Unclear engraving by a laser engraving machine is usually caused by the following 8 types of problems. Just check them one by one in order of their occurrence frequency from high to low

Focal length offset

The distance between the laser head and the material surface deviates from the optimal focus (commonly seen after thickening the material).

Solution: Recalibrate with a focusing scale or the auto-focusing function, lowering the Z-axis by 0.5mm to test the comparison effect and find the clearest point.

Lens contamination

Dust or fingerprints on the reflector, focusing lens or protective lens can cause laser scattering.

Solution: After turning off the machine, use anhydrous ethanol and a dust-free cotton swab to wipe the lens in one direction. If the lens has been burned, it needs to be replaced.

The power/speed parameters are incorrect

Low power or too fast speed leads to insufficient energy, especially when marking dark materials or metals.

Solution: Test on waste materials. First, fix the speed (such as 300mm/s), and increase the power by 5% each time until there are no sawteeth at the edge and no residue at the bottom.

Problems with the material itself

Uneven density (such as inferior acrylic), surface film not removed, or metal not sprayed with marking agent.

Solution: After peeling off the film, clean the surface with acetone. Before marking the metal, evenly spray the special additive. For wood, choose horizontal grain carving for clearer results.

Optical path offset

After long-term use, the Angle of the mirror slightly changed, and the laser was not incident perpendicularly.

Solution: Stick masking tape at the laser outlet, spot and observe whether the light spot is centered, and correct it by adjusting the frame screws. If necessary, preview the entire trajectory with red light.

Laser tube attenuation

When the glass tube has been used for more than 8,000 hours or the power of the gas-filled laser has decreased, it will show shallow engraving and blackening at the bottom.

Solution: Use a power meter to measure the output. If it is 30% lower than the nominal value, the laser tube needs to be replaced. The metal tube can be returned to the factory for inflation.

Abnormality of the cooling system

Excessively high water temperature (common in summer) leads to unstable laser power and uneven engraving depth.

Solution: Check the temperature of the water-cooled machine. If it exceeds 25℃, replace it with pure water and clean the heat sink to ensure that the flow rate is ≥4L/min.

Software Settings error

The wrong "scan mode" was selected (such as engraving vector text in dot matrix mode), or the DPI was lower than 300, resulting in jagged teeth.

Solution: Switch the text mode to "Fill + stroke", set the DPI to 400-600, and enable "bidirectional scanning" to enhance efficiency, but it is necessary to test for ginning.

Additional tip: Cover the material surface with blue masking paper before engraving. After engraving, remove it to eliminate the edge slag. If engraving metal, try using black anodized aluminum as the test benchmark, which can quickly determine whether it is a problem with the equipment or the process.