The influence of thermal lens effect in laser applications
Optics Lens For Fiber Laser,The higher the power and the processing of high-reflection materials, the faster the thermal expansion of the optical element will be, and the more obvious the thermal lens; when the thermal lens effect is generated, the thermal expansion of the optical element will increase the focusing ability, the size of the focused spot becomes smaller, and the focal length and focal depth become shorter. phenomenon. The occurrence of these phenomena will eventually cause the laser processing to be unstable and affect the laser processing effect.
1. The impact on marking
(1) Alumina blackening: When the thermal lens effect occurs, the focal length becomes shorter, the surface energy density of the material is reduced, and the alumina cannot be blackened. In severe cases, the blackness of the center and edge effects is inconsistent.
(2) Metal deep-sculpting: Metal deep-sculpting generally uses a field lens with a short focal length (focus depth). When high-power deep-sculpting, due to the thermal lens effect, the energy density of the material drops rapidly, causing the metal to not be deep. Since the center of the optical element expands more than the edge, the center is shallow and the surrounding is deep.(Post Objective Scanning Price China)
(3) Slice cutting: According to different materials, pulsed fiber laser cutting slices usually adopts two methods of single slow speed or multiple fast speeds. Thermal expansion and cooling retraction can occur in a short time (<1S), so the starting position can be cut through when cutting, and the material cannot be cut through other positions.
2. Impact on welding
(1) Spot welding of metal flakes: For high-power fiber laser spot welding of metal flakes, the thermal lens effect will cause the size of the solder joints to be inconsistent, the welding is not firm, and the drawing force is insufficient.
(2) Continuous metal welding: Compared with cutting, continuous light welding has higher reflectivity. In high-power welding, the thermal lens effect will cause the front part of the welding to be normal, and the rear part of the welding depth is shallow or completely incomplete. Welding aluminum and copper high reflective materials, the thermal lens effect is more obvious.
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3. The impact on cutting
(1) Stainless steel cutting: When cutting stainless steel, the thermal lens effect will cause the cutting surface to be inconsistent, more and more dross, and even continuous cutting problems.
(2) Carbon steel cutting: When cutting carbon steel, the thermal lens effect will cause more and more bottom melting inspections and continuous cutting problems.