Development of a new PET packaging system can be a high-risk, technologically challenging and costly proposition. When considering the broad application of PET packaging, the landscape of challenges is huge. Expansion of this material into new applications such as wide-mouth hot-fill food products, cleaning products and innovative shapes for pressurized packaging, offers technical challenges that will tax any development organization.

It is no longer necessary to rely on purely empirical, trial-and-error methods of development. Popularized more recently in advertisements by auto manufacturers describing virtual prototyping as a means of predicting the performance of a new automobile via computer-based simulation before ever manufacturing one, virtual prototyping and predictive analysis are changing the development processes for new polyester packages as well. Many of the most critical technical design, processing, and stability challenges can be addressed via currently available analytical and computational simulation methods. The scope of available virtual prototyping methods for the polyester packaging industry is described in Figure 1. The goal of using these technologies is to dramatically reduce technical risk and costly, time-consuming iterative trial-and-error development. The result of their application will typically be 50%+ reduction in development schedule and cost, when compared to traditional approaches. Successful case histories are summarized below, including development and structural performance optimization of the Pepsi Cola 32-oz All Sport bottle; blow molding simulation of a 20-oz PET water bottle; and predictive closure sealing and removal torque simulation for a wide-mouth, hot-fill PET package.

Structural Development of the 32-oz All Sport Bottle

A common economic constraint in developing a new PET bottle is the desire to use an existing preform. This was one of the primary economic requirements Pepsi established during the development of the new 32-oz All Sport Package in late 1997 (Figure 2). Faced with the challenge of quickly producing a new bottle for this fast-growing market, Pepsi elected to develop the new package using predictive structural analysis methods, and limit the production of fully functional prototypes. The development relied on virtual prototyping and performance evaluation via computer simulation.

Provided with the aesthetic requirements for the design, the development effort focused on identifying the primary structural details required to develop a bottle that met the prescribed gram weight using an existing preform, while satisfying the top load and low pressurization distortion criterion that had been established. Over a several month period, 22 production-quality virtual prototypes were developed and evaluated. During the development, several limited-function prototypes were blow molded for intermediate marketing reviews and simulation model validation. Figure 3 illustrates the validation of the computer-based structural simulation model via a comparison of the predicted bottle deformation with test results. Figure 4 presents a quantitative comparison of the predicted top load with the measured response for the same test.