The increased complexity and rapid evolution of Microsystems ask for advanced assembly tools based on innovative concepts and methods. In the same time, laser welding of thermoplastics confirmed its advantages and experienced an increased industrial acceptance over the last years. In this study, according to the Pick-and-Join technique, a novel laser based tool with high compactness and flexibility in time and product was developed for transmission welding of thermoplastics. The new tool is able to pick the components, precisely position them and realize the joining using laser radiation. Furthermore, a defined force can be applied on the joining partners eliminating in this way the need of an additional clamping device.
The concept of the Pick-and-Join tool is based on the integration of a continuous wave fiber laser, a galvo mirror system, a device adapted gripper, a process monitoring system and a precise positioning system. The focused laser spot is around 30 µm, factor 10 smaller than for the well established diode laser. Using this set-up, transmission welding of polycarbonate (PC) was investigated. The varied parameters were: feed rate, power and the pressure upon the joining partners. The performance of the fiber laser for welding of thermoplastics is presented and discussed.