Screening method for producing suitable spray-dried HA powder for SLS application

Abstract

Screen methods are time-saving tools, assisting the establishment of a new process or technique for laboratory and industrial scale. This paper presents a step-by-step approach to use spray drying (SD) for obtaining hydroxyapatite (HA) powder, with suitable characteristics to be used as a filler in a polymer matrix, for selective laser sintering (SLS) processing. The proposed method consists of adjusting the departing HA suspension and SD processing parameters, briefly discussing relevant elements that must be considered. Suspension's rheological behavior and spray-dried powder morphological features were investigated, serving as selection criteria for the favorable set-up. Variations on slurry feed and atomization pressure of SD processing parameters have allowed obtaining different powder characteristics. A major influence of atomization pressure variation was identified, a greater pressure value resulted in smaller particle size. Desirability function was employed to determine the optimal SD processing parameters, in other words, conditions that made it possible to obtain spherical particles with the proposed mean diameter in the range of 15 to 25 μm, with narrow particle size distribution.