Patent ID: 7620233

Claim:
A process for checking a laser weld seam, comprising: selecting materials to be welded and the process parameters of the laser welding process for forming a weld seam, determining the time after welding at which at least a thin skin has solidified on the weld seam and setting this as the earliest measurement start time for a characteristic interval, selecting an optical or thermal signal to be emitted onto and reflected from the weld seam during said characteristic interval, determining the minimal length of a time interval necessary in order to receive detectable signal data, and setting this as the minimal duration of the characteristic time interval, laser welding said materials to form a weld seam by a computer controlled process comprising: emitting said optical or thermal signal onto said seam in said area in which at least a thin skin has solidified and detecting reflected signal data, comparing the detected reflected signal data with desired values, providing a violation signal each time the detected reflected signal data does not correspond with the desired values, and evaluating the laser weld seam on the basis of said violation signals, wherein only signals detected within the characteristic time interval are taken into consideration.