New approaches in plastic welding with diode lasers

High power diode lasers (HPDL's) represent an excellent tool for specific plastic welding applications. Current, conventional techniques for joining plastics include heated plates and wires, hot gases, ultrasonic and vibration welding. Fiber coupled diode lasers offer major advantages: high flexibility compared to these: cost-efficiency, on-line process control and high quality. However, specific requirements for process design and materials must be met to apply this new joining technology. Practical applications are currently limited to overlap joints, where one part is transparent and can be penetrated by the laser radiation, allowing the other part to absorb it. This paper focuses on joining translucent materials using an absorbing interface. Various types of absorbing interfaces, such as film, wire, and spray and their applications are discussed. In addition, welding tests using absorbing interfaces are presented and the potential for future industrial applications are evaluated.