What are the reasons for the uneven marking effect of fiber laser marking machines ?

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What are the reasons for the uneven marking effect of fiber laser marking machines ?

Post by perfectlaserChina » Thu Jul 19, 2018 9:03 am

The fiber laser is widely used in marking electronic components, crafts laser marking, non-metal materials, etc. Laser marking is another great innovation after laser cutting, laser drilling, laser welding and other technical applications, which is a new breakthrough in processing technology and a new type of non-contact processing, non-chemical pollution, non-abrasive new marking processing technology model. However, there are some common problems in the application of laser marking machine , such as the marking effect of the laser marking machine is not uniform. Then Perfect Laser would like to explain the reasons why the fiber laser marking machine may mark the uneven effect ?

1.The use of eccentric focus marking a certain range of content
Because each focus lens has a corresponding depth of focus range, the use of off-focus approach can easily lead to a wide range of marking patterns, the edge of the focus depth of the focal point or beyond the depth of focus range, which is more likely to cause the effect of the heterogeneity. Therefore, the method of offset focusing marking must consider the issue of laser energy.

2.The laser output spot is blocked, that is, the laser beam passes through the galvanometer and the field lens, some spots of which is missing and not round enough.
Laser output heads, fixtures and galvanometers are not adjusted well, resulting in partial light spots being blocked when the laser passes through the vibration lens. After the field lens focuses, the light spot appearing on the frequency doubler is non-circular, which may also lead to the effect of the heterogeneity. There is also a case where the galvanometric deflection lens is damaged and when the laser beam passes through the damaged area of the lens, it cannot be reflected well. Therefore, the laser beam has inconsistent laser energy through 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 not the same, so that the marking effect is not uniform.

3.Thermal lens phenomenon
When the laser passes through the optical lens (refracting, reflecting), it will cause the lens to heat and produce a fine deformation. This distortion will cause the focus of the laser to rise and the focal length to become shorter. If the machine is fixed and the distance is adjusted to the focal point, after the laser is turned on for a period of time. The laser energy density acting on the material will change due to the thermal lens phenomenon, resulting in uneven marking effect.

4.The level of the machine is not adjusted well, that is, the laser lens or field lens is not parallel to the processing table.
Because the two are not horizontal, the length of the distance from the laser beam to the processing object after passing through the field lens will be inconsistent. Finally, the energy of the laser beam falling on the processing object will have an inconsistent energy density, and the effect will be exhibited on the material at this time.

5. Material reasons, such as the inconsistent film thickness of the surface of the material or the changes in physical and chemical properties.
Materials are more sensitive to laser energy reactions. In general, under the same material, the laser energy reaches the material damage threshold is certain. When the material coating thickness is different or there are some other physical and chemical treatment process is not uniform enough, which will also cause the uneven effect of laser marking.
Perfect Laser (Wuhan) Co., Ltd.
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