Laser welding can be a fast and economical technique for high-volume butt welding applications. Quality control in laser butt welding can be challenging and the risk of failures or recalls if defective parts reach a major customer can be substantial. A trained operator can identify many flaws with close visual inspection, but an automatic solution is required for truly efficient and competitive production.
Inline coherent imaging can be used to provide immediate, automated PASS/FAIL decisions in butt welding applications, using a direct, in-process measurement of weld penetration. The decision signals from the Laser Depth Dynamics instrument can be sent to the process control PLC for automated rejection of defective parts.
In this example, laser butt welds are performed in 18 gauge (1.27 mm) type 304 stainless steel. The LD-600 is set to pass only those welds where penetration is within the weld quality limits (red lines) relative to the top surface (yellow line). If consistent, full penetration is not achieved, the LD-600 declares the weld to be a failure.
Visual inspection of the top and bottom surfaces of the finished part (photos above) confirms that the LD-600’s immediate, automated QC decision was correct.
For full details on this experiment, other butt welding flaws caught by the LD-600, and relevant systems integration considerations, please download our application note using the form below.