Projects

Efficient emission exhaustion and component cleaning for large-area laser remote processing (CleanRemote)

Thanks to new brillant high-performance laser beam sources and suitable system technology, it is now possible to realize quasi-simultaneous laser processing in large working areas (up to 1 m²). The remote system is a universal tool in which a laser beam is deflected onto the component via fast-tilting mirrors. It can be used for cutting, welding, ablating, marking or hardening various materials such as metal, textiles or plastics. This flexibility and a significant reduction in investment costs have led more and more small and medium-sized companies to consider acquiring this modern system technology. Current concerns are based on a missing understanding of the system design and process as well as environmental and occupational health and safety issues in laser remote processing, since in this case it is not possible to extract at the operating point, but processing emissions occur throughout the entire working area.

These parameters therefore require the setup of a generally valid process understanding as well as the development of flexible gas supply and extraction solutions up to integrated concepts for subsequent component cleaning.

Solution

Flexibilität eines Laser-Remote-Systems für verschiedene Anwendungen: 1: Schneiden von Metallfolien, 2: Schweißen von Wärmetauschern,  3: Zuschnitt von Textilien
© Fraunhofer IWS

Flexibility of a laser remote system for various applications: 1: cutting of metal foils, 2: welding of heat exchangers, 3: cutting of textiles

During laser structuring with high-power lasers, the number and size distribution of the emitted particles as well as the composition of the harmful gases are determined and evaluated on selected relevant materials such as carbon fiber-reinforced plastic (CFRP) with duromer matrix and stainless steel in a closed and exhausted chamber. In addition, samples are taken from the processing chamber in order to subsequently detect the non-exhausted particles by light microscopic classification.

Based on these results, an application-adapted model for flow simulation can subsequently be developed, which enables the generation of design regulations for efficient emission control.

Depending on the particles and contaminations deposited directly on the component, additional local cleaning processes can be integrated into the remote system.

Results

Partikelmessung beim Laser Remote-Abtragprozess ermittelt mit einem Scanning Mobility Particle Sizer (SMPS)
© Fraunhofer IWS

Particle measurement during laser remote ablation process determined with a Scanning Mobility Particle Sizer (SMPS)

Partikelflugbahnen für Partikelgrößen zwischen 5 und 40 µm für die Position "Düse" (links), Position "Mitte" (mitte) und Position "Absaugung" jeweils nach 16 ms (oben) und 32 ms (unten)
© Fraunhofer IWS

Particle trajectories for particle sizes between 5 and 40 µm for nozzle position (left), center position (center) and suction position (right) after 16 ms (top) and 32 ms (bottom), respectively.

To analyze the particles produced at the laser position, size distribution measurements were performed by means of aerosol and SMPS spectrometry (Scanning Mobility Particle Sizer). Resulting gaseous emissions were examined by FTIR spectroscopy. For example, it was demonstrated that CFRP produces a large number of particles of different sizes, with the maximum size range of up to 30 nm (aveolar). In addition, various hazardous gases such as carbon monoxide, nitrogen oxides and formaldehydes could be detected. With the knowledge of the substances and particle sizes produced, suitable particle and gas filters can be recommended to the operator and also tested for effectiveness.

In addition to the analytics of the generated emissions, the results of the flow simulation allowed the development of design guidelines for the optimal integration of crossjet and extraction in order to minimize contamination of the parts during the removal process. A subsequent residue-free and non-abrasive cleaning by means of CO2 snow blasting was integrated into the laser remote system and thus permits a verifiably clean component surface.

Research funding

German Federal Ministry for Economic Affairs and Energy (BMWi)
© German Federal Ministry for Economic Affairs and Energy (BMWi)

German Federal Ministry for Economic Affairs and Energy (BMWi)

Part of this research was funded by the Federal Ministry of Economics and Energy on the basis of the German Bundestag's decision as part of the "CleanRemote" project (Efficient emission extraction and component cleaning for large-scale laser remote processing with high-performance lasers; IGF:19239BR).

Further information

Competencies

Cooperation

Joint project work with the Dresden University of Technology, Department of Chemistry and Food Chemistry, Chair of Inorganic Chemistry I

 

Faculty of Chemistry and Food Chemistry

The Chair of Inorganic Chemistry I investigates modern inorganic materials from synthesis through characterization to application. Research areas are materials for energy system transformation, materials for environmental technologies, light management and surface technologies as well as industrial inorganic chemistry.