Bottom scale assembly lines in gem-gum factories

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This is about assembly lines in gem-gum factories

These assembly lines include:

The special property of these two assembly lines that discerns them from other ones that might be found in gem-gum factories is that the size scale of their component parts is (and needs to be ) squeezed down to the lowermost physically possible size scale that allows for representing the necessary shapes sufficiently accurately.

Necessary components

Back-pressure track segments

In order to keep friction from suberlubricating sliding minimal,
bottom scale assembly line chains should probably run "free floating" as much as possible. It should be avoided to have them slide over over a track or nearby surface as much as possible.

Back-pressure tracks segments are only needed at places where

  • the position needs to be tightly constrained and
  • forces need to be counteracted

like in e.g. in piezochemical mechanosynthesis stations in mechanosynthesis cores.

Care must be taken when chains run onto or off of a back-pressure track segment. During operation the total contact area between chain segments and track segments must vary as little and as slowly as possible. This is because the van der Waals force acts a bit like surface tension. So varying contact area would leads to periodic forces that is dragging the chain in periodic positions with maximal contact area. Given a lot of chain segments and track segments forces can add up badly.

There are two obvious tricks to avert this:

  • V shaped onboarding onto backpressure tracks
  • longer range force compensation via out of phase arrangement of backpressure tracks segments

Attachment chain elements

These must interact with:

  • back-pressure track segments
  • drive wheels (sprockets)
  • adapter pallets
  • (whatever assembles them)

Adapter pallets and tooltip-bases

These must interact with:

Guide and drive wheels

Even numbered wheels

Sprocket style

Requires an attachment chain design that features cylindrical pins. This may need a bit more space but may have other advantages.

Even numbered wheels might be advantageous compared to odd numbered wheels because they potentially could compensate Van der Waals on-boarding and off-boarding forces. Given the force profile is roughly symmetric.

Polygonal

It kinda intuitively does not look good and there might be some truth to it but for other reasons that one would assume.
A main issue with a naive design is that the Van der Waals force has huge discontinuities due to V-brake force spikes. This might:

  • induce vibrations normal to the chains motion axis
  • some pulsating forces in the axis of the chains motion – even for even numbered wheels because the force profile is probably rather asymmetric due to high nonlinearity of the V-brake force spikes.

What would be an issue in a macroscopic implementation is a "sliding off" of the polygonal drive wheels sides. That is not an issue for the nanoscale though because of the high levels of Van der Waals force.

Side-slide wheel

Just an idea.
This would be specifically designed for continuous soft contact area on-boarding and off-boarding.

  • may not be able to support high loads on the chain
  • may have higher superlubricating friction due to higher total contact area

This has no macroscopic analogon. Well, except one fakes VdW force with magnetism.

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