Brief Introduction - Laser Welding of EPB Plastic Shell

EPB is the abbreviation of the electronic parking brake system, and the EPB controls the parking brake through an electronic circuit. The function is the same as that of a mechanical lever. There is no need to manually turn off the electronic brake when starting, and the electronic brake will automatically turn off when the accelerator is pressed to start.

In fact, the electronic parking brake system shows us the electronic handbrake button, which replaces the traditional lever handbrake. It is safer than the traditional lever handbrake, and the braking effect will not be changed due to the driver's strength, turning the traditional lever handbrake into a button within reach.

But the EPB shell is a plastic part, which involves welding, while traditional ultrasonic welding, such as ultrasonic welding, transmits high-frequency vibration waves to the surfaces of two objects to be welded. The surfaces of the two objects rub against each other under pressure to form a fusion between the molecular layers. This is very unfavorable for welding products with gear meshing inside. For example, in the general reflection of ultrasonic welding, there are problems such as high noise, torque influence, ugly appearance, large leakage, etc. This also promotes the application of Plastic laser welding machine. Plastic laser welding itself belongs to non-contact welding processing, with low mechanical stress and no damage to the surface.

Analysis of the product welding rib structure The design direction of the EPB shell follows the design structure of quasi-synchronous laser welding. The welding rib is designed in the light-absorbing layer. The laser passes through the light-transmitting layer and quickly scans along the welding rib to achieve welding. The advantage of this welding method is high efficiency, and the welding depression value can be used as a benchmark for quality judgment.

The material of the EPB product is PBT+GF30, which is somewhat difficult for laser welding. The light transmittance of the material is indeed the most important influencing factor. Generally, PBT materials have poor light transmittance, and the surface is easily burned during welding. In response to this situation, major material manufacturers have developed PBT materials suitable for laser welding, such as BASF and Mitsubishi abroad, and Ukote in China. However, each family has different requirements for the light transmittance, welding window period and injection molding process of PBT materials. Therefore, we hope that customers can choose PBT materials with high light transmittance, long welding window period and low sensitivity in injection molding process as much as possible.

The second is the injection molding technology of PBT products. The injection molding technology of polymer materials also has a great influence on the later Laser welding, which is mainly manifested in the consistency of light transmittance of the light-transmitting layer and the degree of warping of the product. The light transmittance after injection molding is uneven, single-point or multi-segment burns are likely to occur during welding, the light-transmitting layer is severely warped, and welding thermal stress leakage is likely to occur after welding. These problems also plague material manufacturers and injection manufacturers.