How to maintain the laser cutting machine

There are always problems with fiber laser cutting equipment, most of which are due to inadequate daily maintenance, poor state of key components or poor operating environment. The fiber laser itself is maintenance-free, but the maintenance requirements of the surrounding system are more stringent and sophisticated. The following is a set of problem-solving-oriented maintenance guidelines for fiber laser cutting machines. Please give priority to “3 core-foundation”: cutting head, lens, cooling system + machine tool cleaning.

Immediate Action: Quick Diagnosis and Emergency Maintenance Checklist

If the equipment is having frequent problems, please check and maintain it immediately in the following order, which can solve 90% of the common faults:

1. The first suspect point: optical lens pollution (symptoms: cut through, rough section, abnormal spark)

• Action: Stop immediately, remove and check the protective lens in the cutting head.
•  Method: Use special lens cleaner and super dust-free lens paper/cotton swab. Apply 1-2 drops of detergent to the center of the lens and gently wipe it with a cotton swab in a spiral circle from the center outward. It is forbidden to blow with mouth, touch with hand and wipe with ordinary cloth.

Note: At the same time, check whether the sealing ring of the mirror base is aging, and ensure that it is well sealed during installation to prevent dust from entering.

2. The second suspected point: the state and alignment of the nozzle of the cutting head (symptoms: unstable cutting quality, slag hanging, frequent burning of the nozzle)

• Action: Check whether the nozzle diameter matches the thickness of the cutting plate (large diameter for thick plate and small diameter for thin plate). Inspect the nozzle bore for wear, distortion or slag.
• Key step: Correct nozzle center (automatic or manual). This is a procedure that must be done daily or after nozzle replacement. An inaccurate center will cause the beam to deflect and severely damage the cutting head.

Suggestion: The nozzle is a vulnerable part. If it is slightly worn, it should be replaced immediately.

3. The third suspect point: the cooling system is abnormal (symptoms: laser alarm, power drop, cutting head water cooling pipe burst)

•  Action:
• Check the water temperature: ensure that the set temperature of the chiller is between 22-25 ℃, and the temperature difference does not exceed 2 ℃ during operation.
• Check water quality: deionized water or distilled water must be used! Check the cooling water for impurities, scale or algae (yellowing, greenery). Change the water regularly every 3-6 months and clean the filter.
• Check the water pressure and flow rate: ensure that the water pressure and flow rate meet the requirements of the laser and cutting head (refer to the equipment manual).

4. The fourth suspect point: external air source and dust removal (symptoms: oxidation of cutting surface, slag hanging, fast dirty lens)

• Action:
• Check the gas purity: nitrogen (more than 99.99%), oxygen (more than 99.5%), compressed air (must pass through the cold dryer and three precision filter, to ensure that no oil, water and dust).
• Clean the exhaust system: clean the exhaust pipe and dust box to ensure that the smoke and dust can be removed in time. Excessive soot can contaminate the lenses and rails.

A systematic graded maintenance plan (prevention first).

Establish rules to make the following maintenance a habit:

Daily maintenance

•  Clean: blow the metal dust and residue on the machine table, guide rail and rack with an air gun.
• Check: gas pressure, water chiller water level, water temperature, focusing lens appearance.
• Must do: Cutting head nozzle center correction.

Weekly maintenance

•  Lubrication: Clean the linear guide and gear rack with a dust-free cloth and apply special lubricating oil.
• Deep cleaning: clean the ventilation filter screen of the electric control cabinet and the vent of the chiller.
• Check: check the fiber transmission jumper (from the laser to the cutting head of the cable) for obvious bending or damage.

Monthly maintenance

•  Optical system: Clean the protective lens thoroughly and check the reflective lens (if any). Record lens cleaning/replacement date.
• Motion system: check the tightness of the drive belt/gear of each shaft and tighten the bolts.
• Dust removal system: clean or replace the dust filter.

Quarterly maintenance

• Cooling system: completely replace the cooling water, clean the water chiller tank and pipeline (depending on the water quality).
• Air system: exhaust air tank water, check and replace the filter element of the air filter.
• Accuracy check: simple test cutting round hole, square precision, if necessary, the machine back to zero and precision compensation.

Annual maintenance

• It is recommended to contact the manufacturer or professional engineer:
•  Inspection and cleaning of the end face of the laser output head (QBH) (professional training is required, improper operation will permanently damage the laser).
• Machine geometric accuracy (horizontal, vertical) calibration.
• Optical path calibration (to ensure optimal beam transmission from the laser to the cutting head).
• Comprehensive inspection of electrical system.

Must develop good operating habits

1. Strict startup sequence: first turn on the chiller, → wait for the water temperature to reach the set value (about 5 minutes) → turn on the machine tool and laser power supply.

2. Strict shutdown sequence: turn off the laser 1 turn off the power of the machine → let the chiller continue to run for 5-10 minutes, and then turn off the chiller after the laser is fully cooled.

3. plate pretreatment: before cutting as far as possible to wipe the surface of the plate oil, water and floating rust, from the source to reduce pollutants.

4.Scientific parameters: do not use the limit power or speed cutting for a long time, and establish a process parameter library for different material thickness.

Maintenance record sheet (example)

Maintenance Items                                                        Problem found                          Replacement parts                           Status after maintenance

Day protection; cleaning station

Surface, guide rail, calibrate nozzle cente              Nozzle slightly worn                        nozzle (Φ1.4)                                         nozzle (Φ1.4)

Clean protective lenses                                              The lens has oil stain                      None (cleaned)                                    Power Recovery

Final summary:

For fiber laser cutting machines, “lens cleaning, nozzle alignment, and chiller maintenance” are the three lifelines. Please establish and strictly implement daily and weekly maintenance procedures from today. Most of the “total problem” situations will be improved by systematic cleaning and inspection. If there is a problem with the core components (such as the laser and the inside of the cutting head), please be sure to record the fault code and phenomenon, and contact the professional after-sales service personnel of the equipment supplier in time.