In the past few years, demands for comprehensive process monitoring have increased along with the number of high performance laser machines employed in industrial processes. Besides having to fulfil the requirements of the DIN ISO 9000, legal directives also require ongoing documentation of processing steps from the manufacturers (as do the manufacturers' customers).
In online process monitoring, you have pre-, in- and post-process monitoring, depending on the measuring position. Here Precitec offers various process monitoring systems:

Seam tracking (Pre-process monitoring)

Before actual welding can take place, sensor systems are required - they identify the position of the components to be joined and position the laser beam accordingly. Component tolerances and clamping errors are thus counterbalanced. The LPF seam tracking system (Laser Path Finder) not only performs the sensory determination of the joining position in combination with the LD50W linear drive, it also positions the welding head. Thanks to its closed control loop, the LPF system works completely self-sufficiently.

In-process monitoring

For the in-situ monitoring of laser beam welding, procedures are now in place which analyse the radiation created by the interaction between laser beam and workpiece. This analysis enables conclusions to be made concerning process irregularities and welding errors.
Radiation acquisition occurs either one-dimensionally by means of photodiodes or is triggered locally by use of cameras. Photodiodes analyse the radiation in different spectral ranges, while cameras are used for analysing the weld pool and capillary geometry.
The LWM in-process monitoring system (Laser Welding Monitor) processes the signals from the photodiodes and from camera-based detectors.

Seam geometry monitoring system (Post-process monitoring)

After actual welding has taken place, the geometry of the seam upper bead can be measured and analyzed using light stripe technology. The SGM seam geometry monitoring system (Seam Geometry Monitor) measures the geometry of the seam upper bead created during welding and checks the seam for irregularities like pores and holes.