Feedback control of the vacuum assisted resin transfer molding (VARTM) process

The Vacuum Assisted Resin Transfer Molding (VARTM) technique is a liquid-molding process that offers the potential to significantly reduce fabrication costs for large-scale composite structures. The VARTM workcell is used to evaluate control strategies and sensors such as SMARTweave to provide feedback for an intelligent control system. Current VARTM systems lack automated control systems resulting in part to part variability. This research presents a continuously controlled vacuum actuator system and the influence of vacuum gradients on resin now front control. A vacuum controlled VARTM work-cell is presented, which is able to adjust on-line the vacuum levels at several vent locations. The system is based on computer-controlled pressure regulators and venturi pumps. In addition, vacuum sensors are used to measure in-situ the vacuum levels at different locations in the system. This system is able to control accurately and quickly the vacuum levels in the vents. Finally, a case study with controlled vacuum levels showed the potential of this technique for now front control. This approach will lead to a state of the art control system that combines sensor feedback, a rule-based fuzzy logic unit and local process controller into a robust real-time controller for the VARTM technique. The methodology used in this research can be implemented in industrial applications and could ultimately lead to a more cost-effective manufacturing technique to produce high-quality VARTM parts.