Causes of uneven marking effect of uv pulsed laser marking machine

 1. Use off-focus to mark a certain range of content

Because each focusing lens has a corresponding focal depth range, and the use of off-focus method will easily lead to a large-scale marking pattern, the edge is at the focal depth critical point or exceeds the focal depth range, which is easier to cause ineffective results. Uniformity. Therefore, the off-focus marking method must consider the problem of laser energy.

2. The laser output spot is blocked, that is, after the laser beam passes through the galvanometer and field lens, the spot is missing and not round enough

The laser output head, fixing fixture and galvanometer are not adjusted properly, which causes 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. Evenly.　　

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 laser energy of the laser beam passing through the damaged area of ​​the lens is inconsistent with the laser energy of the non-damaged area of ​​the lens, and the final laser energy acting on the material is also different, 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 level is not adjusted properly, that is, the laser vibrator lens or field lens lens is not parallel to the processing table

Since the two are not level, the distance between the laser beam and the processed object after passing through the field lens will be inconsistent. Eventually, the energy of the laser beam falling on the processed object will have an inconsistent energy density, which will show an effect on the material. Uneven.　

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5. The reason for the material, such as the inconsistency of the film thickness on the surface of the material or the change of physical and chemical properties

The material is sensitive to laser energy. Generally, it is certain that the laser energy reaches the destruction threshold of the material under the same material. 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.