Robot-assisted quasi-simultaneous laser welding of thermoplastics

摘要

Abstract The integration of robotics into quasi-simultaneous laser welding (QSLW) represents a significant advancement in materials joining technology, particularly for thermoplastics. This study explores the feasibility and effectiveness of employing a robotic arm in QSLW, a process traditionally carried out using galvanometric scanning heads due to its high-speed nature. The findings demonstrate that, through a robot-assisted process, it is possible to effectively control the meltdown level, a key parameter to ensure hermetic sealing, a typical requirement for this type of joint. This study identifies clamping force, welding speed, and laser spot size as the most significant parameters to achieve proper meltdown conditions at the weld interface. An experimental design, including an L9 orthogonal array and regression analysis, highlights the critical influence of these parameters on joint quality. A second-order regression model was developed to quantitatively describe the relationship between process parameters and material penetration at the interface, which is used as a representative indicator of the meltdown phenomenon. The model shows that the identified factors are mutually independent and, as a whole, accurately describe the behavior of the response variable, with a coefficient of determination exceeding 90%. The scope of this paper is to contribute to a deeper understanding of laser welding processes for thermoplastics, and to introduce a novel robot-assisted approach to QSLW, offering a reliable alternative to traditional galvanometric systems and demonstrating its capability to ensure both manufacturing efficiency and weld quality.