Unclear marking results in laser marking machines are commonly caused by problems in the optical path system, equipment parameters, consumable condition, workpiece surface, and environmental interference. These factors should be checked systematically to locate the source of the problem.
1. Optical Path System Faults
Optical path deviation or contamination: Dust, oil, or loose mounting of optical components such as the fiber end face, beam expander, or field lens can cause laser energy to scatter and the spot to distort, resulting in blurred and unclear marking lines.
Laser power attenuation: Aging of the laser pump source or dust accumulation in the laser cavity leads to a continuous decline in output power, making it impossible to form marks with sufficient contrast on the workpiece surface.
Incorrect focal length matching: Using a field lens with an incorrect focal length or adjusting the marking focus incorrectly causes the focused spot to become too large. Laser energy density then decreases, and the marking trace becomes shallow.
2. Improper Equipment Parameter Settings
Marking speed too fast: The laser stays on the workpiece surface for too short a time, so energy accumulation is insufficient and the marking is shallow and discontinuous.
Power or current set too low: The laser output energy cannot effectively act on the workpiece surface, resulting in pale marks and poor clarity.
Unreasonable marking frequency or fill density: At high frequency, single-pulse energy is insufficient, while at low frequency, line breaks may appear. Low fill density creates unmarked areas, making the overall visual effect blurry.
3. Wear of Consumables and Vulnerable Parts
Galvanometer system abnormality: After long-term use, galvanometer motors may develop sticking or position drift, causing inaccurate laser scanning paths and misaligned or blurred lines.
Contaminated protective lens: Smoke, dust, and debris attached to the protective window of the marking chamber filter part of the laser energy and deform the spot.
Cooling system failure: Abnormal cooling water temperature for the fiber laser, whether too high or too low, causes fluctuations in laser output power and affects marking stability.
When worn mechanical components such as galvanometer motor mounts or protective lens holders need replacement, Hansheng Automation provides custom machining based on customer drawings or samples, including single-piece and small-batch orders.
4. Workpiece Surface and Material Problems
Unclean workpiece surface: Oil, dust, and oxide layers reflect and scatter the laser, weakening the effective marking energy and causing blurred marks.
Material-laser mismatch: If the workpiece material has extremely low absorption at the laser wavelength, effective marking cannot be formed.
Uneven focal distance on curved workpieces: Curved surfaces cannot maintain a uniform marking focal distance. The spot becomes larger in some areas, causing inconsistent marking results.
5. Environmental Interference Factors
Excessive dust in the workshop: Dust attached to optical path components or workpiece surfaces interferes with laser transmission and marking quality.
Abnormal temperature and humidity: High temperature causes laser power drift, while high humidity may lead to oxidation of optical components or short circuits, affecting marking stability.
