Study on magnetic abrasive finishing of the inner surface of Ni–Ti alloy cardiovascular stents tube

In this study, the magnetic abrasive finishing (MAF) method was used to finish the inner surface of the ultra-fine and ultra-long Ni–Ti alloy tube that is used for the manufacture of the cardiovascular stent. During the manufacturing process, it removes the surface defects, including folds, cracks, scratches, and pits caused by the manufacturing process, and reduces the surface roughness. Firstly, we prepared the magnetic abrasive particles (MAPs) with different sizes for the magnetic abrasive finishing of the inner surface of the ultra-fine and ultra-long Ni–Ti alloy tube by using the “gas–solid two-phase double-stage atomization and rapid solidification” method. Secondly, the magnetic abrasive finishing equipment is designed. Finally, the effects of finishing time, tube rotation speed, feed velocity of magnetic poles, magnetic abrasive filling quantity, and magnetic abrasive powder particle size on the surface roughness of the inner surface of the Ni–Ti alloy cardiovascular stent tube and the thickness of the inner surface of the tube were discussed. The results showed that magnetic abrasive finishing removed wrinkles, cracks, scratches, pits, and other defects and the surface roughness decreased from 0.75 to 0.08 μm.