Optical Focusing Lens
An optical focusing lens in a laser welding head focuses the laser beam and determines the power density and focal diameter on the workpiece surface.
Physical-Chemical Mechanism of Action
The optical focusing lens uses the laws of refraction to focus a laser beam. It concentrates the light to a small point called the focal point. This increases the power density of the beam at that point.
Metallurgical Relevance & Risks in Welding
Proper focusing is critical for an effective weld. Too large a focal diameter can cause uneven heating and potential stress buildup, which may lead to cracks. Too small a diameter increases power density and can cause overheating and possible damage to the workpiece.
Shop Practice & Action Guidelines
Set the focusing lens so that the focal point lies exactly on the workpiece surface. This can be achieved by adjusting the distance between the lens and the workpiece. The power density should be in the range of 10 to 20 kW/cm² to ensure optimal weld quality.