Interactive manufacturing process parameter control

Along with the growing demand for continuous fibre reinforced composite structures for future en-ergy efficient aircrafts and vehicles there is an emerging need for highly productive manufacturing strategies. The related high rate production processes will take advantage of a significantly in-creased level of automation to increase production speed and reproducibility. Looking at the proc-ess itself, it will be necessary to reduce infiltration and curing times to optimise process efficiency. Furthermore high rate production processes have to be absolutely mature to minimize quality con-trol efforts and scrap rates. Today the production processes for high performance CFRP compo-nents are restricted, because all crucial parameters like e.g. pressure, cure temperature, dwell time, heat-up and cool-down rates are specified and fixed. In order to meet the demands men-tioned above, a dynamic control of all crucial process parameter based on an online condition monitoring of all important laminate properties should be a viable option. A highly promising re-search approach in this respect is to analyse the laminate throughout the complete process via “Ultrasonic Sensors”. These sensors have to be compatible to the process conditions and the de-rived signal has to be mature enough to correct the process boundary conditions in the required way. Unlike the well known dielectric cure sensors not only the surface but the local volume of the laminate is measured by ultrasonic sensors. This in turn means, that not only resin flow fronts and the state of cure at the sensor surface can be measured but also volumetric conditions like local laminate thickness (important for open mould processes) integrated degree of cure over laminate thickness and possibly also void content can be analysed and utilised to optimise process parame-ters. Within the presentation the development status of ultrasonic online monitoring and the first successful applications e.g. in the field of dynamically controlled coupon panel manufacturing are shown