Heat sink
Heat Sink Manufacturing – Custom Aluminum & Copper Heatsink Solutions
What is a heat sink?
Heat sink is a kind of heat dissipation device for the electronic components in electrical appliances, mostly made of aluminum alloy, brass or bronze plate, fin, multi-fins and so on. Commonly used heat sink material is copper and aluminum alloy, both have their advantages and disadvantages. Copper conducts heat well, but it is expensive, difficult to process, heavy (many pure copper heat sinks exceed the weight limit of the CPU), small in heat capacity, and easy to oxidize. Pure aluminum is too soft to be used directly. For ordinary users, the use of aluminum heat sink is enough to meet the heat dissipation needs.
Heat sink material
Heat sink material refers to the specific material used by heat sink. As for the heat sink material, the thermal conductivity of each material is different. The thermal conductivity is arranged from high to low, namely silver, copper, aluminum and steel. But silver would be too expensive to use as a heat sink, so copper is the best solution. Although aluminum is much cheaper, it clearly does not conduct heat as well as copper (about 50% as well). At present, the most commonly used heat sink material is mainly copper and aluminum , both have their advantages and disadvantages. Copper has good thermal conductivity, but it is very expensive and difficult to process, too heavy (many full copper heatsink exceed the weight limit of the CPU), small in heat capacity, and easy to oxidize. While pure aluminum is too soft to be used directly, only the aluminum alloy used can provide enough hardness. The advantage of aluminum alloy is low price, light weight, but the thermal conductivity is much worse than copper. Some of the heat sink make good use of each strength, in the aluminum heat sink base embedded a copper plate.
How does heat sink work?
1. Heat absorption — absorb heat from hot objects with small volume and area, so that the temperature will not rise sharply due to heat accumulation, leading to various undesirable consequences
2. Heat conduction — transfer the absorbed heat internally to each part of the radiator, making full use of the large heat capacity and surface area
3. Heat dissipation — heat is lost to the air through various heat exchange channels on the surface (mainly heat convection) (forced convection with fans is possible)
Heat sink types
The heat sinks are classified into different categories depended on different criteria. the criteria include materal, manufacturing process, application, cooling medium, etc. Let us consider the major types, namely extruded heat sink, skived heat sink, heat pipe heat sink, folded fin heat sink, boned fin heat sink, active heat sink and passive heat sink, liquid cold plate. Heat sink can be manufactured in a variety of ways, depending on the required performance, cost and volume.
1. Aluminum extruded heat sink
Aluminum is an excellent heat dissipation material widely used in modern heat dissipation. Most of the industry uses 6063 T5 high quality aluminum, which purity can reach more than 98%. It has high thermal conductivity ability, low density and low price, so it is favored by major manufacturers. According to the thermal resistance value and heat value of Intel and AMD cpus, aluminum extrusion manufacturers formulate the corresponding mold, the aluminum ingots are heated to a certain temperature, so that its physical shape is changed, and then out of the mold to get all kinds of original heat sink material we want; It can be used for cutting, cutting, cutting, polishing, deburring, cleaning, surface treatment.
2. Aluminum skived heatsink
Although from the heat dissipation area to solve this kind of aluminum extrusion can not achieve the effect, but now the precision of the mold directly affects the heat sink overall shape and heat sink perfermance.Therefore, cgcooler is the heat sink manufacturer who began to think of use of mechanical precision machining cutting tool to cut into pieces of aluminum ingots directly to the shape we want, so will not appear in the process of machining deformation, won’t make various impurities in the process of aluminum extrusion into the heat dissipation, also enables us to maximize heat dissipation area.Skived heatsink breaks through the limitation of the thickness and length ratio of aluminum extrusion heat sink and can produce high density heat sinks. Blade and base are one body, without any interface impedance problem, heat dissipation effect is very good, widely used in photovoltaic industry, electric vehicles, inverters, communication products and so on.
3. Copper skived heatsink
Aluminum extruded heat sinks that have been used for so long, no matter how to change our processing technology, it is difficult to meet the increasing CPU heat, Some manufacturers have to spare no effort on cost, use copper instead of aluminum, Since the thermal conductivity of copper is much greater than that of aluminum, the thermal conductivity doubles, so It’s good for our cooling. However, copper is much harder than aluminum, so in the process of processing, for the process is a severe test. So the traditional extrusion molding process can not be applied to copper, and have to adopt the skived fin process to cut the copper. So the copper skived heatsink widely used in the high power product, get the wide range of praise from customers.
4. Heat pipe heat sink
5. Active heat sinks
Active heat sinks are generally fan type and utilize power for cooling purpose. They can also be termed as Heat sink wih fans. The heat sink fans are further classified as ball bearing type and sleeve bearing type. The ball bearing motor fans are preferred as their working span is longer and they are cheaper than orther fans, when it comes to a long span usage.The performance of these kinds of heat sink is excellent, but not for long term applications as they consist of moving parts and they are a bit expensive as well.
6.Passive heat sinks
Passive Heat Sinks do not possess any mechanical components and are made of aluminum finned heat sink. These dissipate thermal energy or heat by using the natural convection process. Passive heat sinks are most reliable than the active heat sinks; and, for more efficient operation of passive heat sinks, it is recommended to maintain continuous air flow across their fins.
6. Aluminum die cast heat sink
Although extruded aluminum heat sink price is low, the manufacturing cost is low, but its the limits due to the soft quality of a material of aluminous material itself, his fin thickness and the ratio of the height of the fins is generally not more than 1:18, so heat sink manufacturer for heat dissipation area is increasing, and the heat dissipation space unchanged, under the requirements of heat sink manufacturers put forward a more suitable solution, encryption fins, so as to increase the number of fins; Bending fins to increase heat dissipation area; the aluminum ingots are heated from the solid state to the liquid state through the mold and then cooled to form the heat sink we want.
7. Aluminum, copper fold fin heat sink
One thing is worthy of our attention, that is, cost and profit is always pursues the ultimate goal, so cgcooler began to come up with more optimized solutions, copper, aluminium material with folding way, made into various shapes heat sink we wanted , then it is soldering together with various heat sink base, which not only meets our requirements of heat dissipation, but also speeds up our production progress, making mass production easier
8. Copper-aluminum composite heat sink
The most perfect solution of this eclectic solution should be the copper-embedded technology provide by cgcooler. This is a harmonious combination of the advantages of fast heat conduction speed, high density and strong heat absorption ability of copper and the advantages of traditional aluminum extrusion type, such as light density, cheap price and convenient mass production.
CGcooler another solution is that change the bottom of the heat sink to copper base that touch the CPU, using copper characteristics of fast heat absorption and strong heat conduction ability, rapidly transfer a large amount of heat generated by CPU operation to a nickel plated copperbase. The copper base and the aluminum extruded heat sink are tightly combined with the heat conducting paste, which makes a large amount of heat energy rapidly spread to the aluminum extruded heat sink and be carried away by the rotation of the fan.
9. Bonded fin heat sink
In today when the heat dissipation requirements have been raised repeatedly, cgcooler bonded the thin and dense heat dissipation fin and heat sink bottom plate to with huge pressure. This technology can be used for arbitrary combination and collocation of copper and aluminum fins with copper and aluminum bases. And also effectively avoid defects in the welding process, various solder paste thermal conductivity is not balanced resulting in new thermal resistance. Allows customers to have more options and a variety of hot solutions.However, due to the particularity of its processing, the current mass production still has the problem of too high cost.
10. Water cooling heat sink & Oil-cooled heat sink
Water cooling and oil cooling are collectively referred to as liquid cooling, there are two types of circulation, one is the closed pipe circulation and the other is the open circulation using the reservoir. Liquid cooling is the same as heat pipe, which use intermediate flow to reduce temperature and heat. If water circulation is called water cooling, oil circulation is called oil cooling. Different substances used directly lead to different heat dissipation effects, heat release is better than oil, which is the same as aluminum and copper
The wate absorbs heat slowly and releases heat quickly, oil absorbs heat quickly and releases heat slowly, specific heat temperature depends on the temperature of water or oil temperature you use, If you put ice in the tank you can keep the temperature down.Liquid cooled heat sinks is also the first to bring CPU heat sink temperatures below room temperature. But need to pay attention to is: if the temperature of the circulation medium used is much lower than room temperature, then there will be air condensed water in the circulation pipeline, be sure to prevent its flow to the main board, or just wait to see the smoke.
The heat sinks cooling methods, principles and applications .
The traditional cooling mode is natural convection cooling, forced air cooling and water cooling. Fourier’s law of heat conduction states that if temperature gradient is present in a objects, then the heat will transfer from a high-temperature region to allow- temperature region. And, this can be achieved in three different ways, such as convention, radiation and conduction.
Natural convection cooling
Contact the heating core of the electronic components with the heat sink, and the heat is transferred through the natural convection of the air.
Natural convection cooling’s advantages are simple structure, convenient installation and low cost. Although its heat transfer performance is not as good as that of forced convection cooling. but natural convection cooling is one of the common cooling methods. It has been widely used in society due to its advantages of no additional energy supply, reliable and stable performance, high safety, no noise and low manufacturing cost
Forced air cooling
Contact the heating core of the electronic components with the heat sink,and transfer the heat out the heat sink，the fan is then rotated to increase the flow of air, transferring heat from the heat sink fins to the surrounding environment by forced convection.
Forced air cooling’s advantages are simple structure, low price, safe and reliable, mature technology. cgcooler has strengthened the research and development of the application of forced air cooling technology, and realized the application of forced air cooling for the wind energy converters, Suppressorsphotovoltaic inverters, Rectifiers, Regulator,SVG, Cpu and other high power product.The air cooling heatsink structions have high power skived heat sink with fan or high power skived heat sink with heat pipe, which can greatly improve the heat dissipation efficiency.
Luiquid cooling
Liquid cooling is through the structure of compact and relatively thin plate-like, strip metal internal layout of the fluid channel, so that the fluid and liquid cooling heat sink between the convection heat transfer.
Liquid cooling application refers to the use of liquid cooling plate (also known as water cooling plate) installed in the heat source, combined with heat exchanger and heat pump exchange, to dissipate heat in the way of fluid circulation. cgcooler has recently strengthened the research and development of liquid cooling technology, especially in the liquid cooling product production process innovation, makes the liquid cooling heat sink welding more stable, greatly reduces the liquid cooling heat sink leakage and other bad phenomena, improve the reliability of liquid cooling heat sink.
