Wat is LAPPING?!?!?! Pl Help...

[gannu_rox]

Hi budds...

Seems no one in this thread has discussed abt lapping...

I've headr ppl using sand paper n rubbin it atop the proccy face n Heat sink face to get a mirror-like finish...

Is it helpin in reducin temp???

Eg.. Fer a C2D6600 and d stock cooler... Will this help??? any chances of damagin the proccy???

Pl help...

 

[spynic]

lol.. its no computer question..
neways ill tell ya
lapping is a super finishing process(smwht gives a mirror finish).. wer the surface is rubbed/ground wid a very fine grit emery paper...somewht like polishin..
material removed is about .000002mm(where as in grinding , about .0002)
to obtain a smooth flat surface.. in order to get maximum surface contact..
its usually done on the bottom of a heat sink..to provide max contact wid d procy..(heat transfered depends on area of contact..)

usually done by machines for industrial purposes..
we can use our hands for heatsinks!

dnt do it on ur procy.. it can damage it.. u can do it on ur heatsink.. but
heatsinks come lapped..
if its a custom made heatsink den u can do it..
id recommend the use of some thermal paste... it provides good contact..

 

[darklord]

The IHS on CPUs are sometimes not perfectly finished and hence arent flat.Which results in poor contact between the CPU IHS and HS.
Solution for this is lapping.Lapping is basically rubbing the IHS on waterbased Sand paper to attain almost perfect flatness.

Here are some of my Lapping Pics ,

*img186.imageshack.us/img186/8978/dscn3413no6.th.jpg *img99.imageshack.us/img99/7691/dscn3424ka7.th.jpg *img174.imageshack.us/img174/4315/dscn3441sb9.th.jpg *img254.imageshack.us/img254/4812/dscn3457if1.th.jpg *img184.imageshack.us/img184/3484/dscn3489fm4.th.jpg

*img300.imageshack.us/img300/8964/dscn3494sg1.th.jpg
That is my Intel Core2Duo E4300
Beware: Lapping voids warranty

Darky

 

[gannu_rox]

The IHS on CPUs are sometimes not perfectly finished and hence arent flat.Which results in poor contact between the CPU IHS and HS.
Solution for this is lapping.Lapping is basically rubbing the IHS on waterbased Sand paper to attain almost perfect flatness.

Darky

Hey Darky, Thanx budd...

M jus thinkin whether to lap ma new proccy M gona get-E6600( WEn m gettin it nex month )...

Jus got 3M sand papers today...

Pl temme the grades of sheets used and did u do it manually or using some machine??? Is d overall process risky??? Hw abt lappin the heatsink as well?? By hw much is d temp decreased???

 

[darklord]

Hey Darky, Thanx budd...

M jus thinkin whether to lap ma new proccy M gona get-E6600( WEn m gettin it nex month )...

Jus got 3M sand papers today...

Pl temme the grades of sheets used and did u do it manually or using some machine??? Is d overall process risky??? Hw abt lappin the heatsink as well?? By hw much is d temp decreased???

Use 600-1200-2000 Grit papers.

Here's the procedure -
1] Take a glass top
2] Take the paper and put it on glass top with tape so it doesnt move.
3] our some water on paper
4] Hold the chip and gently start rubbing it on the paper in such a fashion that you create '8' shape when you rub it on paper.I mean the motion while moving should be in 8 shape or so...bleh
5] keep doing it until the IHS is completely flat.
6] Check flatness with Razor blade.Hold it perpendicular to IHS and check the light passes through.When no light passes, the iHS is perfectly flat.
7] There is no need to Lap HS.
8] Be ready for a long and tiring session,few hours for sure

Hope this helps.

 

[gannu_rox]

Gulp... Thanx... Good description...

 

[Kniwor]

Hi gan12320021,

you can also polish the processor after lapping too, though personally I believe it should not be done, and an unpolished one will give better results, but this is a debatable issue. Here are the pics of some polished ones..

(INFO: these are not MINE, they are just copy-paste from other places)

and E4300
*i135.photobucket.com/albums/q148/JAFFA22/lapski.jpg

and E6400
*img412.imageshack.us/img412/8751/cam0756eh4.jpg

I personally believe the way darklord left it is better, for cooling purposes I mean.


@darklord
dude, what are the clock/voltages/temps on ur E4300.

 

[darklord]

@ Kniwor -
Clock - 3GHz
Volts - Dont remember Board is dead and gone for replacement
Temps : Idle - 28-30C Full Load - 36-37C

@ gan12320021
Also its not like i COULDNT give the mirror finish Point is it doesnt help much other than giving you bragging rights to show your lapping prowess. Keeping it a bit on the rougher side gives excellent results. Mirror finish spreads the Thermal paste,rather it should fill the microscopic gaps.
The main intention of lapping should always be to make the IHS FLAT and not mirror polish it.