Burrs on Workpiece Edges During Laser Cutting:
When laser cutting carbon steel, burrs sometimes appear on the edges of the workpiece, resulting in an uneven surface finish. In some cases, these burrs are difficult to remove. This issue is primarily caused by the following factors:
1. Incorrect Laser Focus Position: The vertical position of the laser focus is incorrect. A focus position test must be performed, and adjustments should be made based on the observed focus offset.
2. Inappropriate Nozzle Selection: The selected nozzle is unsuitable for the application; replace the nozzle.
3. Insufficient Cutting Gas Purity or Pressure: The purity or pressure of the cutting gas is inadequate. It is necessary to supply high-quality cutting gas and increase the gas pressure.
4. Optical Path Alignment Issues: If cutting a rectangular shape results in burrs on two adjacent edges, it indicates that the center of the optical path has shifted. The central point where the laser beam exits the nozzle must be re-calibrated. If burrs appear on two parallel edges, it indicates a problem with the perpendicularity of the laser head's mounting relative to the machine tool; the laser head's mounting perpendicularity can be adjusted based on the direction of the burrs on the parallel edges. Additionally, check the nozzle tip to ensure its circularity remains intact; the nozzle orifice must maintain a perfectly circular shape.
Failure to Cut Through the Sheet Metal:
1. Insufficient Laser Power/Aging Laser Source: The laser power has dropped, or the laser source has aged, resulting in insufficient energy in the laser beam and a failure to cut through the workpiece. Adjust the laser power or replace the laser generator.
2. Excessive Cutting Speed: The cutting speed is too high; select an appropriate cutting speed based on the thickness of the sheet metal being cut.
3. Gas Pressure Discrepancy: Verify that the output pressure from the proportional valve matches the cutting gas pressure settings configured in the control software (HMI). Also, check if the oxygen pressure gauge indicates a reading of 10 kg/cm².
4. Damaged Protective Lens: Inspect the protective lens for any damage (scratches, cracks, etc.); replace the protective lens if damaged.
5. Incorrect Focus Position: The focus position is unsuitable for the material; adjust the focus position according to the thickness and type of the sheet metal.
6. Internal Optical Component Issues: Assuming the protective lens, cutting speed, and gas pressure are all confirmed to be in good working order, check the fiber optic interface for any issues. If the fiber interface is intact, inspect the collimating lens and focusing lens within the laser cutting head for damage; replace them immediately if any damage is found.
Rough Surface Finish on Cut Sheet Metal:
(Specific to Carbon Steel)
Rough Upper Surface Texture: If the texture on the upper surface is excessively rough, it indicates that the cutting focus is positioned too far away from the sheet metal; adjust the focus position closer to the material.
Rough Lower Surface Texture: If the texture on the lower surface is excessively rough, it indicates that the cutting gas pressure is too high; reduce the cutting gas pressure.
Overall Rough Texture: If the texture across the entire cut surface is excessively rough, it indicates that the cutting speed is too slow; increase the cutting speed. Centering Offset During Processing:
Causes of Failure:
1. The fiber optic cable is loose.
2. Issues with the centering module.
3. The ceramic body is loose.
4. The nozzle is loose.
Troubleshooting Steps:
1. Check if the fiber optic cable is securely locked in place.
2. Contact the cutting head manufacturer.
3. Check if the ceramic body and nozzle are securely locked; if loose, they must be re-tightened.
Fiber Interlock Alarm:
Causes of Failure:
1. The fiber optic cable is not properly seated/installed.
2. Issues with the internal contacts within the QBH connector.
3. Issues with the laser source's fiber connector.
Troubleshooting Steps:
1. Re-secure the fiber optic cable in accordance with the cutting head's operating instructions.
2. Contact the cutting head manufacturer for assistance.
3. Contact the laser source manufacturer for assistance.
Abnormal Cutting Results:
Causes of Failure:
1. Incorrect cutting parameters selected/loaded.
2. Incorrect adjustment of the cutting focus.
3. Issues with the cutting gas supply.
4. Issues with the cutting head lenses.
Troubleshooting Steps:
1. Verify the cutting parameters and the cutting focus position.
2. Check for sufficient gas volume and gas purity.
Depending on the selected cutting gas (O2 or N2), observe the pressure gauge on the gas cylinder. If using oxygen, ensure the pressure is around 10 kg/cm². Additionally, check if the gas output voltage value displayed by the cutting system corresponds to the value shown on the gas proportional valve (typically, 10V corresponds to 10 kg/cm²). If using nitrogen, make adjustments as necessary based on the thickness of the material being cut. Gas purity can be verified by checking the cylinder label to ensure it meets or exceeds 99.9%. When cutting with nitrogen, you can also perform a diagnostic cut on a piece of stainless steel; if the cut edge appears yellow, the gas purity is too low, and the cylinder must be immediately replaced with high-purity gas.
3. Remove and inspect the protective lens for any contamination; if contaminated, the lens must be cleaned.
4. Following the procedures outlined in Troubleshooting Step 3 (above), inspect the internal lenses of the cutting head and the fiber optic end face to ensure they are in good condition; if their positioning is incorrect, adjust them to the proper alignment.
Abnormal Capacitance Value Alarm:
Causes of Failure:
1. The ceramic body is damaged or loose.
2. The nozzle is damaged or loose.
3. The nozzle connector/contact assembly is damaged.
4. Issues with the signal cable. Troubleshooting Steps:
1. Inspect the ceramic body and nozzle for any signs of damage or looseness; if damage or looseness is detected, replace the component and/or secure it firmly.
2. After removing the ceramic body and nozzle, inspect the contact points at the ceramic body's mounting position on the cutting head for damage; if damage is found, contact the supplier for a replacement.
3. Check the signal cable to ensure it is not disconnected.
If no obvious damage is visible, use a multimeter to perform a more detailed inspection under the guidance of an after-sales engineer.
Nozzle Overheating During Processing:
Causes of Failure:
1. Beam alignment deviation.
2. Contamination of the protective lens.
3. Contamination of the focusing lens or collimating lens.
4. Contamination of the optical fiber.
Troubleshooting Steps:
1. Check if the beam alignment has shifted; if a deviation is detected, perform an adjustment.
2. Remove and inspect the protective lens. Important: After removing the protective lens holder, you must use masking tape to seal the exposed opening on the cutting head; never blow air into the opening after the holder has been removed. If the protective lens is contaminated, it must be cleaned.
3. Inspect the internal optical lenses within the cutting head.
Raise the cutting head to its highest position, activate the red pilot light, and unscrew the nozzle. Place a sheet of white paper approximately 20–40 mm below the bottom of the ceramic body, then move the paper up and down to observe the uniformity of the red light distribution. When observing the red light, try to shield the surrounding area to ensure sufficient contrast, allowing for a clearer view. If distinct dark spots are visible, this indicates contamination on the internal focusing lens, collimating lens, or the fiber end face. In this case, you must contact an after-sales service engineer for guidance on how to proceed; do not attempt to disassemble the laser head yourself, and do not continue to use the equipment, as doing so could result in further, more severe damage.