Bone is one of the most vulnerable tissues in the human body damage to bone may lead to its destruction or replacing by the human body. There are various ways to help bone healing or replacement with new tissues, with limitations such as the need for an environment with geometry and proper structure. In recent years, additive manufacturing (AM), the part fabrication begins with CAD file of parts and complex geometris can be directly created in layer manner, has been proven to generate a new eara in manufacturing. Among AM processes, selective laser sintering (SLS) is a powder bed fusion AM method that are widely used in medical sector for production of guides, scaffolds, implant and so on. The focus of this study is on indirect SLS of porous bioactive part using hydroxyapatite (HA) and polyamide 12 (PA12). In order to manufacture the parts with indirect SLS, the combination of HA (size 63-90 micron) with the PA12 (size 63 micron) has been used as a binding agent. The product of this stage is a green part that by carrying out heat treatment on it, the binder is removed from structure, brown part is created. In this research, HA was produced by natural method (natural hydroxyapatite), characterized by FTIR, EDX and XRD. By mechanical methods HA became powder in a different dimensional range and in next step by different methods mixed with PA12. Porous part were fabricated using SLS then sintered in a furnace. After HA parts were fabricated, all specimens were measured in dimensions and weight before and after the sintering. In order to evaluate the effect of adding different materials on sintering, Stainless steel and silica with 5% vol and average size 40 micron were used. Analyzes include spectroscopic analysis, Xray diffraction pattern, dimensional measurement, porosity and part density, images Microscopy of the surface of the samples and mechanical testing. It was found that while SLS fabricated of HA-PA12 parts had a relative density of 30%, the porosity of sintered samples was reduced to 55%. The parts made of HA-silica were sintered in 1200 °C had a relative density of 85%, compressive strength 10 MPa and Weibull modulus 6.3. The parts made of HA-stainless steel were sintered in 1140 °C had a relative density of 80%, compressive strength 20MPa and Weibull modulus 6.16. Keywords Bone, Additive Manufacturing, Selective Laser Sintering, Hydroxyapatite, Polymer
