The average metal printing at the moment is still kind of a little crude, while it will get better quickly, it still has a lot of negative aspects and limitations… I feel often the people who write the articles tend to be a little generous in their assessments. The metal materials that you can currently get from companies like Shapeways or whomever is currently offering such materials, are great for simple jewelry and art objects… structurally they sorta suck. I wouldn’t use them unless it was to show where a metal part “could” go if the part were co-molded… I’m not scoffing at the technology, its just the really good cutting edge stuff is Uber expensive and hard to come by… the who process is not as simple as the writers make it seem either… the CAD models have to be super tight, clean and WELL thought out. The machines can be cantankerous too… and there are a few brands that have very bad reputations in terms of reliability. When you look at something like the bike, while it is cool, you have to realize that bike probably cost 10X what any traditionally made high-end prototype would have cost… and possibly might even be the best of several attempts or shots at the finished item… and I also wonder how long the printer ran that job once it was set up. I imagine it was probably something like a day or two… where a CNC milling machine could knock that out in a couple of hours. Practically, most of the current machines are not fast enough to produce stuff much larger than the bike and their use still make sense VS traditional methods.
One other thing that few people mention about 3D printed parts, is the finish… even the best parts I seen have had slight eggshell finish… and the average parts tend to have a grainy fine sandstone finish… once again though, that often can be attributed to the operator, printing resolution,speed or the machine condition (as well as materials… the cheap stuff is VERY grainy).
The real cutting edge stuff is the machines that are hybrids… using different technologies to creating parts made with plastic, metal and even elastomeric “rubber” parts… but still most of those are at best at the moment “proof of concept” level.
One thing I have to look into again is clear glass… someone has a machine that prints a ceramic material, but there was talk of making actual OPTICALLY CLEAR glass parts. That is HARD. That would be real cool to see. Probably would be real flimsy stuff, but still would be so cool.