Study of laser metal deposition additive manufacturing, CNC milling, and NDT ultrasonic inspection of IN718 alloy preforms

In this work, a study of the complete value chain for 2.5D preforms manufacturing using laser metal deposition (LMD) was performed. Process development covers the optimization of LMD process parameters and different deposition strategies to generate near-net-shape preforms, including straight ribbed walls made of IN718 alloy. The influence of geometrical distortions, rigidity, and hardness of the obtained LMD preforms was analyzed. Additionally, CNC milling process was performed and analyzed, measuring the cutting forces and surface roughness, and estimating its influence of LMD as-built condition in the final machined component. Finally, a new methodology for automatic ultrasonic testing (UT) of LMD-powder additively manufactured preforms demonstrated the feasibility of detecting and locating surface and internal defectology with sizes between 25 and 200 microns in the studied samples.