> Depending on the nature of the part, it might be necessary to do some post-print surface finishing like sanding or bead blasting to smooth out the layered
surfaces
If this is anything like the powder-bed parts I've handled, the layers are going to be pretty rough. I wouldn't be surprised if they need some degree of post-machining. Don't sell your CNC mill just yet.
Furthermore, 15% shrinkage during sintering? What's the dimensional tolerance on the finished part then? I'm guessing it's not great.
Casting stuff has a ton of overhead cost and is very impractical for low volume production. EDM is expensive as all heck. For stuff that doesn't need to be made out of exotic material this is great.
For low volume production and prototyping this technology is great and cannot become mainstream soon enough. So what if it has to be finished. A casting or forging is the same way.
Forging costs a ton. The die has to be machined by (you guessed it!) a tool and die maker. Those guys are expensive. Once the die is made, however, bashing out the parts with it is fairly cheap per item.
Back when I worked in the aviation industry, sinking a die for a part cost a cool quarter million.
Somehow I doubt it. The shrinkage must be dependent on geometry/density and their method of compensating can't possibly be good enough to hold tight tolerance over an entire complex part.
Forgings and castings all shrink as well, because metal shrinks substantially when it cools. The dies and molds are made oversized.
I corresponded with a guy who was making his own intake manifold for his mopar. (A very cool project.) He made his own molds. I did some calculation, and said he had to make the mold about 10% oversized. He told me I didn't know what I was talking about, he couldn't believe it would shrink that much. His cast manifold wound up 10% undersized :-)
Anyhow, dimensions that require tight tolerances get machined to spec after the forging/casting.
> Forgings and castings all shrink as well, because metal shrinks substantially when it cools.
Forgings and castings also require post-op machining to bring them into tight tolerances, which isn't something that fits the mental model of a lot of people when it comes to 3d printers.
People who don't own 3d printers. There is plenty of cleanup work on a 3d print of any complexity. I find myself even drilling a fair number of holes in some of my prints because the minimum consistent hole size my printer can generate is a few mm.
> Depending on the nature of the part, it might be necessary to do some post-print surface finishing like sanding or bead blasting to smooth out the layered surfaces
If this is anything like the powder-bed parts I've handled, the layers are going to be pretty rough. I wouldn't be surprised if they need some degree of post-machining. Don't sell your CNC mill just yet.
Furthermore, 15% shrinkage during sintering? What's the dimensional tolerance on the finished part then? I'm guessing it's not great.