Zero or close to zero waste
The very nature of 3D printing, creating a part layer by layer, instead of subtractive methods of manufacturing lend themselves to lower costs in raw material. Instead of starting with a big chunk of plastic and carving away (milling or turning) the surface in order to produce your product. Additive manufacturing only "prints" what you want, where you want it. Other manufacturing techniques can be just as wasteful. Thermoforming is a popular way to create thin plastic products, but its almost impossible to never have any waste from this process, due to the fact you need to start with a piece of plastic significantly larger than your final design. 3D printing eliminates much of the manufacturing waste by creating your product or design layer by layer. However, some 3D printed parts require supports to print correctly, but the extra plastic that is printed for the supports can easily be recycled to create new filament for more 3D printing!
On-Demand Manufacturing / Custom Manufacturing
3D printing is the ultimate just-in-time method of manufacturing! No longer do you need a warehouse full of inventory waiting for customers! Just have a 3D printer waiting to print your next order! On top of that, you can also offer almost infinite design options and custom products! It doesn't cost more to add a company logo to every product you have or let your customers pick every feature on their next order, the sky is the limit with additive manufacturing. You don't need a $500,000 injection mold, when one $499 dollar Asterid 3D printer can print your product on-demand!
Better Designs
Whether you are designing tennis shoes or space shuttles, you can't just design whatever you feel like, a good designer always take into account whether or not his design can be manufactured cost effectively. Additive manufacturing open up your designs to a whole new level. Because undercuts, complex geometry and thin walled parts are difficult to manufacture using traditional methods, but are sometimes a piece of cake with 3D printing! In addition, the mathematics behind 3D printing are simpler than subtractive methods. For instance, the blades on a centrifugal supercharger would require very difficult path planning using a 5-axis CNC machine. The same geometry using additive manufacturing techniques is very simple to calculate, since each layer is analyzed separately and 2D information is always simpler than 3D. This mathematical difference, while hard to explain is the fundamental reason why 3D printing is superior to other manufacturing techniques. It almost always better to keep things simple and additive manufacturing is simple by its very nature!