Extent of cure

For the curing of thick components it is necessary to conduct stage curing or debulking to ensure correct curing is given throughout the component. Similarly, complex curing with multiple components undergoing different stages of cure, requires a knowledge of the degree of cure. Several different thermal analysis techniques are commonly used for extent of cure measurements in fibre reinforced organic matrix composites. These include differential scanning calorimetry (DSC) or dynamic thermal analysis (DTA) to measure the extent of the residual curing exotherm and dynamic mechanical analysis (DMA) or thermomechanical analysis (TMA) to measure the glass transition temperature. A alternative means of assessing degree of cure is to conduct a Barcol hardness test (see picture) on a laminate to provide a benchmark against a known hardness for a fully cured laminate.