Influence of build orientation on porosity, strength and dimensional accuracy of laser sintered polyamide porous bone scaffolds

Development of synthetic bone graft via bone tissue engineering involves seeding of patient's stem cells onto a porous scaffold in presence of growth factors. Porosity, strength and dimensional accuracy of the porous scaffold play a vital role in this process. This work aims at ascertaining influence of build orientation on porosity, mechanical strength and dimensional accuracy of the selectively laser sintered polyamide porous scaffolds. Initially, CAD models of test specimens with pre-designed porosity were created in Solidworks (R) (R) software. All the specimens were fabricated on EOSINT P395, a selective laser sintering machine, along various primary (Flat, Edge, Upright and Flat_diag) and secondary (0 degrees, degrees , 30 degrees, degrees , 45 degrees, degrees , 60 degrees degrees and 90 degrees) degrees ) orientations. Results show that measured porosity of most of the specimens was (range: 42.89-35.26%) less than the designed porosity (41.71%). Maximum average tensile strength (16.84 MPa) was recorded for specimens printed along Flat_0 degrees degrees orientation. Specimens printed along Upright_90 degrees degrees orientation showed highest average compressive strength (8.26 MPa). Specimens printed along Flat orientation showed relatively better average impact strength. Best dimensional accuracy was obtained for specimens printed along Flat orientation.