RESIN TRANSFER PROCESS MONITORING AND CONTROL

Resin Transfer Molding (RTM) offers the opportunity for significant co st savings in the fabrication of polymer matrix composite aerospace st ructures. However, the realization of this cost savings has been restr icted by quality problems (e.g. voids, poor fiber volume control, etc. ), inherent to the RTM process. Similar quality issues in autoclave pr ocesses have benefited from the use of advanced process control system s such as the Air Force developed ''Qualitative Process Automation'' a nd ASC's ''Composite Processing Control'' (CPC) systems. These advance d systems utilize sensor feedback and a knowledge base to make control decisions and alter the process in real-time with the goal of improve d end product quality. The effort reported herein applied this advance d control technology to the RTM process. This was accomplished through the development and feasibility demonstration of an Intelligent RTM S ystem. A DC-resistance measurement grid system is used to establish th e resin state and flow front progression. The resin data is then proce ssed in real time via a PC based controller. The ability for the syste m to preform control decisions/actions, based on sensor data and a kno wledge base, has been developed into the system. Control actions possi ble include variations in localized mold heating, vacuum, and resin fl ow location/rate/pressure. The results of this effort demonstrate that intelligent control of the RTM process is feasible.