The principle of laser marking galvanometer and common troubleshooting

Principle of laser galvanometer:

　　The principle of the laser galvanometer is: input a position signal, and the swing motor (laser galvanometer) will swing a certain angle according to the conversion ratio of a certain voltage to an angle. The whole process adopts closed-loop feedback control, which is composed of five control circuits including position sensor, error amplifier, power amplifier, position distinguisher, and current integrator. The principle of digital laser galvanometer is to convert analog signals into digital signals based on the principle of analog laser galvanometers. The scanning laser galvanometer is the core component of the marking machine, and the performance of the marking machine mainly depends on the performance of the scanning laser galvanometer.

The laser galvanometers currently used in China are all analog laser galvanometers. The main implementation is to use analog devices. Because analog devices are easily interfered by electromagnetic radiation from the surrounding environment, there will be scattered points, curved lines, and non-filling characteristics during use. Phenomena such as regular shading. Moreover, the speed of the domestic analog laser galvanometer is slower than that of foreign countries, and its small step response time is above 300um. The digital laser galvanometer uses digital signals to perform operations to control the motor, which can effectively suppress environmental interference. Even if the electromagnetic interference in the working environment is severe, it can be used normally.

　　 This system adopts foreign control technology, and the system response speed is very high, which basically surpasses the same type of domestic laser galvanometer system. The motor adopts special technology, long life, stable and reliable performance.

　　 Scanning laser galvanometer introduction

　　 High-speed scanning laser galvanometer system is a high-performance rotating motor specially designed for optical scanning applications. The motor part adopts a high-precision position sensor. Mainly used for fast and accurate positioning of beams. The high-speed laser galvanometer is the crystallization of years of experience in the development and production of industrial laser galvanometer scanning systems.

　　The motor specially designed for the lens load can achieve the most ideal scanning performance. Special treatment is applied to the bearing part, which is capable of long-term uninterrupted operation. The special design of the bearing enables the system to achieve the highest dynamic performance and resonance characteristics. The international leading digital control method can effectively avoid all kinds of electromagnetic interference in the working environment, and the advanced control algorithm can ensure that the system has a faster response speed.

　　The photoelectric sensor used in the high-speed scanning laser galvanometer has high resolution, very good repeatability and very small drift. The motor has a heating device and a temperature sensor, which can work stably even in the case of environmental fluctuations.

　　 high-speed scanning laser galvanometer can ensure long-term stable operation.

Common faults in galvanometer of laser marking machine

　　 1. The galvanometer motor is not self-locking

　　 First check whether each connection line is open or short, whether the connection is correct, whether the insurance is intact, after confirming that it is correct, turn on the power, and observe whether the indicator light on the galvanometer drive board is green or yellow. If it is not on or the red light is on, unplug the power cord of the drive board and use a multimeter to measure whether the voltage of each terminal of its input end is ±24V. If the voltage is normal, test whether the voltage is normal with the drive board and machine load on the side. If it is not normal, open the control box and test the switching power supply voltage without load. If the voltage is abnormal, just switch the power supply. damage. After the power input is normal, after connecting all the cables and powering on, the motor will generally make two ticking sounds. If there is no sound, gently push the vibrating lens with a little force. If the vibrating lens is not self-locking, drive The board is broken. Of course, when the voltage output is normal, the driver board light is not on or the red light is on. That means there is a problem with the galvanometer driver board or the motor. If the mirror motor is not self-locking, the galvanometer motor is damaged. For the same reason, find a well-confirmed galvanometer motor, connect it to the drive board that is not powered on, and turn on the power. If it is not powered on, the galvanometer drive board is damaged. Such repeated connection and unplugging must be performed when the power is off.

2. The galvanometer motor is self-locking, but it is not strong enough. Use a confirmed galvanometer drive board and a good galvanometer motor to connect to the drive board and the galvanometer to be tested respectively, power on normally, and turn the vibrator lightly by hand. If the mirror shaft becomes "hard", it is normal; otherwise, it can be judged that the galvanometer drive board and the galvanometer motor are damaged.

3. The galvanometer motor does not swing. Check whether the marking card has a control signal output. (Note that the signal is a DC voltage signal from -5V to +5V). , Marking, if there is still no swing, check whether the signal wire is connected in reverse or broken, otherwise, it can be concluded that the drive board is damaged.

4. There is a wave line in the marking, the marking head machine makes a slight cry, and the galvanometer drive board heats up slightly (interference occurs). Check whether the grounding wire is correctly connected (the best grounding method is: X galvanometer signal ground , Y galvanometer signal ground, shielded wire, 220V power supply ground, and the marking casing must be connected), if there is still interference after the ground wire is connected, first check whether the marking card is normal (the inspection method is to use one piece to confirm that it is intact) If there is still interference, check if the galvanometer motor connection line is intact and whether it is entangled with other lines. If everything is normal, first use one to confirm that it is intact. Replace the galvanometer drive board. If there is no interference, it can be concluded that there is a problem with the galvanometer drive board; if there is interference, there is a problem with the galvanometer motor. (Of course, if the company is out of the laser maintenance personnel, please make sure that if the customer’s galvanometer is a product three years ago, the product’s anti-interference ability will definitely be poor. If there are mobile phone signals, motors, motors around the galvanometer marking head, Magnetic field, or the exposure of the RF signal of the Q switch may affect it, and this phenomenon can happen to the new galvanometer)

5. Howling

Same as the fourth step, test the signal of the marking card, wiring, external interference, etc. If there is still howling, then debug the potentiometer on the filter board of the galvanometer driver board. If the howling still cannot be eliminated, you need to return again. The company makes precise adjustments. (Note: Don't be in the whistling state for a long time, so as not to burn the galvanometer motor)

　　6, the marking is not sealed or over-sealed

　　 Change the "jump delay" in the marking software, the delay of light emitting and turning off. If nothing works, the galvanometer has not been fully calibrated and should be returned to the company, and will be returned to the supplier. The qualified laser repair after-sales personnel can make certain adjustments according to the galvanometer debugging steps, but pay attention to several potentials. Is the device moved randomly? (Talk to see the tuning steps of the galvanometer)

　　7. When marking, there is no laser output under the marking head, but there is laser in the laser exit hole

　　 The software marking speed is very fast, the field lens is not installed, the galvanometer does not move and the swing position is not normal, the galvanometer lens falls off, and the galvanometer lens is dirty. The first few problems should be dealt with according to the above method. The galvanometer lens is peeled off and cracked. You have to return to the company to replace the new lens and adjust the laser. The galvanometer lens is dirty with 99% alcohol and absorbent cotton. If the part, or the edge part is larger than 1 square millimeter, the vibrating lens needs to be replaced as if the vibrating lens fell off.