Binder Jetting as Complementary Technology to Metal Injection Molding: Influence of HIP on microstructure and mechanical properties

Binder jetting (BJT) is a binder-based additive manufacturing technology and is especially suited for the shaping of complex parts in small batch series. Further processing (debinding and sintering) is similar to metal injection molding (MIM). For this reason, BJT can beneficially complement MIM, which is an established technology for large-scale production of small-sized, complex net-shape parts. This study compares the performance of BJT parts made of stainless maraging steel AISI 630 (17-4PH) to standard values of MIM parts. Investigations include light microscopy, scanning electron microscopy, hardness and roughness measurements as well as tensile and impact testing. Special attention is paid to the anisotropic properties of BJT specimen. We show that HIP can improve the mechanical properties of BJT parts while decreasing their anisotropic nature. However, properties fulfilling minimum standard requirements are obtained also without HIP what may be sufficient for many applications.