Lantec is running a test to prove reliability of 4D Weld Watcher system. According to the manufacturer, partially ionized metal vapour is created during laser welding, cutting or soldering. This escapes from the weld pool and emits a broadband light, the so-called process light. The WeldWatcher measures this process light using a photo-electric sensor. By doing so, typical features, such as the beam flux density, spectral components, time or progress are analyzed and used for quality control.