Laser transmission welding, also known as transmissive welding, is a dynamically developing technology that is becoming the standard for creating non-detachable joints in thermoplastics. The process allows for joining thermoplastics with a strong and tight weld that is concealed within the material and is often nearly invisible.
Laser transmission welding
For this technology, the materials to be joined must meet several criteria. First and foremost, they must be thermoplastics. The pair of materials should be such that the upper layer is transparent to the laser’s wavelength, while the underlying layer absorbs that wavelength. The welded materials must be materially and chemically compatible; it is not possible to weld two randomly selected thermoplastics. Most combinations of technically utilized polymers (PC, ABS, PMMA, PET, PP, FRP) are relatively well weldable. For the process to be properly feasible, the welded parts must also be clean and pressed together with constant pressure.
Welding of headlight reflectors
Laser transmission welding of plastics enables the joining of parts that can withstand vibrations, moisture, and mechanical stress without the visibility of the joint. This method is used, for example, in welding reflectors inside headlights. The weld is invisible, seals the space under the reflector, and does so without the need for additional materials or further technological steps. The process is energy-efficient, dust-free, and controlled by a pyrometer, which ensures a stable temperature of the melt pool and a perfect weld.
Welding of functional decorative elements
In some applications, this technology can achieve invisible joints, which meets the aesthetic and design requirements for visible parts in automotive interiors or other industries. The weld must be free of large bubbles, color changes, or cracks, while also ensuring sufficient strength to prevent detachment in the event of a crash. This method allows meeting the high demands of customers in various industrial sectors.
Welding of parking sensors
Thanks to the use of fast scanning optics and powerful lasers, it is possible to quickly create complex welding trajectories and weld a large number of small parts in a short time, even when the parts contain delicate electronics. For parking sensors, not even a second is needed. The weld is waterproof and hidden around the edge of the sensor’s rear cover.
