The beginning of summer is one of the 24 solar terms. The arrival of the beginning of summer represents that summer is coming, and the temperature is obviously rising. This is the time of Mengxia. Although it is not the time of scorching sun and scorching heat, the thunderstorm weather is increasing, and the humidity in the air is very high. Frequent rainfall and humid environment, together with the large temperature difference between day and night, will easily lead to internal condensation of the laser, the core component of the fiber laser cutting machine, which will affect the processing accuracy. How can we avoid the condensation of the laser? What should we pay attention to when using lasers in summer?
Although the optical fiber transmission cable of the fiber laser can be used in harsh environments, the laser body has high requirements for the use environment.
The specific use environment (including installation environment, ambient temperature and relative humidity requirements) is shown in the following table:
The installation environment shall be flat without vibration and impact
Ambient temperature 10 ℃~40 ℃
Relative humidity is less than 70%
Definition of condensation: put the object under a certain temperature, humidity and pressure, and gradually reduce the temperature of the object. When the temperature around the object drops below the “dew point temperature” of the environment, the moisture in the air gradually reaches the saturation state until dew is released on the surface of the object, which is called condensation.
Definition of dew point temperature: from the perspective of application, the temperature that can make the air around the working environment emit “condensation water” is the dew point temperature.
1. Operation and environmental requirements: Although the optical fiber transmission cable of the light laser can be used in a harsh environment, the laser has high requirements for the use environment.
If the value corresponding to the intersection of the laser ambient temperature (air conditioning room temperature) value and the laser ambient relative humidity (air conditioning room relative humidity) value is lower than 22, there will be no condensation inside the laser. If it is higher than 22, there is a risk of condensation inside the laser. The customer can improve it by lowering the laser ambient temperature (air conditioning room temperature) value and the laser ambient relative humidity (air conditioning room relative humidity) value. Or set the cooling and dehumidification functions of the air conditioner to keep the ambient temperature of the laser not more than 26 degrees and the ambient relative humidity less than 60%. It is suggested that the customer should pay attention to recording the values of the thermometer and hygrometer in each shift, so as to find problems in time and prevent risks.
2. Avoid frosting: avoid frosting inside and outside the laser without its own air conditioner
Internal schematic diagram of fiber laser cutter laser
Dew condensation diagram of laser without air conditioner
If no measures are taken, the external surface of the laser will start to follow the condensation.
Internal and external condensation diagram of optical fiber laser cutting machine
Dew condensation diagram of internal and external environment of laser without air conditioner
If the laser without air conditioner is used and exposed to the working environment, once the cooling temperature is lower than the dew point temperature of the environment inside the laser, the water will be separated to the electrical and optical modules. If no measures are taken at this time, the surface of the laser will start to follow the condensation. Therefore, once the laser shell is frosted, it indicates that the internal environment has been dewed. The operation must be stopped immediately and the working environment of the laser must be improved immediately.
Solution to laser dewing of fiber laser cutting machine in summer:
It is recommended that the laser be equipped with an independent air conditioning room.
Laser requirements for cooling water
The laser cooling water temperature must be set above the dew point of the most severe operating environment.
Note: The laser damage caused by condensation in the internal environment is not within the normal warranty scope of the laser.
3: Avoid condensation in the internal and external environment of the laser with its own air conditioner
When using the laser with its own air conditioner and exposed to the working environment, the refrigeration and dehumidification effects of the air conditioner will greatly reduce the dew point temperature of the laser environment. Generally, the refrigeration temperature of industrial air conditioner is consistent with that of cooling water.
When the ambient temperature is lower than 38 ℃, the industrial air conditioner can maintain the safety of the internal environment of the laser, but there may be condensation on the surface of the laser shell.
If dewing does not form flowing drops, it is safe. If there are a lot of flowing drops and there are obvious water stains around the laser, a safe working environment without dewing must be established for the laser with air conditioner.
Fiber laser cutting machine with air conditioning laser
Dew condensation diagram of laser with air conditioner
When the ambient temperature is higher than 38 ℃, the cooling capacity of the industrial air conditioner is not enough to maintain the safety of the internal environment of the laser, and the internal environment will still be dewed, and the external environment will also be dewed after a long time.
Therefore, there should be no obvious heat source around the laser, and the hot air outlet of the water cooler should not face the laser directly.
Dew condensation diagram of the internal and external environment of the fiber laser cutting machine with its own air conditioner laser
Dewing diagram of internal and external environment of laser with air conditioner
4. Avoid condensation in the processing head
When the seasons change or the temperature changes greatly on that day, if the laser processing is abnormal, in addition to the machine itself, it is also necessary to check whether the environment inside the processing head is dewed. Dewing of the processing head will cause serious damage to the optical lens:
1. The cooling temperature is lower than the ambient dew point temperature, which will cause dew condensation on the inner wall of the processing head and the optical lens.
2. The use of auxiliary gas below the ambient dew point temperature will cause rapid condensation of optical lenses. It is recommended to add an expander between the gas source and the processing head to keep the gas temperature close to the ambient temperature and reduce the risk of condensation.
Internal schematic diagram of fiber laser cutter laser
It is recommended to add an evaporator between the air source and the processing head to keep the gas temperature close to the ambient temperature and reduce the risk of condensation.
5. Use the dew point temperature query table
Inquiry Table of Dew Point Temperature of Optical Fiber Laser Cutting Machine
The figure shows the dew point temperature query table. The left side is the current working environment temperature, the top side is the current working environment humidity, and the intersection temperature of temperature and humidity parameters is the “dew point temperature” under this environment.
That is, any object below this dew point temperature in this environment will be dewed on its surface.
Therefore, the adjustment principles are as follows:
1. The low temperature water shall be adjusted within the range of 15-30 ℃, and shall not be lower than the dew point temperature of the laser environment, and shall be as close to 25 ℃ as possible.
2. The normal temperature water shall be adjusted within the range of 5-30 ℃, and shall not be lower than the dew point temperature of the working environment of the machining head, and shall be as close to the current ambient temperature as possible.
Otherwise, it is necessary to improve the working environment according to the dew point temperature query table.
Note: If the temperature and humidity fluctuate greatly on the day of use, the dew point temperature must be calculated based on the maximum possible value of temperature and humidity, otherwise condensation may still occur and damage the laser and laser output head.
As condensation is an objective physical phenomenon, it cannot be avoided 100%. However, we should remind everyone that when using the laser, the temperature difference between the laser operating environment and its cooling temperature must be minimized.