I'm currently on a quest to design highly functional robots that can be made with just a 3D printer and a minimum of external parts - so far only bearings, motors, drive belts, batteries and electronics are the non-printed parts needed. I make everything so that it fits together by interlocking or with minimal use of some coarse printed fasteners.

Since nothing needs to be bought from the store that won't be useful if the design changes, it is trivial to iterate and build a newer version.

My hope is that with developers worldwide working on improvements, injection molded versions of the parts would become obsolete before the mold was even cut.

When it comes to manufacturing, 3D printing is a whole different ballgame. No other manufacturing technique can make so many complex parts without human intervention. This means it opens up all new possibilities for how we manufacture things - like continuous iteration of shipping hardware.