CO2 cutting and engraving system,laser engraving shows unevenness at the bottom,what should you do?

RDC6442G, RDC6445G, RDC6585G and other CO2 cutting and carving series control systems. If there is unevenness at the bottom of the carving, it can be adjusted according to the following methods.

1. Calibrate the Optical Path System to Ensure Stable Energy Focus Core
An uneven bottom is often a direct result of uneven laser energy distribution. First, systematically inspect and calibrate the entire optical path. Ensure the laser beam is perfectly centered from the resonator output, through all reflecting mirrors, to the focusing lens. Even minor deviations can cause the focused spot to deform or create asymmetric energy density distribution (such as coma), leading to uneven stripes during scanning and engraving. Simultaneously, it is crucial to clean contaminants from all optical lenses (especially the focusing lens), as oil stains or dust can significantly interfere with beam transmission, causing localized energy attenuation.

2. Optimize Dynamic Processing Parameters for Uniform Energy Input
Once the hardware optical path is confirmed correct, parameter settings become the decisive factor. Excessive processing speed reduces the dwell time of the laser beam per unit area of the material, resulting in insufficient energy accumulation and intermittent grooves resembling "plowing." Therefore, the primary measure is to appropriately reduce the scanning speed. More critically, simultaneously increase the output pulse frequency (switching frequency) of the laser. At a reduced speed, a higher pulse frequency means denser and more continuous energy application points, achieving a "filling" effect that evenly covers the engraved bottom, effectively eliminating horizontal ripples or dot-like marks caused by excessive pulse intervals.

3. Optimize Assist Gas Strategy to Ensure Complete Slag Removal
For cutting or deep engraving operations, the role of assist gas cannot be overlooked. The gas flow must be precisely adjusted: insufficient flow fails to effectively remove molten and vaporized material residues, which can re-solidify and adhere to the bottom of the cut or groove, forming uneven accumulations; excessive flow may interfere with the laser beam and unnecessarily cool the material. It is recommended to use side-blowing whenever possible, aligning the airflow direction at an optimal angle to the laser head’s movement direction. This ensures continuous and smooth expulsion of slag and dust to one side, preventing rebound and deposition within the processing area and maintaining a clean workspace.

4. Match Focusing Lens to Processing Depth to Control Energy Interaction Morphology
The choice of focal length directly affects the size of the focused spot, depth of field, and energy density. For engraving requiring a flat bottom, prioritize short-focal-length lenses (e.g., 1.5 inches or 2.0 inches), as they produce smaller spots and higher energy density, resulting in sharper cut lines. However, it is important to note that short-focal-length lenses have a shallow depth of field. Therefore, when adjusting the focus, the planned engraving depth must be a core consideration. If the engraving depth exceeds the lens’s effective depth of field, the beam will diverge due to defocus at the bottom, causing widening, insufficient energy, and roughness. For deeper engraving, a layered multi-pass scanning strategy may be necessary, ensuring each layer operates within the focal depth range.