Abstract：Based on the classifying process requirements of titanium alloy powder (Ti-6Al-4V) used for 3D printing, the LNIST-180 A-2 closed argongas protection classification system was used to classify the powder. Particle size, morphology, fluidity and oxygen and nitrogen contents of the powder were indicated by laser particle size analyzer, powder rheometer, and oxygen nitrogen analyzer. The experimental results show that the titanium alloy powder can be effectively classified into the target particle size (cyclone separator: 0 ~ 20 μm, half vortex classifier:20 ~ 50 μm) using the new classification system. When the speed of the first grade classifier and the second grader are 1 500 r/min and 1 620 r/min respectively, and the system pressure is controlled at 0¹.2 k Pa, the output of titanium alloy powder is 8.24 kg/h.Meanwhlie, the aeration rate of the graded titanium alloy powder increases from 4.3 to 72.6, and the liquidity performance is greatly improved. Moreover, the contents of oxygen and nitrogen of titanium alloy are all up to the national standard after classification. After testing, the system can meet the industrial grading requirements for titanium alloy powder in 3D printing.

Keywords：titanium alloy; 3D printing; closed-loop argon protection grading system