In-situ thermographic monitoring and numerical simulations of laser-foil-printing additive manufacturing

Laser-foil-printing (LFP) is an additive manufacturing (AM) technique offering advantages over traditional powder-based methods. A deeper understanding of the melt pool dynamics is crucial for optimising process parameters and achieving high-quality builds. This paper presents a combined approach utilising numerical simulations and in-situ thermographic monitoring to investigate the relationship between scanning strategies, melt pool dimensions, and cooling rate in LFP. The numerical simulations are employed to predict melt pool behaviour using a time-dependent thermal finite element analysis (FEA). Results demonstrate that the simulations accurately predict melt pool dimensions, showing strong agreement with experimental data. Simultaneously, real-time melt pool dynamics were monitored through in-situ thermographic techniques, with calibration performed using an empirically known melt pool width for emissivity determination. The continuous line scanning strategy resulted in a gradual increase in cooling rates along the scanning path, while the discrete spot scanning strategy maintained stable cooling rates at each weld spot.