The mirror additive manufacturing process for tool-less fabrication of continuous carbon fiber reinforced thermoplastic resin matrix composite

A mirror additive manufacturing (MAM) process has been proposed, in which dual mutually supported robotic heads simultaneously perform placement and in-situ laser heating curing of thermoplastic prepreg tapes. This approach overcomes the reliance on complex tools in conventional processes, enhancing manufacturing flexibility, cost-efficiency and production efficiency as well as the applicability to special environments such as space, remote areas and disaster zones. The severe instability of temperature and rolling force during the MAM process was effectively addressed by the proposed control strategy combining reinforcement learning with a PID algorithm. Moreover, ply-by-ply decrease in temperature is caused as the cumulative heating effect of the mirror heat sources weakens with the rise of laminate thickness, which is precisely compensated by the proposed temperature stabilization control method, enabling stable temperatures across each ply. Compared with the open-loop MAM system, the stabilization control of temperature and rolling force significantly improves surface quality, reduces internal defects and enhances macro-mechanical performance. The effect of process parameters such as laser power, rolling force and placement speed on surface roughness, internal defects and macro-mechanical characteristics has also been clarified.