RepRapMicron

> We now have 3d printers that can reliably make almost anything you want by fusing filament

I bought a cheap, used, Bambu Lab A1 printer after reading a comment here on HN a few months ago saying that it was basically now "download and print". And it's just that. Not saying Bambu's practices are great: what I'm saying is that 3D printer now work better than inkjet 2D printers ever did.

> What an amazing time to be alive.

I agree. In a few days I learned to model 3D pieces myself in OpenSCAD (and there are many other options than OpenSCAD) and I've already done "print in place" pieces (pausing the print, inserting a metal piece, continuing the print) to fix stuff around the house (and in the cars).

If you had told me 30 years ago that I'd be 3D printing pieces and getting help from LLMs, I wouldn't have believed it.

I think we tend to underestimate the importance of precision manufacturing in science.

For example, we attribute general relativity to Einstein, fair enough. We generally acknowledge that he built his work on mathematical foundations by Lorenz, Minkowski, Poincaré, Riemann,... But what really made general relativity into a concrete theory rather than just a cute math problem is that it solved the problem with the orbit of Mercury. And the reason we knew there was a problem with the orbit of Mercury is that we had instruments with enough precision to measure it, if we didn't, then general relativity would have been useless.

Newton couldn't have come up with general relativity, not because of math or because he wasn't enough of a genius, but because with the level of precision their instruments had, it had no reason to exist.

Do you have any links/sources about that Wyler Inclinometer you could share?

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This video was amazing, thank you for sharing. What are the main applications for this technology with a home setup?

Woah, this is so cool

Just need a garden shed: https://youtube.com/watch?v=HfSO-LCKmrA

To be serious, maybe not 18 months but 2-3x that.

A mechanism that works at scale X doesn't necessarily work at scale Y.

Different forces and material properties are all at relatively different levels.

The one I know offhand that will mess with stuff is the square-cube law. If you double the linear dimensions of something, it's twice as big, linearly, but 4 times the surface area and 8 times as heavy. The strength of anything that depends on area (like friction) won't scale at the same rate as anything that depends on mass or volume or anything.

Not to mention I'm sure this thing can only print a few different materials. Unless those are also _all_ of the materials it's made out of, it couldn't even make itself.

The history of precision machinery is a steady ladder of using old machines to produce new more accurate components, and then new more accurate machines.

But simply making something smaller is not synonymous with it automatically becoming more accurate or capable of achieving higher resolution. If anything, very high precision machines are typically larger in size than the less accurate ones.

Calling it a RepRap, with full explanation that that means a printer that can print itself, does make it sound like it could be a goal

But even if you could get a positioning system that small, I'm pretty sure you can't scale resin printing down three orders of magnitude smaller than this printer. Maybe a tiny CNC?

Or more likely they refer to eventually printing the mems devices used in the printer

Scale matters. For example, at large scale you might be able to essentially ignore the friction between two materials, but at 1/1000 scale it might be the same order of magnitude as the forces expected during operation.

While a large piece of sheet metal might slide down a given ramp, a 1/1000 scale bit of foil of that same metal would probably just sit on that same ramp and not move.

There are lots of constants that, by definition, don't scale.

You can only print brackets that join frames together with help of screws, not electrical and/or mechanical components. The latter two must come from AliExpress/Amazon, and 1/1000 scaled ones that do not exist have to exist for that to work.

That's so cool, I see no reason you couldn't use a uv-sensitive conductive resin. Does anyone know more about this?

It’s a fun thought experiment! Napkin maths assuming max 78RPM at 300mm, min 33RPM at 80mm (I think inner groove is bigger than this but wateva) gives ~3 to ~30 microns for half-wavelength of 20kHz (not that 20k is really stamped into vinyl). Actually, not bad.

Amplitude though, 78s are the best case scenario, and assuming mono for simplicity, they have lateral displacement of about 76 microns peak to peak. So assuming 1 micron resolution that’s just over 6 bits of dynamic range absolute best case. Crunchy.

Dodgy maths aside there are lots of reasons this would not produce a good sound. There are maybe clever things you could do with a spinning bed or something? but even then.

At that point though even a normal analogue cutter head will be easier!

See lathetrolls.com if this particular kind of masochism interests you.

It's because it's only 8mm cubic volume.

But you can get etched glass scale encoders that will give you 1um accuracy for basically nothing these days (IE <50 bucks).

You'd still be better off just using cheap linear motors with encoders built into the rail though.

If you get this to print conductive resins you could probably build a number of mems devices. Accelerometers, gyroscopes, tiny speakers

Being able to make structures this small could maybe make DIY inkjet printers viable, if you can simplify them enough?

The most exciting are the applications nobody has thought of yet

Core memory.

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These aren't exactly RepRap-friendly. The piezo buzzers are too soft. For a proper multilayer piezo actuator you have to either go to Thorlabs (a bit expensive) or other manufacturers (either expensive or "don't bother us until you are ready to buy a few thousands"). AFAIR MLCC ceramic capacitors actually can make half-decent actuators, but not sure if these are suitable for precision position. Baking your own would be doable, but who wants to deal with lead? And once you got the chips, there is another problem: how do you couple it to a plastic flexture? "Adult" stuff uses wire-EDM-cut metal flextures. While not completely impossible to DIY, wire-EDM a whole undertaking in itself, and an expensive one.

Piezos are sure the way to go for a fab-in-a-shed youtuber, but not yet for those who want to make it reproducible by others.

Some people do when building AFMs, but the piezoelectric stack voltages to get a few mm dynamic range are often around 160v to 600v.

After playing around with several options, piezoelectric was the path I chose for a sub-micron stage. It took a bit of research, but it does make things much easier when done right.

Most hobby work is kept private now... due to safety issues with people without lab-training attempting complex builds. Indeed, a few fools still die every year attempting things they saw on you-tube ("Lichtenstein burning" etc.) =3

You still need the position feedback and you're almost certainly going to need to make a two-stage coarse-find design, which is a pain.

So that's existed for a long time in the form of OpenFlexure. The microscope is a pretty easy / fun build.

Sounds like they are used for homing. For that they just need to observe a tiny spot at known distance with high resolution

To look at the output they recommend a separate regular microscope

Phisics dictate they have a small depth of field but they can be absolutely incredible.

To see the print? Weird comment.

Imagine yourself, not everyone is willing to make the tradeoff. Also, fuck bambu so much.