Resin Transfer Molding Process Monitoring and Control

Resin Transfer Molding (RTM) offers the opportunity for significant cost savings in the fabrication of polymer matrix composite airframe structures. However, the realization of this cost savings has been restricted by quality problems (e.g. voids, poor fiber volume control) inherent to the RTM process. Similar quality issues in autoclave processes have benefited from the use of advanced process control systems such as the Air Force developed "Qualitative Process Automation" and Aerospace Service and Control's (ASC's) Composite Processing Control (CPC) systems. These advanced systems utilize sensor feedback and a knowledge base to make control decisions and alter the process in real-time with the goal of improved end product quality. To date, no known parallel has been attempted for the RTM process. This effort proposes to apply this advanced control technology to the RTM process. This will be accomplished through the development and feasibility demonstration of novel Process Monitoring and Control System. The system would be based on ASC's proven CPC system and would utilize a recently demonstrated DC-Resistance measurement system to establish the resin state and flow front progression. This data would be processed in real time via a PC based controller. A graphical representation of the flow/resin state would be continuously available to the operator. The ability for the system to make control decisions/actions, based on sensor data and a knowledge base will be developed into the system. Control actions would include variations in localized mold heating, vacuum, etc. afforded through multi-zone control. Anticipated Benefits: Military Benefits: Provide structural quality improvements required to realize cost savings potential of RTM in airframe application. Near term applications include: F22 and F/A 18E/F. Commercial Applications: Any item fabricated by RTM including: aircraft, automotive, marine, infrastructure and recreational products.