Laser Welding Process

A laser welding method for welding together two plastic components, a first plastic component (1) i.e. one that is permeable to laser radiation and a second plastic component (2) i.e. one that is non-permeable to laser radiation, in which method a laser beam (3) is directed through the first component into the second component and the laser beam is moved along a predetermined path (4); the components are held substantially in engagement with one another at least in the area of welding and during the entire welding, resulting in that as the laser beam is absorbed in the second component, the latter starts to melt in the area of radiation, thereby melting the first component so that the molten areas of the components adhere to one another forming a seam, and the components are welded together; criteria for an acceptable seam are determined; and a product is accepted when the criteria for an acceptable seam are met . According to the invention, the laser beam is moved several times along a predetermined path; the melting of the components and the formation of the seam are monitored substantially continuously using image processing technology as the welding proceeds through the first plastic component; criteria for the image of an acceptable seam are determined, and the welding is stopped as the criteria are met.