.jpg)
Car lumbar supports (seat lumbar support/lumbar support airbags) are typically inflatable airbags made of multi-layer TPU films through high-frequency heat sealing or pulse heat sealing processes. They are integrated into the car seat and their support is adjusted by inflation and deflation.
Heat sealing is a critical process.
Alignment of Upper and Lower Sheets:
The cut TPU upper and lower sheets are precisely aligned on the welding worktable. Positioning pins are usually used for assistance.
High-Frequency Heat Sealing:
The aligned films are placed into the high-frequency heat sealing machine, along with the inflatable hose to be heat-sealed.
The mold is pressed down, applying uniform pressure.
The high-frequency generator is activated: A high-frequency electromagnetic field is generated, causing intense friction between TPU molecules, instantly generating high temperatures (approximately 180-220°C) at the mold contact area.
Fusion and Cooling: Under pressure, the TPU in the contact area melts and fuses together. It is then cooled and solidified under pressure, forming a permanent seal.
Discharge: The mold is lifted, and the workpiece is removed. At this point, the main sealing profile of the lumbar support has been formed, and the inflation hose has been heat-sealed with the inner lining of the lumbar support airbag.