Modelling of geometrical deformation and compensation during sintering of binder jetting

Binder jetting three-dimensional printing (BJ3DP) opens a door to efficiently fabricate parts with intricate geometries. However, the binder jetted parts typically suffer from undesired shrinkage and distortion during the sintering process of BJ3DP. Nevertheless, the distortion mechanism and shape maintenance method during BJ3DP remains unclear. In this paper, an integrated deformation prediction and geometrical pre-compensation framework is developed. A thermo-elastic-viscoplastic constitutive model is used to capture the shrinkage and distortion after sintering, where the effect of thermal, plastic, creep, and porosity evolutions is incorporated. Subsequently, a reverse shape pre-compensation model is proposed to generate the desired pre-compensation scheme. The constitutive model enables an efficient prediction for the sintering-induced shrinkage and deformation of various binder jetted parts with complex geometries, with the maximum relative error being within 8% relative to experimental and reported results. Furthermore, the simulation-based pre-compensation model can lead to a significant improvement in the dimensional accuracy of as-sintered parts. Compared to computer-aided design models, the maximum geometrical deviations of printed pre-compensated structures after sintering can be lower than 3%. The proposed model can serve as an effective tool for the design and production of binder jetted parts with high dimensional accuracy and mechanical performance.