Where did the concept for the RepRap come from, what was its inspiration?
Really it was inspired by symbiosis. The classic example, of course, is the symbiosis between flowers and insects, which has been going strong for 140 million years. As every school pupil knows, the flowers give nectar to the insects, which then transport the flowers' pollen because the flowers can't move. Both species benefit.
I thought: suppose one made a machine that copied itself and lived symbiotically with people? Specifically, the machine (analogous to the flowers) would make other goods (analogous to the nectar) in addition to itself, and people (analogous to the insects) would help it to reproduce by putting its parts that it had made together. That should be a stable symbiosis that would be proof against, for example, mere legal or financial pressures.
Why is the primary goal of the RepRap project to replicate itself, and not just to build anything?
Because self-replication is the most powerful and stable force we know. It gives exponential growth (which is always checked by finite resources). And it is subject to Darwin's law of evolution, which drives it towards evolutionarily stable strategies (like the symbiosis I mentioned).
Once you have a machine that can copy itself, you have a path to being able to make anything under the laws of physics.
Who is the RepRap aimed at and what need is it addressing in today's society?
Initially it is aimed at geeks and hackers, like any new technology; they are the ones with the skills to make early machines work. But of course it will evolve - that inescapable Darwin's law again. And one very strong evolutionary direction will be towards simplicity of assembly and use. The simpler it is for people, the greater the population of symbionts the machine has to collaborate with.
What is the benefit of having the entire project under the GNU GPL license? What benefits are there in RepRap being open source?
If you have a machine that copies itself, the only thing you can do with it is to give it away. Try to sell it, and you only sell one... Try to protect it legally and you spend the rest of your life in court trying to stop people doing with the machine the one thing it was designed to do...
The GPL forces people who improve RepRap to make those improvements available to everyone, thereby maximising the rate of evolutionary progress. I personally gain nothing from giving it away, of course. But I don't need anything, and I enjoy running the project, so that's fine.
What kind of software does the RepRap run on?
RepRap software is platform independent and runs on Linux, Windows or a Mac. But all our development is done under Linux, and will almost certainly continue to be so.
Since the RepRap makes its own parts which can then be used to build another RepRap which can be used to build another, and so on, will there be a degradation of mechanical accuracy with successive generations?
Good point, but not a problem. Or rather, this was a problem solved centuries ago at the start of the industrial revolution. Lathes, for example, are made with screw adjusters so that you can get everything aligned and parallel, even if the parts aren't quite true. All you need to be able to do is to make something on the lathe and then measure it accurately to prompt the adjustments. That is simple. RepRap works in exactly the same way.
How much of itself can the RepRap manufacture?
Not counting nuts and bolts (which outnumber everything else in RepRap by an order of magnitude), about 65 per cent.
What parts of itself cant the RepRap manufacture?
Mainly motors and electronic chips. We have designed the RepRap machine so that every part that it can't make for itself is available all over the world from multiple suppliers (usually the corner hardware shop...) and is cheap.