Determination of the optimum cure cycle of carbon fiber reinforced composite materials using taguchi method

Composite materials are widely used in industry in many advanced applications that require high mechanical properties and low weight. Composite materials consisting of carbon fibers previously impregnated with resin are called prepreg. These materials are widely produced in the most advanced applications such as the aerospace industry employing the autoclave method, which is a high temperature and pressure furnace. However, since both autoclave's initial investment costs and operating expenses are high, unit product costs are very high. Therefore, out-of-autoclave manufacturing method research is hot topic in the field of polymer matrix composite materials. In this study, it was aimed to determine the optimum cure cycle in infrared curing method, which is one of the alternative out-of-autoclave manufacturing methods. Infrared has potential advantages such as volumetric heating with electromagnetic waves, rapid heating, more controlled and homogeneous heating compared to autoclave. In the study, it has been determined whether these advantages can shorten the processing time by providing a faster cure. In addition, optimum heating speed, maximum temperature and maximum temperature residence time (plateau time) that will maximize the tensile strength have been determined by using the Taguchi method. The results were compared with the technical data of the material and the sample produced in the autoclave with the optimum curing cycle determined for infrared. The tensile strength value was 6.2% higher than the highest results of the infrared cure cycle before the verification tests, while the tensile strength value was 18.8% higher for the autoclave production in the technical datasheet of the material. In addition, while the recommended curer cycle for the autoclave is 130 minutes in total, the recommended optimum cure cycle for infrared is 85 minutes. Therefore, the cycle time was shortened by 45 minutes and 35% of time was saved.