After metal sheet cutting and stamping, burrs generated on the edges increase the risk of injury to personnel and may also damage or scratch objects in contact with them. For this reason alone, it is necessary to remove these burrs from the edges. By using laser technology to remove the burrs, not only can the edges be selectively reinforced, but the fatigue strength of the parts can also be improved, reducing the tendency to form cracks. The Fraunhofer Institute for Laser Technology (Fraunhofer ILT) in Germany has developed the most advanced laser deburring processes.
In the automotive industry, laser deburring has been widely used in some mass production processes over the past decade. Dr. Edgar Willenborg, an expert in laser polishing and deburring at Fraunhofer ILT, stated, “But the potential of this technology is far from being fully exploited.” Laser deburring of metal sheets is not complicated, and it not only improves the quality of the parts but also increases production efficiency, as processing speeds can reach up to 12 m/min.
In principle, deburring is necessary to minimize the risk of injury.
Furthermore, sharp burrs on the cutting and stamping edges often scratch the surface of cables, causing damage and potential risks. So far, the most commonly used method for deburring is mechanical processing. However, Fraunhofer ILT’s research shows that laser technology has significant advantages in the deburring process. The laser deburring process itself is simple. Willenborg explains, “The laser focus must be positioned at the front part of the sheet metal edge and cover the entire edge completely.” The focused beam briefly melts the metal edge and burrs. Then, the molten metal smooths itself out under the influence of surface tension. This creates a rounded edge. “With proper process control, not only can the edge be smoothed, but the edge can also be selectively reinforced,” says Willenborg.
To achieve this goal, Fraunhofer ILT increased the laser power.
More energy input allows more material to be melted, forming reinforced, rounded seams around the edges.
Smooth, rounded edges help prevent scratches and damage to cables or other objects in contact with the edges. In addition, laser processing offers other benefits, such as the formation of defect-free edges.
Willenborg emphasizes, “Defect-free edges will give metal sheet components a significant advantage in terms of fatigue strength and mechanical forming behavior.”
Tests on high-strength steel show that laser deburring increased its fatigue strength by 220%, while also improving deformation resistance by 240%. Additionally, laser deburring can prevent edge cracks. The laser melting during the deburring process eliminates the micro-defects that mechanical processing often creates at the edges. These microscopic, invisible pre-damages are typically the starting point for crack formation.
Laser Deburring: Fast, Clean, and Cost-Effective
Willenborg states that another major advantage of laser deburring compared to mechanical processes is that it does not generate abrasive dust. The laser process only briefly melts excess material rather than removing it, making it relatively easy to integrate laser deburring into existing process chains and production environments. When integration is feasible, the advantages of laser deburring quickly become apparent.
He emphasizes, “Laser deburring is particularly suitable for high-stress components.” Taking automotive chassis parts as an example, the increase in fatigue strength at the edge areas allows manufacturers to design parts thinner and lighter, ultimately leading to more fuel-efficient vehicles.
For molded 3D sheet metal components, the laser can be mounted on a robotic arm to perform the deburring operation. Fiber-coupled semiconductor lasers are already being used for deburring processes, and standard lasers in the near-infrared spectrum are affordable and readily available.
