In the design of multi-layer insulation components (MLI) for spacecraft, the thickness of each layer of material directly affects the weight budget of the entire satellite. Traditional MLI uses a 25 μ m or thicker aluminum coated PI film as the reflective layer - reliable in performance but substantial in weight.

If the substrate thickness is reduced from 25 μ m to 12.5 μ m, the amount of polymer material used can be reduced by about50%For a satellite containing dozens of layers of MLI, this weight reduction is quite significant.

2、 Why 12.5 μ m: The 'Golden Thickness' in Aerospace and Electronics

In the product spectrum of PI aluminum plated film, commonly used thicknesses include 7.5 μ m, 12.5 μ m, 25 μ m, 50 μ m, 75 μ m, 125 μ m, etc. The reason why 12.5 μ m has become one of the most widely used specifications is due to its comprehensive advantages in multiple engineering dimensions:

3、 Vacuum evaporation: "growing" optical grade aluminum layer on 12.5 μ m substrate

The aluminum layer preparation of 12.5 μ m PI aluminum coating film adopts vacuum evaporation process - in a vacuum environment, high-purity aluminum wire or aluminum block is evaporated into gas by heating, and then deposited on the surface of PI film to form a coating. This process requires precise control of multiple parameters on a 12.5 μ m substrate:

Process maturity:Compared to 7 μ m ultra-thin substrates, 12.5 μ m substrates have higher mechanical strength and heat capacity, better tolerance to temperature and tension waves, easier guarantee of aluminum layer uniformity and adhesion, and high stability in mass production.

4、 Aluminum layer thickness: performance span from 0.1 μ m to 1 μ m

Based on a 12.5 μ m PI substrate, aluminum plated film products with different aluminum layer thicknesses can be prepared by precisely controlling the evaporation process parameters. The thickness of the aluminum layer varies from 0.1 μ m to 1 μ m, and different thicknesses correspond to different performance focuses:

Note: The thickness of the aluminum layer is the nominal reference value, and the specific performance is subject to the actual product specifications.

5、 Key performance: 12.5 μ m specification technical foundation

6、 Three major application scenarios: from spacecraft to precision optics

7、 Selection considerations: from aluminum layer thickness to application scenarios

8、 Conclusion

The essence of 12.5 μ m PI aluminum plated film is to find the optimal balance between the lightweighting and processability of PI film as an engineering product. It is not the thinnest or thickest, but it is the most universal choice for high-end applications such as aerospace thermal control, flexible shielding, and precision optics: capable of meeting the performance requirements of extreme space environments, supporting the bending needs of flexible circuits, and maintaining high yield in mass production.

For engineers, understanding the engineering logic behind the thickness of 12.5 μ m - why it is 12.5 instead of 7 or 25- is more valuable than simply remembering a specification. On this thickness platform, customizing products with different properties by adjusting the thickness of the aluminum layer (from 0.1 μ m to 1 μ m) is a key step in transforming "standard thickness" into specific engineering solutions.