医用接骨螺钉超声-磁流变抛光励磁装置设计  

Design of ultrasonic magnetorheological finishing excitation device for medical bone screw

作　　者：纪阿祥 王鸿云 毕成 徐爱群 JI Axiang;WANG Hongyun;BI Cheng;XU Aiqun(College of Mechanical and Energy Engineering,Zhejiang University of Science and Technology,Hangzhou 310023,China;School of Aeronautical Engineering,Taizhou University,Taizhou 318000,China)

机构地区：[1]浙江科技学院机械与能源工程学院,浙江杭州310023 [2]台州学院航空工程学院,浙江台州318000

出　　处：《光学精密工程》2022年第18期2219-2231,共13页Optics and Precision Engineering

基　　金：国家自然科学基金项目(No.51205367);浙江省科技计划项目(No.2014C31090);浙江省自然基金项目(No.LY15E050009)。

摘　　要：为解决现有医用钛合金接骨螺钉结构复杂、尺寸不一、表面毛刺较多等抛光难点,提出了一种新的抛光方法——滚筒式超声-磁流变复合抛光,并自主设计了滚筒式超声-磁流变复合抛光装置。该装置采用三磁极励磁结构的电磁铁励磁方式,通过理论计算与Maxwell仿真分析确定该励磁装置结构尺寸与线圈参数。搭建滚筒式超声-磁流变复合抛光实验平台,开展励磁电流单因素抛光实验,对抛光装置中磁流变液磁感应强度进行测试,并与仿真结果进行对比。当电磁铁励磁装置N极宽度为35 mm,线圈匝数为1080匝,线径为1.25 mm时,可通入线圈的最大电流为5 A,抛光区域可形成良好的磁路特征,磁场分布可形成磁流变抛光区与磨粒更新区,磁流变抛光区磁感应强度最高可达0.57 T。滚筒内抛光区域磁流变液磁感应强度的测试值小于仿真值。抛光前后工件表面粗糙度变化率随励磁电流的增大先升高后降低,当电流为4 A时,表面粗糙度由1.39μm降至0.435μm,此时表面粗糙度变化率取得最大值68.7%。三磁极励磁结构的电磁铁励磁装置磁感应强度能够满足磁流变液在抛光时对磁场的要求,有效抛光区域较大。To address the finishing difficulties of existing medical titanium alloy bone screws,such as complex structure,different sizes,and surface burrs,a new finishing method known as drum type ultrasonic magnetorheological compound finishing was proposed,and a drum-type ultrasonic magnetorheological compound finishing device was designed independently.The device adopts an electromagnetic excitation mode with a three-magnetic pole excitation structure.The structural size and coil parameters of the excitation device are determined by theoretical calculations and a Maxwell simulation analysis.A roller-type ultrasonic–magnetorheological compound finishing experimental platform is built.An excitation current single-factor polishing experiment is performed.The magnetic induction intensity of the MR fluid in the finishing device is measured and compared with the simulation results.When the width of the n-pole of the electromagnetic excitation device is 35 mm,the number of turns of the coil is 1080,and the wire diameter is 1.25 mm,the maximum current that can pass through the coil is 5 A.Moreover,the finishing area can form a good magnetic circuit,the magnetic field distribution can form the magnetorheological and abrasive finishing areas,and the magnetic induction intensity of the magnetorheological finishing area can reach up to 0.57 T.The magnetic induction intensity of the MR fluid in the finishing area of the drum is less than the simulation value.The surface roughness change rate of the workpiece before and after polishing increases first and then decreases with an increase in the excitation current.When the current is 4 A,the surface roughness decreases from 1.39μm to 0.435μm,and the maximum surface roughness change rate is68.7%.The magnetic induction intensity of the electromagnetic excitation device with a three-pole excitation structure can meet the requirements of the magnetic field in the finishing of MR fluids,and the effective polishing area is large.

关 键 词：磁流变抛光 励磁装置 超声振动 接骨螺钉 有限元 

分 类 号：TG175.3[金属学及工艺—金属表面处理]