Bathsheba Grossman prints 3D objects into metal by renting time on the EX ONE Prometal solution. By uploading a CAD file, you can have a prototype printed and delivered back to you in a few days.
Shapeways is another “upload your design to be printed” service.
While not a pure 3D printing solution, DoItYourself CNC machines are another approach. Many DIY-CNC solutions are beginning to blur the boundaries between using CNC milling on existing materials blanks and actually printing materials into a 3D pattern. Several of the high end 3D metal printing solutions (for precision aerospace and automotive applications) already combine both techniques. Some of these solutions now use laser or sonic cutters to complete the final milling after the initial 3D printing process.
Some DIY-CNC solutions can be found at http://www.instructables.com/id/DIY-CNC/; here’s one that uses legos and prints 3d objects in chocolate.
In use cases where you need to duplicate an existing part, you’ll might need a 3D scanner. There are a variety of ways to do this. The optimal choice can vary based on the size, shape, color, transparency, and reflectivity of the target object you wish to duplicate. Numerous services are emerging with prices ranging from $50 to $500 per scan depending on object type, required detail, and the required file output formats.
3D printing in plastic:
- Overview (wiki) of the RepRap opensource 3D printer.
- official RepRap website
- You can build a RepRap as a DIY project, or you can buy parts and/or a fully assembled unit from places like BotMill.
- HP’s 3D printer, works with ABD plastics, uses 1200 watt power source. The HP machine costs about $15K. The DIY RepRap projects range from $400-1600.