Suppose the surgical equipment here is a surgical knife. Now that would be easy to make since there is just one component and that component is the knife itself. Suppose also the hospital has the surgical knife 3D printer, the design blueprint and also the metal raw material, would the hospital want to "print" out the surgical knife?
Now, let's extend this to other surgical equipment. Would there be a need for hospitals to "print" out any surgical equipment?
You're not going to print out a knife. It's far cheaper and more effective to run a manufacturing line and churn out a million scalpels.
What you'd use the printer for is stuff like custom-fitted implants (like
this jaw). Rather than having to use an off-the-shelf part (which probably doesn't exactly match the original equipment), you can implant a device that is exactly the right size and shape.
Suppose you are going to make spare parts for machines, what material are you going to use? Where would you get the design blueprints? Would you need the right kind of printer?
Suppose you want to build your own cars and the printer(s) can "print" out all the required components. Would you need a set of many printers, a set of many design blueprints and a set of many different types of materials? If buying and maintaining them is not trivial, wouldn't it be better to just buy a car?
1. Whatever material is appropriate for the part.
2. You make it. Or you scan the broken part, reassemble it in software, and print it.
3. Yes. You also need the right wrench to adjust a bolt.
4. "Just buy a car"? We're talking about stuff like classic cars. You don't "just buy" one of them.