Not to be harsh, or dis-respectful, but there's an unfortunate amount of incorrect, or obsolete, information in the comments on this article. Let me see if I can do better...

-- Full disclosure: I used to (relatively recently) work for a vendor of 3D-printing technology.

It is important to consider the full 'volume' range of manufacturing, when evaluating a particular process or technology. Some will be good for making ONE part; and some for a million+ parts, and some in the middle. It's also important to consider the intended usage: for example, prototypes and military and medical parts may not be cost-sensitive, but, say toys, or consumer electronics are the opposite. Speed of manufacture is a key cost driver, especially in high labor-cost countries. Raw material wastage, and cost of energy can also be key cost drivers in manufacturing.

With regards to 3D-printing (more formally known as: additive manufacturing), I have to admit that I _used to_ be a skeptic, too. I can't tell you the number of: toys, action figures, souveniers, etc. that I saw printed from low-end, plastic 3D printers--and they just struck me as 'junk'. And even a lot of the industrial parts that I saw from middle-tier, plastic 3D printers were...unimpressive. I few years ago, I even thought that I was detecting a 'backlash' against 3D printing, at least at the hobbyiest level. And it is true that there has been some consolidation of vendors of low-end/hobbiest 3D printers.

But, there's also been a gradual, and now accelerating maturity in AM, and also an increasing diversity in approaches, and in uses. In particular, most people only think about 3D printing in plastic. But metal AM, and also directional-composite (e.g., oriented carbon-fiber) printing is really coming along.

In particular, AM lets us create parts that have voids (of controlled size/shape) throughout the part. That may not sound like a big deal, until you think about weight-sensitive transportation usage. If you can get 20-30% of the normal weight out of a part, that's huge for cars; and game-changing for aerospace. Here's one case-study, where they're claiming a savings of 3,180 kg of fuel, per-year, PER-PLANE: https://www.autodesk.com/customer-stories/airbus

I noticed that lots of commentors are discussing how much 'better' injection molding is than 3D printing in plastic. Sure, for anything above prototyping quantities, that's probably true. But, also think about the manufacture of the _molds_ for those machines. What if you could cut your mold production time by 30%, and your mold production cost by 90%? Here's a case study on that: https://www.desktopmetal.com/resources/builtrite-3d-printed-...

What if 3D printing--including in METAL--wasn't a S-L-O-W process. Here's some folks that can do metal AM at very high speed: https://www.digitalalloys.com/
The caveat there is that the resulting part has pretty crude tolerances, so a finish pass (with conventional CNC machining) may be needed. But there's some higher-quality, and pretty high-volume, metal AM processes coming along, for example: https://www.desktopmetal.com/products/production and: https://www.exone.com/

Lastly, AM opens up some design space possibilities, that previously were either wickedly cost-prohibite, or were completely impossible to do. For example, the previously mentioned _molds_ for injection molding machines. Being able to carefully control the mold temperature is a key process parameter. With 3D printing, 'conformable' cooling channels can be designed-in to the mold. And these channels can basically be any geometry that is needed--looking like animal veins, for example, to give optimal cooling.

It's probably going to take a new generation of designers and mechanical engineers, before the full--and I use this word deliberately: disruptive--effects of AM are 'internalized', and used to their best potential. For example, here's a (software) CAD tool that produces 'organic' designs, and ones that would only be practical to manufacture with 3D printing: https://www.desktopmetal.com/products/software/live-parts/