Brazing-The next level in making waterblock |
Aug 10, 2006 |
How to manufacture a reliable waterblock
After several years of research and development, liquid cooling is
finally being accepted in the mainstream gamers and manufacturers.
However, liquid cooling is still not to be taken lightly as it is extremely
difficult to create a constant leak-free liquid cooling system that is still
able to keep the manufacturing cost low enough for the average
consumer to buy. We will introduce to you the technology Thermaltake
uses to manufacture our waterblocks that are safe and reliable.
CPU Waterblock Brazing Process
The average waterblock on the market are usually soldered. Soldering
temperature is usually between 200 to 350℃, which is also called
low temperature welding. We consider tin soldering on waterblocks
are very inappropriate since the internal temperature of the waterblock
will slowly corrode the soldering over time, inducing a leak in the
future. For this reason, Thermaltake chooses to use welding with
copper material that contains 5% to 15% silver. The welding temperature
of the material is between 705 and 850℃ and is called brazing, also
known as high temperature welding. Brazing features both excellent
mechanical and chemical properties, thus is very reliable. Users will
be able to use brazed products in their computer systems without
having to worry about leaks over long periods of time.
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Usually, when designing
a waterblock, we separate
the waterblock into a top
and a bottom portion.
The bottom portion is
the part that makes
contact with
the CPU
surface and
transfers
the most
heat.
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Before brazing, there is need for a set of fixture
to contain all parts and their relative position.
The fixture should be made of stainless steel or some kind of high temperature-resistant material
to prevent the fixture from deforming during
the high-temperature process. If the fixture
deforms, the product is ruined
and the fixture is also ruined. |
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Put the top and bottom portion of waterblock on the
fixture and position the welding material around its
four edges. The melted welding material will then
join the top and bottom portion of waterblock by
capillarity and complete the welding process.
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Next, we adjust the temperature inside the
oven. Normally, we would have a preset
temperature, and the temperature is usually
set at 50 to 80℃ below the welding
temperature.
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Here are the specifications of
the brazing oven:
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1. Total length: 18 meters
2. Five segments of heat preparation,
highest temperature is 1050℃
3. Adjustable belt speed,
highest tread
speed
570 mm/min
4. Gas used: 75%H2+ 25%N2 |
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We carefully place the
mold and prepped product
onto the conveyer belt,
thetemperature inside the
oven is now around 705
to 850℃
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The time it takes for the product to complete brazing
process is about one hour. The fixture and product
is still at high temperature during this stage
and takes about 1 hour to cool down to
engage in the leak testing.
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Leak Testing
After the brazing process, materials will have some minor changes which would
increase perforations significantly. If the perforations are too big, liquid may leak
through them, thus we use compressed air to test the product. |
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The leak detector is shown at left.
The green container contains approximately
1.2Mpa of air pressure. The transparent obser
vation cylinder is the device to check if there
are leaks.
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While controlling the pressure, we usually set
between 2 to 3 kilograms (or 0.2 to 0.4 Mpa)
of pressure. According to statistics, the pressure
on fluid of liquid cooling systems in computers is less than 1.0 kilograms, so we
use higher pressure during testing to ensure the waterblock does not leak during
regular usage.
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The compressed air is injected into one side
of the roduct, and the other side of the
waterblock is sealed off to prevent air leak.
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If the product has holes or was not welded
properly, the transparent cylinder will have
a bubble inside as shown at right:
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After testing, if the product is not good, we will choose to re-brazed the unit.If the unit is still not good, we will scrap
the unit to ensure the quality of waterblock we deliver.
Brazing process is being used on the following products:"Silnet Water"、"Tide Water"、"Tide Water Plus"、
"Symphony"、"Symphony mini"、"Rhythm".
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