A Stereolithography-Based Sugar Foaming Method for Porous Strucutre Fabrication

Porous structure has wide application in industry, thanks to some of its special properties such as low density, low thermal conductivity, high surface area and efficient stress transmission. Both templating and foaming agent methods are used to fabricate porous structures. However, these methods can only produce simple geometries. In recent years, many research studies have been done to use additive manufacturing (AM), e.g. stereolithography (SLA), in the fabrication of porous structure, but the porosity that can be achieved is relatively small due to their limited accuracy in building micro-scale features on a large area. This paper presents a projection based SLA process to fabricate porous polymer structures using sugar as the foaming agent. With a solid loading of 50wt% of the sugar in the resin, the method can achieve a porosity over 50%. This method can be used to increase the porosity achieved by current SLA methods by over 100%.