Debinding, A Key Stage in the Manufacture of Inconel 718 Parts by Metal Binder Jetting

Abstract

Metal Binder Jetting (MBJ) is an indirect, non-melting additive manufacturing (AM) technique. It involves selectively spraying a polymer binder onto a powder bed, layer by layer. A green part is obtained after curing and depowdering. A debinding stage removes polymer residues before final sintering to perfect mechanical properties. Poorly controlled debinding leads to carbon contamination, causing carbide precipitation during sintering and impacting the microstructure. Thermogravimetric experiments combined with SEM observations allowed to better understand the thermal and thermochemical degradation of the polymer to achieve optimal sintering. A new debinding cycle has been developed to completely remove the polymer while limiting oxidation of the surface of the powder particles.