Synergy Effect of Abrasive Blasting and Large-area EB Irradiation on Surface Finishing of AMed Titanium Alloy

Among a broad spectrum of AM technologies, electron beam melting (EBM) is widely applied in AM process for producing titanium alloy parts. In general, AMed metal products have very rough surface of more than 200µmRz, since relatively large beads are arranged on their surface by scanning electron beam. Moreover, surface irregularities such as spatter and cavity are also generated on the surface. Rough surface and surface irregularities would lead to reduction in surface strength and poor appearance. Therefore, post surface finishing processes are required to smooth the surface of AMed metal products. One of the common surface smoothing processes is abrasive blasting. Large surface roughness can be decreased by abrasive blasting, and compressive residual stress can be introduced to the surface. However, there is a limitation to reduction of surface roughness. On the other hand, in large-area electron beam (large-area EB, LEB) irradiation method developed recently, mold steel surface can be finished by melting it in a few minutes. However, it is not easy to smooth surface with large initial surface roughness, and a tensile residual stress may be generated on the surface.