Modeling simulation and analysis of patient specific implant for rapid manufacturing

Abstract

Rapid Prototyping (RP) is a technique used to generate any complex shape object within hours directly from its digital representation in a CAD system by the addition of materials layer by layer fashion. The opportunities of using this technology are time gain in product development, freedom of design and tool free fabrication. More recently, implants with optimised geometries have been fabricated directly in high-strength final materials using advanced processes such as Electron Beam Melting (EBM) and Direct Metal Laser Sintering (DMLS). In this work, a three dimensional (3D) Finite Element model (FEM) of the left tibial bone of an adult male was developed from Computed Tomography (CT) scan. With the help of image processing software, Materialise s Interactive Medical Image Control System (MIMICS), the exact geometry of the bone is reconstructed through the process of segmentation and region growing by defining the threshold value and converted into a Computer Aided Design (CAD) Initial Graphics Exchange Specification (IGES) format. It is used to create solid CAD model using CATIA by Non-Uniform Rational B-Spline (NURBS) functions and patient-specific implant is designed by extracting the surface model of the bone. Both static and dynamic analyses are carried out to validate the modeland find the fracture risk area. Fracture is simulated using element removal techniques and implant is fitted. Based on FEA results, patient-specific implant is fabricated by EBM and DMLS processes using Ti-6Al-4V and SS GP1 respectively for the position 2. Dimensional accuracy, surface roughness and hardness are measured to study and compare the mechanical properties of implants to reduce the implant failure and hence enhance comfort to the patient. newline newline newline