Laser densification of alumina powder beds generated using aerosol assisted spray deposition

Layered manufacturing involves a range of techniques in which objects can be constructed in a laminated form. Therefore, the deposition technique is a critical part of direct-layered fabrication technologies. In this paper, aerosol assisted spray deposition has been applied to generate spraying of a suspension to prepare powder beds for subsequent selective laser sintering. First, an investigation on preparation of the alumina suspension by adding polyacrylic acid dispersant is presented. An emphasis has been given to identify the most effective dispersant to enhance the dispersibility of alumina suspension for aerosol spraying deposition. Subsequently, a laser has been used to selectively densify the alumina powder beds to produce ceramics. The effects of the laser processing parameters such as scanning speed, power and beam size on the microstructural evolution of the powder beds are investigated and discussed. Also, a laser densification mechanism is also proposed and discussed.