Photosensitive binder jetting technique for the fabrication of alumina ceramic

Abstract

Abstract The fabrication of ceramic using additive manufacturing has been a promising technique thanks to its abilities to form complex structures and customized shapes as well as to reduce wastes in comparison with conventional methods. Concerning the lithography-based technique, its limitation includes the deterioration of large-sized parts in fabrication process owing to the excessive amount of vaporized pressure caused by debinding of polymeric binder in ceramic slurries. Besides, the binder jetting technique involves more complexities due to the powder modification in preparation for the solidification by water-based binder. Photosensitive binder jetting techniques fabricate ceramic parts using an inkjet system to deposit photo-curable polymers onto ceramic powder bed with the shape of the parts. The binder is polymerized by the ultraviolet light to entrap the ceramic powder and form the three-dimensional object. The heat treatment process is then applied to remove the binder and sinter the part. In this research, the shrinkage, density, porosity, microstructures, mechanical properties, and printing patterns of ceramic alumina fabricated by the photosensitive binder jetting technique were investigated. The results reveal that the full printing sample exhibited the shrinkage of 11 %, the density of 39 %, the flexural strength of 1.04 MPa and the compressive strength of 1.78 MPa, whereas the checkerboard-patterned sample with 50 % reduction of printing area exhibited the density of 33 %, the flexural strength of 0.42 MPa and the compressive strength of 0.72 MPa. Through the medium of checkerboard-patterned printing with 50 % of binder’s quantity at core areas, this technique enables crack minimization in the fabrication of the large-sized part (60 mm in diameter and 30 mm in height). Furthermore, the additional modifications of ceramic powder are not required.