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#1 SpleenBeGone

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Posted 29 April 2016 - 07:25 AM

This is one of those things that technically I understand how it works, but it's so far away from how I expect magnets to work it might as well be magic.

Imagine anything with a spring or latch being replaced by magnets.


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#2 idk

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Posted 30 April 2016 - 02:06 AM

I wonder if these are similar to the sheets of magnet paper that can be fed through (SOME) printers. I remember making my own graphics on printed magnets with an old Kodak inkjet I had. Haven't seen those magnet sheets in a while though.


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#3 SpleenBeGone

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Posted 30 April 2016 - 07:24 AM

I'm pretty sure those are just fridge magnets, not actual printed magnetic fields. 


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#4 Australopithecus afarensis

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Posted 30 April 2016 - 09:39 PM

That is really fucking cool. When can I get a printer that can do that. So many possibilities


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#5 SpleenBeGone

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Posted 01 May 2016 - 11:02 AM

I'm not sure when something like that will be available, I'm just excited to get the products.

I wonder if you could make a maglev track using them and not have to have superconductors. 


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#6 idk

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Posted 02 May 2016 - 12:38 PM

I'm not sure when something like that will be available, I'm just excited to get the products.

I wonder if you could make a maglev track using them and not have to have superconductors. 

Sounds like spleen is planning a multi-room model railroad...

 

Or already has one.


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#7 HammerBammer

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Posted 14 September 2017 - 07:09 AM

I'm not sure when something like that will be available, I'm just excited to get the products.

I wonder if you could make a maglev track using them and not have to have superconductors. 

 

That's... That's not... Ok.

 

A permanet magnet, like the ones in the video or the ones on the fridge, create a strong magnetic field. When that field interacts with other ferromagnetic materials, like the fridge door, they induce a magnetic moment on that material, attracting the two bodies - aka, the magnet sticks on the fridge.

 

A superconductor REPELS magnetic fields - the Meissner effect. No field lines penetrate the superconductor. 

That's why you see magnets floating above superconductors. 



#8 SpleenBeGone

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Posted 14 September 2017 - 08:42 AM

Right, but the same magnetic poles also repel each other. I'm thinking specifically where you see a superconductor floating over a magnetic track. In theory you should be able to print a magnet to float over another magnet without it just flopping off to the side when you try to move it.


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#9 HammerBammer

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Posted 14 September 2017 - 11:08 AM

It's not that simple. The repulsion between two magnets is not a stable state. You can feel that when you point two equal magnetic poles towards each other. Yes they repel each other, but to stay aligned you need to hold them. 

Nature tends to states with minimum energy, and in this case that is two opposite poles pointed toward each other.

 

Even if you manage to print something that doesn't just flip over, you're still gonna have a magnetic field "run" over another magnetic field. That is going to induce some electrical currents and, depending on resistivity, probably heat.

 

That's basically how electromagnetic brakes and induction heating work. Permanent magnet are metals (can't think of one that isn't) and thus are conductive. If you have a varying magnetic field (like a magnetic train moving over a magnetic rail) you will have an induced current. And that is just bad.

 

That is one of the reasons why room temperature superconductive materials would revolutionise everything. Since the magnetic field doesn't penetrate them, there would be no induced currents. 

 

But you should check the Hyperloop project. They use magnets to center the "train" inside the tube and not let it touch the walls (no friction = no slowing down).



#10 SpleenBeGone

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Posted 14 September 2017 - 03:21 PM

Yeah, I'm aware that it's way more complex than I put in the post. I just feel like this technology might be a step in making stable repulsion. 

Electrical current isn't something I thought of. I wonder what sort of issue it is with the more complex prints in the video, or if it's on too small of a scale to matter. 

 

I'm pretty interested in the Hyperloop project, though I'm not terribly well versed in it at the moment. It really is a fascinating idea. 


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