The Research Of Precision Control And Structural Machinability For FDM Molding Pedicle Nailing Sight

Current clinical applications of pedicle nailing navigation template can help doctor's quickly complete path planning,more accurately guide the implant within the plant.But this kind of light curing?SLA?based navigation template mainly exist two aspects of the defects:one is the template thickness thin,poor rigidity,is not convenient to intraoperative holding,easy to shake while drilling;two is without wear-resisting sleeve is easy to wear or melt,and wear sleeve form between the sleeve and the catheter for clearance fit and relative rotation,these defects will affect the accuracy and using effect.To solve the above problems,this article is based on fused deposition molding?FDM?technology to design and manufacture with its vertebrae positioning?M-M type?and locate in adjacent vertebrae?L-M type?two kinds sight structure,make it has better rigidity,durability and reliability.To coordinate the relationship among sight structure strength,the 3D printing quality and production efficiency,this article from the molding process,control precision,the finite element analysis and so on aspects make theoretical and experimental research,the main research contents and results has:?1?Had carried out the structure of double side positioning sight design and structural manufacturability analysis based on the parallel technology.On the basis of vertebral anatomy morphology,forming characteristics of 3D printing and nailing operation condition,designed two kinds of different forms of sight structure;determined the M-M and L-M sight positioning surface respectively are target vertebrae and adjacent vertebrae outline of the vertebral plate,the rear part of the transverse process and dorsal spines root;to the target vertebral spines,articular process and transverse process interference in the M-M type sight made avoid empty design,to the target superior articular process,transverse process and adjacent vertebral spines interference in L-M type sight made avoid empty design;body based on man-machine engineering view in sight two sides of before and after set four nest loading refers to the pit or the pressure surface with antiskid refers edges for convenient holding and pressure.Structural manufacturability analysis shows that two forms of sight all meet the 3D printing technology,the use of position precision and realize the catheter to the demands of the drill set of transition fit.?2?Had carried out finite element analysis of sight structural.Under the drill deflection extreme condition to the sight deformation carried finite element analysis,provide the basis for sight reliability argument.Considering mechanical performance particularity of the 3D print workpiece material,PLA material mechanics performance parameters adopted by the finite element analysis are based on the mechanics experiment measured and calculated results,the compaction force of the sight all based the measured values.?3?Had carried out accuracy control experimental study of the 3D print.Layer thickness,print,temperature,printing speed as variables carried on L₈?2⁷?FDM-3D printing orthogonal experiment for the eight prism with hole.Through the intuitive analysis and variance analysis optimized the technological parameters of print,based on regression analysis method predicted the error,raised artificially set by mistake method for error correction and verify the effectiveness on the model;provides the technical support in order to ensure the attached with a good agreement between sight and vertebrae positioning surface,tube and metal drill sleeve form transition fit.?4?Had proceed experiment research for the two forms of sight use effect and technology economy.Dye penetrant inspection showed that sight locating surface and vertebrae surface attached with a good agreement,meet the requirements of the position precision;close to the pedicle the passage diameter drilling experiments show that two forms sights all meet the requirements of using positioning accuracy,and the pressure surface with antiskid refers edges more comfortable,nailing process is not easy to vibrate and slip.Technical economy analysis shows that two forms of sight can satisfy the requirements of nailing,L-M type sight has smaller size,lighter weight and less print time,from the blade size,production cost and response speed,L-M type sight has better technology economy.