elysium said:
What is lapping?
Please understand this question on behalf of my location and explain it a bit in detail, please.
Ely
Your heatsink is grinded by mechanical sanding units which will smooth out your HSF. Although the machine aren't always accurate and it gets uneven, thus when slapping on your heatsink, it'll be uneven, and your thermal compound may or may not take over depending on how much you used, but either way it doesn't get enough contact.
When lapping it, your heatsink becomes very flat making 100% contact, before it, it made only 70-85% contact.
When lapping it, you'll see the sides coming in, and then you'll eventually see everything in one flat layer other than bumps.
This is done through:
Waterproof Sandpaper (200-1500grits [1500 Grit is my opinion others say 600 is enough. The 1500 I prefer because, it takes more sanding grinds off the bottom of your heatsink, and it gives you a mirror finish] using the wet option of the waterproof sandpaper)
Lapping on a flat surface (I use glass)
And lapping the heatsink itself.
The water is meant to not scratche the heatsink while lapping. Another reason why you lap is that, the sanding by manufacture leave heavy scratches after, so you also won't get full contact.
... Anymore questions.. go ahead ...
