AM DfAM Series - Binder Jet Processing: What Happens After Printing? A Review of Key Process Steps & Design Considerations
Kirk Rogers and John Barnes, The Barnes Global Advisors
In our previous article, we covered design considerations for Binder Jet Processing (BJP) by highlighting the critical process steps which also form design constraints. In this article, we take a deeper dive into the details of de-binding and sintering.
Two powder particles walk into a binder jetting bar. The first says it is looking for some capillary action. The second says it is saturated from the impact of his joke. Later, when they were caught necking, they blamed it on the diffusion of the potent liquid binder they’d been served and didn’t appreciate being made the sinter of attention. Yes, we just made a binder jetting joke. However, the art and science of processing in binder jet processing is no laughing matter. In fact, it is the diffusion of that matter that makes it a solid part of our article.
Previously we introduced the concepts of de-binding and the 3 stages of sintering and key MfAM (Modify for AM) and DfAM (Design for AM) implications. Now we will concentrate on the thermal processing required to achieve density and therefore mechanical properties for the part. The thermal process includes two key, and quite different, thermally driven events: de-binding and sintering. Figure 1 shows the progression of treatments applied in steps, or over time, beginning with two steps associated with de-binding and three steps associated with sintering. The green line denotes the transition from de-bind to the initial stages of sintering.
