Results of a computer simulation of a liquid molding process for manufacturing high strength polymer composite automotive body panels. The simulation shows how the liquid polymer is injected into the mold and predicts the flow front position as a function of time. The results of the simulation are used to better understand the design of a particular mold and part and to select polymers and preplaced fiber preforms.
In the future, one of the keys to optimizing new product designs and manufacturing processes will be the ability to model and simulate production methods using advanced computer hardware and software. Today, the development of many products, including those that require castings, forgings and injection-molded parts, for example, typically require lengthy and expensive prototyping and experimentation to refine details of the product design, tooling, and manufacturing parameters. The use of computerized process modeling and simulation will eliminate much of this prototyping and dramatically reduce product development times and costs.
The traditional approach of using experimentation and prototyping to refine production processes is indicative of the fact that manufacturing practices have historically been based as much on "art" as on sound scientific understanding of the processes involved. This is changing rapidly as a result of research to achieve better theoretical understanding and predictability of specific processes and materials and their effect on product performance and costs. Improved theoretical frameworks are advancing progress on a wide range of manufacturing applications, processes and materials, including stamping and forming, machining, powder compaction processes and even assembly of parts.
Process modeling and simulation is being pursued by a number of organizations, including the National Institute of Standards and Technology (NIST). For example, as part of a cooperative agreement with Ford, Chrysler and General Motors, NIST is conducting research into the use of polymer composites for structural applications in automobiles. As part of the project, NIST has developed a finite element simulation of the mold filling process used to manufacture high strength body components. In a similar manner, NIST is developing process models and simulations for robotic manufacturing operations and production of powder metal particles.
Much of the ability to apply new theoretical understanding depends on the performance and cost of advanced computing technologies. Process modeling and simulation draws heavily on computationally intensive techniques in such areas as heat transfer and solidification kinetics, coupled fluid flow, finite difference approximations, turbulent viscosity calculations, fracture mechanics, stress analyses, and three-dimensional graphics and visualization techniques. Advanced computing technology directly affects the speed and level of detail that can be incorporated into the models, and therefore the realism and benefits that can be obtained.