Opportunities and limits of infrared thermography during autoclave curing cycle

Abstract

In respect of climate and environment protection, resource-preserving processes are a central field of research in the 21st century. Energy and efficiency analysis show the need for sustainable and high quality processes for the manufacturing of high volume and complex CFRP components. The objective is the optimization of processes before and during the curing cycle inside the autoclave. For this purpose the DLR Stade autoclave is realized with a new concept that is characterized by the process-accompanying availability of quality relevant process data via sensor technology. The main focus of the research is on the temperature as it resembles a main parameter of the autoclave process. The currently used sensors for evaluating local temperature are firmly anchored into the tooling which results in the disadvantage that the temperature can only be measured in the defined area. Temperature measurements outside this area are not possible. The aim of this project is to resolve this problem and provide an extensive temperature measurement inside the autoclave. Besides the overall temperature measurement of the part, thermography can be an alternative leakage detection concept. As shown in previous trials outside the autoclave thermography is able to detect leakages in vacuum bagging and provides the exact position of the leakage on the part. As a leakage during the autoclave cycle is one of the most common failures during the curing it would be a huge quality improvement to be able to detect the leakages not only in advance but also online inside the autoclave. This present report describes the technology development to implement a thermography camera inside the autoclave and how to evaluate the concept throughout tests.