Aug 28, 2020
1. Use off-focus marking
Because each focusing lens has a corresponding focal depth range, and the use of off-focus methods will easily lead to large-scale marking patterns, the edge of the pattern exceeds the focal depth range, which is easier to cause uneven marking. Therefore, the laser energy must be considered when marking off-focus.
2. The laser output spot is blocked
The laser output head, fixing fixture, galvanometer, etc. are not adjusted properly, causing part of the laser spot to be blocked when the laser passes through the galvanometer. After the field lens is focused, the spot on the frequency doubler is non-circular, which may also cause marking Uneven.
There is another situation, that is, the deflection lens of the galvanometer is damaged. When the laser beam passes through the damaged area of the lens, it cannot be reflected out well. Therefore, the energy of the laser beam cannot be evenly distributed, which makes the marking effect uneven.
3. Thermal lens phenomenon
When the laser passes through the optical lens (refraction, reflection), the lens will generate heat and produce slight deformation. This kind of deformation will increase the focus of the laser and shorten the focal length. If the machine is fixed and the distance is adjusted to the focal point, after a period of time after the laser is turned on, the energy density of the laser acting on the material will change due to the thermal lens phenomenon, resulting in uneven marking effect.
4. The machine is not leveled
The laser vibrator lens or the field lens lens is not parallel to the processing table, which will cause the laser beam to reach the processed object in the length of the distance after the field lens is inconsistent. Eventually, the laser will have inconsistent energy density when it falls on the processed object. The marking is uneven.
5. Material impact
The material is sensitive to laser energy. Usually, under the same material, it is certain that the laser energy reaches the material destruction threshold. When the thickness of the material coating is not uniform, or some other physical and chemical treatment processes are not uniform, the effect after laser marking will also be uneven.
Treatment method for uneven marking effect:
1. Disassemble and replace the laser power supply for testing.
2. Reduce the production processing rate.
3. Check the laser light path to ensure that the laser light path is accurate.
4. Using short focal length optical lenses, the focal length adjustment of the lens should take into account the depth of the production process.