Copper heat sink

[Cobbler]

Diamond is even better

A Double Diamond is even better, “A Double Diamond Works Wonders” you need to be of a certain age to remember that one.

 

[Brad93]

sounds like you've got one of the cameras that films the weld in Infrared and gives a real time idea of penetration, heat input and heat affected zones?

 

[mike os]

Have it printed?

Introducing 3D Printed Copper

Markforged is excited to launch its next metal material: Copper

markforged.com

Heat conductivity is not that good on printed copper … no idea why,

 

[Onoff]

Heat conductivity is not that good on printed copper … no idea why,

This is the data sheet for the Markforged 3D printed stuff:

 

[sako243]

Dow Corning was always my go to for heat sink paste.

That's the stuff we used to use! Seeing the name now it's obvious.

 

[eLuSiVeMiTe]

Heat conductivity is not that good on printed copper … no idea why,

Assume because it's because it's formed in layers rather than cast?

 

[Brad93]

Assume because it's because it's formed in layers rather than cast?

Is it not sintered?

 

[Maker]

Heat conductivity is not that good on printed copper … no idea why,

Laser sintering probably produces smaller grains than good old fashioned casting and drawing, every grain boundary is a tiny thermal interface so the more crystalline grains in the material, the worse it performs. I'd expect there to be pores and defects in a 3D printed part too.

 

[eLuSiVeMiTe]

Is it not sintered?

Yup but it's still being built up layer by layer.

 

[Brad93]

Yup but it's still being built up layer by layer.

If heat treated after sintering don't the molecules all bond together?

 

[Onoff]

I posted the data sheet with the thermal conductivity properties. Is it that bad?

 

[stuvy]

So the camera can run to 40°C ambient but is overheating and shutting down?

Thinking outside the box but wouldn't you be better off trying to reflect a load of the heat away (think tin foil) since there's a fair amount of radiant heat from welding.

As an experiment can you just wrap everything bar the lense in tin foil (literally) and see if it makes a difference. My suspicion is it will.

If you've got somewhere to attach a heatsink I'd then look at possibly a heat pipe (they are phenomenally good) to move the heat away from the camera to somewhere else you can cool it? Water cooler?

Camera has a temp gauge built in. Im WFH for a few days so cant test anything as of yet.

What about a Peltier cooler; this is the biggest that RS has but I'm sure there are biggers ones https://uk.rs-online.com/web/p/peltier-modules/1743123

The guidance notes pdf on that page is really interesting.

Currently looking into this as one of our chaps suggested it so going to try what we have first

That size block won’t dissipate that much heat once it is up to temperature… I assume you will fin it in some way? Or is the heat input relatively small ?

will be sending it out to our machinish to add fins, from what iv researched so far the fins need to have more than 3mm gap or in not going to work

Selecting the best type of heat sink for your application | Heat Sink Calculator-Blog: Focused on Heat Sink Analysis, Design and Optimization

By using a few guidelines the most appropriate heat sink for your application can be selected

www.heatsinkcalculator.com

I suppose that rules out adding a fan to force some air over the heatsink?

Iv ordered this from RS to try with a cheap aluminium heat sink iv got

MF92251V1-1000U-A99 | Sunon M Series Axial Fan, 12 V dc, DC Operation, 87.5m³/h, 1.68W, 140mA Max, 92 x 92 x 25mm | RS

uk.rs-online.com

plus thermal paste

Can you put a thermocouple on the part that's shutting down, log the temp and see how hot it gets before/after the welding starts?

I.e. is it mostly self-heating, or infrared from the welding that's the problem? The answer to this will determine the best way to attack it.

As mentioned earlier, at normal heatsink temps convection dominates over radiation. But if there is strong external IR from a welding arc or similar, a highly reflective coating on the heatsink might help. Gold (even a fraction of a micron of plating will work) is one of the best IR reflectors you can get. The usual black heatsink finish will make things a lot worse in this case.

it self heats to 40 and when we run the machine it reaches 86C then the picture disappears, currently takes 20 mins to not effectively work

it being flat is most important, polishing not past like a 400 grit finish - it generally makes it worse after that.
Yes, big difference on thermal compounds.

If the interface is small is it possible to incorporate heatpipes instead?

what are the heat pipes filled with, air or liquid?

where are you roughly?

our laboratory is MK, feel free to pm me

Might be an obvious question, but have you looked at CPU and GPU heatsinks?
They are available in a range of different shapes and sizes and they are pretty efficient and well optimised.

Might be a lot easier to find one that is close and adapt it rather than reinvent the wheel.

yep currently have these on the shelf waiting for me to get back to work and build one up

Maybe a heat pipe type cooler and a fan.

any links to a heat pipe? Fan is on my desk at work

Have it printed?

Introducing 3D Printed Copper

Markforged is excited to launch its next metal material: Copper

markforged.com

wont work
Due to the pores, cavaties and other defects thermal performance gets worse
Fewer grains then grain boundaries the better the thermal efficiency
However this does not mean that you need very big grains as the grain texture might influence thermal behaviour.

This is from a chap that studied material science and works in 3D metal printing. Is regarded as one of the best in his sector.

sounds like you've got one of the cameras that films the weld in Infrared and gives a real time idea of penetration, heat input and heat affected zones?

Xiris XVC-1000 Welding Camera

www.tpsweldtech.com

this one, they do offer a different one with an air cooler called a vortex

Heat conductivity is not that good on printed copper … no idea why,

see above

Laser sintering probably produces smaller grains than good old fashioned casting and drawing, every grain boundary is a tiny thermal interface so the more crystalline grains in the material, the worse it performs. I'd expect there to be pores and defects in a 3D printed part too.

see above


Thanks to all who posted on this so far I truly value all of your input chaps

 

[stuvy]

If heat treated after sintering don't the molecules all bond together?

will ask next time Im down at quantum in mk. We use them for heat treating

 

[stuvy]

Forgot to add, The COO at work wants to minimise risk of using a water cooled heatsink unless its the only solution that is

 

[Maker]

what are the heat pipes filled with, air or liquid?

A low boiling solvent and a metal "wick". The solvent evaporates at the hot end, flows to the cool end and condenses, then is drawn back to the hot end. Because there's actual mass transfer, the thermal conductivity can be far higher than solid metal (250 times better according to wiki!). You'll still need a heatsink on the heat pipe, a heatpipe alone will eventually reach equilibrium and work no better than a copper pipe.

 

[stuvy]

A low boiling solvent and a metal "wick". The solvent evaporates at the hot end, flows to the cool end and condenses, then is drawn back to the hot end. Because there's actual mass transfer, the thermal conductivity can be far higher than solid metal (250 times better according to wiki!). You'll still need a heatsink on the heat pipe, a heatpipe alone will eventually reach equilibrium and work no better than a copper pipe.

Im gonna run with what I have and try the ali and CPU fan, then the copper should be here and I can get that machined to spec, then look at the cooling tubes as there arent very expensive in the RS catalogue

 

[PhillipM]

Honestly if you can add a fan like you're saying that will make a massive difference anyway, the boundary layer with little airflow will be incredibly thick - probably why the 3mm fin spacing was suggested (And a lot of passive heatsinks use a lot more than that)

As Maker says, heat pipes are filled with liquid, either a low boiling point solvent or a water mix under a vacuum to bring the boiling point down, it flashes to gas, takes the heat away from heat of vaporisation and then condenses on the cold end of the heatpipe, and is wicked back down usually by a porous lining to the hot end. Conductivity is well above a block of copper and if the hotspot you're trying to cool is fairly small it's going to make even more of a difference.

I wouldn't even consider Peltiers unless you have to, they're incredibly inefficient and then you have to try to get rid of the extra heat they generate too.

 

[a111r]

Could a forge-ist help you?

10 Kg / £60 of scrap bright copper wire would give you a nice, pure big block to machine down.

 

[stuvy]

A low boiling solvent and a metal "wick". The solvent evaporates at the hot end, flows to the cool end and condenses, then is drawn back to the hot end. Because there's actual mass transfer, the thermal conductivity can be far higher than solid metal (250 times better according to wiki!). You'll still need a heatsink on the heat pipe, a heatpipe alone will eventually reach equilibrium and work no better than a copper pipe.

https://docs.rs-online.com/d08f/0900766b813eb684.pdf looking at the tech document im not entirely sure which one to go for

Maybe

SF-08-150-S | SPREADFAST Heat Pipe, Heat Pipe, 8 x 150mm | RS

uk.rs-online.com

SF-08-350-S | SPREADFAST Heat Pipe, Heat Pipe, 8 x 350mm | RS

uk.rs-online.com

SF-12-150-S | SPREADFAST Heat Pipe, Heat Pipe, 12 x 150mm | RS

uk.rs-online.com

SF-12-300-S | SPREADFAST Heat Pipe, Heat Pipe, 12 x 300mm | RS

uk.rs-online.com

These are in stock and its a PITA to start a new suppliers form up at work as the accounts lady is... awkward to say the least

Just thinking i can get the block machined to take these

Could a forge-ist help you?

10 Kg / £60 of scrap bright copper wire would give you a nice, pure big block to machine down.

Iv ordered a 4"x2"x4mtr piece for £71 will try a few different designs

 

[Kram]

Thats about 7kg, is it for welding heatsink, power electrics or sensitive electronics?

If its to make a finned heatsink it will be hard to beat a mass produced one, particually where heatpipes are used.

Heatpipes need to be tuned for the system. You need the working fluid to be evaporating and condensing and that wont happen with one deaigned for too much heat. If its too small, the fluid will never condense and the performace will be poor. With either its little better than the plain heatsink design.

Very difficult to beat water cooling if thats an option. Ive made some miniture water blocks that add the minimum annoyance to maintaining a system. The risk of a leak is very small.

Also consider weight and torque. Chips are fragile. Big heavy heatsinks, or hoses can /have crushed parts, so smaller can be better. is hour camera fixed or moving around?

In that case, silver has a slightly better thermal conductivity than copper...

Ive got a small lump of pure silver I made a water cooling block with years ago. The specific heat is about half, it performs better than the numbers would suggest.

Peltiers are risky, theres a good chance of bad condensation, freezing or cooking your part if you dont have it quite right.

It does not take much to lower coppers conductivity, but a free sintered part should be adequate. I have used FS copper and worked well, although mine were cold pressed/formed after.

Copper can also be grown to complex shapes. 3d print a negative finned former, coat with conductive paint. The copper will grow onto it. To get good quality it is a very slow growing process.
All you need is copper sulphate, a lump of scrap copper, and electrolysis.