•Laser power is controlled via triangulation camera in a remote laser welding system.•Relationship between interaction zone's area and process parameters is discussed.•Stable partial penetration is ...achieved for investigated welding parameters.
Remote laser-welding systems are being used more frequently because of their larger working areas, shorter downtimes and ability to weld different seam types with high accuracy at greater speeds in comparison to conventional welding. Therefore, precise process-monitoring methods are needed in order to achieve weld traceability and good process and quality control to accompany different welding situations. This paper proposes the use of optical triangulation feedback on a remote laser-welding system that makes it possible to monitor a larger working area. This configuration means we can monitor the interaction zone itself, analyze the 3D position of the laser beam and key process estimators as a result of laser welding. AISI steel plates were welded in a lap configuration to show that stable partial penetration can be achieved. First, a dependency matrix was constructed for the different welding parameters (material thicknesses, welding speeds and laser powers) in order to describe the change of the weld's penetration depth with respect to the key estimators. An approximation was used to characterize the change of the weld's depth according to the change of the estimators. The experimental results demonstrate that the interaction zone's area can be used to successfully control the laser's power output in order to achieve a stable partial penetration with an error of less than 7 % of the desired target weld depth. Longitudinal macrographies show a significantly more constant weld penetration depth and laser-induced plume reduction during welding.
Remote-laser welding shortens processing times but bring reservations in the field of small series and user-customized manufacturing, where product individualization requires flexible and adaptive ...systems with simplified clamping devices. Also, the workpiece geometry is not exact due to thermal deformations during welding. To solve this, we have developed an innovative system, which enables in-line adaptive 3d seam tracking and laser power control. The system consists of an industrial robot, scanning head with optical triangulation feedback and fiber laser. It enables shorter and easier welding trajectory teaching, laser focus positioning precision of under 0,06 mm and stable partial penetration welding process.
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