A diffusion-controlled kinetic model for binder burnout in a green part fabricated by binder jetting based on the thermal decomposition kinetics of TEG-DMA

Thermal debinding is a core process in indirect additive manufacturing processes of metals. Inappropriate debinding methods can introduce impurities into the interior of the formed green part, thus limiting the upper limits of the mechanical, electrical, and thermal properties. However, while binder jetting (BJT) is one of the most popular indirect 3D printing methods, its debinding process has largely been overlooked. This study models and analyzes the thermal debinding process of the binder jetting green part (BJGP) based on the Gaussian multimodal fitting (GMF) method; further, the grayscale-printed green part (g-BJGP) is analyzed for the first time. The results indicate that the GMF model is effective for fitting the thermal decomposition kinetics of the binder, with R² values of greater than 0.97 under heating rates of 5, 10, and 15 ℃/min. Based on analysis of the thermal debinding model, the maximum monomer content inside the green part during the thermal debinding process of g-BJGP is only 1/10 of that of conventional BJT printing under heating rates of 5, 10, and 15 ℃/min. This suggests that grayscale printing may help BJT become one of the least-polluting indirect molding methods. This study provides a detailed reference for the thermal debinding process of BJGP.