Detailed explanation of millimeter wave radar housing plastic materials and how to weld them

With the development of science and technology today, millimeter-wave radar is the core sensor of automotive ADAS. It uses a plastic shell as the protective shell of ADAS. So what kind of plastics will be used for automotive millimeter-wave radar, and what is its welding method?

The basic structure of millimeter-wave radar includes radar antenna cover, electromagnetic shielding material, RF front end, antenna substrate, bottom plate, etc.

The materials used for the radar antenna cover must consider several points, such as low dielectric constant, low dielectric loss, low warpage, laser welding, chemical resistance, etc. Considering the above, the optional materials can be PBT, copolymer PC, PPO, PEI and other materials.

In addition, the selection of the back cover base material is also required, which needs to achieve EMI electromagnetic shielding and thermal conductivity, low warpage, laser welding and laser marking, and chemical resistance. The materials can be PC/PBT, PA, PPS, PPO/PPA, etc.

Why does millimeter-wave radar use laser welding?

Let's take PBT as an example. Using high-penetration PBT material is the best way to solve the surface burns when PBT material is welded. Another effective way to solve the burns of PBT materials during laser welding is to use specially designed fixtures. During the plastic laser welding process, the possibility of burns is reduced by continuously cooling the surface of the weld of the penetrating part.

In addition, good laser plastic welding equipment can also reduce the probability of PBT plastic burning during laser welding. Imported plastic laser welding equipment uses a high-brightness light source with good beam quality. Some plastic laser welding equipment suppliers also have special spot shaping technology, which makes the distribution shape of the spot and the energy density distribution more suitable for laser welding of PBT plastic.

Finally, the current equipment has welding process monitoring and quality monitoring, which can greatly reduce the probability of PBT surface burning through closed-loop monitoring of welding temperature.