Abstract

This project aims at developing new cellulosic bio-based materials for additive manufacturing (AM) by extrusion to produce complex and multi-materials 3D parts. First, this project has evaluated the compatibility of aqueous and high solid content formulations with AM by extrusion. Formulations composed of micrometric organics fillers (cellulose fibers or powder and graphite powder) and cellulose derivatives (carboxymethyl cellulose) were investigated and results in a selection of homogeneous pastes with strong potential for AM by extrusion and limited deformation of the printed part upon air drying. The second stage of this project focused on adjustment and optimization of AM by extrusion equipment and the related settings to guarantee an optimum shape accuracy of 3D printed parts compared to the 3D numerical model. A printing setting guideline and design limitations adapted to the developed paste were suggested. To characterize the printing parts, different innovative methods such as the temporal monitoring by X-ray tomography of a printed part upon drying were implemented. The results of this project lead to the AM by extrusion of complex part 100% cellulose based with mechanical properties close to thermoplastic materials commonly used with fused filament fabrication process.

Key-words: 3D printing, cellulose, extrusion, bio-based material, 3D structure