Laser weld process monitoring in production of tailor-welded blanks

High-volume production of high-quality laser welds in tailored blanks requires stable laser devices, precision part preparation and handling, on-line monitoring of the weld process, and postweld inspection. We present here, results of an investigation of simple, robust sensors for weld process monitoring in a tailored blank production environment. A compact research sensor package was assembled to record ultraviolet through visible optical spectra, time-resolved plasma light emission, and time-resolved acoustic emission. Data were recorded for a series of weld conditions representative of parameter variations (weld speed, power, tracking error, and gapping) within and outside of bounds known to produce good welds. Correlation of the various sensor outputs with these parameter variations will be presented. Among the monitored elements the plasma light emission appears to offer the most straightforward correlation to the welding process.