Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cutting tool,while coatings often deteriorate them.Focusing on the diamond coated WC-Co milling cutter,the abrasive flow machining (AFM) is selected for reducing the surface roughness and sharpening the cutting edge.Comparative cutting tests are conducted on different types of coated cutters before and after AFM,as well as uncoated WC-Co one,demonstrating that the boron-doped microcrystalline and undoped fine-grained composite diamond coated cutter after the AFM (AFM-BDM-UFGCD) is a good choice for the finish milling of the 6063 Al alloy in the present case,because it shows favorable machining quality close to the uncoated one,but much prolonged tool lifetime.Besides,compared with the micro-sized diamond films,it is much more convenient and efficient to finish the BDM-UFGCD coated cutter covered by nano-sized diamond grains,and resharpen its cutting edge by the AFM,owing to the lower initial surface roughness and hardness.Moreover,the boron incorporation and micro-sized grains in the underlying layer can enhance the film-substrate adhesion,avoid the rapid film removal in the machining process,and thus maximize the tool life (1040 m,four times more than the uncoated one).In general,the AFM is firstly proposed and discussed for post-processing the diamond coated complicated cutting tools,which is proved to be feasible for improving the cutting performance