Exploring optimal adaptive process parameters for curved infill paths of additive manufactured carbon fibre reinforced polymers

Material Extrusion (ME) based Continuous Fibre Reinforced Polymers (CFRP) is a potential solution to the poor mechanical properties of ME parts, but the process-induced defects from the ME process can lower the quality of CFRP parts. In this work, we proposed a vision based measure algorithm with two custom metrics to quantitatively evaluate two typical defects: misalignment and twist, in the ME based CFRP fabrication process. Based on the proposed algorithm and metrics, we explored the effects of four printing parameters on the defects under different path radii for co-extrusion based process with Taguchi method. The experiments illustrate Fibre Feed Rate and Printing Speed have significant influences on fibre misalignment, whereas these parameters only show minor influences on fibre twist. Additionally, it is found that reduced printing radius can introduce more error to the defects, especially for fibre twist. Based on the analysis, optimum conditions for infill path with different curvature radii are proposed and the results of confirmation experiments support the proposed adaptive search method for printing parameters.