Towards Self-Replicating Rapid Prototypers

Neil Halelamien writes "Researchers at the University of Bath are developing a rapid prototyping machine capable of making copies of itself and other products, reminiscent of the Universal Constructor proposed by von Neumann. The so-called Replicating Rapid-Prototyper (or RepRap) would produce items from raw materials and small components like microchips. If successful, this could make rapid prototyping cheap enough for regular in-home usage, especially since the project's lead, Dr. Adrian Bowyer, will be releasing his project's designs under the GNU GPL. It's previously been proposed that a similar system would be useful for space exploration and industrialization."

Comments

Required materials & handling technologies.

[G4from128k]

I think self-replicating machines might be further in the future that this article suggests. I notice, for example, that the little robot contains several crucial non-self-replicated components such as the chips, motors, rubber tires, and batteries. This leads to thoughts of a complete list of the materials needed for a true self-replicator. These materials, and the self-replicating systems to handle them, must provide capabilties that include:

1. Structure: The core parts of the device need a strong, stable material that can hold everything together.
2. Motion: The device needs materials that convert energy into mechanical motion. These materials might include electromagnetics, electrostatics, piezoelectrics, shape-memory alloys, chemo-dynamic protein muscles, thermodynamic cycle systems, etc. Each of these types of motion-creating materials has special needs/chemicals that might require special handling devices that, in turn, must be made out of the materials in the self-replicating device. Motion is often tricky because it requires specialized assemblies of materials (think of the complexity of a simple DC electric motor or the gears and linkages in a robotic arm).
3. Control: The device needs some form of logic that can read some analog of a blue-print, ROM, DNA, etc. and direct the fabrication process. If based on standard electronics, this would include materials that act as insulators, conductors, and semiconductors.
4. Power: This may be the trickiest because creating sufficient power requires purified, highly engineered materials. Self-replicating a modern alkaline battery would be quite a feat. Perhaps the semiconductor technology of the control materials could be leveraged for solar panels.

I suspect that one of the trickiest part of all this is in handling and converting bulk materials (usually a liquid, powder, or solid ingot) into a shaped and controlled component or assembly. The replicator must interface with raw materials supplies, move bulk materials to a fabrication point, and convert the bulk material into a usable component in its offspring. Space exploring self-replicators face an even greater challenge of processing raw space materials (moon rock, asteroidal metals, etc.) into refined feed-stocks for replication.

Its a tricky problem, but one that we will eventually solve.

What they really did

[Animats]

Basically, they spent some time playing with a rapid-prototyping machine that builds solids up from ABS. Then they made what's basically a printed circuit board. But they did it by making a blank board with slots for the "wires" and metal parts, then pouring in a low-melting-point metal to create "wiring".

All this was done in a very crude way, as if they were developing a process for home use. Their metal casting technique is scary. They used "Wood's Metal", which is a solder-like alloy of tin, lead, cadmium, and bismuth. All of which are toxic. Lead and cadmium cause heavy-metal poisoning, and the body won't clear either of them. No serious precautions seem to have been taken against inhalation - they just used gloves. At one point they tried powdered metal, which is much more of an inhalation hazard than molten liquid. They need to run their people through the usual checks for heavy-metal poisoning.

There are rapid prototyping machines that deposit metal, and that's probably a more useful direction.

All this is a long, long way from self-replication.

Re:Huge economic change

[Atario]

Right now, it makes no sense to make something repairable. It is cheaper to build something that can't be fixed and throw it away. When we get very distributed manufacturing however, things will be built with only one or two raw materials. Things will be built so they are easy to assemble. It would make sense to build a new heating element for your coffee pot.

I think you have that exactly backwards. It is only the high cost of manufacturing a new instance of something (above a certain price limit) that lets us repair anything at all now. If we had make-anything machines, we would not repair anything. We would simply feed the broken thing into the machine's materials hopper (perhaps with a lil' something extra in case of lost parts) and tell it to make a new one. New lamps for old -- literally.

N.B.: If the make-anything machine uses a high enough amount of energy, this could still be uneconomical and your repair scenario might make more sense. Alternately, you could consider the re-creation process to be a kind of ultimate repair.

Waste would go down.

You got that much right. In fact, garbage dumps might become valuable mines of material.