Accuracy of 3D Printing with Geopolymers

Abstract

3D-Printing is a technology which emerged back in the 80s and which has been, gaining in popularity in the last decade for its feature of being sustainable. Being based on a powder bed, it allows the user to have more architechtural freedom by building structures with a more complex geometry. Moreover the usage of geopolymer, further embodies the feature of sustainability. To verify the accuracy of this printing process, multiple parameters have to be consid- ered. First to assure a good accuracy of the product, the powder bed must be homogeneously distributed and has to have a high packing density, so that the binder flows without ease. This is done by choosing an appropriate particle size distribution. The surface roughness can be limited by using a specific binder droplet diameter or by using different grain sizes. The flow will eventually halt, thereby reaching an equilibrium state, and from this, the penetration depth will indicate the optimal layer thickness assuring the cohesion between layers, crucial for the accuracy of the part. This cohesion is assured for a specific saturation and other values will negatively impact the accuracy. Also a low printing speed minimizes the dimensional inaccuracies and it is recommended to print one line at the time instead of multiple, one next to the other.