Scientists at Southwest Research Institute in San Antonio, Texas, have shown the feasibility of using smart processes to control the curing of polymer resins and processing of other materials. ``The approach holds much promise, for it can be applied over an exceptionally broad range of materials and process scenarios,'' John F. Maguire, Southwest Research staff scientist and program director, said in an Oct. 11 presentation to the Society for the Advancement of Material and Process Engineering technical conference in Albuquerque, N.M. The four-day conference focused on smart processing of polymers, metals and ceramics.
Maguire identified three keys: advanced sensor technology using miniaturized-diode lasers and fiberoptics, powerful computer capability in a small housing and artificial-intelligence software able to model the chemical cure kinetics process.
``Fiberoptic technology allows us to take the laboratory to the process with considerable cost-reduction and improvement in on-line quality,'' he said.
The system controls manufacturing equipment and ``uses advanced sensors, mathe-matical models and heuristic reasoning to determine au-tomatically what the best processing parameters should be,'' he said. ``The machine itself figures the best recipe'' as the processing takes place. Benefits include reduced processing time, less scrap and no need to manually transfer samples from the process to the lab for analysis.
The system applies light-scattering sensor concepts. The material scatters visible incident radiation. A receiving optical fiber detects the scattered radiation and carries it for analysis under the Rayleigh effect on scattered protons and/or the Raman effect in frequency domain.
``This approach allows an essentially complete chemical and physical analysis of the material being processed,'' Maguire said.
Based on sensor input and modeling predictions, the materials-and-process module decides on necessary changes and sends control signals to the plant's process equipment to adjust the controllers.
``We hope within two years to have commercially available systems, and we expect to achieve up to 50 percent reductions in cure times,'' Maguire said.
The system can control any chemical reaction that occurs in a hostile and inaccessible environment. Besides the polymer resin application, these include oil refining, chemical processing, food processing and surface modification.
``In all cases, the product quality is sensitive to the raw materials' state and processing conditions,'' he said.
The institute, an independent nonprofit organization, employs about 2,500 and spent $243 million in fiscal 1994 on applied engineering and physical sciences research and development.
