Effect of variable power control in quasi-simultaneous fiber laser welding of polymers

Abstract

In transmission laser welding of polymers, the process nature is dependent on rapid melting of the absorbing part. This melting creates the heat transfer to the transmissive part which is then melted and after the cooling period, a weld is created. Typically in quasi simultaneous laser welding (QSLW) material heats up towards the end of the welding cycle. With this new variant, the idea is to heat the material as fast as possible to the molten state and then keep it there for the rest of the welding time. With variable power control during the welding, the power level can be adjusted to melt the material effectively, and keep it molten during the whole welding time without overheating the material. This way the weld is given a longer time at melt so that more material would be mixed. Optimal power curve can be extracted with a pyrometer and then used in production.This paper presents the basic design variable of the power control system and shows how the quality of the weld is affected with its utilization. Welding results are compared to traditional QSLW and also to samples which are welded with only three power steps during welding.In transmission laser welding of polymers, the process nature is dependent on rapid melting of the absorbing part. This melting creates the heat transfer to the transmissive part which is then melted and after the cooling period, a weld is created. Typically in quasi simultaneous laser welding (QSLW) material heats up towards the end of the welding cycle. With this new variant, the idea is to heat the material as fast as possible to the molten state and then keep it there for the rest of the welding time. With variable power control during the welding, the power level can be adjusted to melt the material effectively, and keep it molten during the whole welding time without overheating the material. This way the weld is given a longer time at melt so that more material would be mixed. Optimal power curve can be extracted with a pyrometer and then used in production.This paper presents the basic design variable of the power control system and shows how the quality of the weld is affected with its utilizatio...