Machinability of Electron Beam Powder Bed Fused Ti-6Al-4V in Face Milling with Coated Carbide End Mill

This study investigates the machinability of electron beam powder bed fusion (EB-PBF) fabricated Ti-6Al-4V specimens across a range of build orientations. Specimens were machined using a AlTi-coated four flute carbide tools with a 12.7 mm diameter at a constant spindle speed of 500 RPM and a radial depth of cut of 5 mm. The axial depth of cut was varied between 0.2 and 0.8 mm, while the feed rate were varied from 25.4 to 177.8 mm/min. Force data were recorded using a rotating dynamometer, and surface integrity was assessed through optical and contact profilometry, optical microscopy, and microhardness measurements. The optimal machining parameters for single pass face milling with an endmill are as follows: axial depth of cut of = 0.8 mm, feed rate = 77.2 mm/min. The optimum condition provides a good balance between lower cutting force, tool longevity, surface roughness, and machining time. The cutting coefficient of EB-PBF Ti6Al4V is ~ 2016 N/mm². The optimal parameters were utilized to understand the relationship between cutting force and build orientation, and support structure in the 0°, 15°, 45°, 75°, and 90° oriented specimens. The cutting force varies non-linearly with build orientation and is influenced by roughness, hardness, and the availability of materials during cutting process.