The design of heat sink is the most important determinant of the heat dissipation efficiency of heat sink. From the perspective of heat dissipation process, it is generally divided into three steps: heat absorption, heat conduction and heat dissipation. Therefore, the heat sink design should start with these three steps to improve the performance of heat absorption, heat conduction and heat dissipation respectively, so as to obtain a better overall heat dissipation effect. The manufacturing material of the heat sink is an important factor affecting the efficiency, which must be paid attention to when selecting, but the material of the heat sink cannot determine its overall performance. The real essence of improving the performance of the heat sink is product design.
The Design Principle of Heat Sink
When designing the heat sink in electronic products, it is the most common way to use thermal resistance to design. The definition of thermal resistance is: R=△T/P.
△ T means temperature difference, while P represents the heat consumption power of the chip. Thermal resistance represents the difficulty of heat transfer of the device. The larger the value, the worse the heat dissipation effect of the device, and the smaller the value, the easier the heat dissipation.
The General Design Guidelines of Heat Sink
1. Volume design of heat sink
Volume of heat sink means the volume occupied by heat sink . Generally speaking, the larger the heating power of electronic products is, the larger the volume of heat sink required. In the process of heat sink design, preliminary design can be carried out according to the volume.The relationship between heating wattage and volume is shown as follows: LogV=1.4 X IogW-0.8, in which, The minimum value of V is 1.5 cubic centimeters.
2. The thickness design of the bottom of the heat sink
In the design process of the heat sink, its bottom thickness has a great impact on the heat dissipation efficiency. In order to make the heat energy can be transmitted to all fins, it is necessary to ensure that the bottom of the heat sink is thick enough, so that the fins can be fully used. However, the thickness of the bottom is not the thicker the better. If it is too thick, it will cause greater material waste, increase costs, and at the same time, it will cause heat accumulation, reducing the heat transfer capacity. When designing the thickness of the bottom of the heatsink, the heat source part should have a thicker thickness, while the edge part should be thin, so that the heat sink can quickly absorb the heat near the heat source, and transfer it to a thinner area to achieve fast heat dissipation. The relation between heat dissipation wattage and bottom thickness is as follows: t=7xlogW-6.
3. Fin Shape Design of heat sink
Inside the heat sink, heat transmission is mainly carried out by convection and radiation, of which convection accounts for a large proportion. Based on this nature, three aspects should be considered in the design of fins: first, the fin spacing design. To ensure smooth convection between fins, the spacing should be kept above 4mm, but it should not be too large. Too large will reduce the number of fins that can be set, which will affect the area of heat dissipation, The effect of heat dissipation is affected. Secondly, the angle design of the fin, the fin angle is about three degrees, the better. Finally, after determining the thickness and shape of the fin, the balance of its thickness and height becomes very important.
Except above heat sink design guidelines, When encountering specific projects, we need specific analysis and flexible use of technical knowledge to supply high efficiency heat sink
Heat sink Design Expert ︱Famos Tech
Famos Tech specialize in metal heat sinks R&D,manufacturing,sales and service for over 15 years, have rich experience from design ,prototype, test to mass production. so far, we have more than 50 engineers and 10 thermal solution experts, total 465 stuff working in our factory, we provide LED heat sink, CPU heat sink and other electronic industry extruded heat sink, die casting heat sink, skived fin heat sink etc various heatsinks for domestic & overseas customers.
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Types of Heat Sink
In order to meet different heat dissipation requirements, our factory can produce different type heat sinks with many different process, such as below:
Post time: Jan-09-2023