Optical path calibration process:

Reflector alignment and verticality check: 

Use an infrared observation card and collimator to ensure that the laser beam passes through the center of each reflector, with a verticality error of ≤±0.05°. If the spot ellipticity is >10%, clean or replace the lens.

Zero focus calibration: 

Cut test lines at different Z-axis heights to find the smallest cut gap position as the physical zero focus, then set the compensation value in the software (such as W-axis retraction distance + 1 mm).

Temperature and humidity control: 

The workshop temperature must be maintained at 22±2℃, with humidity ≤60%, to prevent thermal deformation of the lenses. For example, every 5℃ fluctuation in temperature may cause a 0.03mm shift in the focal point position.

High reflectivity material processing:

When cutting materials such as aluminum and copper, use surface blackening treatment (such as anodizing) to increase laser absorption, and move the focal point appropriately upward (such as 0.5 mm above the surface) to reduce energy loss caused by reflection.

Thick-walled pipe cutting:

For pipes thicker than 10 mm, enable pulse mode (frequency 50-200 Hz) and dynamically adjust the focal depth using a capacitive sensor to ensure a stable molten pool. For example, when cutting a 12 mm stainless steel pipe, set the focal position to 2 mm below the surface and the auxiliary air pressure to 2.0 MPa.

Focus shift: 

If slag appears on one side of the cutting surface, check whether the cutting head is loose, or recalibrate the focus position using the “CNC positioning and marking method.”

Sensor failure: 

Switch to manual mode, temporarily adjust the focus using the target paper marking method, and replace the faulty sensor at the same time.

Regular Maintenance Checklist:

Every 50 hours: Clean the focusing lens and protective lens, and check the sensor probe for wear.

Every 200 hours: Calibrate the optical path verticality and test the capacitive sensor response time (should be <5ms).

Every 500 hours: Fully calibrate the mechanical axis (rail level ≤0.1mm/m) and replace aged reflectors.

Through the comprehensive application of the above technical measures, laser pipe cutting machines can achieve high-precision control of the focal position during the cutting process (typically with an error of <±0.05 mm), significantly improving cutting quality and efficiency. This is particularly suitable for fields with strict precision requirements, such as aerospace and automobile manufacturing.