Show us your IHS with a large dollop of lapping

[Justintime]

LOL

 

[xolotl]

What I never got with lapping was the obsession with shiny.

You want it flat, and unless you have it properly set up in a jig lapping by hand ain't going to do this.

The whole point of thermal compound is to fill in the minute imperfections in the two contact surfaces.

Flat is good, shiny is irrelevant.

 

[Justintime]

What I never got with lapping was the obsession with shiny.

You want it flat, and unless you have it properly set up in a jig lapping by hand ain't going to do this.

The whole point of thermal compound is to fill in the minute imperfections in the two contact surfaces.

Flat is good, shiny is irrelevant.

Well.. i've seen as much as 8C difference in the past after a good lapping, so shiny it was but it performed good too.

 

[Jleo]

What I never got with lapping was the obsession with shiny.

You want it flat, and unless you have it properly set up in a jig lapping by hand ain't going to do this.

The whole point of thermal compound is to fill in the minute imperfections in the two contact surfaces.

Flat is good, shiny is irrelevant.

Shining with a lapping/cutting paste not a household wax polish LOL

HS 1
A flat and shining surface = near scratchless surface = less TIM needed = more metal to metal contact = better heat absorption = better heat dissipation = efficient

HS 2
A flat surface that doesn't shine = more scratches = more TIM needed = less metal to metal contact = less absorption = less dissipation = less efficient

 

[fornowagain]

This always makes me laugh. From an Engineering Metrology point of view surface waviness is in the order of a 1000 times more important for contact than roughness.



You not going to get a HSF really flat by hand lapping, flat is a surface grinder with a fine wheel and a micron scale. Hand lapping would need a jig to keep it square for a start. Hand lapping, assuming you don't make it worse (the times I've seen "use a figure of eight motion" give me a break), is improving the horrible (milled) surface that a lot of these firms think is acceptable. "Shiny" means absolutely nothing if its not flat.

 

[Justintime]

Wow now the big time experts have spoken, i must have imagined all of those C drop in those chips and sinks i've occasionaly lapped over the yrs, silly me.

 

[Jleo]

This always makes me laugh. From an Engineering point of view surface waviness is in the order of a 1000 times more important for contact than roughness.
You not going to get a HSF really flat by hand lapping

I am glad I don't have to. I only lap to get rid of the rough surface I have to rely on the HS manufacturer to have a least made it near flat to start with

This always makes me laugh. From an Engineering point of view surface waviness is in the order of a 1000 times more important for contact than roughness

This wouldn't be laughable if the engineering application required the to surface's to stay together from a structural pov. Its is more effective to have gripping surfaces than smooth surfaces, blimey can you imagine the London Eye/Eifel Tower constructed with flat shiney surfaces on all the ajoining beams/supports, we would never have seen it in its upright glory my apologies if I am stating the obvious
Did you ever see a new pair of vice grips with flat shiney jaws? hehehe

Edit
How can this be I have seen the iron/steel being smelted/produced what is done to it to determine either finish?

 

[fornowagain]

I am glad I don't have to. I only lap to get rid of the rough surface I have to rely on the HS manufacturer to have a least made it near flat to start with

Thats correct and milling is anything but flat. Annoys the hell out of me why they dont grind them in the first place, should have seen this Tuniq.

This wouldn't be laughable if the engineering application required the to surface's to stay together from a structural pov. Its is more effective to have gripping surfaces than smooth surfaces, blimey can you imagine the London Eye/Eifel Tower constructed with flat shiney surfaces on all the ajoining beams/supports, we would never have seen it in its upright glory my apologies if I am stating the obvious
Did you ever see a new pair of vice grips with flat shiney jaws? hehehe

For a friction surface the Ra is the defining factor, the surface flatness is just as important if not more so. An example is a contact surface that is ground flat then knurled to create grip. Vice grips are hardly an example for a flat application and yes I've seen smooth jaws, there used for holding ground stock.

How can this be I have seen the iron/steel being smelted/produced what is done to it to determine either finish?

Normal stock is rolled, its as rough as ar**hol**. You can buy smooth, its actually described as ground stock from the stockist. Its ground on the biggest surface grinder you can imagin I've seen it at work. There are thousands of specifications for surface finish, fits and tolerances. It a large part of Engineering.

 

[mrthingyx]

Wow now the big time experts have spoken, i must have imagined all of those C drop in those chips and sinks i've occasionaly lapped over the yrs, silly me.

Or maybe your heatsinks just needed remounting?

I work as a surface engineer so all of you who are worried about your surfaces being flat, send the heatsinks to me.

I'll use my profilometer to measure their surface roughness and draw you a nice Excel graph to show you how flat they are prior to machine polishing down to a finish of your choice (120micron ---> 1/4 micron and even further (no visible scratches at 4000x magnification under an electron microscope)) and provide you with another Excel plot that shows the difference.

 

[fornowagain]

I'll use my profilometer to measure their surface roughness

I used to work with Renishaw and helped design the first gen of Nikon non contact CMM's. Does that use Ruby/Diamond probes like a Talysurf or is it non contact?

 

[fornowagain]

Wow now the big time experts have spoken, i must have imagined all of those C drop in those chips and sinks i've occasionaly lapped over the yrs, silly me.

Yes, silly you.

You may improve it, but it's not flat. An machining deviations on the surface will be reproduced. Back in the day, I often lapped precision tools for a few microns and it needs a jig and a granite or cast iron table. Hand lapping produces pressure differences and curves the edges something awful. There is a difference between flat and flat enough. My point is, don't worry about shine, get it flat first.

If you want to hand lap, use a mirror, glass is often made by passing through rollers and is not flat. Float (windows, mirrors) glass is best, its made by floating on a molten lead surface and is flat ish. Let gravity do the work, try not to apply pressure, you can't hold it flat. Only move in one direction for a set number of times then rotate 90 degs, don't figure of 8. And don't use lapping polish to get a shine, it'll move to the suface depressions and just makes it deeper. Use a finer and finer fixed abrasive, wet and dry, and clean off the loose grit often. Keep going till its shiny if you can, but it takes ages and it should if your doing it right. I use a finishing stone that can bought for a few quid and is very flat, couple of passes with that does wonders.

 

[Jleo]

Normal stock is rolled, its as rough as ar**hol**. You can buy smooth, its actually described as ground stock from the stockist. Its ground on the biggest surface grinder you can imagin I've seen it at work. There are thousands of specifications for surface finish, fits and tolerances. It a large part of Engineering.

Good to know, my general engineering knowledge never required that depth, but I can see the relevance to more aesthetically eye pleasing engineering projects. My Leatherman for example cool piece of engineering never get tired holding it and looking at it even use it the odd time too Does that sound insane

 

[Jleo]

I used to work with Renishaw and helped design the first gen of Nikon non contact CMM's. Does that use Ruby/Diamond probes like a Talysurf or is it non contact?

Okay the rows out, he just used 5 words/terms that I didn't understand. LOL

 

[mrthingyx]

I used to work with Renishaw and helped design the first gen of Nikon non contact CMM's. Does that use Ruby/Diamond probes like a Talysurf or is it non contact?

The one we have is a diamond Talysuf thingy, although we've also got a 3D laser one (I have to have a good reason to use it... ).

 

[fornowagain]

The one we have is a diamond Talysuf thingy, although we've also got a 3D laser one (I have to have a good reason to use it... ).

The last one I was involved with the chassis was made of an incredibly stable composite aggregate material. Used lasers and optics to get in the nano range and the lab had to be held at +-1C, breathing on a componet can change it. It was used for anything from Rolls Royce engine parts to hedge shears, I kid you not.

 

[Jleo]

The last one I was involved with the chassis was made of an incredibly stable composite aggregate material. Used lasers and optics to get in the nano range and the lab had to be held at +-1C, breathing on a componet can change it. It was used for anything from Rolls Royce engine parts to hedge shears, I kid you not.

I've came across that, here is a very similar version I think it was made by Blourown a German company Click here [right click and select open]

 

[Justintime]

Yes, silly you.

You may improve it, but it's not flat. .

And thats all i was hoping to do, never said it was purely flat or that i had the machinery to do it, sometimes the sinks or IHS is totally off and a little lapping helps a lot.

 

[Justintime]

Or maybe your heatsinks just needed remounting?
.

Funny, it constantly gave good results after the lapping whilst no matter how many times pre-lapped it was mounted it gave the same hotter result. I'm not a big lapper but have tried it over the years and its shown results, but as always there'll be detracters to a theory and expert opinions from various people etc.. thats y'alls belief and i won't disagree with you, you got your opinion and i gots mine Moot point about IHS lapping, i usually just pop it off these days.

 

[Jleo]

And thats all i was hoping to do, never said it was purely flat or that i had the machinery to do it, sometimes the sinks or IHS is totally off and a little lapping helps a lot.

Agree, my Scythe Ninja had a very defined rippled milled finish, it is no more

 

[fornowagain]

Funny, it constantly gave good results after the lapping whilst no matter how many times pre-lapped it was mounted it gave the same hotter result. I'm not a big lapper but have tried it over the years and its shown results, but as always there'll be detracters to a theory and expert opinions from various people etc.. thats y'alls belief and i won't disagree with you, you got your opinion and i gots mine Moot point about IHS lapping, i usually just pop it off these days.

Its not a belief, I've actually stuck my hand lapped heatsinks on very expensive metrology machine and been surprised just how bad my efforts have been. I've posted what I've found to be the best techniques up above. A bad hand lapping can make it worse very easily.

And I'd like to see you pop off a conroe IHS, well maybe with a blow torch.