Method of assembly

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Self-assembly

Radical Abundance:
"Let parts move at random and require each part to 
encounter and bind to its own special place"

If you haven't heard about self assembly yet please consult wikipedia.
Since nano-biology uses self assembly extensively today (in the molecular sciences) self assembly is perceived as natural in the nanoscale although its very alien at the makroscale.

• Video showing self-assembly of a thumb sized a virus model in a glass jar
• Video with two models forming at the same time

advantages of self-assembly

• putting things together requires no machinery

disadvantages of self-assembly

• all pieces in a complex non-periodic structure need to have unique shapes like in a puzzle which makes the pieces bigger
• all bonds need to be weak such that wrong matches open up again
• finished pieces necessarily have irregular seams

These issues make design difficult. (folded polymeric chains)

Stereotactic control

See main page: positional assembly and mechanosynthesis

It's the common sense method of putting things together by pick and place operations.
Like e.g. sticking sleeves on axles.

Radical Abundance: 
"the ability to guide molecular assembly by guiding molecular motions ... move parts into place and put them together"

Since nano-biology uses stereotactic control only in loose and somewhat hidden ways (in the molecular sciences) self assembly is perceived as rather alien in the nano-scale although it can work perfectly well.

Sidenote: Why not call it "robotic control"? [todo: link article "why I hate nanobots"] Like the term "nanotechnology" the term "robot" is not well defined and can be bent a lot. The term "stereotactic" comes like a quick google serch shows from brain surgery where you need everything in a global coordinate system and need to tightly constrain any shaking to the minimum - a quite fitting therm here.

disadvantages of stereotactic control

• putting things together requires advanced machinery

advantages of stereotactic control

• all pieces in a complex non-periodic structure can have identical shape and minimal size.
• all bonds can be as strong as possible
• finished pieces can have maximally smooth seams

Loose stereotactic control with self assisted assembly

It seems that to remove the sole disadvantage of stereotactic control one needs the advantages of stereotactic control. (see: why advanced APM systems are not a castle in the sky).

By combining loose stereotactic control with self-assembly one can climb an incremental path to full stereotactic control.

Characteristics of intermediate systems

• usage of bigger building blocks and sufficiently distinct binding sites in position and possibly shape
• usage of "soft machines" for the selection of the local binding site environment
• usage of snap in / localized self-assembly / self-centering / self-alignment / self assisted assembly

Related

• 1D brownian walk; ribosome; analogy to transport along microtubuli
• Mechanosynthesis
• Self assembly (and Self assembly without thermal motion)
• Positional assembly