Laser Source Protection During Cold Seasons

When it's cold, the laser source and water chiller may need your protection.

Basic principle and method of anti-freezing:

There is a "freezing point" in the cooling water. When the temperature of the cooling water is lower than the "freezing point", the cooling water solidifies and expands at the same time, resulting in the expansion and deformation of overflow components in the laser cooling system, such as water cooling plate, water separator and other components, and even expansion and cracking. For high-power lasers, the core optical components are installed on the water-cooling plate. The expansion and crack of the water-cooling plate will directly lead to the laser having to be returned to the factory for maintenance. In addition, the waterways of chillers and laser heads will also cause expansion cracks, which will bring great economic losses to users.(Note: the equipment damage caused by icing is not within the scope of warranty) therefore, anti-freezing measures must be taken for the laser in winter. The following are three solutions:

1) Keep the chiller running. When there is no power failure locally, keep the chiller running, and set the low temperature water and normal temperature water to about 5 ℃ (ensure that the cooling water is higher than the freezing point and save electric energy at the same time);

2) Drain the cooling water in the machine. Drain the cooling water in the laser and water cooler after each use.

The following is the drainage method:

Remove WAETR IN pipe from water chiller, and then use compressed gas to blow away the water from WATER OUT. (for water chiller)

Remove WATER IN pipe from laser source, and then use compressed gas to blow WATER IN till water coming out from WATER OUT.

(Note: WATER IN and WATER OUT must be covered by water pipe or rubber plug while finishing the drainage.)

(For single-mode laser source)

3）Replace the cooling water with antifreeze. Antifreeze must be used when the environment is often powered off and the conditions for draining the cooling water every day are not available.

Selection of antifreeze:

1. Please select the antifreeze with appropriate freezing point according to the local air temperature. The selection of antifreeze is not the lower the freezing point, the better. But the antifreeze shall be slightly lower than the local air temperature according to the local minimum air temperature

2. Professional brand antifreeze is recommended, for instance, Clariant

Note: Any antifreeze solution cannot completely replace deionized water and is not recommended to be used for a long time throughout the year. After winter, it is recommended to use deionized water or distilled water to clean the pipeline and restore the use of deionized water or distilled water as coolant.

In case of long-term shutdown (such as during the Christmas Holiday shutdown), it is recommended to drain the cooling water in the equipment and blow out the residual water in the equipment (including laser source and chiller) with compressed air.

Optical Fiber Precautions

1. Once the optical fiber output end contacts the external air, before re inserting it into the processing head, be sure to clean the optical fiber output end face with a special microscope and cleaning tools according to the standard steps. After confirming that the cleanliness of the output end face meets the standard, it can be connected with the processing head.

2. Regularly check the cleanliness of the protective film.

In the process of laser processing, the protective sheet will inevitably be polluted by dust or splash. Once the pollution is serious, it will not only attenuate the energy reaching the workpiece surface and degrade the beam quality, but also damage the safety of the laser.

3. When pulling out or inserting the optical fiber output end into the processing head, it is necessary to avoid dust and other dirt polluting the lens. It is recommended to place the processing head horizontally and return the processing head to the normal position after it is connected with the optical fiber.

4. When using the equipment to drag the optical fiber, it must be noted that the minimum bending radius of the laser optical fiber is 200mm.

5. In the process of laser processing, it is also necessary to pay attention to the state of each auxiliary gas to ensure that the lens will not be damaged due to timing, lack of gas and other factors.

6. When the output energy drops suddenly during use, do not increase the power blindly. Check the protective lens, focusing lens, swinging lens, collimating lens and optical fiber head in sequence.