How does, or how might, nanotechnology work?

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Trekkin Trekkin's picture
How does, or how might, nanotechnology work?

I'm just curious how people deal with the actual nuts and bolts of nanofabrication, since my players are deliciously meddlesome/crazy and I just know they're going to start playing with it. What, for instance, does a cornucopia machine look like, both outside and inside? How does it position and bond feedstock into a finished product? How do healing vats coordinate their nanites to correctly form macro-scale structures?

Or, in more prosaic terms, if I were to stick my hand in a CM and pull out my hat when it's half-finished, am I going to get half a finished hat (cut off nicely or raggedly) or a pile of textile fibers? What algorithms govern what parts of a given item are produced in what order?

Also, what parts of the fabrication are most time and energy-intensive? Is it possible to produce more efficient templates by minimizing these, as opposed to just lightening the finished product?

Sorry for the storm of questions; I just have no idea how this is envisioned to work.

Lorsa Lorsa's picture
These are all good questions,

These are all good questions, unfortunately I don't have any good answers. I've been thinking about this myself but unfortunately I have no clear vision yet.

DivineWrath DivineWrath's picture
If you put your hand into a

If you put your hand into a nano-fabricator, all you are going to pull out is a bloody stump. Not only would your hand be considered raw materials, nano-fabricators have a taste for blood ;)
/joke

All joking aside, I remember watching a good video of how a nano-fabricator might work. It involved a multistage process. First, the atoms are assembled into simple molecules. Those molecules are moved to the next assembly level above where they are assemble into more complex molecules. Those molecules are moved to the next assembly level above it and further assembled, and so on. Eventually, they start assembling the final product, where every molecule or component is added to the final product.

So if you were to yank out a half finished hat, you would get a hat that probably looks like it was cut in half. I wouldn't recommend opening a nano-fabricator though, as you might let dust in. For a machine with tools to work with atoms, dust are like giant boulders and can cause serious damage if they get inside.

I don't know where the vid I saw is right at the moment. I'll post it if I find it.

Trekkin Trekkin's picture
DivineWrath wrote:If you put

DivineWrath wrote:
If you put your hand into a nano-fabricator, all you are going to pull out is a bloody stump. Not only would your hand be considered raw materials, nano-fabricators have a taste for blood ;)
/joke

All joking aside, I remember watching a good video of how a nano-fabricator might work. It involved a multistage process. First, the atoms are assembled into simple molecules. Those molecules are moved to the next assembly level above where they are assemble into more complex molecules. Those molecules are moved to the next assembly level above it and further assembled, and so on. Eventually, they start assembling the final product, where every molecule or component is added to the final product.

I figured it'd be bad to open a cornucopia machine up, but it makes a handily(ha!) relatable example.

If we assume a hierarchical process like what you describe, how are the stages related in space? I mean, is there some print head with enzymatic factories built into the cartidges, or are we assuming fractal fronds of manipulators wafting over the finished product? Maybe electron gun type arrangments to fire the finished macromolecules into the target?

Arenamontanus Arenamontanus's picture
As I describe them, standard

As I describe them, standard CMs are like microwave ovens. They have a vacuum sealed compartment where various robotic arms and nanostructures work, and you can watch it through the diamond window. Opening the door while the CM is working is going to put it in emergency shutdown and quite likely damage delicate subsystems. When it is finished it retracts the work surfaces, repressurises the compartment and with a "bing!" opens the door. The product is typically warm to the touch and often surrounded with easily disposable scaffolding material (put it in the recycler receptacle below). And then there is that lovely "new nanoassembly smell".

If you have ever seen a 3D printer working, you will know that the actual building even of a simple object like a cube consists of nontrivial patterns. Quite entrancing to watch. The algorithms can be quite complex. If there is no need for enormous strength the CM will not fill all of the object but will leave empty spaces honeycombing it. If the object needs to have some heft they can be filled with water. The internal structures can be extremely complex and optimize for strength and resilience like cancellous bone, with thin arcs and sheets following lines of force.

How objects are built up depends a bit on the CM design. Oldfashioned fabbers have writing heads moving above the workpiece. A classic nanoassembler model might have a sheet of assemblers where the object is magically extruded from "nothing". A more efficient convergent assembly would have tiny robotic arms assembling pieces produced from small compartments containing tinier arms taking pieces from smaller compartments with even tinier arms... A more general CM might have internal nanoswarms or nanosuspensions in a liquid, growing the object inside out.

CMs generally take a decent amount of power: they will have fans or even need coolant pipes. Think of them as ovens. To save energy they often make use of nano lego-pieces and pixels: standard modules that can be assembled with a minimal amount of energy and effort, provided in toner-like cartridges or via the feedstock pipes.

Extropian

Madwand Madwand's picture
A nice link to anwer your question.

Here is a really nice link provided by someone else on the forums that answered this question for me:

http://e-drexler.com/p/04/04/0507molManConvergent.html

Acorrding to that, what you'll remove from the CM halfway through is a bunch of hat fragments (and a bloody stump, but that's a separate issue).

Trekkin Trekkin's picture
Convergent assembly makes

Convergent assembly makes sense, and looks easily explainable to my players. How small does it go? Are nanoscale arms gluing atoms into molecules, or does it make all the materials to some small scale first as an inventory, then feed it into the convergent assembler at some small intermediate step?

Madwand Madwand's picture
Any of those are options. In

Any of those are options. In my head, I imagine that the CM works on some kind of feedstock. What that feedstock is varies with the kind of CM it is and what is being made; you could have something built up from individual atoms or the feedstock could come as a set of molecules to be assembled, or really at any size you want on up to visbile blocks of matter and components -- you just end up eliminating later and later stages of the assembly process if you have the right feedstock.

Modern inventors are trying to get 3D printers to accept a "feedstock" of electronic components in order to build electronics via printer. Pretty cool if it ends up working.

athanasius athanasius's picture
As i suggested in another

As i suggested in another topic (here ) i view CM as large scale engeneering progect done by pico-nanoscale workers, for pure economy of energy i suppose the use of fractal robotics arms.
The arm have less travel time from start position to the nucleating site of the obyect and work as logistic chain for feedstock and coolant, on the branch of the arms there are molecular sorting-assembly sites that expose the currently need elements and smaller digits catch and place them, this kind pf process can be fractalized too, using a part of arm as molecular assembler, another as picoscale composer and glueler and up to the final obyect.
I also suppose the use of prefab feed, a lot of objects probably use a limited range of common structures as structural material (nanotube, alluminium fibre, diamondoids...), the disassebly phase can conserve this molecule for reuse.
As visual effect you have some arms extending to the centre of CM assembly volume and begin to "buzz"forming nucleating sites that expand to the final obyect, if you stop the process you have different results depending on the current completed passage: from a dust of nucleating sites to an almost finished obyect. As rule in my game CM are filled by liquid for cooling and, in gravity enviroments, for reduce the needs of lifting or supporting the forming obyect.

Arenamontanus Arenamontanus's picture
Yes, there ought to be

Yes, there ought to be scaffolding and support material, whether liquids or solids. Solids will likely have nanopatterned cooling lines and all sorts of interesting microstructure: more like plant materials than plastics. Liquids still need to circulate to cool efficiently: I envision "smart gels" where embedded nanostructures make them flow in prescribed patterns for maximal efficiency.

Extropian

Trekkin Trekkin's picture
I wonder then, with the

I wonder then, with the advantages of effectively hollow construction and the need for thermally conductive scaffolding, if most voluminous general-purpose objects aren't effectively filled with smart gel and microfluidic piping left over from the construction process to add mass and thermal inertia.