View source for Assembly level 2 (gem-gum factory)

The '''from crystolecules to crystolecular unit''' assembly level.

* '''Previous processing step:''' [[Assembly level 1 (gem-gum factory)]]
* '''Next processing step:''' [[Assembly level 3 (gem-gum factory)]]
* Up: [[Assembly levels]]

== Overview ==

* '''In go:''' fully mechanosyntheized [[crystolecule]]s without or with some bonds intentionally left open (including [[crystolecule fragments]])
* '''Out go:''' assembled [[crystolecular unit]]s (including bigger [[Diamondoid crystolecular machine element]])
Processing is done:
* '''Where:''' [[crystolecule to crystolecular unit assembly chamber]]s. Possibly mill style.
* '''What:''' Pick and place assembly (think of putting rings on rods) with various adapters for basic end-effectors. <br>Assembly including more or less of [[covalent welding]] depending on the nature of the product under construction.<br>
* '''How:''' [[seamless covalent welding]] covalently by pressing compatible ''[[surface interfaces|sinterfaces]]'' together, <br>[[vdW sticking]], [[form closure]], [[energetic flexlocks]]

== On (ir)reversibility ==

This assembly step potentially still involves irreversible steps. But less so than [[assembly level 1]]. <br>
That is: Not all small crystolecules that are assembled can be removed again.
* Some [[seamless covalent welding|covalently weld]] together to form larger machine housings frames of [[crystolecular unit]]s
* Some get irreversibly form closed in into these larger machine housing frames

Note that not all covalent welding is necessarily irreversible. <br>
It is especially likely to be irreversible if it is:
* seamless and 
* not at a sharp neck of geometry that forms an [[intended breakage point]] 

== Adapters ==

It makes sense to have for each type of input [[crystolecule]] an [[adapter crystolecule]] such that 
* only one single manipulator can via those adaptors grip a multitude types of [[crystolecule]]s. <br>
* small [[crystolecule]]s (with little surface area to spare for assembly specific details) do not need to adhere to specific shapes constraints just to be grippable by the manipulator <br> This is less critical in the next (the  third) assembly level because <br>bigger [[crystolecular unit]]s have more surface space to spare for such adapting to constraints imposed by the manipulators geometry.

== Constraints on the assembly of parts that shall remain movable ==

[[Machine phase]]:
Parts which are supposed to remain moveable in the final product must be temporarily held down by one of the following means:
* VdW forces – a very convenient option
* sparsely distributed covalent bonds (which can serve as predetermined breaking points for later break-free) 
* a second manipulator holding it in place till it's locked otherwise
These are possible but typically not needed:
* Energetic flex-clips would provide way more than necessary energetic barrier against disassembly.
* Form closure for a part can typically only be applied after addition of that part except by [[one way clips]] which are difficult to operate efficiently and difficult to disassemble.

'''Why that constraint?'''

Holding stuff in place during assembly is absolutely necessary because thermal motion still has a strong effect at this size scale. <br>
Any part that is completely free and no longer held in place shoots off with high speed. <br>
High speed is due to kinetic energy by the fact that every degree of freedom of motion gets kT worth of thermal energy on average ([[equipartitioning theorem]]). <br>

Well, what actually more likely happens is that parts just stick to places tey are not supposed to.
Also parts could theoretically skitter along some perfectly planar surface till they get stuck in some random corner and held there by VdW forces.
Consequences:
* The part is missing where it would be needed and 
* where the part ended up it may or may not get in the way of other machinery motions. 

To gain an intuitive feeling how violently/fast stuff shoots of once no longer holds onto it see page: [[Intuitive feel]].<br>
Thermal motion drops quickly with bigger sizes (by third power).

== Questions ==

* Inhowfar is [[parallel robotics]] for increased [[stiffness]] from choice of structure at this size scale still needed?
* After all [[covalent welding]] still needs [[positional atomic precision]]

== Related ==

* [[Productive Nanosystems From molecules to superproducts]]
* [[Gemstone metamaterial on chip factory]]

[[Category:Far term target]]