No offense, but...

I think RepRap is awesome and if you ever get it self-replicating, it'll be really cool and I will want one.

HOWEVER, I'd like to point out a couple things:

1) RepRap is hardly the first device that can manufacture itself. Machine tools (particularly the lathe) have been able to do this for a long time. (And if you take a more diffuse view, a properly-equipped workshop could replicate itself as well.) A mini-lathe is around $500, the same price as the RepRap.

2) How on earth did you guys make it into Make Magazine based on almost nothing, especially as they must have written the article a month or more ago? The article and your own website make it sound like you are only minutes away from self-replication, but the actual output I see consists of a tiny cup and some barely-working gears. To keep new users from getting their hopes crushed (cf jetpacks and flying cars), maybe it would be a good idea to tone down the claims or at least make it clear you aren't very close to meeting them yet.

Oops, forgot to get to my real point on #1: Since machine tools like the lathe can replicate themselves but there's been no exponential explosion of everyone owning one, I have to wonder how realistic your vision is.

1) You've got a good point regarding being lathes able to self-replicate, as do kilns and smithies. We've never claimed otherwise. If I wanted to quibble I'd say you need a lathe + a set of castings, and a way to make the electric motor.

However, a lathe can only replicate itself in the hands of a skilled operator, and it's still quite a bit of work. An untrained ten-year-old can build a RepRap using another RepRap, in a week or so, just by hitting print and leaving the machine alone most of the time.

2) We're reasonably close to self-replication, once we've figured out how to build the angle brackets and such. We've already demonstrated making extruder parts. We don't think this will take more than a year.

Another aspect of RepRap is utility: being able to make arbitrarily-shaped objects, like a pikachu doll or, more practically, a sink U-bend. For that you'd need to use your lathe to build a 4-axis router/mill, whereas with a 3D printer it's more a matter of just hitting print.

"the article and your own website make it sound like you are only minutes away from self-replication, but the actual output I see consists of a tiny cup and some barely-working gears."

You missed, I think, the blogging by Vik when he printed a set of parts for a Mk II extruder on his Zaphod prototype a few months back. Vik has subsequently assembled the parts set that he printed into a new Mk II and is using it.

You can see the Mk II parts in his album here...

[picasaweb.google.com]

As well, I am in the process of printing a polymer pump for a variant on the Mk II that prints HDPE as we speak.

While your comment about "only minutes away" is well made, please understand that a lot of people are coming fairly close to having the mechanics of prototype 3D printers working. It's natural that considerable excitement should accompany that kind of milestone. A few of us, however, have scaled that peak only to see a whole range of other mountains that we are going to have to scale as well with respect to getting the completed printers to print useful, detailed objects at ambient temperatures from engineering plastics. That task is very hard work as I can attest and I am sure Vik can as well.

Edited 3 time(s). Last edit at 05/18/2007 10:14AM by Forrest Higgs.

I think you put it very nicely there.
The need for skills is drastically reduced in a 3d printer.
Most of the information you need to produce something by reprap comes in a object description file you download from the net or load from a disc. This massive distribution idea is rather crucial, by reducing the cost of distribution to nearly 0.

On the other hand, if you try to get some part machined, you will need to pay for that service, basically renting machine time and skills: Imagine ordering some guy to reproduce for you the complete set of machining tools he has in his workshop. First he will say you're nuts ( ), then he will charge you more money than buying the same machines in a shop would cost you. That's the real show stopper.

Also, consider the price of the base products used in 3d printing. It is deliberately pushed down to it's lowest limit while still trying to diversify the range of materials the machine can apply by a manifold, and still keeping the printer compact.

Edited 1 time(s). Last edit at 05/18/2007 10:50AM by Fernando.

Okay, i've been giving this question some more thought and i wanted to put the crucial issues in as little words as possible, so that everyone can understand what this project and it's likes is all about and to give you the means to discriminate between projects that are just the same old, same old, and the ones that have the potential to bring an industrial revolution.

In as few words as possible:

Any production process that achieves that the cost of replication of all the instruments that constitutes it is less than the cost of the primordial building process, will lead to an industrial revolution.

this is the crux!

i think you guys all summed it up pretty well, but i cant resist.

yes, this is a difficult project, and nobody is pretending to have achieved full replication yet. it is also a very lofty goal. infact, it is one that may never even come to fruition! we could fail horribly and have nothing but plastic blobs and a website to show for it.

however, we are reasonably confident that it *can* be done. plus if it does end up being possible, then the implications of this technology will be far reaching and have the potential to change the lives of every single human on the planet. this technology would be on par with the printing press, computers, and the internet.

i'd say thats worth the risk any day of the week.