General guidelines for heat sink design

Design of natural convection heat sink:

 The design of heat sink can make a preliminary design on the envelope volume, and then make a detailed design on the details of heat sink, such as fin and bottom size.

1. heatsink volume

2. Heatsink base thickness:

    A good bottom thickness design must be thinner from the heat source part to the edge part, so that the heat sink can absorb enough heat from the heat source part to quickly transfer to the surrounding thinner part.

3. Fin shape:

      The thickness of the air layer is about 2mm, and the fin spacing needs to be more than 4mm to ensure smooth natural convection. However, it will reduce the number of fins and reduce the area of heat sink. 

   When the fin shape is fixed, the balance of thickness and height becomes very important, especially when the fin thickness is thin and high, it will cause difficulties in heat transfer at the front end, so that the efficiency of the heat sink can not be increased even if the volume increases.

Forced convection heat sink design:

1. Increasing the air flow rate is a very direct method, which can cooperate with the fan with high wind speed to achieve the purpose.

2. The straight fin is cut into several short parts by cross cutting, which will reduce the heat dissipation side, but increase the heat conductivity and pressure. When the wind direction is uncertain, this design is more appropriate.

3. Needle fin design needle fin heat sink has lighter and smaller n points, higher volume efficiency and, more importantly, equal directivity, so it is suitable for forced convection heat sink。

Heatsink design points:

1. The larger the surface area, the better the heat dissipation effect.

2. If the heat sink is placed in favor of air circulation, the thermal performance  can be improved.

3. Copper and aluminum have high heat conduction efficiency and are the first choice of heat dissipation materials.

4. Increasing the thickness of the heat sink is more effective than increasing the length.

5. Surface anodizing treatment can resist oxidation and corrosion, improve radiation capacity and stabilize heat dissipation effect

6. The production cost and practicability of processing.

Heatsink design steps:

1. Make the outline drawing of  heatsink is designed according to relevant constraints.

2. According to the relevant design criteria of the heatsink , the fin thickness, fin shape, fin spacing and substrate thickness of the heatsinkare optimized.

3. Check and recalculate, do necessary thermal simulation if possible.