TWINQUASI – A new method for quasi-simultaneous laser welding of polymers

Quasi-simultaneous laser welding (QSLW) of polymers has been studied, developed and used both in academia and industry for many years. The process has high flexibility and lot of advantages but it has some limitations especially when short welding time is required. The short welding time requires a scanner with extremely high speed and accuracy which usually limits the maximum dimensions of the joint and products to be welded. This paper presents a new method to utilize a QSLW-process with two lasers and optical scanners (TWINQUASI) for quasi-simultaneous laser welding of polymers which enables welding of larger components within a short welding time. The paper demonstrates TWINQUASI and compares its performance to those of traditional QSLW. Results show that with this method the length of the weld can be doubled within the same welding time while still keeping equal scanning frequency to that of the conventional QSLW-process. It is shown that with the TWINQUASI method, larger components can be welded with quasi-simultaneous method compared to shown earlier. Another advantage of the process is the ability to program scanning paths of both lasers individually. Because of this, the TWINQUASI method enables also variation of the weld width within one weld seam giving even more flexibility to the process.