Since the beginning of The Virtual Foundry, I’ve been experimenting with nearly every variation, adaptation and enhancement for the most common methods of sintering for 3D Metal prints. One that we have not yet perfected but shows tremendous promise is Liquid Phase Sintering. This technique provides a method of producing a part of very low porosity and close to zero shrinkage. We’ve had intermittent success. I think we’re very close to having a fully deployable solution. If you would like to participate in developing this process, please contact me at [email protected] I can put you in contact with other people that are developing this process.
This technique can overcome some of the limitations of Powder Metallurgy in a way that is so elegant that it sounds too good to be true. First, let’s look at a dictionary definition of the Term:
In a nutshell, you print your part with Stainless 316, for example. You sinter it using your normal debind and sinter recipe, but you do this in the presence of a metal has a lower melting point than you base material. In the example photo I printed with 316l, but put it in contact with Bronze. As the sintering temperatures for the 316l are reached, the Bronze will be in a liquid form. Since all sintering is a process involving Surface Tension, once the bronze whets the 316l it will become soaked into the 316l as if it were a sort of sponge. This technique is pretty normal for stainless parts that are created using the Binder Jet method. Here’s a link to a very good explanation of the process. In this video they are using an ExOne powder-bed system. My link here will take you right to the interesting part, but the whole video is worth watching. How It’s Made: Metal 3D Printing