Surface characteristics of laser polished Ti-6Al-4V parts produced by electron beam melting additive manufacturing process

Additive manufacturing (AM) offers high design flexibilities and challenging approaches to produce highly complicated and intricate parts, which could not be possible to produce with traditional manufacturing methods. However, one of the significant drawbacks of AM processes is of course poor surface qualities, which are not acceptable for end products. Laser polishing (LP) offers an innovative surface-finishing technique that could be used to reduce the surface roughness by melting a thin layer of material on the rough part surfaces. This research work presents an extensive investigation of surface texture observed on laser polished surfaces of Ti-6Al-4V parts produced via electron-beam-melting process. A complete surface analysis of possible defects such as cracks, oxidation, and elevated edges and their causes are discussed in detail. It has been found that LP is capable of improving surface finish and the highest reduction in surface roughness can become from Sa = 44.14 μm to Sa = 3.69 μm. It is also shown that laser polishing might produce some surface defects and two detrimental surface cracks such as longitudinal and transverse might be evident depending upon the laser scan direction.