Fitment Study of Porous Polyamide Scaffolds Fabricated from Selective Laser Sintering

Abstract

In this study on fabrication of scaffold from polyamide PA-2200, a biocompatible material, was conducted. The data for fabrication of scaffold was extracted from the human skull through MRI/CT scan. The data was first converted into STL (sterolithography) format using MIMICS. The STL model was converted later into IGS (Initial Graphic Specifications) format by creation of NURBS patches on the surface of model and fitting the same NURBS (Non uniform rational B-Spline) into model using POLWORKS 12. The created solid model in IGS format was edited with the help of SOLID WORKS 2004 wherein pores of desired shape and size were modeled. The CAD model was in the required shape of scaffold. The size of scaffold pores was selected in such a range so that growth of new bone cells within it could take place. After completion of CAD model, it was again converted into rapid prototype defecto standard (STL format) so that fabrication could commence in selective laser sintering machine. Prior to fabrication, errors of the CAD model were removed using MAGICS. The scaffolds were fabricated through selective laser sintering process using EOS 380P Sinterstation. The functional dimensions of fabricated scaffold were measured through reverse engineering method. The dimensional deviation responsible for fitment of scaffolds was found maximum up to 1.3 percent where as dimensional deviation for pores were observed up to 7.5 percent. The dimensional tolerances were obtained of the order of IT07 to IT16. Fabricated scaffolds with clearance fit into the fabricated skull holes/recesses demonstrates the proof of concept for the followed procedure and use of selective laser sintering technique in manufacturing human scaffold through MRI/CT scan data. Present literature reveals the in grow of new bones cells into dimensional deviation of 7.5 percent fabricated pores of scaffolds despite