What are the reasons for uneven marking effects produced by the fiber laser marking machine?

1. Use the defocus mark to indicate a specific range of content. 

As a manufacturer of fiber laser marking machines, since each focusing lens has a corresponding depth of focus range, and the defocusing method can easily result in the formation of large-scale marking patterns, the edges located at the critical point of the depth of focus or beyond the depth of focus range are more likely to lead to ineffective results. Therefore, the uniformity of the defocused marking method requires consideration of the laser energy issue. 

2. The laser output spot of the fiber laser marking is blocked. That is to say, after the laser beam passes through the galvanometer and the objective lens, the spot is lost and is not circular enough. 

The laser output head, fixation device, galvanometer, etc. were not properly adjusted, resulting in some laser spots being blocked when the laser passed through the galvanometer lens. After passing through the focusing objective lens, the light spots on the frequency doubler were non-circular, which could also lead to invalid results.

There is another situation where the deflection lens of the mirror is damaged. When the laser beam passes through the damaged area of the lens, it cannot be reflected properly. Therefore, there is a difference in the laser energy of the laser beam passing through the damaged area of the lens compared to the laser energy in the undamaged area of the lens. This also results in different laser energy acting on the material, leading to uneven marking effects. 

3. When the laser passes through the optical lens (refracting or reflecting), the lens will generate heat and undergo slight deformation. This deformation will increase the laser's focus and shorten the focal length. If the machine is fixed and the distance is adjusted to the focus point, then after a period of time after turning on the laser, due to the thermal lensing effect, the energy density of the laser acting on the material will change, thereby causing uneven marking and affecting the quality. 

4. The machine was not properly adjusted at the machine level, specifically, the laser vibration mirror or the objective lens was not parallel to the processing table. 

Since the two are not parallel, after passing through the objective lens, the distance between the laser beam and the processed object will be inconsistent. Subsequently, the energy of the laser beam landing on the processing object will have inconsistent energy density, which will show the effect on the material. Uneven. 

V. Material-related reasons, such as inconsistent film thickness or changes in the physical and chemical properties of the material surface 

This material is sensitive to laser energy. Generally, it can be determined that the laser energy reaches the material's failure threshold under the same conditions. When the thickness of the material coating is uneven, or when certain other physical and chemical processing procedures are not uniform, the effect of laser marking will also be uneven.