Design Of Porous Titanium Orthopaedic Implants And Research Of 3D Printing Fabrication Technology

In recent years,titanium alloy has been more and more widely applied in the field of orthopedics implant.The porous titanium alloy can reduce implant's weight,and reduce the implant's elastic modulus while keep the compressive strength.It can also form more holes for cell growth.Traditional methods to fabricate porous titanium alloy have many shortcomings.With the rapid development of metal 3D printing technology,how to fabricate porous titanium alloy orthopedic implants using 3D printing technology so that it can have better mechanical properties and biological properties,has been a research hot point today.In this paper,firstly,use software UG10.0 to design a variety of diamond molecular structure porous titanium with different hole size,and then use two kinds of metal 3D printing technology,SLM and EBM,to fabricate these porous titanium scaffolds.Through visual observation,optical microscope,scanning electron microscope,the outline of poles made by two methods are found both rough,and are both covered with small metal particles.The error of SLM is smaller than EBM,and the outline of the poles than is clearer than EBM.Through the static compression test,it is found that porous titanium scaffolds fabricated through two methods both have the elastic modulus amount to human bone,and both have good compressive strength,but these scaffolds made by SLM have higher compressive strength than those made by EBM.It is also found that,under the same fabrication process and molding conditions,the greater porosity the scaffold has,the smaller its compressive strength became.In addition,through dynamic compression test,it is found that under the same fabrication process and molding conditions,the fatigue strength of scaffolds is positively correlated with its static compressive strength.Use two method to modificate the surface of the scaffolds,the alkali heat treatment /SBF soak and PLGA-HA coating.SEM shows that both methods can form nano-roughed surface consist of HA,which can improve the biological activity of porous scaffolds.Use CH and HA to composite with porous titanium scaffold,and it is found that there are micro porous structure formed by CH/HA in the middle of pores of porous titanium scaffolds,which can improve the bone conduction properties of porous titanium scaffolds to allow cells growth better.Use porous titanium structure to design a variety of orthopedics implants,including fusion cage,long bone tumor prosthesis,artificial spine,dental implant,acetabular cup and femoral stem.Introduce the process of 3D reconstruction of medical model and the application of 3D printing customized implants in a clinical case of a lumbar spine deformity.