My multi spiral concept.

[Roscal]

Originally posted by Cathar
I investigated sand-casting. The channels are too fine for anything other than a one-off cast as the fins of the mould would snap as they are too deep. At least this is what about 20 different sand-casting places told me before I got the hint...

The only way to cast copper for thin and tall fins is a metallic mold with copper injected under pressure. We'll use this method to do our block, we are allowed to do 0.5mm length elements and fins like 1mm*12mm tall it's not a problem . All is possible !

A gravity sand-casting is good for big elements not complex, precision is not very good against metallic mold..

[Cathar]

Originally posted by Roscal
The only way to cast copper for thin and tall fins is a metallic mold with copper injected under pressure. We'll use this method to do our block, we are allowed to do 0.5mm length elements and fins like 1mm*12mm tall it's not a problem . All is possible !

A gravity sand-casting is good for big elements not complex, precision is not very good against metallic mold..

Be sure to let us know how it goes. I also investigated injection casting into a metallic mould. It can be done - but the experience of the caster's informed me that since it is copper - it wouldn't be "clean". The copper captures and traps oxygen bubbles, even under pressure. I would imagine that vacuum injection casting is the only way to do it properly.

Then again, maybe you've got something sorted out. There's more than one way to skin a cat, and getting down to 0.2mm channels isn't that hard to do with conventional machining methods, just requires a fair bit of setup overhead.

[nicozeg]

Well, I need to invertigate more on casting techniques, but sure jewelers can cast complex shapes in silver. maybe I need to look into lost wax process.

[Cathar]

Originally posted by nicozeg
Well, I need to invertigate more on casting techniques, but sure jewelers can cast complex shapes in silver. maybe I need to look into lost wax process.

Jeweller's style lost-wax casting can generate comples shapes, but it's important to remember that it's a one-off casting process, and more importantly to remember that silver is a much better behaved metal than copper. Casting is silver is relatively easy compared to copper. Ring up a few lost-wax casting foundries (I did) and most of them will shudder audibly down the phone when you ask them about casting in copper. It's a horrible metal to cast.

[Roscal]

Have a look to some shapes that the firm which cast our bloc can do :


Notice than the shape of the impeller is like the bloc of Nicozeg so you can cast it very easily!

They are specialized in high precision casting copper or anything else you want (we will use EDM too to do the mould in order to have 0.3mm precision for edges fins ). Firm is in Switzerland and very good contact with them so it will be great for us

Even your WW Cathar is really easy to cast..

[nicozeg]

WHAT'S DOING MY BLOCK IN THERE!!

Man, you're so lucky of being able to use that technology.

Normally that only pays for a very big production run.

[Roscal]

Really nice, isn't it?

[jaydee]

Originally posted by Roscal
Have a look to some shapes that the firm which cast our bloc can do :

That impellor has no relation to how hard nicozeg's cocept block will cast. It is 10-20 times larger!! And is that Brass or is that all Copper? Looks like brass?

[SysCrusher]

Originally posted by nicozeg
Could be good, but may produce a huge pressure drop. :shrug:

You'll get a pressure drop after the impingement but along comes the velocity with it. You want slightly less pressure after the impingement for the impingement to actually do it's work. That'll send the water through the channels and thinning the boundary layer as it hits the base and shoots across through the channels. That's how Cathar's works but his is designed also to aid in flow to all the channels - Hence the rectangle nozzle. I'm still undecided about the pin concept since I havn't tried it yet. I know it helps eliminate the stagnation point where warm water can get stuck inside the jet but I think it would allow heat to travel up in the pin and heating the water before it hits the base. Not sure, probably a give and take situation.:shrug:

[nicozeg]

Being playing around shaping the intake, trying to optimize between contact surface and ease of flow. I’ve reduced and rounded the center pin, to guide the water to the channels avoiding stagnation areas. What do ya think?

[bigben2k]

A ball mill would do that.

You know... you might consider playing with the vertical angle of the fins...

[jaydee]

Originally posted by bigben2k
A ball mill would do that.

You know... you might consider playing with the vertical angle of the fins...

bah, hard to fins 1/16" ball mills capable of milling copper.

[nicozeg]

Originally posted by bigben2k
A ball mill would do that.

You know... you might consider playing with the vertical angle of the fins...

That will require a five axis mill... No thanks!

It still could be milled with cnc and 1mm ball end, but I'm heading to rapid prototyping.

OT: Can't post on my PC, I spilled a glass of water at the keyboard and it died. tomorrow I post more improvements of the design.

[bigben2k]

Well, the reason I brought it up is that I see this spiral pattern as having an advantage, where you *might* be able to direct the colder water molecules on the outside of the curve. Of course this effect cancels itself because it's the opposite on the other side of the channel.

But if you curve/bend the fins, you *might* be able to redirect the cold molecules up against the baseplate, where it's most needed... See my point?

5-axis, I know. I guess I'm just riding you because I don't see the purpose (nor benefit) of curving the channels.:shrug:

On the other hand, if you had the ability to control a rotation, you'd only need one more axis...

[LiquidRulez]

Originally posted by nicozeg
That will require a five axis mill... No thanks!

It still could be milled with cnc and 1mm ball end, but I'm heading to rapid prototyping.

OT: Can't post on my PC, I spilled a glass of water at the keyboard and it died. tomorrow I post more improvements of the design.

SIDENOTE

Invest a few bucks in a key cover. i did..great little investment...cheaper than buying keyboards(even though I dont have a good reason for telling my wife that I need to go buy a new one anymore)
Im a damn nightmare on my keyboards too. Got like 10 of them that had soda,beer,wine spilled on them and traces eaten completely off.

[winewood]

You know that a non-usb keyboard can be completely submerged in water and/or placed in a dishwasher?
After drying out completely.. just plug in and type away.

[bigben2k]

Originally posted by winewood
You know that a non-usb keyboard can be completely submerged in water and/or placed in a dishwasher?
After drying out completely.. just plug in and type away.

Just remember to stop it before the "Dry" cycle

I clear stuck keys myself with WD-40.

[nicozeg]

You know that a non-usb keyboard can be completely submerged in water and/or placed in a dishwasher?

In this case it was standard ps2 keyboard and it's clearly dead; unless you can type whitout the two lower character rows, plus some others between the remaining.

I disassembled it completely and had some corrosion on conductive traces in plastic sheets. Cleaned every piece and put it back but the damage was done.

bigben, the purpose of spirals is being able to control fin and channels dimensions, as well as flow speed, in smooth transitions. It can acomodate different cpu sizes from a naked die to a P4. Another advantage is in the outlet system (more details later)

This is the current state of the design: Lowered the fin height at the beginning of the channel, and opened it at the end to reduce speed. Also provided space at the edge to an oring.

[nicozeg]

Here's what I've thought for the outlet:

A growing section perimetral channel that collects the water smoothly into a single exit. With this the water travels without sharp direction changes and complicated systems that add an aditional head loss.

[bigben2k]

I think you've got the "growing" part backwards

The flow will take the path of least resistance, and that's the channel(s) closest to the outlet.

But if you reverse the "growing" part, then you're left with a small outlet unless you make it all bigger

Flow tuning... I hate it.

[electrip_flip]

Originally posted by bigben2k
I think you've got the "growing" part backwards

The flow will take the path of least resistance, and that's the channel(s) closest to the outlet.

But if you reverse the "growing" part, then you're left with a small outlet unless you make it all bigger

Flow tuning... I hate it.

This a major misconception.
The path of least resistance is _all_ possible paths in parallel.
Especially when each single spiral channel is a sufficient resistance
to the flow caused by the pump flow is distributed more equally.

The whole block looks like francis-turbine with its rotor not rotating
and reverse flow direction (pump setup).

Sorry for my english,
i'm from good ol' europe.

Philipp

[nicozeg]

Originally posted by bigben2k
I think you've got the "growing" part backwards

The flow will take the path of least resistance, and that's the channel(s) closest to the outlet.

But if you reverse the "growing" part, then you're left with a small outlet unless you make it all bigger

Flow tuning... I hate it.

nope, just look at a good quality centrifugal pump, it's the same.

The water rotate at the same speed in all the collector channel, and the section grow to receive each new water stream. resistance at each inner channel is equal.

If don't believe me just look at turbines of hydro electrical power plants.

[bigben2k]

Uh... ok, guess I'm off my rocker then!

[nicozeg]

Originally posted by electrip_flip

The whole block looks like francis-turbine with its rotor not rotating
and reverse flow direction (pump setup).
Philipp

Couldn't explained it better.

[hara]

That would be killer if it could be cast out of silver and perspex.