Architecture of Ti–6Al–4V thin-walled microthrusters fabricated via laser powder bed fusion

Advances in small-satellite platforms have intensified the demand for microthrusters that offer structural robustness under stringent mass constraints. While laser powder bed fusion (PBF-LB/M) enables the realisation of complex geometries, the application of PBF-LB/M to fabricate such devices has posed critical challenges, including dimensional inaccuracies, limited feature resolution, and process-induced defects that can compromise mechanical reliability and propulsion performance. This work addresses these issues by optimising the process to fabricate thin-walled (0.5 T) decomposition chambers and injector orifices as small as 180 µm – the minimum resolvable feature size – achieving significant weight reduction and enhanced precision. Dimensional accuracy measurements showed a maximum deviation of just 4.1% from design specifications, with high relative density (∼99.9%). During 60 s hot-fire tests at 700°C, the microthruster demonstrated stable, repeatable performance without structural degradation. Propulsion efficiencies were also high, with characteristic-velocity and specific-impulse efficiencies reaching 84.3% and 91.7%, respectively. The combination of dimensional accuracy and feature resolution enables reliable propulsion performance, suggesting its applicability for microthruster fabrication at this thrust level and presenting it as a viable alternative to conventional MEMS-based manufacturing approaches. This work proposes the potential of PBF-LB/M as a viable manufacturing route for next-generation, lightweight, high-efficiency micro-propulsion systems.