Using CFRP booster housings, MT Aerospace AG in Augsburg, Germany, manufactures large CRFP components (carbon fiber-reinforced plastic) using vacuum infusion processes. In vacuum infusion, a dry-wrapped pre-form is inserted in a vacuum bag and is infiltrated with resin while slowly rotating in an oven. Intelligent sensors are required in order to monitor the flow front of the in-flowing resin and to optimize processes. Scientists from Fraunhofer LBF and their industrial partners are embedding fiber-optic sensors into the component as early as the winding process in various 3-dimensional positions. These then control resin distribution during this important production step.
The Digital Twin Plays an Important Role
Each sensor fiber contains several of the more than 60 glass fiber sensors. The flow front is the line when the resin first gets in contact with the dry fibers. The signals are transmitted from the rotating part in the oven to an outside computer in situ in order to digitally monitor the process. A digital representation of the sensor position on the component shows when the flow front reaches the sensor. “We are receiving transparent information for the manufacturing process of these thick-walled parts for this first time. This increases process reliability for vacuum infusion processes,” explains Martin Lehmann, Research Associate at Fraunhofer LBF.
The new manufacturing process makes previously hidden processes visible and digitally controllable, thereby increasing process stability. Information gained by resin flow monitoring ensures reproducibility and quality of the new product, enabling timely intervention if required during production. Production ramp-up can be accelerated with this improved control. This increases the company’s competitiveness.