Composite Manufacturing NDE Using Active Infrared Thermography

R. B. Dinwiddie and B. J. Frame

The Oak Ridge National Laboratory (ORNL) has successfully demonstrated using internal R&D funding the application of active infrared (IR) thermography as a viable NDE technique for detecting porosity, resin starvation, and other flaws in uncured composites. The advantage of active thermography for this application is that it is completely non-contacting, using remote heating and remote detection to make the measurements. Dynamic measurements made as part of this research indicate that the technology has potential for deployment as a QA tool in continuous manufacturing processes such as pultrusion and filament winding. Although other NDE technologies currently exist for detecting large areas of porosity, resin starvation and other flaws in composite structures, these methods rely on the composite first being cured prior to inspection. The manufacturer must therefore complete the fabrication and incur the costs associated with cure, tooling removal and handling before a determination of the composite's quality can be made. At that point, corrections to the process can only be made for subsequent fabrications while the defective composite hardware is scrapped. By detecting flaws prior to the costly and time consuming curing step, active IR thermography can provide a great benefit to the composite manufacturing industry.