Electronics > Projects, Designs, and Technical Stuff

general heat sink rules for fin dimensions

<< < (5/5)

ahbushnell:

--- Quote from: coppercone2 on July 13, 2019, 12:10:39 am ---I thought about that and I thought I might be able to fill them with wax or something in between cuts

maybe hot glue, not sure what kind of strength you need

--- End quote ---

I know for custom heatsinks there are vendors that use ganged saw blades to cut them all at once.

3D printed metal would work.  But that would be expensive. 

3D print plastic and make mold and then cast the aluminum.  Good home project.  :)

Just make the fins a little thicker and machine them.  Do it slowly. 

Good luck

coppercone2:
hehe vaccum silver casting would do the trick

I think it offers very good resolution.

a big to-220 heatsink is 51gm, so you get something like 19cm3,

19cm3 of silver is 200gm, 106$

Now, how do you get the black anodized coating on silver (obviously a problem) to increase its performance like with Aluminum?


Given the price of a LT3080 is 6$ in single unit quantities, the heat sink price is slightly less absurd. Even more worth it for a LT3083 high grade part (11$+) :-DD


add the absurd cost of a stainless screw and thermal compound and it makes more sense

could aluminum plating the silver and anodizing the aluminum and dyeing it do the trick?

CatalinaWOW:
The common thread running through many of the answers here is that there is no single rule of thumb or design equation.  Optimum depends on the particular problem being solved.

For you, it seems that the problem be solved is how to put your mill to use.  So the answer may revolve more around what can it do, what is good enough for cooling purposes, and perhaps what clever mounting technique can you mill in that lets you optimize around your willingness to invest design and machine time in a unique design.

That line of thinking lets you ignore ganged saws which is really the only good way to cut fins, even if cutting is the right answer.

If getting a usable heat sink is the priority your best bet is probably to find or buy some extruded finned aluminum and then mill as appropriate for mounting purposes.

duak:
Silver naturally combines with sulfur to make silver sulfide that is quite black, and commonly called a tarnish.  You'll just have to accelerate the process.  Black and white film and papers use various finely divided silver halides to produce quite black coatings.  I don't know how hard these coatings are, but silver tarnish is hard to remove.  I do know that aluminum oxide (anodized finish) is quite hard and that's why it's used.

I've got a few copper server processor heat sinks that were scrapped because of machining faults eg., broken drill bits or taps embedded in them.  Pure copper is hell to machine.  BTW, I had never heard of tellurium copper.  Thanks for the tip - it seems like it's much more machinable than ordinary copper.

In addition to the heat sinks, I have some spot welder tongs that I'd like to make black to improve heat dissipation.  Copper tarnishes all by its lonesome but I've never tried to do any sort of coating myself.  I understand there's a process using "Liver of sulphur" (Anything like eye of newt or horn of toad?) that is a conglomeration of potassium-sufur compounds.

coppercone2:
careful its still dangerous, at least on a lathe, just less so (in terms of getting machine tools stuck in the ceiling or your head). Much nicer though (hence the ultra machinable), but not as nice as normal metals

I wonder if the tarnish improves the thermal conductivity as does black dye anodizing (5% or so)

I don't think the oxide needs to be black, more like you need a ultra thin film to lock in a black dye (but I guess a naturally black oxide would be better? I don't really understand the dynamics.

I kind of wonder if undistributed, would the ultra-black soot of an air acetylene flame out perform all these things. Maybe vacuum deposit the thinnest layer of super glue on it afterwards to protect it a bit?

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod