They can actually be quite strong, but it requires using the right alloys and specialized equipment that is often proprietary. GE is investing billions into 3D printing complex shapes like turbine and compressor fan blades for turbofan and turbojet engines. It allows them to create complex shapes not possible with machined parts.

It would be fun, but to be useful you have to invest real money. To get the accuracy to scan and reverse engineer parts you're still over $10k just for the scanner, and most of those are size limited.

I haven't done anything with 3-D printed metal parts yet. I know Engineers who do - as I understand it the process seems to work best with some of the more exotic metals and alloys. I'm told that the parts can be stronger than traditional sintered parts and more precise than traditional lost wax cast parts. It's not necessarily cheap but they are getting parts that are difficult to make any other way.

The earlier and less expensive plastic printers tend to produce parts that are less dense and/or have poor shear bonding between layers - hence the reputation for being weak.

I recently designed a complex plastic clamp that's about 6" in diameter and 2-1/2" tall, with hinges and destaco clamps mounted with screws in inserts. Each half weighs about 1-1/2# and Shapeways made our prototype from their "strong and tough" plastic in less than a week for $200. each piece. That part has stood up to not only demonstrating that the idea works but to demonstrations and abuse both in our shop and at several customer sites. We are machining the production parts from Acetal at much higher cost - not because we think it's stronger but because we can't get an acceptable material certification from Shapeways. If it was for our use or for a less discriminating customer we would use the printed parts.

I've been printing and using ABS parts for years. A little post processing goes a long way, usually a spraying of acetone to smooth and double check all the layers bond well. As long as the parts are designed for printing, they work great.

I did a complete seat pan and headlight assembly for a cafe bike last year. Never had an issue.

https://www.thingiverse.com/thing:2467933
https://www.thingiverse.com/thing:2467959

http://forums.pelicanparts.com/uploa...1518638000.jpg
http://forums.pelicanparts.com/uploa...1518638000.jpg

Working on some adapter manifold for an induction project right now and considering printing in carbon/nylon with some threaded inserts instead of cnc cutting from aluminum. Worth a try.

I also printed a wing core for my track car that has a carbon spar, and will be laminated in carbon this spring. Should work great. Did some VR work with it for fun.

http://forums.pelicanparts.com/uploa...1518638294.JPG

I'm watching for when I print metal at home, hopefully in the next few years.

As soon as I make an enclosure for my printer I will be testing out polycarbonate filament. Its suposed to be the strongest plastic filament currently available. It is maginally more expensive then the biodegradable PLA stuff I make toys out of.

Let us know how the PC goes. I tried a roll of Nylon and it was a nightmare. Had to dry it for several hours, but could never get the bed adhesion and stop the severe warping. May try a different brand.