This is a big topic that I’ll get in to more detail on as we go along. It’s a very important concept. Nearly all of our users are harnessing Shrinkage to increase part density. This is pretty normal in Powder Metallurgy. But there’s another option that needs more exploration.
Infiltration, also called Liquid Phase Sintering, LPS, Metal Matrix Composites. Plus a few other terms that I can’t think of right now. They’re all basically the same thing. Picture you FFFMetal Print as a sponge, and the infiltration metal as water. When you place your print in contact with a metal with a lower melting point during sintering, your part will soak up the lower melting metal.
What’s even more interesting is that this property of Capillary action is powerful enough to lift the melted metal several feet. (sidebar: It’s the same force< capillary action> that lifts water to the top of a tree. So it will likely lift the metal at least several feet.)
What’s more interesting is that you can use this technique to create pure metal parts with very little shrinkage. In fact, we’ve gotten to 97+% solid with little shrinkage and only minor distortion.
Here’s an email blast from one of our metal suppliers on this topic. It provides some baseline info that’s helpful.
Here’s a photo of an engine block model I printed with 316l and infiltrated with Bronze. I’ve attempted this probably a dozen times. The successes are spectacular, but my failure rate is about 80%.
I’m really hoping that some more people start working on perfecting this process for our open architecture strategy here. It’s done every day in industrial settings. I’ll be doing a sort of brain-dump in the forum here. I’ll be going back and sharing all of my notes and photo’s. This engine block is from about 2.5 years ago. I haven’t had much time to work on this process since then.