Overview of common faults and troubleshooting methods for laser marking machines

1. Fault phenomenon one: The laser marking machine does not produce laser light
The troubleshooting steps are as follows:

Power supply inspection: Firstly, it is necessary to confirm whether the power supply wiring of the laser is correct, including whether+24V and GND are reversed, and whether the ground wire is properly grounded. Test whether the power supply meets the actual needs in both unloaded and loaded states.

Card signal detection: Check the signal status of PIN18 and PIN19 pins to ensure that the power supply of the marking card is normal, and verify whether the signal of the control laser is correct.

Emergency switch verification: Check if the emergency stop switch (PIN23 pin) of the device is working properly. When the laser is working, the switch should be in a high level state.

Marking software settings: Confirm if the software settings are appropriate and use the software's laser testing function to observe if there is any light spot output. In addition, laser parameters are tested by debugging software to ensure accurate settings.

DB25 signal confirmation: In the marking state, it is necessary to ensure that the indicator light signal remains at a low level (PIN22 pin is at "0" level). If the guiding light signal is unexpectedly at a high level, the laser will prioritize outputting the guiding light. At this point, it is necessary to carefully check whether the wiring of the DB25-pin serial port complies with the specifications.

Red light signal priority: If the red light signal is at a high level, the laser will prioritize outputting red light. For the built-in red light laser, it is possible to determine whether the optical path is normal by detecting the red light output.

Isolator status assessment: Finally, it is necessary to confirm the spot status of the isolator. A properly functioning isolator should present a circular and dark spot free spot.

2. Fault phenomenon 2: Weak laser output

The troubleshooting steps are as follows:
Working current inspection: Firstly, confirm whether the power supply is stable and check whether the current reaches the rated working current of the laser.

Optical mirror cleaning: Next, check whether the output mirror of the collimator is contaminated. If there is contamination, gently wipe it with anhydrous ethanol, and pay attention to protecting the mirror coating from damage. In addition, other optical lenses such as red light combining lenses, galvanometers, and field lenses need to be checked to ensure that they are not contaminated.

Power attenuation consideration: After 20000 hours of use, the power of the laser will decrease, which is a normal phenomenon.

Signal interference investigation: The disconnection problem that occurs during the marking process may be caused by signal interference. Therefore, it should be ensured that the leads of weak and strong electricity are not tied or on the same side, and signal lines with shielding function should be used. At the same time, it is necessary to check whether the ground wire of the power supply is in good contact.

Interface parameter verification: Check if the pulse width and frequency are set within the required range.

Confirmation of optical path issues: Finally, ensure that the light spot status of the isolator is normal, that is, the light spot is round and free of dark spots. At the same time, check whether the output light of the laser is blocked, and whether the output end of the isolator is on the same horizontal line as the mirror port.

3. Fault phenomenon three: unstable laser output

The troubleshooting steps are as follows:
Recheck the power supply: Firstly, recheck the stability of the power supply to ensure that the current reaches the rated value.
Signal interference elimination: The disconnection problem during the marking process is often caused by signal interference. Therefore, it is necessary to avoid bundling weak and strong electrical leads together or walking on the same side, and to use signal lines with shielding functions. At the same time, check if the 25 pin signal cable is an anti-interference cable and ensure that the port contacts are good.
Temperature monitoring of laser and isolator: When the temperature of the laser or isolator casing is too high (close to the critical temperature of 45-47 ℃ ambient temperature), unstable light output may occur. Therefore, it is necessary to monitor and maintain an appropriate temperature.

4. Fault phenomenon four: Low laser power

The troubleshooting steps are similar to the second fault phenomenon, which also requires checking the power supply, optical mirror status, and isolator operation. Ensure stable power supply, clean and pollution-free optical mirror, and pay attention to the spot status of the isolator and the obstruction of output light.

Consideration of service life: The laser of the laser marking machine will experience power attenuation after 20000 hours of use, which is a normal phenomenon.

Signal interference investigation: If there is a disconnection problem during the marking process, it may be caused by signal interference. Therefore, it should be ensured that the leads of weak and strong electricity are not tied or on the same side, and signal lines with shielding function should be used. At the same time, it is necessary to check whether the ground wire of the power supply is in good contact.

Armor cable bending inspection: It is necessary to confirm whether the bending radius of the armor cable is too small, which may affect the output quality of the laser.

Marking parameter verification: For MOPA series laser marking machines, it is necessary to check whether the pulse width and frequency are set within the required range.

5. Fault phenomenon five: Laser pen breakage

Working current inspection: Firstly, it is necessary to confirm whether the power supply is stable and check whether the current has reached the rated working current of the laser.

Signal interference investigation: The disconnection problem that occurs during the marking process is often related to signal interference. Therefore, it is necessary to ensure that the leads of weak and strong electricity are not tied together and not on the same side, and to use signal lines with shielding functions. In addition, it is necessary to check whether the ground wire of the power supply is in good contact.

Laser temperature monitoring: When the temperature of the laser casing is too high, it may affect the stability of the laser output. Therefore, it is necessary to monitor the temperature of the laser to ensure that it does not exceed the critical temperature (e.g. reference temperature is 53 ℃).

Board problem detection: Check whether the wiring of the board is correct and the contact is good. At the same time, use an oscilloscope to detect whether the 19 pin signal (board output, control board input, and sampling resistance signal) is normal.

Other possible fault phenomena and handling methods include:
Laser power supply issue: If the laser cannot be powered, check whether the power supply wiring is correct, especially whether the+24V and GND wiring are reversed, and whether the ground wire is well grounded. At the same time, confirm if the power cord is in good contact.
Isolator spot abnormality: Check whether the output spot of the isolator is normal, that is, whether the spot is round and free of dark spots.