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PGS heat sinking question..

Lifetime17

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Hi ,
Ok we all know about the secret material that was bounced around . So if there was a supply of PGS in a solid round bar form would you guys think it would be worth the attempt to machine a full size heat sink? Give me your feed back for the heck of it. Don't hold back i can take it LOL !!

Rich:)
 

ElectricPlasma

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Rich I can't say you'll have much luck finding that material in bar stock, yet alone as a consumer rather than in bulk. If you can then hell yea give it a shot, would make for something unique. But starting to make many hosts from it sounds a bit overdone, since aluminum and copper work absolutely fine and look great too.
 

Encap

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Good thought Lifetime and not a silly one--but the secret material does not exist in such a form.
You were hoodwinked by a troll into thinking it did--there is no magic super conducting material that can be used to make a 5W host with unlimited run time that is the size of a 18650 battery.

The functionality of PGS sheet depends it being very thin.
PGS (Pyrolytic Graphite Sheet)” is a thermal interface material which is very thin, synthetically made, has high thermal conductivity, and is made from a highly oriented graphite polymer film.
Would be useless at those thicknesses in building laser pointers.
The PGS sheet is only 1/10 mm and thinner to 1/100th mm. Is used instead of say copper or Al foil and dissipation of heat limited by the interfaces, contacts, and surrounding materials/environment
See: https://industrial.panasonic.com/ww/products/thermal-solutions/graphite-sheet-pgs/pgs

If you want to see for yourself what thick pyrolytic graphite does --just get a solid piece of high conductivity pyrolitic graphite, machine it an see what it does but high conductivity pyrolytic graphite is quite fragile and expensive which is a disadvantage. You can buy some here: Pyrolytic Graphite

See for chart of thermal properties of graphite materials Carbon Fiber Properties-Heat Conductivity

From there on out you can google all sort of research and applications :beer:
 
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Lifetime17

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Hi Guys thank you that might basically sum thing up. Graphite bar HMMM.. Wow talk about self lubeing material.

Rich:)
 
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IMO, it wouldn't be worth it unless a material with such a conductivity only cost so much more than copper, and then you gotta take design into consideration. Thermal resistance is a great thing to minimize, but being that conductivity is a function of length, the issue is normally, "how small can we make this component?" Whereas convection is actually just a function of geometry and how much surface area you can put into something. So you wouldn't want to spend thousands on raw materials for a truly full-sized hs to begin with, cuz the convection defeats the purpose after a certain point
Edit: no, the smaller a part, the better the conduction. what am i even saying
 
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Alaskan

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Question I have if the transfer of heat is increased to 100 percent, how much lower would the componet heat be? Are a few degrees improvement even worth the expense of high tech? If you are running a laser diode component that close to max, just increase the heat sink size instead. Show me the percentage of heat sink size reduction a 100% lossless heat transfer will produce (not that you can get it), I bet not a huge amount of heat sink size reduction if you had a 100% efficient coupling. This would be an interesting study, I bet someone has already calculated the difference for electronic components 1000 times, just need to find the info.
 

Lifetime17

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Hi,
Ok am receiving some great conclusions from some of the best in the forum.All replies very welcome ,i can compile these answers and and then see if its worth the time .Thank you gents ..

Rich:)
 

diachi

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Even if it was available as bar stock it'd likely be stupidly expensive. A 90mm x 115mm x 0.1mm sheet from mouser is $24 CAD. We also don't know what a bar of it would be like when it comes to machining it. Copper is relatively cheap, and we know how to work with it, even if it's not the easiest material to machine.
 
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Question I have if the transfer of heat is increased to 100 percent, how much lower would the componet heat be? Are a few degrees improvement even worth the expense of high tech? If you are running a laser diode component that close to max, just increase the heat sink size instead. Show me the percentage of heat sink size reduction a 100% lossless heat transfer will produce (not that you can get it), I bet not a huge amount of heat sink size reduction if you had a 100% efficient coupling. This would be an interesting study, I bet someone has already calculated the difference for electronic components 1000 times, just need to find the info.
That, my friend, is the question of nightmares. I can say that if temperature stops increasing, the heat transfer rate is at steady state, or 100%. But beyond that you have to treat your problem as a thermal resistance problem. If you're generating 10W, and a solid cylinder without fins, you're going to have a bad time unless the volume of the cylinder is increased so much that the surface area of it has increased to allow for much more convection. But if you cut some fins into it, it won't need to be that large. Regarding material size reduction, just know that all solid material is a thermal resistor. You'd really just have to sit down for a week and simulate what geometry would work best, make some spreadsheets to calculate optimal fin spacing and design a heatsink for your temperature or heat transfer rate
 
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Alaskan

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I don't even want to try thermal calculations with a calculator, software maybe. I'd handle it differently, just make a heat sink of a given size, see how hot it gets and duplicate it with a heat sink split in half and use Arctic Silver, or a synthetic diamond powder based heat sink compound and see how much difference it makes, or rather, how much hotter the device gets. Yes, a seat of my pants method, but I had to take a lot of math in college, many years ago, I will spare myself thermal calc's now.
 

Lifetime17

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Hi Chris,
Yes adapt and modify method sounds fine it cant hurt to try. If it works well great if not oh well back to the drawing board. Bore out a piece of CU or AL and press in the graphite core. I ordered a piece of graphite to play with 3" x 6" coming this week. This should be interesting. Thanks again buddy and all who contributed their comments and solutions.

Rich:)
 

Encap

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Hi Chris,
Yes adapt and modify method sounds fine it cant hurt to try. If it works well great if not oh well back to the drawing board. Bore out a piece of CU or AL and press in the graphite core. I ordered a piece of graphite to play with 3" x 6" coming this week. This should be interesting. Thanks again buddy and all who contributed their comments and solutions.

Rich:)
What type of graphite material did you order? 3" X 6" X what thickness?
 
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Lifetime17

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Hi E ,
Ok not 3x6 but 1-1/2 D x 6 L Its a solid compressed fine grain rod . Its cylindrical..

Rich:)
 
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Hi Chris,
Yes adapt and modify method sounds fine it cant hurt to try. If it works well great if not oh well back to the drawing board. Bore out a piece of CU or AL and press in the graphite core. I ordered a piece of graphite to play with 3" x 6" coming this week. This should be interesting. Thanks again buddy and all who contributed their comments and solutions.

Rich:)
Lifetime.. This material only exists as a sheet... which I have 20 meters off :)

Solid graphite does not have these properties and can only reach 500W value while copper is around 400...

I have checked with tens of factories... it is not worth machining this solid graphite. I also planed to press a graphite core in a copper heat sink... but again you only gain 20%.

PGS works so well because it is more near to graphene... which is a single layer of graphite.

Anyways, let us know your resutls, but regular graphite... which is my best guess is what you ordered only has a conductivity of 325...

I can share with you further in PM, but good idea. Maybe you can vote me some reps.
 

Lifetime17

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Hi Solomon,
i should receiving the graphite soon. This is just an experiment nothing etched in stone. Graphite does have heat absorbed properties and is electrically conductive , So if it works fine and if it doesn't well at least i gave it a shot . I will bore out an AL sink and press in the graphite core . I say if you don't try it you will never really know. If it won't work out at least i won't have to give up my first born, Nothing lost o my end, But i gain some satisfaction for myself. And thats worth it to me.
I also wish you luck with your project may the Swartz be with you..

Rich:)
 




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