Revision as of 15:28, 22 March 2014

The assembly levels describe how an advanced productive nanosystem of technology level III will be organized. They constitute a greatly implementation agnostic scheme for the organisation of an advanced productive nanosystem on the bottommost levels.

Since waste is a serious danger of this potentially clean technology a special focus on recycling is taken here.

Note:

• Do not confuse convergent assembly with exponential assembly.
• A concrete implementation of all the assembly levels but IV is visible in the official productive nanosystems video [1]. The absolutely necessary airlock step is not shown.
• The here used terms in italic are newly proposed.
• Assembly levels aid in advanced nanofactory design

Levels

Level 0: (preparating tooltips)

Here the tooltips are loaded with feedstock molecules (moieties), sent to level I and return empty to be reloaded again. A closed cycle is a lot more complicated than this suggests. A lot of work has been done here: A minimal Toolset. For further information visit the pages about mechanosynthesis and tooltip chemistry.

Level 0a:

Filtering & gas / solution phase processing.

Level 0b:

Machine phase tooltip preparation. Tooltip chemistry in the tooltip preparation zone.

Level I: (DME synthesizing)

Here small diamondoid molecular machine and structural elements (DMEs) are mechanosynthesized in the robotic mechanosyntesis cores.

DMEs are most useful when they are designed to be reusable standard models. In any kind of nanosystem from every type (or set of types) of DMEs an enormous number of identical copies is needed. An example for a set of standard parts is e.g. the set for minimal dynamic systems. For an efficient system lots of specialized building chambers for the different DMEs make sense. This naturally leads to a kind of nanofactory system design.

Recycling: Mechanosynthesis is not reversible. If diamond is used as building material the bound carbon can only be brought back to the biosphere by burning of the DMEs. There are other diamondoid materials that are slightly water soluble and may allow for an unattended route back to the biosphere.

Leve IIa: (sinterface welding & DME assembling)

Here level I Diamondoid Molecular Elements (DMEs: DMMEs & DMSEs) are assembled to bigger non disassemblabel microcomponents. They are built in an evacuated building chamber thus their size is limited. They are assembled covalently by pressing compatible sinterfaces together and structurally by pick and place (think of putting rings on rods). To counter the thermal shaking effect (let go of a piece and it josts away instantly) which is prevalent in this size range parts which are supposed to move in the final product are held down by either VdW forces or sparsly distributed covalent bonds (predetermined breaking points) or a second gripper.

Finished microcomponents ready for assembly level III are complex or simple conglomerates of many small DMEs. The step from assembly level II to III is the soonest point where product parts can be expulsed to a non vacuum environment. Expulsion requires that all non encloded unterminated radicals that should remain in the final product must be sealed. The consequent ban of irreversible surface interfaces makes the creation of monolithic non-modular non-reusable structures harder. (Finished microcomponents must only use interlocking or weak VdW sticking for interconnectivity.) Microcomponent expulsion sets a clear line preventing inter-mixture between assembly level II and III. For certain products (e.g. diamond single crystals) it would be necessary to defer product expulsion to higher assembly levels. Metamaterials from passivated microcomponents should be capable of fulfilling almost all our needs though.

Enclosed radicals may be used for locking mechanisms, springs, energy- and data-storage.

Recycling: In this assembly level surface interfaces of DMSEs are "welded" together. This step in most cases is irreversible. For recycling of the whole finished microcomponents it is highly advisable to keep all the outer interlocking mechanisms reversible and to physically tag all microcomponents so that they remain recomposable later-on even after they where shuffled. Open documentation will also improve chances for reuse and thereby help to minimize biosphere pollution.

Since at this level only whole DME blocks are handled most overhangs should be "printable" with only three degrees of freedome.

Level IIb: (component tweaking)

Finished level II microcomponents might provide some adjustability and or means for functional mechanical testing. General purpouse maintainance units (level II & III) which remain in the final product should be able to operate these functions. And repair/replace/remove them based on the results.

Level IIIa: (component composing)

Here out of microcomponents finished in level II structures of arbitrary scale are built. Connections are made via interlocking in an ambiet pressure envirounment. Dirt like chain molecules viruses and dust must be considered. Positional accuracy may be lower than atomic. The connectors restore atomic resolution by guidance.

Recycling: Note that there is a tradeoff between functional-density and module-reusability. The smaller the units get the more fundamental and reusable they will be, but they'll have much interlocking surface eating up quite a lot of otherwise usable volume.

Level IIIb: (component recomposing)

General purpouse maintainance units can recompose components to completely different makroproducts. Compared to "rezzing" products from level 0 this produces considerably less heat and can be done considerably faster. Hopefully a global network of machine phase component redistribution pipes will emerge at some not too late point in time.

Level IV:

An optional step. Some layers of convergent assembly can be added to boost performance. One can think of convergent assambly as putting microcomponents together from the leaves to the root of an octree.

Todo: Find out the advantages of convergent assembly over direct assembly. (It's not speed.) They are mentioned but not really explained here: [2] Exponential assembly is more sensitive to disturbing vibrations / accelerations than direct assembly. Proucts are more anisotropic. A lot of quick macroscopic handling (makro scale reconfigurations) may be automated in a convergent assembly nanofactory capable of dealing with dirt from recycling. Interfaces / surfaces capable of self alignment and bonding from crude alignment by hand (quasi welding) would allow the topmost convergent assembly stages huge fault tolerances.

Recycling: A level IIIb and IIb system may be included into the product that bypasses Level IV so that products can execute self repair actions while running.

Related topics

Interleaved component router systems and stocks

For the transport of unfinished product parts of different sizes from lower to higher assembly levels nanofactories may use routing structures.

The routing structures can either have separate or merged multiplexing and de-multiplexing steps where the former provides redundancy of rails. (Nanosystems Fig 14.7.)

There are two in some respects similar yet in other respects very different steps where this can occur.

• when diamondoid molecular elements (DMEs) are transported from assembly level I to II
• when microcomponents are transported from assembly level II to III

For all the optional steps in convergent assembly (assembly level IV) the lower stages should be programmable/steerable enough that no further shuffling is required. (Depending on the programmability the lower stages may too be simplified.)

Since direct control of the bottommost systems could clog the IO bottleneck hirachical heterogenous nanomechanical computing system must be integrated in parallel (one layer might suffice). Temporary storage facilities for microcomponents are optional (they may also be useful as seperate macroscopic entities).

[Todo: explain free space designs, analyze parallelism]

Product expulsion

In any technology level III productive nanosystem that uses vacuum up to the topmost assembly level (blending assembly levels, allowing for unrecyclable macroscopic maximum performance single crystals) a macroscopic perfectly tight lockout mechanism is necessary.

In E.Drexlers new book "Radical Abuncance" [add ref] the outlined system differs to the presented assembly levels in that it keeps the process in vacuum/noble-gas till the product is completely finished. This design avoids the complexity of dealing with dirt but introduces the complicity of providing appropriate vacuum at all convergent assembly levels (level IV). Note that for recycling one has to deal with dirt at least on the products surface in any way. An "isolation till finished macro-product" approach would further allow intermixing for Level II & III and thus allow for undissasemblable unrecyclable macro-products like one big diamond crystal. Such products may only be of interest for products that not just ought to work but are supposed to push the limits like in motor sports and in military interests. Well designed form closure connectors can retain almost the full material strength and may suffice for aerospace applications.

Recycling

A very important issue whenever responsibly designing nanomachinery is to aim for best waste avoidance. It does not come for free. The history of plastics show the dangers pretty well. But with APM systems one can take a range of countermeasures starting in their inherent design and buildng up with additional functions. Very desirable would be some kind of global microcomponent redistribution system parallel to our current water supply.

Relation to product structure

Somewhat complementary to the assembly levels is hirachical product structure. A given product description (e.g. implicit volume definition) can be reversely subdivided into assembly level assembly steps and the assembly levels can be used as a guide for foreward product design (which is most prominent with microcomponents). [TODO: link Nanosystems]

External links

• Motivations for splitup into assembly levels (Level1 & Level2) can be found in Considerations for Self-replicating Manufacturing Systems by J. Storrs Hall, PhD. Institute for Molecular Manufacturing