Ra machining 4 roughness 4 3D printing 3 CFRP 3 FDM 3 History of engineering & technology 3 PLA 3 UNS A97075 3 additive manufacturing 3 aluminum 3 drilling 3 dry drilling 3 dry machining 3 forming 3 fused deposition modeling 3 fused filament fabrication 3 incremental forming 3 infill density 3 layer orientation 3 magnesium 3 manufacturing systems 3 mechanical properties 3 microstructure 3 occupational accident 3 rapid prototyping 3 repair and maintenance operations 3 risk assessment 3 risk management 3 surface integrity 3