Investigation and Simulation of the Surface Contact Characteristics of Sinter-Joined Binder Jetting Components

Binder jetting holds great potential for revolutionizing conventional production processes for high-performance components. However, current applications face significant challenges regarding the depowdering and cleaning of complex internal geometries. A novel approach to these challenges is splitting the desired component into smaller, easy-to-clean parts and using sinter bonding to achieve the desired shape. This greatly reduces manual cleaning and preparation time during the production since sintering is required in any case. The sinter joint is currently significantly weaker than the rest of the part and may pose a risk of failure. This study focuses on the effects of different parameters that influence the joint strength and the contact surface between two parts. With different experimental setups, a variety of influences is identified and quantified: depowdering air pressure, component orientation in the build box, initial contact pressure between the green parts, and macroscopic component deformation. The experimental results are supported by a modified Boussinesq contact model. Combining experiments and simulations, it was found that the relative contact between two green parts varies between 5 and 26%, depending on the parameter set used. In this study, the authors introduce the idea of two-part manufacturing in metal binder jetting and subsequent joining of the components in the sintering process.