How Does the Shape of the Laser Lens Affect Laser Welding?

Laser lens plays a vital role in the laser welding process, affecting the focusing characteristics of the laser beam and the welding quality. The shape of the lens directly affects the laser beam characteristics during the welding process, including the focal position, energy density, spot shape, and welding depth. The following are several major lens shapes and their effects on laser welding:

1. Laser Lens Type

• Spherical lens:

Suitable for wider beams and can effectively focus the laser. However, due to the diffraction of light, the spot around the focus may not be uniform enough.

• Aspherical laser lens:

Has better focusing performance and can concentrate the laser beam into a smaller spot, thereby increasing the energy density and is suitable for high-precision welding.

2. Focal Length

• Short focal length lens:

Can produce a smaller spot diameter, suitable for deep penetration welding (deep welding), but may cause the heat affected zone (HAZ) during welding to become smaller and the control difficulty to increase.

• Long focal length lens:

Generates a larger spot diameter, suitable for welding thicker materials, can distribute heat more evenly, but may cause a decrease in welding depth and energy density.

3. Spot Shape

• Circular spot:

Usually used for standard welding operations, circular spot provides uniform heat distribution and is suitable for most welding applications.

• Rectangular or other shaped spot:

By using specially designed laser lenses, a spot with a specific shape can be achieved to facilitate welding of joints of specific shapes or more complex welding processes.

4. Lens Material

The choice of laser lens material (such as optical glass, fluoride or plastic) directly affects its ability to transmit laser light. Excessive absorptivity of the material will cause the lens temperature to rise, which may eventually affect the output quality of the laser and the service life of the lens.

5. Temperature Control

During the welding process, the shape and material of the laser lens also need to consider its cooling ability to prevent performance degradation and deformation caused by overheating.

Summary

The shape of the laser lens has an important influence on laser welding, including:
The distribution of energy density, which directly affects the quality and depth of welding.
The position and size of the focus affect the heat affected zone of the weld.
The heat input of the weld joint, which in turn affects the physical properties of the material.
Therefore, when selecting a laser lens, it is necessary to reasonably match it according to the specific welding requirements, material properties and welding parameters to ensure the best welding effect.