What is the reason for the uneven marking effect of the fiber laser marking machine?

First, use a bias to mark a certain range of content

Because each focusing mirror has a corresponding depth of focus range. And the method of deviating from the focus will easily lead to a large range of marking patterns. The edge is at the critical depth of the focal depth. Or beyond the depth of focus, which is more likely to cause effects. Uniformity. Therefore, the method of defocusing marking must consider the problem of laser energy.

Second, the laser output spot is blocked, and the spot is not enough. The laser output head, the fixed fixture and the galvanometer are not adjustable. Some of the spots are blocked when the laser passes through the vibrating lens. The spot on the doubling sheet after focusing by the field lens is non-circular, which may also result in uneven effect.

There is also a case where the galvanometer deflecting lens is damaged and cannot be reflected well when the laser beam passes through the damaged area of the lens. Therefore, the laser beam is inconsistent with the laser energy in the damaged area of the lens and the non-damaged area of the lens. And the laser energy ultimately acting on the material is also different, thereby making the marking effect uneven.

Third, the thermal lens phenomenon

When the laser passes through the optical lens, it will cause the lens to generate heat and produce a slight deformation. This deformation causes the laser focus to rise and the focal length to become shorter. If the machine is fixed and the distance is adjusted to the focus, after the laser is turned on for a while, the laser energy density acting on the material changes due to the thermal lens phenomenon, resulting in uneven laser marking.

Fourth, the level of the machine is not adjust, the laser lens or field lens is not parallel to the processing table.

Because the two are not horizontal, the length of the laser beam passing through the field lens and reaching the workpiece is inconsistent. The energy of the laser falling on the workpiece will have an inconsistent energy density. And the effect will be exhibit on the material. Not uniform.

Fifthly, Reasons for materials, such as inconsistent film thickness or changes in physical and chemical properties on the surface of the material

Materials are sensitive to laser energy reactions. Generally, under the same material, the laser energy reaches a material damage threshold is certain. When the thickness of the material coating is not uniform. Or ome other physicochemical treatment process is not uniform enough. It will also cause unevenness of the effect after laser marking.

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