“Selective Inhibition Sintering”
Colour me intrigued. It looks as though this technique might be suitable for experiments, since it doesn’t require a metal-sintering laser (which we don’t have).
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So from what I understand, the parts are hollow?
No, they can be solid if you want just like normal SLS. If you want them hollow though, you should plan an escape route for the powder 
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I may be misunderstanding how this works, but…if it’s spraying an additive onto the powder you DON’T want printed, is there a way to separate the additive from the powder afterwards, or is all the negative space just wasted? That would seem far too wasteful to be how it works. Does the additive solidify to a point where you can remove just the part to be baked, or do you have to run the entire print bed through the oven?
Wherever you didn’t spray would be solid metal fused to other solid metal beside it via the oven. Everywhere you did spray would still be powder. So you pull the bin out and brush the powder off of the solid bits.
Normal SLS just uses a laser to fuse the powder together to each other. SLS requires a high enough power laser to fuse the material together. The beauty of the “SIS” approach from this paper is you just use an inkjet (with sugar water basically) on the powder and send it to an oven/kiln. The oven kiln would potentially cost less than even the power supply of the laser.
What I mean is, after you bake the part solid, wouldn’t all the excess powder still have the sugar-water-like fluid saturated into it, preventing it from being recycled over for a new part? Wouldn’t all the excess have to be thrown out, or is there a way to remove the inhibitor?
This seems like a really cool idea, I’m just not grasping how you recycle the powder that has already been treated so that it WON’T fuse, back into powder that CAN be fused in the oven.
Ah, I misunderstood and now I understand what you’re asking. I’m not sure if you could recycle the powder. You’d obviously want to remove that sugar somehow. Maybe just ants? 
I suppose the inhibitor would have carbonized in the oven, although part of it may still be water-soluble. In that case, you might be able to remove the carbon with some kind of solvent, or else burn it out with oxygen, depending on the metal.
No, the inhibitor is applied only to the outline of the part being fabricated. However, the excess material is not directly reusable, as it all has melted and re-solidified.
The last 30 seconds of this video demonstration clearly demonstrate:
http://www-bcf.usc.edu/~khoshnev/RP/SIS/SIS-Movie.wmv
I copied the link from the following URL:
http://www-bcf.usc.edu/~khoshnev/RP/SIS/Selective%20Inhibition%20of%20Sintering.htm
Further references: