Physics change aware scale transposed prototyping
This is about using macroscale manufacturing techniques to prototype and/or investigate future (not yet buildable) atomically precise nanosystems made out of gemstone like compounds. For this not to be pointless and the results to have at least some semblance of actual future nanosystems one must be attentive to the changes of physics that occur at these much smaller nanoscales.
For why this makes sense at all despite natures life fro the most part not doing cogs-n-gears at the nanoscale see pages: Macroscale style machinery at the nanoscale & Why gemstone metamaterial technology should work in brief
Contents
[hide]Under and over-engineering
(wiki-TODO: Venn diagram of what applies to macroscale what applies to nanoscale and what applies to both scales.)
Avoid under-engineering (forcing macroscale over-engineering)
- small scale limit (i.e. nothing can be smaller than atoms) => e.g. avoid small screws with even finer threads
- effect of thermal motions on mechanical deflections (shouldn't be too much of an issue - so long no mechanosynthesis is involved)
- atomic corrugations (hard to account for, but should be ignorable in many cases - see superlubricity)
- absence of friction (replaced at nanoscale by corrugation sticking - that alone could suffice for positive locking against fall-apart)
- blurry surfaces (but not soft - see next section)
- …
Tolerate over-engineering (as macroscale under-engineering just does not work)
Important context - right intuition on stiffness
"speed scaled effective stiffness" of nanosystems
is vastly higher than in macroscale systems due to …
- diamond being vastly stiffer than even the best steel
- proposed operating speeds being ~1000x slower than macroscale robotic motions
- these two effects multiply
It is way too easy to get thoroughly misled on this nanoscale physics aspect for several reasons…
- (1) there's a scaling law that says that absolute stiffness actually falls with size
- (2) molecular dynamics simulations show diamondoid machine element mechanisms jiggle around like jelly.
But …
- (1) What actually matters is the lesser known scaling law of same relative deflections across scales
- (2) MD simulations are necessarily run at absurdly high speeds.
See pages: Misleading aspects in animations of diamondoid molecular machine elements & A better intuition for diamondoid nanomachinery than jelly
(wiki-TODO: Eventually define speed scaled effective stiffness mathematically precisely!)
Macroscale systems can't be made anywhere near as filigree as nanosystems (and micro-systems) could be made
No matter what macroscale material one picks,
macroscale materials are soft like jelly compared to systems made out of crystolecules operated at proposed speeds.
adding to that are gravitational loads present on the slightly larger (meters) macroscale that need to be counteracted against.
Caveat: For nanosystems that are supposed to do mechanosysnthesis one still will
want to stay bulky in order to keep thermal motion amplitudes minimal.
Manufacturing methods for the prototyping - PROs & CONs
Shoestring budget DIY home accessible:
- FFF/FDM 3D printing (CON bigger parts & less accurate layers, PRO more strong plastics options)
- SLA (resin) 3D printing (PRO smaller parts & more accurate layers parts, CON lesser strong plastics options)
- casting resin (G27 2compunent PU - EU legal access restrictions for private customers?, CON lesser strong plastics options)
- lasercutting (via makerspace, mostly way too restrictive in possible geometries)
Industrial:
- industrial metal 3D printing (too expensive, chapepet most viable: aluminum)
- subtractive CNC milling (too expensive)
Exotic:
- Galvanic methods like (electroforming) …
- Solvent evaporation casting?
Neither fish nor fowl issue
Prototypes systems may turn out to potentially also be useful in other contexts such as e.g. …
- robotic in space systems and
- local DIY home robotic systems
… but this will put a forcing function on
culling back on intentional over-engineering for nanoscale compatibility.
Calling for the integration of "vitamins" like e.g.
small screws that'd become subatomic in size when scaled down.
Allowed cheating
Adding in metal ball/roller bearings where, when scale transposed down to nanoscale, the balls/rollers would become smaller than atoms may actually be an OK case as such ball bearings could be replaced by a sliding sleeve bearing. Basically replacing the ball/roller bearing with nothing. Some cost in friction but still no wear for the AP nanoscale system.
The macroscale system may critically need a bearing as just sliding friction under gravitational loads alone may be on a quickly self-destructive level. At least for FDM/FFF plastic 3D printed structures that can most certainly be the case. Author speaking from experience.
This is a disallowed vitamin from a RepRec local at home DIY self relicating pick-n-place robot though. So a slight conflict of interest here. Relating to the "neither fish nor fowl" topic section.
