Effect of processing conditions on the quality of out-of-autoclave laminates made by automated fiber placement

Over the years, out-of-autoclave(OOA) processing has become an integral part of composites technologies, which uses conventional oven and atmospheric pressure to make structural components at comparatively lower price. Meanwhile, Automated Fiber Placement(AFP) technology brings to manufacturing fast rate of material deposition repeatability and consistency, also allows for complex geometries, which traditional layups cannot match. Therefore, the combination of AFP and OOA technology can not only increase manufacturing rate but also help deliver parts of superior quality. However, reducing the voids content and controlling the quality of parts give challenges to the manufacturing. In this paper, the effects of processing parameters on the quality of OOA composites manufactured by AFP have been investigated, including lay-up rate and compaction force. Porosity in the parts was determined by optical microscopy and image analysis. From the comparisons of voids content in the parts, lower lay-up rate and higher compaction force can help to reduce voids. The slight gaps and overlaps induced by AFP processing between each tow and their effects on the variation through thickness have also been identified. The optimum parameters in CYCOM5320-1/IM7 composites manufactured by AFP are 1.5 in./s laying-up speed, 40lb compaction force and 100℃ nozzle temperature. In addition, the AFP samples have better results on 0°tensile and in-plane shear tests, when compared with HLU samples, while the 0°compressive properties need to be retested using thicker coupons.