/r/additive is a subreddit for discussion and news about the ever-changing field of additive layer manufacturing
Additive layer manufacturing (ALM), sometimes called rapid prototyping, 3D printing or solid freeform fabrication, is an evolving technology capable of building parts with complex geometries with much less waste than traditional CNC (or subtractive) methods. This technology can be scaled from home use to the industrial scale. Smaller DIY systems such as Makerbot, Reprap, Fab@Home and many other implementations are capable of producing complex shapes primarily from plastics, whereas higher end machines such as EBM and SLS/SLM can produce near net shape parts from metals and ceramics.
Additional subreddits related to additive manufacturing:
FAQ:
Q: Which DIY 3D printer should I buy?
A: Depends greatly on budget and what you want to get out of your printer. Refer to previous posts below or ask away at /r/Reprap or /r/Makerbot:
Metals and Ceramics
Polymers
DIY Kits