The use of plastics has been steadily increasing for more than fifty years. For example, an average car contained 100 pounds of plastic in 1977, while in 2003 it contained about 275 pounds (Figure 1). Increased usage of plastics is particularly evident in the packaging industries. The European flexible packaging market expects to grow from $10.5 billion to $11.8 billion between 2003 and 2008. The average per capita plastics consumption is forecasted to increase by 46% in the United States and Western Europe, by 85% in Southeast Asia and by 104% in Eastern Europe between 2001 and 2010.

With this increased usage, manufacturers are beginning to more closely examine the processes that form the plastic products and bring their products faster and cheaper to the market. Extrusion is one of the most widely used processes for polymer processing. Examples of extrusion include film, pipe, sheet, profiles, fiber and filament, wire and cable, and coatings co-extrusion. In each type of extrusion, the polymer is forced through a die to create the desired shape. Meeting the current and anticipated growth in demand of complex extruded shapes requires quick and accurate die design from the start. Ideally, the design of the die will minimize the process of trial and error and avoid costly shut down of production lines. Computer simulation (science) using computational fluid dynamics (CFD) can supplement existing experience (art) in the die design process by providing a cost-effective tool to investigate new design options. Moreover, coupling computational modeling with existing in-house experience facilitates the transfer of knowledge to the entire die design team and increases the range in possibilities for innovative approaches.