Experimental study on the influence of abrasive flow machining on the surface quality and mechanical properties of BCC lattice structure manufactured by L-PBF

During the L-PBF process for preparing porous biomaterials, the "spheroidization effect" and the "stair-step effect" lead to defects such as pore clogging and rod diameter thickening in the actual components. These defects affect the part's dimensional accuracy, which in turn has the critical influence on the mechanical properties of the workpiece. Thus, suitable post treatment methods are required to improve the surface quality of porous biomaterials. This paper aims to investigate the effects of abrasive flow machining on the surface quality and mechanical properties of body-centered cubic (BCC) lattice-structured specimens molded by L-PBF at different pressures and abrasive concentrations and their mechanisms. Experimental results indicate that the number of powders adhering to the rod diameter of the member is significantly reduced after the abrasive grain flow process treatment. The roughness of the rod diameter surface is reduced from 17.48 mu m to 6.82 mu m, and the surface finishing is improved by 60.98%. The abrasive flow machining can effectively eliminate the "spheroidization effect" on the mechanical properties of the lattice structure. The maximum compressive strength of specimens subjected to abrasive flow machining have all been increased. Especially, with the abrasive flow machining under the pressure of 4 MPa and the abrasive grain concentration of 60%, the maximum compressive strength of the specimens was even been increased by 8.89%.