An intelligent, closed-loop expert system has been developed for the widely used high performance polyimide PMR-15. This expert system has been used for intelligent, automated sensor/model control of the fabrication of flat panels in both the autoclave and the thermal press. Panels have been made, ranging in thickness from less than 1/8 inch to 1/4 inch, using PMR-15 prepreg. Various prepreg samples have been used, ranging in age from fresh to one year old under freezer storage conditions. These materials exhibit significantly different processing properties as a result of the aging process. This expert system uses in-situ Frequency Dependent Electromagnetic Sensing (FDEMS), the Loos processing model for PMR-15, and the Qualitative Processing Automation Language (QPAL) software shell developed by Frances Abrams in conjunction with the Universal Technology Corporation for the United States Air Force.