Regarding the Heat sink Paste between the component and the Heat sink

[prakashvenugopal]

Hi,

Can any one tell me the difference between applying and not applying the heat sink paste between the
Component and the Heatsink. Is there any improvement in heat dissipation while applying the heat sink paste.
Applying the heat sink paste is equal to butting the component with heat sink?

Please let me know.

Thanks,
V. Prakash

 

[tpetar]

Difference is big.


When combined with specialist fillers the silicone grease will allow the efficient transfer of heat from one surface to another. These materials are more precisely known as Heat Transfer Compounds because they are not lubricants as such.

The ability of a material to transfer heat is quoted in W/mK; for a material to offer any significant benefit it would have to have a figure above 0.4 W/mK. Standard silicone compounds will normally have a figure of 0.18 W/mK.



https://en.wikipedia.org/wiki/Thermal_grease

 

[alexan_e]

Wikipedia to the rescue...
https://en.wikipedia.org/wiki/Thermal_grease#Purpose

Applying the heat sink paste is equal to butting the component with heat sink?

I don't know what butting is.

Alex

 

[betwixt]

Ales - "To make contact when pushed together."

The transfer compound is a fluid with good heat conductivity but low enough viscosity that when placed in the gap between two 'almost' planar surfaces and put under pressure between them, flows to exclude air and fills any voids. It maximizes the contact area as far as heat is concerned and therefore allows best heat transfer. If the two surfaces were perfectly flat it would be better NOT to use paste as it isn't a perfect heat conductor but in real life where surfaces are far from perfect, using it is beneficial.

Brian.

 

[mtwieg]

In practice no amount of lapping and butting is perfect. The best solution is practically always is to lap as best you can, and then use an appropriate amount of thermal compound (the smoother and flatter the surfaces, the less compound is necessary). The manner in which the compound is applied and distributed, and how the device is secured, makes a difference as well. But the point is, when used correctly thermal compound will always help.