Process monitoring for Laser based manufacturing

© Fraunhofer IPT
Water jet guided in-line laser process control for depth controlled production of microstructures with high aspect ratios.

Laser processing systems are becoming increasingly important in the industrial production of micro and macro components for various industries and applications and are thus establishing themselves as an important tool for production. Their technical characteristics such as high precision, reliability, material diversity and the low thermal load of the components contribute to this development, as does the good automatability of the laser process.

However, the required low component tolerances and short cycle times present laser processing with ever new challenges. The stability of the process plays a major role here: Since laser processes are influenced by different machine, workpiece and environmental factors, even small parameter changes can result in the produced components no longer being within the specified tolerances. Particularly in the manufacturing of precision components, the process window, i.e. the range of permissible parameter deviations, is extremely narrow. Therefore, thorough monitoring and precise control of the process is indispensable in laser micromachining.

Our service

The Fraunhofer IPT uses measurement systems based on low-coherence interferometry, camera- and diode-based process emission measurement, laser triangulation and chromatic confocal distance measurement. Integrated into the laser processing units, they provide direct process monitoring. The sensor systems can use the same beam path of the laser beam or be introduced with an offset or angle. In this way, the modular inline measurement systems can analyze the component before, during and after processing, depending on the measuring principle. These solutions allow accurate, robust monitoring and control of laser processes that can handle even complex tasks.

Measurement principles

  • Low coherence interferometry
  • Characterization of process related emissions by laser-induced plasma spectroscopy, cameras and/or photodiodes monitoring
  • Laser triangulation (coaxial and offset)
  • Chromatic confocal distance measurement

Fields

  • Laser cutting
  • Laser welding
  • Laser transmission welding (polymer-polymer/hybrid-welding)
  • Laser micromachining/structuring
  • Laser desposition welding
  • Additive manufacturing (Laser powder bed fusion)

Our service

  • Development of special measuring systems and needs-based measurement software
  • Project management, requirements analysis, design and implementation
  • Integration into your production
  • Validation and characterization

Technical possibilities

Before machining

  • Recording of the component position and topography for alignment of the workpiece as well as adaptation of the machining strategy and the CNC code
  • Automatic process initialization
    (laser parameter setting)

During the machining

  • Inline measurement of ablation depth
  • Detection of process deviations and control
  • Inline monitoring the focus position
  • Early identification and correction of manufacturing defects

After the machining

  • Quality assurance directly in the machine (using machine coordinates)