UV or green laser marking machines problems and failures

Release time:2021/09/15

UV or green laser marking machines problems and failures

Many companies and manufacturers have purchased laser marking machines and experienced abnormal problems such as reduced output power, inability of the laser beam to mark, failure to reach the expected marking depth, printing distortion, etc., and then they looked for repairs everywhere, that is, A waste of money and a waste of resources. RFH Laser will help you understand the abnormal malfunctions of laser marking machines and help you easily solve problems during use in the future.


Laser marking machine problems and failures


  1. Methods to eliminate causes of abnormal phenomena


1. The power indicator light does not light up.

1) AC 220V is not connected properly.

2) The indicator light is broken.

  Connect the power cord and replace it.


2. The protection indicator light is on and there is no RF output.

1) Internal overheating, protection unit operates.

2) The external protection contact is disconnected.

3) The Q component does not match the driver, or the connection between the two is unreliable, causing excessive reflection and causing the internal protection unit to operate.

  Improve heat dissipation conditions. Check the external protection contacts. Measure the standing wave ratio.


3. The running indicator light is on, but there is no RF output.

1) The light control signal is always valid.

2) The RUN/T-on/T-off selector switch is in the wrong position.

Check out the light control signal pulse. Turn the switch to the correct position.


4. Processing images and text are confusing.

The effective light level setting is wrong. Reset the effective light level.


5. The laser power that can be turned off is too small.

1) There is a problem with the Q switch component.

2) The output RF power is too small.

Check the Q switch. Adjust the output RF power.


6. The peak power of laser pulse is too small.

1) The average laser power is too small.

2) There is a problem with the Q switching element.

Adjust the light path. Check the Q-switch element.


2. General common faults and solutions:


1. Reasons why the laser output power of new equipment that has not been used for a long time is weak:


① Whether the laser output power measured at the factory reaches the technical specifications;

② Whether the accuracy of resonant cavity adjustment meets the requirements;

③ Check whether there is light leakage from the fully reflective diaphragm;

④ Check whether the insertion loss of the acousto-optic switch is within the specified range.


2. Reasons why the laser output power of the laser decreases after being used for a period of time:

① Whether the laser resonant cavity changes: fine-tune the resonant cavity lens to make the output spot the best;

② Check whether the full-reverse and output diaphragms are stained;

③ The acousto-optic crystal is offset or the output energy of the acousto-optic power supply is low: adjust the position of the acousto-optic crystal;

④ Whether the temperature difference between the water temperature setting of the cooling water tank and the ambient temperature exceeds 5℃;

⑤ Whether the service life of the krypton lamp has expired;

⑥ The laser entering the galvanometer is off-center: adjust the laser;

⑦ If the current is adjusted to about 20A and the light sensitivity is still not enough: the krypton lamp is aging, replace it with a new one.


3. The laser output power is normal, but the laser beam cannot play a marking role:


① Whether the adjustment of the optical path system is accurate;

② Whether the sound and light switch can function as a switch;

③ The D/A card controls whether the sound and light output signal reaches 5V.


4. Reasons why the acousto-optic switch cannot switch the laser:


① Whether the RF output power of the acousto-optic power supply is normal;

② Check whether all power switches are in the correct position;

③ Whether the RF line connection is reliable;

④ Is there any stain on the light-operated end surface of the Q switch?


5. Reasons why the expected marking depth cannot be achieved:


① Whether the laser output power meets the requirements;

② Whether the shut-off power of the sound and light switch meets the requirements;

③ Whether the optical path adjustment is accurate;

④ Whether the position and direction of the beam expander are adjusted accurately;

⑤ Is there any contamination on the lens surface?

⑥ Whether the workpiece surface is on the focal plane;

⑦ Whether the laser power supply output DC voltage 28V drops, causing the laser output power to drop.


6. Reasons why krypton lamps cannot be ignited:


① Whether the krypton lamp has reached its service life;

② Check whether the connection between the electrodes at both ends of the krypton lamp and the laser power supply cable is secure;

③ Check whether the laser power supply is in normal working condition.


7. Several main problems manifested by D/A cards:


① There is no sound and light turn-on signal (+5V) on pin 4, causing the sound and light power supply to fail to turn on;

② The analog signal output cannot accurately reflect the design content, that is, garbled characters appear;

③ AD is not working properly and the printed lines are dotted lines.


8. Several main problems manifested by galvanometer scanning heads:

① Standard squares are printed into trapezoids or diamonds;

② The square frame is deformed into a pincushion or barrel shape.


9. Solution to the printing distortion of the galvanometer scan head:

① The generation of pincushion or barrel distortion is an inherent phenomenon of galvanometer marking, which is determined by the scanning method of the galvanometer. The solution is to perform signal correction on the distortion;

② There are two correction methods. One is hardware correction, which is rarely used at present. The other is software correction, which is the one we use more now;

③ The method of hardware correction is to pass the analog signal output by the D/A card through a correction card to change its voltage value according to certain rules, and then transmit the signal to the galvanometer;

④ The method of software correction is that the marking software itself has a correction function. During the marking process, the digital signal is first processed according to a certain method, and then the signal is transmitted to the D/A card.


10. Laser print lines into dotted lines:


① Whether the signal line is connected well and whether there is any weak soldering;

② Is there any problem with the connection line from the galvanometer driver board to the motor?

③ Whether the D/A card is in the correct position when inserted into the PCI slot;

④ Whether AD is working normally.


11. Circuit problems:


① Due to long-term operation, the krypton lamp terminals become loose, causing the krypton lamp to fail to ignite or spark;

② If the air conditioner does not cool due to long-term operation, you should first check whether the connecting parts are tight, and secondly check whether the upper and lower temperature limits of the temperature controller are reasonable. The upper and lower limits of the temperature controller should be set according to the ambient temperature ±4°C. If there is Freon leakage, the connecting parts should be reinforced and professionals should be asked to add Freon.


12. Problems with optical paths:


① Due to long-term operation, the krypton lamp ages, resulting in a decrease in laser output power;

② Due to long-term operation, the dielectric diaphragm is stained to varying degrees, resulting in light leakage or output power reduction of the full mirror;

③ Due to human factors, problems caused by the customer's adjustment without understanding the specific situation.


RFH Laser recommends that you send your own professional employees to handle problems that can be solved by yourself. If the problem is complicated, you can contact after-sales service!

关键词: UV,green laser marking machines