Are there things beyond modeling where 3d printing is useful? The parts I've seen using dlp or sla never seem structurally useful to me. Sintered metal printing seems like although it may be less precise might be more useful structurally?
Small scale stuff you want on premise is a decent use case. The prime example being medical/dental. Imagine a patient with a crushed jarbone. You can model and print a custom prosthesis on premise and print it in maybe 16h-38h. Compare that to sending the job to some lab, custom molds being created and waiting for the item to be delivered (while the patient is waiting).
I know it's used quite a bit for custom tooling as well. Think special tools needed on an assembly line in automotive where pausing the assembly is very expensive or lead times for some custom tool to grab a wheel while working on it and whatnot are expensive.
I think one of the biggest success stories is cutsom made hearing aids. Return rate a lot lower, easier to iterate and produce the perfect fit etc.
Another example (maybe a bit more high end) is turning some item that is made out of many parts into a single item both for cost saving and other reasons. Iirc NASA uses ultrasonic welding (which is 3d printing of sorts) for this.
I'm guessing the resin used for medical applications isn't the cheapo toxic stuff.
Neat use cases though, and certainly makes some sense. I guess I would've expected precision cnc to be faster/better for such cases though, unless you absolutely need the impossible to create voids
I've used nylon SLS for lab and commercial optical work. It's strong and you can tap it. It's much cleaner than dealing with resin prints. The quality is fine if you're making simple polygonal shapes and unless you need really fine detail it's enough. You can also do things easily with SLS which are really annoying to do with printer technologies that need removable supports, like cavities and overhangs.
