Scraper plate as an overclocker tool

This cruel world of thermal chaos

We live in the computer world, and modern electronics in terms of silicon "brains" is quite a warm thing - the processors heat up mercilessly, both basic and specialized, for example, GPUs. In every electric product there are passive radiators and if a lot of heat needs to be dissipated, then fans too.
As you know, electrical engineering is the science of contacts. It is also possible to say that heat engineering is also the science of contact, of thermal contact and transfer of heat from warm to cold through convection and / or radiation. But we will not go into this, let's talk about a specific solution aimed at reducing the overheating of equipment and the accompanying noise from active air-cooling systems in a metal-to-metal pair.

What is a radiator or a little tediousness

This is a plate of heat-conducting material with a developed surface, tightly attached / pressed to the heat source and having quite measurable parameters - fins and thermal conductivity. The more edges there are, the greater the area of ​​contact with the air, the edges can be “partly” expressed to a certain extent through cunning equations with Reynolds numbers, the concepts of “laminar” and “turbulent” flow, “surface layer”, etc. Next - the air "stuck" and does not cool.

Do not delve into it, in a nutshell - the radiator has a power dissipation limit and can be increased by replacing the material with a more thermally conductive (silver or gold for example) or blowing a radiator with a fan. For some reason, the second option got accustomed more for some reason, this is an active air cooling system.
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So what?

But the cooling of the radiator itself is not our goal. The goal is to pick up heat from the heat source (transistor, microcircuit, processor), heat the radiator and effectively dissipate it in the surrounding air. And the bottleneck in this chain is the contact of the radiator with the heat source.
Ideally, a heat source with a radiator is an inseparable piece of metal, but not always so for obvious technological reasons.
Usually there is a source and a radiator, and they are connected by a point of thermal contact, and we consider this option.
Ideally, two carefully treated surfaces are tightly pressed together and exchange heat well.
In practice, this is unattainable, since to make two surfaces with a cleanliness class of at least 10 is hard and expensive, the silver radiator looms again on the horizon.
In addition, it is necessary to ensure perfect horizontal surfaces, which is also not easy, and the radiator becomes gold.

There is a solution!

This thermal paste, a special case of a thermal interface, is a fine (and even nanodispersed) mixture of highly heat-conducting material in a weakly evaporated liquid such as oil or special glue that hardens from heat or simply from contact with air. This paste is placed between the heat source and the radiator and fills surface irregularities, increasing the area of ​​thermal contact, which is extremely positive for heat exchange.
It is quite obvious that the best paste layer is zero thickness, as it was written above, but we are in the real world and get quite acceptable results with inexpensive surface treatment and average consumption of thermal paste.

And what is number 2?

Perfectionism does not give rest, I want to achieve even better heat exchange, if only because, as a rule, the command to “add turns and noise” gives the fan the built-in temperature sensor of our mini-stove. Reducing the loss in transmission-> more heat goes to the radiator and dissipates-> "stove" feels comfortable -> "fan - do not turn" - something like this train of thought. The emphasis is, of course, on the quality of the contact surface from the radiator, there is not much point in improving the rather high-quality surface of an expensive chip, and there is a loss of warranty ...
Looking at the bottom of a typical CPU radiator like Intel or AMD, we understand that you have to pay for everything, and the surface often has traces of mechanical processing, usually these are traces of the cutter are cylindrical, butt-shaped, or even concentric, and their depth drives into a spline. They look accordingly as parallel stripes, parts of arcs and as concentric circles with a clear center in the center of the radiator.
Get rid of this can be a few available "on the knee" ways.

Grinding

We take a hard, flat surface - usually a sheet of high-quality glass; on it we put a sheet suitable for the scale of irregularities of the emery paper with the working layer upward and above we begin to rub the radiator foot, painting all sorts of chaotic shapes, such as rays of the sun. In process of obtaining result we change an emery paper on smaller up to the smallest that exists. Details and nuances of this action are repeatedly painted on the web.
This method works, the result is. But there are difficulties with the execution, namely:

• it is difficult to withstand the randomness of the movements - we get irregularities, replicas
• it is not easy to have an equal clamping force when changing the direction of the radiator movement; a feature of the structure of the arm muscles
• It is very easy to “fill up the edges”, make a lump in the center and rounded edges - for the previous reason
• there are radiators where one simply does not physically get into the glass and sandpaper (see below)

As a result, the surface, although it will glitter, will not be even in geometrical terms. Persistent workouts can improve performance, but why? There is no goal to grind radiators all my life.

Scraper plate processing

The scraper plate is a hard alloy plate (usually based on tungsten carbide) with a very accurate geometry.
It came to me as a random gift, in her life she can perfectly sharpen all the knives, scissors, scrape something from the metal and until she could find something she cannot handle. For a couple of years did not even dulled in any way. It has a smooth surface, quite weighty for its size. Pay attention - the form is not a pure square, not only are the two sides convex, and one is asymmetrical, this is a marriage of a concrete plate, it should be symmetrically semicircular from 2 sides to produce rough metal works similarly to the wood floor tile. We will use straight edges as a tool for finishing the surface of the radiator.

Usage example

The first patient is the Radeon 6950 graphics card, it makes noise, overheats, and performs the thermal throttling trick, that is, it just dies from the GPU overheating. The temperature of the chip under load exceeds 100C °, and it is also unsweetened to idle time - about 60C °. We disassemble the video card, and we see quite a composite radiator with heat pipes, it looks decent and neat, it only confuses the dark spot in the center.

Take the plate at an angle of about 30 ° to the radiator and make the first movement. Yes, somehow not very surfaced, it is necessary to correct, it immediately became clear what the stain was and where it came from. Using movements as with sandpaper, we smoothly draw the surface into a much smoother state in a fairly reasonable time. It is a pleasure to plan copper and aluminum with a scraper plate - it is just like using a penknife to scrub a branch, it’s just inconvenient to hold with your fingers, it’s not easy to hold the right angle.

The pressure must also be selected, with a strong plate, it is easily buried in the metal, the movement of the hand continues, an ejection from the fossa follows and again buried, and so on, a jerky movement is obtained and the surface is notched at all. Also, do not forget about the same point of copper and aluminum so that copper does not "dig" a hole. This is just the promised case where sandpaper is not to fall from behind the racks, and even if, then “filling up” the surface is easier than ever.

Sharpen ...


Sharpen ...


And finally!


As already said, in order to avoid “burying” in the place of the chip, one should not be lazy, scrape wider and not be modest. Extreme tool movements should be done easily and fully, it gives the desired evenness and fine processing pattern. For aesthetes, you can make a couple of passes with sanding-out “nulevka” + GOI paste, tried it, the result is a mirror, but not every paste will take it and stick to this surface like this.

According to the results of the assembly, the temperature in idle time dropped to ~ 45 ° C, did not rise under load above 87 ° C. The goal is achieved.

Example 2

One of the subsequent patients was a tower radiator from the manufacturer with blue propellers, cost was not too low, but had completely indecent traces of face milling, over which they were boldly coated with chrome, which of course did not save from incomplete adhesion to the AMD top processor. The cutter pattern, decorated with thermal paste, looked distinctly and shameless on the radiator removed.

It is necessary to correct.

Chrome was removed for a couple of dozens of movements, and the very first movements on bare copper showed a characteristic “cushion” that arose as a result of tightening the bolts for contacting the sole and heat pipes. Shaberil as in the first case. There are scratches visible on the heat pipes - the scraper is a very sharp instrument, it just jumped off a couple of times. Although they did not cut themselves.

This is an intermediate result, the final photo, unfortunately spoiled on the memory card, turned out very well and smoothly at the end. The radiator was installed and tested, the result is a temperature drop of 10-13 degrees when the processor is fully loaded.

findings

• Chipping at home works
• The procedure is simple and reproducible.
• There are measurable work results
• It became quieter
• Reduced consumption of thermal paste =)

Minuses:

• inconvenient to hold the scraper plate
• the processing area is small, the processing technique is required, you can certainly buy a scraper wider, but universality is lost, it pulls a set of such plates

Yes, and where does overclocking?

Although the story about the air radiator, this technology was successfully applied to the NWO, and then a friend did not hesitate to overclock and was glad to gain something about 2% in performance. Trifle, but nice. Against the background of total costs, the scraper plate came out at a price like a meter of tuned water hose.

I struggled with the noise and for the stability of the work and I succeeded.