This is magic, big news, both, or neither. It’s so exciting to see magnets behave in this bizarre and wonderful way that we think it’s hard to forecast where this will go. Shown above is a pair of magnets that have several modes of operation. They attract each other, but repel when less than a centimeter apart. However, give one a twist and the two will strongly attract.
The behavior is thanks to a new process of 3D printing magnets to manipulate where the fields occur. With the behavior just described, they would function well as a cabinet latch which has soft close and positive lock, all built into two magnets.
This comes from one of our favorite YouTube channels, [SmarterEveryDay], who just toured Polymagnet — a company that has figured out how to actually print magnetic fields.
So how the heck does it work? Well, your standard magnet has a north face on one side, and a south face on the other — creating a magnetic loop between the two. But what if you could put north and south on the same side of the magnet, and vary their position and size? It means you can control the magnetic field down to the magnetic pixel, or as Polymagnet calls them — a Maxel.
Here you can see some magnetic film (which reacts visually to magnetic fields) put on top of the two parts of the demo magnet. The printed design is very similar to a mechanical mechanism. We’d explain more, but [Destin] does a great job teaching about the tech in the video found below.
Is this the dawn of magnetic mechanisms? We certainly have never seen anything like it.
The applications for this technology are endless. Controllable, permanent magnetic fields of your own design? From locking magnetic latches, to shock absorbers, component coupling, positional control… this is going to be revolutionary in product design.
I like this!
This is pretty epic…
Could they make tiny little gears that don’t have physical notches and that would be useful in medicine or surgery?
Yes, I’ve seen a video (they’ve been public for more than a year or so) that act like gears that don’t touch (imagine two magnetic discs next to each other). The only problem is there is a point where the torque is stronger and the gears slip. Or if you stopped one gear abruptly, the other may spin a bit more. Nonetheless amazing stuff.
More like3 or 4 years – polymagnet has been out for a while. Used to be you could actually buy the printer to make them, but they didn’t sell enough, so now they are app specific.
I’m actually suprised it took yall this long to pick up on it.
That’s not a problem. It’s magnetic clutch that can limit torque.
Those are already in use in many places. The company I work for uses something similar as a safety clutch.
Micropump uses magnetic coupling in tons of their pumps.
While aren’t gears there are drive shaft couplers that use I can imagine magnets being use to build right angle gears boxes and reversing gear boxes, if an application called for that. But I can’t imagine “magnetite gears” being use to adjust shaft speeds or multiplying torque. The magnetic fields would be like loose belt on worn out pulleys
Okay, I now want a magnet printer! – Do these magnets decay over time, if so any idea how long?
Same as neodymium, they decay at a rate of 1% per 100 yrs unless you overheat them or introduce a huge magnetic field. http://www.polymagnet.com/faq/
should add – I see you can buy these… but I’ve no idea which one the spring and lock magnet is on their web page. If someone finds the part number could they post it.
http://catalog.polymagnet.com/spring-latch-demo.html
I just ordered myself one. $16 with the slow shipping to California.
Thanks!
f***ing 100 bucks shipping to germany :(
Seems to be the same for all of Europe :(
Hi Hassi,
Polymagnet here – we’ve had our commerce site up since Jan of this year, but haven’t had a lot of international orders until now. We’re looking for less expensive options for shipping from our offices in the U.S. to Europe right now…. stay tuned
time to build and design our own smart magnet printer? controlled localized heating of a “maxel” on neodymium magnet, while applying a strong magnetic field, then actively or passively cooling the maxel below curie point while maintaining the magnetic field, on to next maxel… I wonder what the heat conductivity and heat capacity of both the magnet material itself and the protective layers are. And of course what that means for the best heating mechanism, inductive heating? laser heating? for lines it may be better not to work with maxels, but trace the lines?
I’m in Momtreal and ordering from China is less expensive than from the States.
Guess where is the future economy and which one is in decline?
It is mentioned in the video that it is a special “spring” and there are only 2 magnets in their “Spring” Family part of the catalogue (they function in a pair) and the magnetic pattern (details and click on the pdf) that they have is not the same as in the video. So I suspect that they do not sell the pair shown in the video (yet).
DOH $48 to ship snail mail to where I am, they are nuts.
Yep $46USD seems to be the minimum non-domestic shipping cost.
We are working on the shipping costs to Europe. Our site has mostly been serving corporate customers that want samples as soon as possible. We’ll have more options soon.
Really cool. I wonder if you could get a similar effect by 3d printing a part with a matrix of holes, then glue in lots of small rod magnets in some pre-determined pattern. Not as awesome as the polymagnet technique, but could work for one-offs.
Yes, I think you’re going to end up with a huge physical thing that negates the use of it.
Along the same lines though, how far can this resolution be increased. Is it possible to build nano devices on the scale of MEMS dlp, etc.
Sure, but you would have to print at that resolution (and keep track of / sort everything) and things don’t always work how you think they would in the nano scale.
https://www.youtube.com/watch?v=v1MnNO4I9aU
Has a great deal of theoretical potential however.
Can’t remember where, but I have seen many of the effects shown in the video before. They were accomplished by gluing together small magnetic cubes. So your idea sounds reasonable. Resolution would be limited of course. But I don’t think you’ll necessarily “end up with a huge physical thing that negates the use of it” as Mike said.
IMO, the most generally useful polymagnets demoed in the video were also the simplest and lowest resolution, and I suspect that will usually be the case. For example, the medium/short throw polymagnets have a simple alternating pattern, and could be accomplished with small cubes/discs/rods. With or without a 3D-printed support.
The one that attracted at distance then repelled when close until turned, could also be built up. But it would be simpler and more efficient to cut down a few magnets to the required shapes, since for this one it’s an issue of geometry rather than lots of poles. Watercutter immediately comes to mind as a good option. Maybe a mill or other tools, so long as you keep the magnets below the Curie point.
The most complex and highest resolution one, the “Smarter Every Day” polymagnet, was pure novelty; and there’s no practical reason anyone would want to duplicate that.
I think you’re right, you could create it by carefully installing 1/16″ diameter rod magnets into pre-drilled holes. I don’t know how I’d ever use it, but I think you could make these with discrete magnets fairly easily for one-offs.
Just checked their website though, and in all honestly they aren’t that expensive, like $1.50 to $3.00 each. Better off just buying from them unless you’re really on a budget. Or in Europe as the shipping is expensive.
Unless like he mentions – invisible maze. Or perhaps something else cools comes somebodies mind – you never know.
I believe you heard about Halbach array. That’s quite the same principle, focusing the magnetic field on one face and almost neutralising it on the other face.
First thought, as well… Doesn’t *have* to be printed on a single-surface, right…?
Or does something about the strength (and the ability to have varying strengths in different locations) have something to do with the magnets’ poles both being on the same surface?
E.G. Cylinder magnets would have a north at the bottom (unused in the mating/’spring’/latch ‘circuit’) and the corresponding south at the mating-surface. Whereas with these printed magnets it’s more like having a flat bar-magnet (or maybe even a horseshoe) where both north and south are at the mating-side. Does that matter…?
In the “nano” realm, is this significantly stronger than, e.g., the varying poles “printed” on a hard-disk platter, or on a cassette-tape?
Cool mechanisms, regardless.
It will only be revolutionary if it can be done cheaply enough, but may still have some neat niche applications.
Like most things, it *can* be done cheaply enough but right now it is very specialized. Those custom 3D printers they showed in their video are not cheap when you make them one at a time out of precision components. If there is demand and a market, it will likely fuel the growth of more, easier and cheaper production. Unless it all gets locked down by patents for two decades or more, like most 3D printers used to be.
which recent patents exactly?
patterning magnetic fields? => magnetic tape storage
magnetizing by letting magnetizable material cool down from above curie point under a strong magnetic field? => “poling”
patterning by means of CNC? => CNC
what you want is either a strong permanent non-target magnet that is kept cool close to the localized heated target magnet, or an electromagnet
2D CNC + MOT + FNH elecromagnet (Big and DC)
what does MOT abreviate in this context?
@Ludwig: microwave oven transformer. I could not reply directly, your comment is too deep for Hackaday :)
@[ludwig]
Just like [Miroslav] said except that I thought MOT was for Microwave *Output Transformer. Not that it makes any sense to me because it doesn’t output microwaves so it’s more like an input transformer. It think MOT is a Merican thing. Here they’re just called line transformer of mains transformer that just happen to be in a microwave.
In any case it’s a 800W to 1000W transformer that you can re-wind for lower voltages. Just strip out the secondary first as it’s about 1.8kV and you definitely don’t want to play with that.
They re-wound for things like spot welders where you new amp amp amp at next to no volts. In reality they can be rewound for just about any lower voltage but you may not get the full 800W.
Uses
2 second car battery charger. Blast shields required.
Pencil lead vapor testing. Gas mask required.
iPhone destructive testing. Colleges phone required.
Nichrome cutter. Nickel Chromium for Mericans because you still have imperial atoms.
Unbreakable Bench power supply. Set current limit to 350 Amps. Charge LIPO
Soldering Iron PSU – temp set to 1650 degrees – check
Metal muscles – expanded 2% then vaporized
Reverse it for a DC to 110V / 240V inverter
Replace “cheaply enough” with “in China” and you’re there. As soon as the Chinese reverse-engineer that printer thing, it’s curtains for those guys in the U.S.
To be fair, controllable, temporary magnetic fields of your own design are available now and have been for quite some time. This is exciting and reasonably novel in how they are approaching it though. Would love to see what applications this enables.
First thought: That Is COOL!!!
Second thought: Where / what can we do with this.
Third thought, Isn’t this how hard drives work?
Yes, yes this is how hard drives work, only a bit stronger magnetic fields.
Tho, one could do this in the kitchen sink with a powerful U shaped electric magnet, and some material that likes being magnetized.
Mind=blown. Astonishing work.
I remember seeing something like this a few years ago. IIRC they heat up the magnet to the curie point, then use a strong electromagnet to write a new magnetic pattern on the magnet.
I think some guy was thinking about a way for toys to assemble themselves, and that’s how he came upon this idea.
That seems similar to recording on magneto-optical media like Mini-Disc. In that case the selective heating is done with the laser.
If true, this would enable power generation. They claim that 2 magnets first attract, but when at a centimeter distance, they repel. Put a coil of wire on one magnet, and changing field from this movement should induce some voltage.
@Miroslav If you mean that it will be even easier to con people with a perpetual motion or over-unity machine on Kickstarter, then you’re right.
Actually that does bring to thought of printing a magnet that has a strong attraction at one end but angles into a weak end, like a triangle shape. I wonder if applied within a stator in a specific configuration if it could improve on either torque or efficiency of a motor. So a predictable magnetic field shape. I also wonder how this would fit into superconducting magnetic systems, I.E. Spin Alignment vs Electron Pairs could somehow be controlled when they get this down to a smaller scale in the area. Pretty cool stuff though.
It’s time to stop with the conservation of energy thing – we are fully capable of creating completely unbalanced magnets right now (stronger on one pole than the other). We can even create meta-materials that can can turn on and off their magnetism (and no, I’m not talking about electromagnets). An unbalanced magnet can easily be made to spin without any external power being applied, and if large enough, this spin would be at high torque levels as well. Thus, it is completely within the realm of reality that we could construct turbines for use in power generation that do not require external fuel sources (other than the magnets themselves).
the field has to change relative to the same spot on the coil to make power. just placing a coil in a differential magnetic field does nothing. you need motion to add energy to the system, otherwise you violate conservation laws.
Ah yes. Just add a spring btw the two. According to this article, they will first attract, then repel. There is your motion, and via coil, our voltage. I do think the whole story is a scam though.
*shakes head*
I imagine in 1000 years there will still be idiots arguing for “perpetual motion” and “free energy generation”
Nope, they will just stay at equilibrium point. That attract/repel is just like a spring, you can’t generate energy with just a spring. Spring will bounce for a moment but friction will stop it.
Like anything else, you would still need to add motion. The friction in the system would very quickly cause it to reach equilibrium. Yes, it would probably bounce a few times, but it would not stay in motion without external input.
OTOH… Maybe something like a “magnetic bearing” could be printed… wherein there could be a completely-frictionless mate between the rotors and stators used in the vast-majority of power-generation systems ;)
which is why you need 2 instances of the described setup to keep each other in power: the friction for one is overcome by the motion of the other and vice versa. Much like the self-fulfilling self-sustaining prophecy of 2 transistors in a flip flop, or 2 short duration (perhaps just microseconds of prescient power) tachyonic antitelephones / “tib”s (reverse memory reverse of “bit”s) to produce an indefenite one ;)
As in the expression: can I haz 10ktib ?
being able to make materials with custom magnetic fields is a significant advancement. in theory, this could be used to make a magnetomechanical computer with parts that never even touch. while large, it would be able to function for hundreds of years.
This was LITERALLY my first thought. I wonder how fast you could get it to operate? Not that optical / quantum wont beat it to death soon anyway…
It would only function as long as the magnets can produce a useful field strength. Permanent magnets aren’t permanent, and the composition of the magnet plays an important role in it’s field strength and retention.
stable nuclei are not stable, in the end it will all be iron or so…
I’m curious the potential for application such as sensors i.e. seismometers, geophones, microphones, stress, strain, shear, torsion, etc. I could see how it could be used to make a dampened, strong motion (large earthquake) sensor or possibly weak signal motion sensors (micro-seismic).
Mind blown. This is more magic than radios, and that’s saying a lot coming from a ham.
Very cool
This reminds me a lot of the magnetic keys (i.e., keys with coded patterns of magnets in them) that popped up 20-30 years ago. Looks like Chubb still makes them. https://en.wikipedia.org/wiki/Magnetic_keyed_lock (or did, a decade ago)
Just thinking of magnetic keys and locks… Something occurs to me that’s surely too obvious to be the case –
Do they work by having magnets in the key in pre-set positions, set as north or south? And the relevant magnets repel or attract them, to move rods (or the like) clear of the lock mechanism?
Doesn’t that mean, that with a thin coil, you could make your own sensor in the size of a key? Have it sense the polarities and position of the lock’s magnets, as it’s moved into and out of the lock. Then you have the secret!
To open the lock, either make your own key or use the coils as electromagnets and -click!-
Surely I haven’t cracked it? What am I missing?
Yep. You cracked it.
Okay… to extend my awesome powers of logical induction once more… Does that mean –
There are quite a few cheap and easy electromagnetic lock picking sets for these…
Nobody uses these locks much because of this large vulnerability…
Nobody uses these locks for some other reason to do with convenience or price or whatever, so there’s not much point in investing in picking tools, because they’re so rare in the wild. Perhaps a locksmith might have an electronmagnetic lock pick still in it’s box in the back of the shop…
?
This is now on my “idle investigation” list, surely there must be more to it that just having some little N / S fields at the right spot? Like moving parts on the keys? Moving parts on the lock that need activating in the right order, that move other magnets around if they’re not activated, to confuse detection? Something?
Something to do with the fact that a lock only needs to be the least-strong point in a system? Otherwise they’ll just smash the door in, or tunnel through the floor.
Is the system *really* as simple as I think it is?
Nobody uses them because they have the same problem that the magnetic stripe on credit cards have. They can be demagnetized, or the field strength of the poles can be reduced to the point where they don’t work.
Ta for that. Wasn’t wanting to labour the point, I just thought surely there HAD to be a better system to it than just that! Apparently not! Ta for the information.
to avoid entry through a weaker spot, our lock company suggests building the door, walls, ceiling and floor of the room entirely from our locks exclusively… this may seem like a high price to pay, but not paying it will only result in you regretting to buy any lock at all…
Yes you have the understanding correct.
If you just want to open the lock just use an AC wave form and rattle the magnets around until the lock opens. Tends to destroys the lock but works well enough.
If your looking to create a duplicate key then yes, in fact the key on my desk has several “pins” that are vacant. of the 16 individual “cells” only 6 react to a paperclip.
This is one of those things that make you think “I don’t know what the hell to do with it now but I’m sure I could think of a million things.”
They call them self engineers, but can’t figure out how that spring/lock thing work! Ever hear of halbach array?
The making process is interesting, but can it print GOOD halbach arrays? How stable (long lasting) is it in this configuration, or does the alternating strong fields fade out?
this. If we could print a tight enough Halbach array, we can get almost to a magnetic monopole. Still not all the way there, but maybe close enough to start experimenting with the things that could only be done with such an animal.
you are confusing “a strong field strength of many alternating poles on one side of the magnet” -which is possible- with “a strong total flux on just one pole of the magnet” -which is not- obviously.
Right now one of the flaws of halbach arrays for things like MRI imaging or desktop NMR is that field homogeneity is poor. If this process could produce halbach arrays or corrective magnetics for more conventionally made arrays that could open up a lot of applications.
Are the machines actually printing or are they realigning the field in an existing surface?
Realigning fields
I was thinking the same thing but in the context of using them for levitation, as in the Hendo hover engines. I imagine it could make for cheaper production if they can print them. I’m pretty sure right now Hendo pretty much glues a bunch of magnets to a plate(i may be wrong).
Regardless, the Hendo “engines” work by spinning the magnet assembly. And they work fine. This doesn’t seem to be anything revolutionary. It’s clever, and it’s something apparently nobody thought of, thus far. But it’s not a miracle. I can’t see an obvious way applying this to the Hendo boards would help.
The neat thing with Hendo is you only need magnetics on one side.
If you use these you would need magnetics both sides.
That said, you could probably do that easier with this then with other methods – which take more work to get the stability.
I have played with one of the regular magnetic ‘springs’ from this company (not the latching kind as shown in the video) and honestly the dude is right, it doesn’t come across nearly as crazy on video as it does when its in your hands. It’s like all your years and years of interacting with magnets gets thrown on its head. I also played with one that had sorta ‘gear’ teeth thing, you could spin one and it would spin the other, but too much force on either side and they would slip. Very very very cool.
It isn’t 3D printed! They place a solid and complete “blank” in the device and write the field into it. It is just the equivalent of a powerful VCR write head on a CNC machine. My guess is that you heat the surface with a laser or induction to the Curie point then as it cools you expose it to a very strong magnetic field with the desired polarity.
Very nice engineering work but not fundamentally new and certainly not magic!
You could 3D print magnets but it would be tricky as you need to control the mix of magnetic particles in a fluid polymer and hold their orientation while the plastic binder hardens, so it would probably be very slow. However if it enables some really funky types of motors or even devices that use magnetic logic it would be worth the effort to get it to work.
You don’t need to jump to say it is not 3D printed. It is printing in a 3 dimensional space, therefore, it is 3D printing. It may not be laying down material but that’s not the definition of printing. They use a CNC gantry with some sort of magnetic print head like you said is in a VCR, just way more powerful… my point is… dont be that guy…
It is not 3D printing, there is no indication that they can do more than have a 2D array of areas with an either up or down state. Nothing more complex.
If this is the case then IT IS NOT 3D! Otherwise prove me wrong.
So until you can do that, how about you don’t be “That dishonest guy who gets found out in the end?”
The height of the magnetic field varies in accordance with the strength and organization of the printed state.
It cold be argued that they are printing a 3D magnetic field with the bias magnetism being the Z-axis.
Just throwing that out there.
If you wanted to mislead and confuse people, perhaps. At best somebody like you could call it 2.5D but 3D would require the ability to make the field for any given vertical column (the normal to the magnet face) be more complex than a gradient.
If it was true 3D it could emulate any possible combination of magnetic wires intertwined and bent into any possible shape, assembled in a 3D volume, and as far as I can tell it does not even come close to doing that.
Get over it, IT IS NOT 3D PRINTING.
The screen of a 3D TV is flat. lol
There is definitely two lines of thought on this and although I am more aligned with your interpretation, I still acknowledge the other train of thought.
I first worked with binocular vision imaging systems in the late 80’s, they are not 3D they just have two fields one for each eye, and that is a completely different area anyway.
If it can’t satisfy my “wire tangle” test it ain’t 3D printing, period.
last time I checked, the magnet’s surface looked pretty 2D.
It’s not actually “printed” though. Which normally means through some sort of impression transferring, but whichever, this is just manufactured. When the highlighted text says “3D printing magnets” you get a false impression.
Since it is not 3D printed it is therefore garbage and Not A Hack, shame to all of those involved, as usual.
It would make a great component of an innovative hack, so it is definitely worth knowing about and has a place on HaD, however being misleading about what it really is just makes it harder for people to get their heads around what it really can do and therefore what it is potentially useful for.
Magnetic stripe cards are printed by a magnetic stripe printer.
We used to “print out” punched cards.
Once again, sarcasm doesn’t really come across well to most people through text.
On the plus-side, folks like us know better than to believe everything we hear/see.
On the minus-side, our aversion to oft-ill-used buzz-words like “3D-printed” (or “Arduino”…) tends to either make folks like us miss-out on some really-awesome-stuff, or tends to cause us to waste precious time, commentary-space, and others’ emotional-stability on stuff that’s, really, nothing more than a bunch of chest-puffing (What’re we, apes? Oh… RIght.).
Maybe what we need is a website with repetitive arguments like these already written-out. And instead of wasting everyone’s time, the first person who thinks to can just poke a link to e.g. “wikiGetItStraight.org/3d-printing/” (Of course, that site is to *view* things… wikiPuffYourChest.asshat/3d-printing/ would be where you enter your argument.)
Meanwhile, the rest of us who’ve actually grown past ape-like chest-puffing can actually be inspired by and maybe even inspire others with some really interesting ideas to do with things like this.
Hmm… That shaft through the pair looks important to maintain a stable equilibrium point.
Earnshaw’s theorem show it’s generally impossible (*) to make a permanent magnet (or any configuration of magnetic poles) to stay stable in one spot in space. (*: unless you have active stabilization, or possibly a diamagnetic component)
So that does reduce the possible application space, but there is still a ton of things this could be used for, particularly if you aren’t limited to configuring the poles solely on a single plane.
Did anyone else find it mildly amusing that the door on their 3D printer still latches with the same bog standard magnets the rest of us have? https://www.youtube.com/watch?v=IANBoybVApQ&t=499
I strongly suspect the following product to make use of this technology:
* https://www.kickstarter.com/projects/hexlox/hexlox-anti-theft-for-saddles-wheels-and-more-made
Could you agree?
Wait..couldn’t you just produce a powerful magnetic field to disrupt the existing field and just suck the locking device out?
~$3 domestic shipping to OH on the demo repelling/attracting magnets shown in the video. :-)
wow!
These might be handy for hover-boards, IIRC one of the big limitations with Hendo’s system is the need for expen$ive neodymium supermagnets.
I’ve got some ideas here but hesitant to share them because it would get me in trouble, essentially a way to make a hover-board that works on any suitably hard surface not just conductive. It uses new physics I discovered in 2008 but until about a month ago the materials were not available commercially anywhere.
Shoot Son,
We would love to read more about that.
Love
The Internet
Why exactly would you be in trouble for revealing your revolutionary physics theories? Worried that the government Science Police will disappear you?
I recognize your mindset, I was the same when I went through my perpetual motion phase. Build your idea, it won’t work but you’ll learn a lot and those weeks where you think you’ll change the world are thrilling.
Your use of a dollar sign as a letter has been convinced of your credentials.
Poly in polymagnet had me confused, because it had me thinking polymers, so I looked up poly, OK poly as in many magnets perhaps. I believe I’m correctly picturing how the printer does it’s thing. I can see conventional machining, and manufacturing being able to produce similar products.. The printer probably is more configurable, but it might be slowed down by the time the print head has to linger at each magnet location. Heck a handful of people in a moderately equipped shop could duplicate a short run of the products, if they wanted to.
So if you can print any magnetic field shape you want, why not print a sphere with all the North poles facing in and all the South poles facing out? Or vice versa it doesn’t really matter which is out or in.
Would that not create a simulated mono pole?
Then once that done, print a surface with all North facing upwards and place the sphere on top. It should, if the magnetic fields are strong enough, repel the sphere causing it to hover. Maybe I’ve got it wrong, but that seems like it should work.
https://en.wikipedia.org/wiki/Magnetic_monopole
I know what a monopole is, I’m talking about creating a magnetic sphere with one pole facing outwards, one in. I know that’s not a monopole, I’m only suggesting that sphere made in that way may behave like a monopole.
Any particular reason you posted a link to the wiki page for monopoles. If you found something not feasible with my idea say it here for all to read. Just posting a link does little to explain your intention.
I had that thought many years ago. I always wondered how it would act.
@ jack324 and Danny
lets assume a perfect spherical infinitesimal shell of homogenously distributed perfect ideal dipoles:
an ideal dipole is the superposition of a positive and a negative equal but opposite infinitesimal charge seperated by an infinitesimal distance. so now you can replace the original shell of dipoles with 2 inifnitesimally seperated shells each with equal but opposite (monopole) charge. Now fields are additive, so now we consider just one such shell at a time and then add them together afterwards. The field of spherical shell of charge is zero inside the sphere (calculus), and outside the sphere the field is the same as if the total charge of the shell were centered in the sphere’s … center! (calculus)
But we have 2 spherical shells of equal but opposite charge, so the field outside the spheres cancel as well…
In other words, the field is zero everywhere, except in the infinitesimally small region between the 2 shells….
This is valid for both electrical and magnetical fields and poles… So this setup does not produce a monopole…
OK, I might accept that, but therein leads to another question… Similar to that of superposition of light (and, I might just be admitting my ignorance/forgetfulness, here… those classes were 10-15years ago).
So, two coherent light sources are interfering and 180deg out of phase, the net-result is no light appearing anywhere along their path, right? Except, technically, the photons are still travelling, and they have energy…
So, you’ve got two *really strong* lasers with 180deg phase-shift aiming down the same beam, producing no visible light, but *shittons* of energy, still, is being transferred down that beam. What’s happening?
Now your suggestion with the magnets is that the net-result is no fields, except there’s no doubt that each of those infinitesimally-thin layers contains a *shitton* of magnetic-fields, it’s just their net-field seems to be cancelling. What happens to all that…. “energy”? Is this “monopole” sphere going to explode? Surely that’s not the case with a “weak” magnetic field, but still the net-result would be zero, according to your logic… What we got, a material that wants to destroy itself, but still held together by its atomic-forces? (oooh, then, can we create a material wherein its magnetic and atomic forces nearly cancel, and the otherwise solid-state medium is almost gasseous? Like tiny molecule-sized “spring”-latches like those in this post? Wherein I might just be admitting today’s overconsumption of coffee.)
the physicist immediately sees that dipole terms never become monopole terms and vice versa…
ahem,… “except vice versa”
@esot.eric
sigh,
OK, I guess I could have made the derivation a lot simpler and more general: a monopole generates a non-zero total flux through any closed surface encompassing it. A multitude of charges generates as resulting total flux through the same surface the sum of the total fluxes of the individual charges. Now remove all charges from within the surface, and only allow in dipoles (hence with equal and opposite charges): no matter how you arrange the dipoles the total flux through the surface will hence be zero, unlike if a monopole were present…
I wonder if you could make four speaker feet that would allow the speaker box to levitate, thus cancelling any possible vibration.
An audiophile’s dream come true.
Google “magnetic bed” but use rubber strings instead of steel cables. Also need $$$
Too bad it wouldn’t matter, seeing as how any vibrations there are on the ground would also be travelling through said audiophile.
It reminds me of those cheap rubbery magnet cards you get at the expo. Stick two of them back to back, and then slide them apart lengthwise… They catch and release, catch and release every 1/16″ or so, making a funny noise. Then rotate one of the magnet cards 90° and the effect goes away. I’ve always wondered if the staggered magnetism was intentional for some reason (storing a bunch in a box for delivery?) or just a result of manufacturing. I would think you could make a puzzle that would only fit together 1 specific way, or magnet alphabet for children that require the letters to match the baseline and only stick in alphabetical order, or any order but always rotate themselves to be vertical.
Let’s just put this here…
https://en.wikipedia.org/wiki/Levitron
https://upload.wikimedia.org/wikipedia/commons/2/2f/Levitron-levitating-top-demonstrating-Roy-M-Harrigans-spin-stabilized-magnetic-levitation.ogg
That needs to spin though. I *think* with this you could make something like it without needing to spin. maybe.
Ah! That’s super amazing. That can have a lot lot an a lot of applications.
Pretty cool stuff. I wonder about resolution and interference. I see how the sheer size of the magnetic region could create a viable “S/N ratio” but what if you want to create a tight, complex pattern? The machine may have the resolution capability but is there a point where external magnetic fields will “blur” the fields of the pattern? I’m thinking about this for use in medical devices and then considering all the magnetic “noise” created by devices used in the same space.
Why does this need to be permanent magnets? Imagine arrays of addressable electromaagnets. You could (for instance) dock supply modules to the ISS by magnetically locking in at a distance and manipulating the interacting fields to align perfectly.
Of course, powdered iron clutches are essentially variable-strength magnets that have been around for decades, although they do use electricity.
CMR employee here (I’m David in the polymagnet video), we don’t “3D print” magnets, the metaphor is poor when comparing to 3D printers. there is no extrusion per say or consumable material in the magnetization process. we take existing magnetic material and magnetised it in whatever way we see fit.