What is a laser?
Being invented in the 1960s, A laser is a device that emits light through a process of optical amplification. The laser’s ability to read, cut, mark and bind tough materials and etc. is widely used in many industries.
What can lasers do?
In the consumer industry, since the year 1974, laser scanners for reading universal product codes (UPC), or bar codes, have become common in retail stores.
In manufacturing, lasers are a universal tool for engraving, drilling, and marking a broad range of materials.
In the medical industry, lasers can be used for surgical removal of tissue, eye surgery, laser beauty, and etc.
In the military applications, the high energy lasers can be used as a weapon, Now it has been used to destroy the unmanned aerial vehicle.
Why does a laser need thermal management?
In the energy conversion process that occurs with lasers, only a portion of the electrical energy is converted into laser energy, and a large amount of energy becomes heat that needs to be quickly diffused away or carried away.
Temperature not only affects the function and life of the laser device but also affects the frequency of light output. So for a laser sometimes the temperature needs to be controlled to a high degree of precision.
How to apply thermal management for a laser?
For those lasers heating up quickly like CO2, disk, diode, and fiber lasers: they all need a reliable and efficient cooling method for their resonators, optics, and laser heads, even during load fluctuations, to provide consistently high performance.
Effective solutions to control the heat generated by lasers include the use of industrial chillers. A chiller should always keep the temperature at a suitable value and fluctuate preferably as little as possible when the laser is both at full load or partial load. The higher the temperature control accuracy, the better the laser performs. Nowadays, the industrial chiller is a universal way to help manage the heat produced by lasers.
How to choose a chiller to cool the lasers?
The chiller provides coolant at a consistent temperature and flow rate to the laser’s resonators, optics, and laser heads. So it’s essential for a chiller to accurately control temperature and water pressure. The waste heat must be removed from a laser which is also called heat load. Usually expressed in units of watts or BTU/hr. The heat load is the minimum capacity of a chiller to cool a laser.
Every chiller has a cooling capacity curve. Normally, nominal cooling capacity is given at 25℃ coolant output temperature and 25℃ ambient air temperature. For example, when the ambient air temperature is 20℃, the liquid temperature is 20℃, the nominal cooling capacity is 550W.
If you don’t know the heat load of your laser, you can try to get the power consumption of your laser. The heat load is certainly less than the power consumption, so you can choose an industrial chiller whose cooling capacity is no less than the power consumption of the laser machine.
Coolant is the key part of the chiller running process. And not every laser uses the same coolant. We need to choose the appropriate coolant based on different conditions. The main coolants are tap water, water-glycol, and deionized water. The most coolant is ordinary distilled or tap water. It is often treated with additives which include algaecide to prevent algae growth, and/or ethylene glycol to prevent corrosion and lower the freezing point of the fluid. Some lasers require deionized water, which can be very corrosive to many materials. If this is the case, the chiller must have only DI-compatible materials in contact with the coolant, and it should be equipped with a deionization box to maintain the required resistivity level. And if you want to use your laser at a low ambient temperature, then you should use 50% glycol and 50% water as coolant for preventing icing. Also, you should ask the industry chiller supplier whether there is a heater in the water tank because you will need to heat the coolant before using the laser machine.
The proper pump is also an important factor for the chiller, which can control the liquid flow rate and pressure. A positive displacement pump provides a steady flow rate regardless of the recirculating system pressure drop or increase. There are two important parameters for the pump, one is flow rate and the other is pressure(also called water head). The pressure is too high or too low are both not good for use. High pressure may damage water pipes and cause leakage. A low-pressure pump cannot provide enough water flow. In one word, for laser use, the most important thing is the final flow rate of your application.
Other features.
1) Communication features. It allows the chiller to connect with a computer. Interfaces such as RS-485 enables remote operation of a chiller from a computer. With this kind of interface, the chiller can be remotely monitored and set. Including set temperature, actual coolant temperature, coolant pressure, fault conditions, and etc.
2) High/low-temperature alarms help prevent damage from coolant that is too hot or too cold.
3) Low-flow alarms protect both chiller and laser from the frozen coolant.
4) Coolant filters protect the laser and the pump from harmful particles.
