Preparatory experimental component R&D – RepRec and ReChain

A bit of info about what I'm on-off working on these days.

My idea is to prototype for future gemstone based (diamondoid) nanosystems at scales that are currently experimentally accessible for VERY cheap prototyping. Meaning macroscale 3D-printing (FFF, resin, ...).

Obviously one needs to consider the changes in physics across scales to do reasonably reliable conservative exploratory/preparatory engineering.

– http://apm.bplaced.net/w/index…ture-backward_development

– http://apm.bplaced.net/w/index…e=Exploratory_engineering
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Nanoscale physics aware macroscale engineering

Regarding the concern that structures would just not be stiff enough.

The concern of "falling material stiffness with scale" …

( Math: http://apm.bplaced.net/w/index…ness_of_smaller_machinery )

Coming from the suppression of thermal motions in mechanosynthesis point of view

I was initially (quite mistakenly) worried that macroscale style machinery at the nanoscale might not provide enough stiffness as it's not designed sturdy enough in choice of geometries.

But regarding deflections form accelerations from motions for pick-and-place assembly working it out I found that
falling stiffness and falling mass exactly cancel each out for scale-natural-machine operation frequencies (i.e. constant absolute speed across scales).

See here for the math: http://apm.bplaced.net/w/index…deflections_across_scales

Beyond that …

– one wants to go slower (for lowering friction losses) and

– one does get way better material properties (flawless nano-gem >10% bendable).

So effectively using FFF printed plastic is an excessively conservative constraint. So much so that it may lead to quite excessive overengineering for the nanoscale which is a problem in it's own right. Oops.

Heck, aluminum or titanium prints would still give hugely conservative overengineered systems.

But durable metal 3D printing is still way too expensive for shoestring budget prototyping.

Similar story with bearings. At the nanoscale often slide bearings will be usable even for bigger parts (no gravitative loads on the bearings).
FFF printing needs gear bearings which would be merely an overengineering at the nanoscale. Macroscale one can also use factory pre-made ball bearings.

That would be cheating with parts that would get smaller than atoms when scaled down but allowedly cheat as these parts could be replaced with a mere sliding interface, basically a replacement with a "nothing".

I hope this is comprehensibly formulated.

Interestingly (and conveniently) it turns out that design constraints of FFF printing and mechanosynthesis share some slight similarities.
Like a limit of detail enforcing the aversion of small screws (that would get smaller than atoms) and the overhang limitations.
Most FFF-printable geometries should be mechanosynthesizable too at quite small scale heavily discretized by atomic granularity.

More on this here: http://apm.bplaced.net/w/index…r_nanomachine_prototyping

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The project

I call this project the RepRec project.

– for Replicating Recomposers … pointing to part recomosability and recyclability

– in naming analogy to project RepRap

The idea is to demonstrate a distributed self replicative robotic system.

Not ultra compact in a self contained free floating box.

So this is quite unlike the outdated molecular assembler concept.

Rather similar to what Matt Moses demonstrated 2014 in the paper:

"An architecture for universal construction via modular robotic components"

https://rpk.lcsr.jhu.edu/wp-content/uploads/2014/08/Moses13_An-Architecture.pdf

… but with more focus on actual productivity. Not just self replication for the sake of self replication.

That is: Systems need to be …

– designed such that they can operate reasonably fast and

– capable of producing products that do not carrying too much system artifacts into the product

(unlike LEGO which carries anisotropy and usually too much surface jaggedness into it's products).

Here is an image showing the idea conceptually.

Prototyping macroscopically (bulk limit) but such that the ideas can eventually be

relatively easily translated into atomically precise atomistic designs.

Actual designs will likely feature quite a bit more atoms per base part than in this conceptual illustration.

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Macroscale usefulness too (sub-project)

Yes, This is future backward preparatory work ...

I still put this under the category of "near term pathways" as it
is something we can do experimental work on today.
And even easily and cheaply.

While the whole project is dauntingly ambitious, I've managed to identify and split off

a sub-project that is much more likely to succeed early. The frame system.

As a modularly extensible frame system is an essentially necessary core part or any RepRec system.

I call it the ReChain (sub)project.

More on the naming later.

You may be wondering:

What's so special about yet another frame system? 🥱 Yawn.

There were many inventors inventing new frame systems.

So isn't this just yet another frame system among dozens if not hundreds?

I'd argue no.
I'd argue I found something fundamentally new and revolutionary here.

Remember the focus on conservative design for the nanoscale that I've mentioned before?

This leads to quite peculiar design constraints that you'll see nowhere else.

And a lot of these design constraints already manifest in the sub-project of the frame system.

That is: The ReChain project is already embodying a lot of the consequences of nanoscale design constraints.

No need to go all the way to RepRec to see a lot of this.

Concretely:

– assuming zero static friction and thus opting to positively lock absolutely everything

– averting the need for (at the lower physical size limit necessarily big) screws at every connection by employing form closure in combination with pretensioning

– generous tolerance self centering for all interfaces

– and a few more

I think of ReChain frame systems as a whole class.

Just like I think of RepRec systems and RepRap printers as a whole class.

A nice aspect of ReChain frame systems is that they could potentially become useful at the macroscale too.

You may argue that the conservative design constraint for the nanoscale will clearly mismatch ideal designs for the macroscale at least in some regards. And you may be right.

Surprisingly I found that this is barely the case though.

Especially for fully FFF-printed systems trying to avert factory made fine detail carrying metal screws and metal ball bearings.
Which was/is a goal of the RepRap project. Minimizing non-locally factory made vitamin components.

ReChain … Re stands for both reusability and
for rebar as in pre-tensioned concrete, but a removable chain instead of irreversibly embedded metal rods.

…

Let's go back to the bigger picture.

In the context of future gemstone metamaterial on-chip nanofactories.

This is mainly about the second assembly level (likely a layer in stack on a chip).

That is the prototyping here is not about the piezomechanosynthesis

of the base parts in the first assembly level but rather it is about

the pick and place assembly of the already pre-made parts (crystolecule parts).

Second assembly level:

Umbrella project

Even more generally I have the umbrella project

ReMec (for Reusable mechanical components).

ReMec also includes mechanical analogons to electrical standard components

( springs <~> capacitors, and such )

( some details here: http://apm.bplaced.net/w/index…electrical_correspondence )

ReMec also includes parts for the first assembly level. Like wedge parts for semi hard-coding mill style standard part mass piezomechanosynthesis.

Though these design efforts are all not really useful at the macroscale. I mean one can do mechanical pulse with modulation and buck conversion at the macroscale, yes, but beyond educative value there is rather little point in doing so.

( Kinda like this cool little educational kit here: https://www.kickstarter.com/pr…build-mechanical-circuits )

If you want to read more about the basic ideas of the project

then I have some introductory pages on RepRec and ReChain online.

Each in the context of atomically precise manufacturing and the context of RepRap. See:

– RepRec (nano): http://apm.bplaced.net/w/index…-and-place_robots_(GemGum)

– ReChain (nano): http://apm.bplaced.net/w/index…tle=ReChain_frame_systems

– RepRec (macro): https://reprap.org/wiki/RepRec_Pick_&_Place_Robots

– ReChain (macro): https://reprap.org/wiki/ReChain_Frame_System

Here's a very early ReChain strut prototype that I've published recently. Much to fix and improve.

– https://www.printables.com/mod…rechain-strut-prototype-1

I still have most of the work I've done so far not published yet on a local desktop wiki.

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Contributing

I'm all ears for realistic ideas about for ways of fund this work.

Such that the (not easy to explain) core values do not get lost.

Like ReChain devolving into just yet another frame system that's

not longer useful for future advanced gemstone based nanosystems.

Also interested in hearing productive feedback.

And maybe even receiving some 3D modelling help.

I do all 3D modelling programatically in OpenSCAD, hoping that this eventually

will allow for parametrically reconfigurable systems way beyond what

(proprietary) graphical UI point & click 3D modelling tools could ever do.

See: http://apm.bplaced.net/w/index…_as_dumbed_down_functions

Images:

Here is a screen-capture from Matt Moses paper showing the quite elegant system geometry that has been chosen there.
This would need some significant change for becoming suitable for nanoscale physics and for becoming actually viable at the macroscale.
For details on that please follow the links in bold I provided precedingly.

Also here's a rough (also still quite conceptual) sketch of one possible robotics geometry resulting from a large number of design constraints. Details also discussed where the links point to.

Don't take this too seriously though. It's juts good to have at least one high level conceptual vision for concrete geometry in order to spread the general idea in a memorable way.

~FIN~ for now