Macroscale style machinery at the nanoscale
Physics changes when one scales down things. This may pose serious problems.
People educated in physics and nanotechnology might be inclined to quickly point out
that this will not work because of the effects of one or more of
the following scaling laws (here listed informally):
- rising surface area (per volume)
>> concerns: rising friction; rising corrosion; clogging - rising tendency towards thermodynamic equilibrium -- (Thermal decay at room temperature, Thermodynamics)
- rising influence of thermal motion -- (Jittery finger problem)
- rising influence of quantum mechanics
- falling available space (obviously) -- (Fat finger problem)
- rising influence of inter-molecular forces -- (Sticky finger problem)
- falling material stiffness (less obvious) -- (Sloppy finger problem)
- rising effect of viscosity
But: All of these potential concerns have been analyzed.
The result: In total things change for the better rather than for the worse.
That is: For macroscale style machinery the change of physics is actually improving the situation rather than worsening it.
Why nature doesn't do it this way albeit it being a better way is a topic different in kind.
A concern not based on physically quantifiable scaling laws.
See the main article: "Nature does it differently".
Limits to similarity – this is not a naive copy-paste fantasy
While superficially the targeted advanced productive nanosystems look very similar to macroscale machinery,
looking just a bit deeper the similarities quickly start to fade.
Major differences that crop up include:
- Very different types of used materials (no metals but gemstones instead). That:
prevents parts to cold weld to others,
prevents oxidation (in the rare case the nanomachinery sits exposed on a products surface),
prevents eventually possible diffusion (metallic bonds allow for easier thermal activated slide-hops) - More sturdy designs (for molecule fragment handling)
low material stiffness at small scales meets low forces from accelerations but thermal excitations are high
(designs that avoid mechanical ringing by electrical design principles)
For what not to use see: pure metals and metallic alloys - No lubricants used. They would only cause massive viscous drag.
- Operation at slower speeds. "Exploding" productivity at small scales allows that.
(Note that this is about lower absolute speeds, not lower frequencies. Operation frequencies are way higher.) - Designs heed the Van der Waals forces that originate from the near background. (they need to either be balanced out or used)
- Other means for connecting parts, differing to the ones encountered at the macroscale
E.g.: No usage of nuts and bolts (at least not in the classical sense where nuts and bolts are usually tiny compared to the linked parts and held in by friction) - Mandatory existence of mechanical backup systems (or more advanced redundancy)
- Electrical motors based on electrostatics instead of magnetostatics.
- ... the list goes on ...
Related: Design of Crystolecules
High level considerations
It turns out that all the above mentioned common concerns:
- either do not hold at all under closer inspection
- or they are partially true but overcompensated by other less known factors
For detailed explanations regarding the individual concerns please follow the links above.
(wiki-TODO: complete those links)
Related
- Friction
- Why gemstone metamaterial technology should work in brief
- How macroscale style machinery at the nanoscale outperforms its native scale
- Common misconceptions about atomically precise manufacturing
- How to deal with common critique
- Nature does it differently
- Scaling laws
- Applicability of macro 3D printing for nanomachine prototyping
- RepRec pick and place robots
- Often overlooked: Higher throughput of smaller machinery – Scaling laws
- Deliberate slowdown at the lowest assembly level – in combination with – Higher throughput of smaller machinery
- Self assembly vs positional assembly on different size scales
- The finger problems
