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1. Material selection: balance between high thermal conductivity and heat resistance
1.1 Aluminum alloy material
Aluminum alloy has become a common material for micro motor shells due to its good thermal conductivity, light weight, corrosion resistance and easy processing. In particular, certain specific types of aluminum alloys, such as 6061-T6 aluminum alloy, have a thermal conductivity coefficient of up to about 200W/mK, which is much higher than ordinary steel. It can more effectively conduct the heat generated inside the motor to the surface of the shell, and then dissipate it through air convection or radiation.
1.2 Copper material
Copper has more superior thermal conductivity, and its thermal conductivity can reach more than 400W/mK, which is more than twice that of aluminum. However, copper is more expensive, has a high density and is difficult to process, so it is rarely used alone in Micro Motor Shell. However, it can be considered to use copper inserts or coatings in some key heat dissipation parts to improve local heat dissipation efficiency.
1.3 High thermal conductivity plastics
With the development of materials science, some high thermal conductivity plastics have also emerged. These plastics improve their thermal conductivity by adding thermally conductive fillers (such as graphite, carbon fiber, etc.). Although their thermal conductivity coefficient is still lower than that of metal materials, they have the advantages of light weight, good insulation, and easy processing and molding. They can be used as an alternative in some micro motors that require weight and insulation.
2. Material treatment: improving thermal conductivity and mechanical strength
2.1 Surface treatment
Surface treatment of metal shells, such as anodizing, sandblasting, electroplating, etc., can not only improve the corrosion resistance and aesthetics of Micro Motor Shell, but also improve its thermal conductivity to a certain extent. In particular, anodizing can form a dense aluminum oxide film on the metal surface. This film not only has good insulation, but also increases the contact area with the air through the microporous structure, thereby improving the heat dissipation efficiency.
2.2 Heat treatment
Heat treatment of metal shells, such as quenching and tempering, can adjust its internal structure, improve hardness and wear resistance, and also help improve its thermal conductivity. However, it should be noted that the heat treatment process may have a certain impact on the dimensional accuracy and shape stability of the shell, so it needs to be strictly controlled during the processing.
III. Material combination: achieving multifunctionality and heat dissipation efficiency improvement
3.1 Metal-plastic composite materials
The combination of metal and plastic can make full use of the advantages of both. For example, a layer of high thermal conductivity plastic is injected on the metal shell, which can not only maintain the high thermal conductivity of the metal, but also take advantage of the light weight, insulation and easy processing of the plastic. This composite shell has a good application prospect in micro motors.
3.2 Multilayer composite materials
Through multilayer composite technology, different materials are superimposed in a certain proportion and order to form a shell with excellent heat dissipation performance and mechanical strength. For example, a metal layer with high thermal conductivity can be compounded with a ceramic layer with a low thermal expansion coefficient to improve the thermal stability and heat dissipation efficiency of the shell. However, it should be noted that the processing cost of multilayer composite materials is high, and the processing accuracy and process requirements are also high.
IV. Precautions for material selection and optimization
4.1 Cost considerations
When selecting and optimizing the shell material, the cost factor needs to be fully considered. Although metal materials with high thermal conductivity have good heat dissipation effects, they are expensive; while plastic materials have low costs, but their thermal conductivity is limited. Therefore, it is necessary to comprehensively consider cost-effectiveness while ensuring heat dissipation efficiency.
4.2 Processability Considerations
Different materials have different processing difficulties and processing costs. For example, aluminum alloys are easy to process and form, but they are prone to burrs and deformation during cutting; copper materials are difficult to process due to their high hardness. Therefore, when selecting materials, it is necessary to fully consider their processing performance and processing costs.
4.3 Compatibility Considerations
When selecting the shell material, it is also necessary to consider its compatibility with other components inside the Micro Motor Shell motor. For example, the metal shell may affect the electromagnetic field inside the motor; while the plastic shell needs to consider whether its insulation performance and temperature resistance are consistent with the motor requirements.
