Advances in Binder Jetting: Reducing Defects & Enhancing Properties for Optimal Performance

Binder jetting in additive manufacturing has shown significant promise for industrial applications, yet challenges in defect mitigation often impact the quality of printed components. This presentation addresses these challenges by examining binding mechanisms, identifying common defects, and proposing targeted strategies to address these issues during printing and post-processing. One approach, Hot Isostatic Pressing (HIP), is particularly highlighted for its role in reducing porosity and enhancing mechanical properties. This study showcases, for the first time, the successful binder jetting of AISI M2 tool steel, a tungsten-molybdenum high-speed steel valued for its durability in cutting tools such as drills, end mills, and broaches. Our primary focus is on the influence of printing parameters and sintering conditions on the resulting microstructure and mechanical performance of binder-jetted M2 tool steel. Green parts were sintered at temperatures of 1270°C, 1280°C, and 1300°C, followed by distinct cooling methods: furnace cooling (FC), air cooling (AC), and water cooling (WC). Post-HIP treatment notably increased sintered densities from approximately 89-95% to a remarkable 98-99.8%, underscoring the efficacy of densification. The microstructural analysis also revealed a uniform dispersion of MC and M6C carbides, contributing to enhanced wear resistance. Regarding mechanical properties, furnace-cooled samples demonstrated a ~40-45% increase in hardness, while air-cooled and water-cooled samples showed decreases of ~15-18% and ~20-22%, respectively. Compressive strength also improved, with gains of 50-65% for furnace-cooled samples, 30-55% for water-cooled samples, and 10-15% for air-cooled samples. The presentation will also explore the feasibility of processing M2 high-speed steel using selective laser melting (SLM), comparing the microstructural, mechanical, and wear properties of SLM-processed parts to those created through binder jetting. This research contributes valuable insights into enhancing binder jetting quality, with implications extending beyond M2 tool steel to broader applications in high-performance manufacturing.