PRE-TREATMENT
POST WELD LASER CLEANING
Weld cleaning using lasers is a highly efficient and precise method for removing contaminants, oxides, and discoloration from welded surfaces in the steel fabrication and processing industries. It’s particularly effective for stainless steel, Al and other alloy metals. By focusing a laser beam on the affected area, the unwanted material is vaporized, leaving behind a clean, smooth surface. This process improves the weld quality, appearance, and can also enhance the corrosion resistance on some alloys.
Overall, a laser system can effortlessly be built into an existing process or production line, speeding up the complete process. Laser cleaning offers several advantages over traditional methods such as mechanical, abrasion or chemical cleaning, including precision, non-contact operation, minimal heat-affected zone, and environmental friendliness (no use of chemicals or abrasives).
STAINLESS STEEL
Laser cleaning of steel and Al welds utilizes the principles of laser-material interaction, specifically laser ablation. When a high-intensity laser beam is focused onto the surface of a welded metal, the laser energy is absorbed by the surface contaminants, oxides, and impurities present on the weld surface. The thermal load of the beam rapidly heats the contaminants, causing them to reach their vaporization temperatures in milliseconds, upon which they are immediately converted directly from solid to vapor phase, bypassing the liquid phase. This vaporization process effectively removes (ablates) the unwanted material from the weld surface and also dislodges any remaining debris or residue on either side of the weld seam.
This vaporized material forms a plume above the weld surface, which is typically removed through suction or extraction system or blown away with compressed air. As the laser beam scans across the weld surface, the contaminants are continuously vaporized and removed, resulting in a clean, residue-free surface. Cleaning speeds are comparable with welding speeds, so it is easy to include a new laser cleaning system in an existing line.
ALUMINIUM
The effects of good weld preparation were determined with an investigation we did on aluminium a few years ago. We compared good and bad weld preparation, meaning all oxides were eliminated via surface cleaning on one part, and no cleaning was performed on the reference part.
On the left side of the picture you can see a lower porosity as a result of good surface cleaning, while on the right, one can see an increase in porosity, possibly leading to weld fatigue and potentially catastropic failure. The less porosity in a weld, the less chance it will break over time.
In addition, the laser cleaning process on the Al surface increases its corrosion resistance due to the action of the beam passivating the Al surface.
High speeds can be reached when preparing and cleaning the welds on aluminium, which makes laser cleaning a very effective solution.
