Optimising The Dynamic Process Parameters In Electron Beam Melting (EBM) To Achieve Internal Defect Quality Control

Electron Beam Melting (EBM) is an Additive Manufacturing (AM) process which can be used to fabricate complex 3D Ti-6Al-4V components. However, defects are often found in the as-built components, which can make a significant difference to the fatigue resistance of the parts. In this study, dynamic process parameters, including reference current, speed function, beam focus and line offset were investigated and a response surface methodology used to develop a regression model to correlate the effect of those parameters on pore characterisations. The pore size, pore morphology and volume fractions were characterised using X-ray Computed Tomography (XCT). The as-built component porosity were found reduced from ~0.2% (based on the default melting theme) to ~0.06% through parameter optimisation, where all the resolved pores under the new melting theme were found as spherical gas pores (<300 μm). This work will enable EBM users to manufacture components of better quality.