Laser engraving technology has slowly entered our daily life. When we use laser engraving patterns, we often encounter such a problem:
“Why is the actual effect of laser engraving uneven?”
1. The content of marking the corresponding area with offset focus: The method of marking with offset focus must take into account the problem of laser energy. This is because each focusing mirror has a matching depth of focus area, and using the method of offset focus will easily lead to the fact that the edge is at the critical point of depth of focus or beyond the depth of focus area when marking a large area, which will easily lead to the nonuniformity of the actual effect.
2. Thermal lens phenomenon: When the light passes through the optical lens (refraction, reflection), it will make the lens hot and cause small deformation. This deformation will raise the focus of the spotlight and shorten the focal length. If the machine and equipment are fixed, when the distance is adjusted to the focal point, after a certain time of turning on the light, it will be due to the thermal lens phenomenon that changes the light energy density acting on the raw material.
3. The focus output spot is masked, that is, after the focus beam passes through the galvanometer and the field mirror, the spot is missing and not round: the focus output head, fixed fixture and the galvanometer are not aligned, resulting in a part of the light spot is masked when the focus light passes through the galvanometer, and the light spot displayed on the frequency multiplier after the focus light passes through the field mirror is non-circular. Another case is that the galvanometer deflection lens is damaged. When the light beam passes through the damaged area of the lens, it cannot be reflected effectively. Therefore, the laser energy of the laser beam passing through the damaged area of the lens is different from that of the non-damaged area of the lens, and the result is that the light energy acting on the raw material is also different.
4. Due to the raw materials, such as the different thickness of the film on the surface of the raw materials or the change of physical properties: the raw materials are particularly sensitive to the response of the light-emitting energy. Generally, under the same raw material, it is corresponding that the light energy reaches the raw material damage threshold. When the coating thickness of the surface layer of raw materials is different, or some other physical processes are not uniform.
5. The same horizontal plane of the laser engraving machine equipment is not aligned, that is, the delivery galvanometer or field mirror lens is different from the production and processing table. Since the two are different horizontal planes, the distance between the delivery beam and the production and processing objects after passing through the field mirror will be different. As a result, the energy of the delivery light falling on the production and processing objects will have different energy density.