Troubleshooting Methods for Laser Marking Machines
A laser marking machine is a low-power laser device that operates as follows: The input graphic—whether scanned or designed within a computer—is encoded as digital signals (in both row and field directions) under computer management and control. This data undergoes digital-to-analog (D/A) conversion and analog-to-digital (A/D) conversion. A/D conversion. The amplified signal then drives the motor in the control unit, which deflects the mirror in the required direction. This creates an extremely fine trace (the desired pattern) on the surface of the object being marked.
The following faults commonly occur during laser marking machine operation, typically stemming from issues with the laser power supply.
Fault 1:
Symptom: When the main power switch is turned on and the trigger button is pressed, the power supply fails to activate.
Cause: This fault occurs due to the protection circuit activating, preventing the application of 380V AC voltage.
Troubleshooting:
First, push the “AC380V Power” switch and press the power “Start” button. Observe whether the AC contactor operates. If it does not, first check if the cooling system is functioning (water circulation). If the cooling system is normal, inspect whether the water pressure protection device triggered by water circulation is activated. If not, the AC contactor is damaged.
Second, use a multimeter set to the R×1K range to check if the 2K/10W power resistor in the power circuit is damaged. If open, replace it.
Finally, verify the 12V power supply to the optical deflection motor. Measure for 12V voltage across the motor terminals with a multimeter. If absent, inspect the rectifier circuit input (AC 17V). If still absent, check for AC voltage at the transformer's input (220V) and output (17V). If 220V is present but 17V is absent, the transformer is damaged and must be replaced.
Fault 2:
Symptom: The marking machine operates normally, but adjusting the “Current” knob causes the power meter to display zero continuously.
Cause: If no display appears at all, the power meter's power supply is faulty. If it consistently shows zero, the power meter's sampling signal is interrupted.
Troubleshooting: Check if the rectified DC voltage (12V) supplied to the power meter transformer is normal. If normal, verify if pin 3 of the 7805 regulator has 5V. If no 5V is present, the 7805 regulator is damaged. Replace it to resolve the fault.
If the power meter consistently displays zero, the power meter's sampling signal is interrupted. Troubleshooting Method: Using a multimeter set to the R×1Ω range, trace the circuit in reverse according to the schematic diagram to locate the open circuit.
Fault 3:
Fault Symptom: The laser marking machine operates normally, but adjusting the “Current” knob causes the power meter to show no display, consistently reading zero.
Cause: If no display occurs, the power meter's power supply is faulty. If it consistently shows zero, the power meter's sampling signal is interrupted.
Troubleshooting: Check if the rectified DC voltage (12V) at the power meter is normal. If normal, verify if pin 1 of the 7805 regulator has 12V voltage. If present, the 7805 three-terminal voltage regulator is damaged. Replace it to resolve the issue.
If the display consistently shows zero, the power meter's sampling signal is interrupted.
Troubleshooting Method: Using a multimeter set to the R×1Ω range, trace the circuit in reverse according to the schematic diagram.
For more information about laser marking machines, laser welding machines, and laser cutting machines, please visit the official website of Wuxi Top Optics Laser Technology Co., Ltd.: http://www.tollaser.com