How does one maintain quality? To go beyond a single part, they will probably need to do geometric tolerancing to account for all the component variations. Also, distributed manufacturing may not be as efficient.
Mao actually experimented with "crowdsourced" manufacturing in his Great Leap Forward. To boost steel production:
Mao encouraged the establishment of small backyard steel furnaces in every commune and in each urban neighborhood
The results were low quality steel and probably lots of environmental damage.
They know the capabilities of the machine that will produce the part.
It is a misunderstanding of the process to think that slapping geometric tolerances on a drawing will change the part. If the process specified produces the desired part within tolerance then there is no need to specify it further. If the process can not produce the part reliably then adding tolerances to a drawing is not going to help. They do mention the one functional specification they need -a press fit into a bearing
Although they do a press-fit test, what about the outside dimensions? What about material quality? The purpose of geometric tolerancing a design is so that when you assemble all the pieces together with varying tolerances, you have a good chance that it will all fit together.
I've worked with machines with stepper motors in the past and they can get out of alignment.
Don't get me wrong. I think the whole maker movement is really cool. I'm just saying that manufacturing a quality product is not easy.
I'm even thinking about buying one, however, if I bought a kit and the pieces didn't fit together very well, that would be frustrating.
Well anything you design in the real world needs tolerances. There are many ways to go about that, but the question is simply how accurate can the machine be? It won't be as good as milling or molding but it might be workable.
MakerBot and RepRap have a lot of overlap in ideas and people. MakerBot founder Zach Smith is a long-time RepRap contributor and also runs the RepRap Research Foundation (http://www.rrrf.org/). MakerBot's "Cupcake CNC" fabricator is based on RepRap hardware and software. MakerBot also sells RepRap parts in their store.
Mao actually experimented with "crowdsourced" manufacturing in his Great Leap Forward. To boost steel production:
Mao encouraged the establishment of small backyard steel furnaces in every commune and in each urban neighborhood
The results were low quality steel and probably lots of environmental damage.
http://en.wikipedia.org/wiki/Great_Leap_Forward