in 35 countries, Sonoco produces packaging for a variety of industries and many of the world’s most recognized brands, serving customers in 85 nations.