1. Focus Shift
Laser cutting relies on precisely focusing the laser beam onto the surface of the material. If the focus point is too high or too low relative to the material's surface, the energy will not be concentrated enough to fully penetrate the material.
Causes of focus shift include:
Incorrect focus setting during setup.
Change in material thickness without re-adjustment.
Wear and tear on the focusing lens or drive mechanism.
Inconsistent workpiece flatness or warping.
Solutions:
Use autofocus systems when available.
Regularly calibrate the focal position.
Ensure material is level and held flat on the cutting bed.
2. Insufficient Laser Power
If the laser's output power is too low for the material thickness or type, it may not generate enough energy to vaporize or melt the material fully. This can happen even with high-power lasers if the power delivery is unstable or degraded.
Common reasons for insufficient power:
Aging or degraded laser source (especially with fiber or CO₂ lasers).
Power loss due to dirty or damaged optics or fiber connectors.
Incorrect parameter settings (e.g., speed too high for the power level).
Solutions:
Check actual output power using a power meter.
Clean or replace optics regularly.
Adjust parameters to balance cutting speed and power.
3. Lens Contamination
The laser system uses a series of mirrors and lenses to direct and focus the beam. If these optical components are contaminated with dust, smoke residue, or metal splatter, the beam quality can degrade significantly, leading to poor cutting performance or failure to cut through.
Indicators of lens contamination:
Irregular or unfocused cut edges.
Burn marks near the focus area.
Decreasing performance even after power and focus adjustments.
Solutions:
Implement a regular cleaning schedule for all optics.
Use appropriate protective windows and gas shields to prevent contamination.
Always use lint-free tools and avoid touching lenses with bare hands.
--Rayther Laser Lyra Zhang