| DENG Yue-ming,ZHAO Yu-gang,SONG Zhuang,LIU Guang-xin,GAO Yue-wu,LIU Qian,ZHANG Xia-jun-yu,DAI Di.Study on Surface Quality of Inner Wall of Ni-Ti Alloy Cardiovascular Stents by Magnetic Abrasive Finishing by Magnetic Pole Slotting[J],51(2):322-330 |
| Study on Surface Quality of Inner Wall of Ni-Ti Alloy Cardiovascular Stents by Magnetic Abrasive Finishing by Magnetic Pole Slotting |
| Received:September 28, 2021 Revised:December 07, 2021 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.02.032 |
| KeyWord:magnetic abrasive finishing magnet poles groove Ni-Ti alloy cardiovascular stents surface roughness |
| Author | Institution |
| DENG Yue-ming |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| ZHAO Yu-gang |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| SONG Zhuang |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| LIU Guang-xin |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| GAO Yue-wu |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| LIU Qian |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| ZHANG Xia-jun-yu |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
| DAI Di |
School of Mechanical Engineering, Shandong University of Technology, Zibo , China |
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| Abstract: |
| In order to improve the surface quality of the inner wall of Ni-Ti alloy cardiovascular stents pipe and the efficiency of magnetic abrasive finishing, and to study the effect of slotted and non slotted magnetic poles on the surface quality of Ni-Ti alloy cardiovascular stents pipe. The finite element simulation model is established to simulate the magnetic induction intensity distribution of slotted magnetic pole and non-slotted magnetic pole. Combined with the simulation results, the magnetic abrasive finishing equipment for the inner wall of the Ni-Ti alloy cardiovascular stents pipe was used, and the magnetic abrasive finishing experiments for the inner wall of the Ni-Ti alloy cardiovascular stents pipe were carried out with slotted magnetic pole and without slotted magnetic pole. Super depth of field 3D microscope was used to measure the surface roughness before and after grinding, and scanning electron microscope was used to analyze the microstructure of inner wall surface. Under the conditions of the process parameters combination of pipe rotation speed 100 r/min, feed velocity of magnetic poles 5 mm/min, magnetic abrasive filling quantity 0.1 g and size of diamond MAPs 100 μm and one-time reciprocating machining, the surface roughness Ra of the inner wall of the pipe decreased from 0.5 μm before machining to 0.24 μm, which decreased by 52%; the surface roughness Ra of the inner wall of the pipe decreased from 0.5 μm to 0.11 μm, which decreased by 78%. Pole magnetic field distribution is greatly improved after grooving, after notching the tooth part of the magnetic induction intensity produced several poles “tip”, because “tip” magnetic induction intensity is relatively uniform, processing of magnetic abrasive will be gathered in a multiple pole tooth position of the uniform, avoid most of the magnetic abrasive gathered near the pole ends phenomenon, The grinding pressure of magnetic abrasive particles on inner wall of pipe is increased. After the pole is slotted, the magnetic induction intensity of the pole has a more complex gradient change, which solves the problem of weak magnetic induction intensity in the middle region of the magnetic pole surface, and is more conducive to magnetic particle grinding. At the same time, the hysteresis phenomenon of magnetic abrasive particles caused by the magnetic driving force generated by the magnetic poles is not enough to overcome the friction between the magnetic brush and the pipe workpiece is avoided. When the magnetic driving force can drive the magnetic particle brush to move, the hysteresis phenomenon will inevitably appear, and reducing the hysteresis becomes the key. The hysteresis is related to the magnetic induction intensity, the greater the magnetic induction intensity, the smaller the hysteresis, the smaller the magnetic induction intensity, the greater the hysteresis; The hysteresis is also related to the inner wall quality of the processed workpiece. The greater the friction coefficient, the greater the hysteresis of “magnetic particle brush” and magnetic pole, and vice versa. In addition, the hysteresis is related to the axial size of the magnetic pole and is approximately 1/3~1/2 of the axial size. At the same time, two working strokes are processed, and the magnetic particles on the inner wall of Ni-Ti alloy cardiovascular stents pipe are carried out by slot magnetic pole. |
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