Do you know how to maintain your water chiller?

March 24, 2023
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The chiller, which is usually called "laser water tank", is not only used to cool down the laser source, but also serves as the cooling system of the laser cutting/welding/cleaning head.

Following is the knowledge of working principle, daily maintenance and precautions related to water chiller.

01 Why does laser equipment need a chiller?

The main working principle of laser equipment is to convert electrical energy into light energy, for the conversion is not 100%, so when a part of the electrical energy is converted into light energy, the other part is converted into heat energy; in addition, the operation of the equipment and the friction of the metal will also cause the laser welding/cutting/cleaning head to generate a lot of heat.

Heat energy stays inside the laser and welding/cutting/cleaning head, which can affect the processing effect at least, or damage the internal components at worst. Everyone knows that the cost of lasers and welding/cutting/cleaning heads is high, and the repair and replacement after damage are also very expensive. Therefore, the use of water cooling can reduce the loss rate of equipment and reduce maintenance costs.

02 How does the chiller work?

Water chiller is a cooling water device that can provide constant temperature, constant flow, and constant pressure. Water chillers are divided into two types: air-cooled chillers and water-type chillers. Water-type chillers are common in laser processing. The machine is also the model to be discussed in this article. Common laser equipment chillers can provide two cooling media with stable temperature, one uses low-temperature coolant to cool down the laser, and the other uses normal temperature coolant to cool the welding/cutting/cleaning head.

Schematic diagram of water cooler


The chiller is to convert electrical energy into mechanical energy, use its built-in compressor to compress the superheated steam into high-temperature and high-pressure gas, then discharge it to the condenser and convert it into high-pressure liquid, and then flow through the throttling device (expansion valve or capillary) depressurization, and finally become a low-temperature and low-pressure supercooled liquid, which then enters the evaporator to vaporize and absorb heat to become superheated steam, and then returns to the compressor to enter the next cycle to realize the refrigeration function.


03 How can we maintain the chiller daily?

The first is routine inspection. Every other week, check whether the water level of the cooler meets the requirements, and check once a month whether the water quality of the water cooler has changed (color, smell, impurities, etc.). The second is regular replacement and cleaning, you can refer to the following replacement and cleaning cycle.

Filter cleaning cycle: according to the water quality, check once a week whether the filter is blocked (laser water inlet filter, water cooler filter), the laser water inlet filter is in the laser water inlet Y-shaped mouth.

Laser water inlet filter

Remove the water cooler filter

Dust filter cleaning cycle and cleaning steps: The dust filter is on both sides of the water cooler, and the dust filter is easy to remove. When there is a lot of dust, the cleaning frequency can be increased. Remove the dust screen and use an air spray gun to remove the dust on the dust screen. For oily dirt, please clean it with a neutral detergent. Before reinstalling the dust screen, rinse and dry it.

Chiller Dust Filter

Filter element replacement cycle: Check whether the filter element of the water cooler is polluted, and the filter element of the water cooler needs to be replaced once every six months at most (according to the actual model, some have no filter element).

Cooling water replacement cycle: replace the cooling water according to the water quality, and the cooling water needs to be replaced once every 3 months at most. The water tank of the water chiller is not sealed. Long-term exposure to the dusty environment, dust, metal filings and bacteria enter the cold water to cause water deterioration, and produce insoluble water substances that adhere to the inner wall of the laser waterway, thereby blocking the waterway and causing water flow. Decreases the cooling effect. If this happens, drain all the deteriorated cooling water in time and replace it with new cooling water.

Contaminated filters, filter elements and laser waterways


04 How to choose the correct cooling water?

Cooling water chooses distilled water and deionized water. The reason for choosing these two kinds of water is that distilled water or deionized water is not easy to produce scale during the circulating heating process. It is strictly forbidden to use bottled pure water and tap water.

Distilled and deionized water


05 How to replace the cooling water?

Procedure for replacing cooling water

1. Disconnect the equipment power supply and water cooler power supply.

2. Drain the water in the water cooler and laser, clean the water tank and drain the water.

3. Clean the water filter and filter element of the water cooler (some water coolers do not have a filter element, please consult the water cooler manufacturer for specific conditions) and the filter of the laser water inlet.

4. Install the filter screen and filter element.

5. Inject distilled water into the water cooler to reach the standard liquid level.

6. Turn on the water cooler to circulate the water, check the liquid level display of the water cooler, and add distilled water if the liquid level drops. Note: To prevent the growth of bacteria and algae, 10% alcohol can be added to the cooling water.


06 What else needs special attention in the daily maintenance of the chiller?

When the ambient temperature is 0 degrees or below, it is recommended that users add antifreeze to the cooling water of the laser. After adding antifreeze, the freezing point of the water can be lowered so that the cooling water does not freeze.

Antifreeze cannot be used for a long time: any antifreeze cannot completely replace plasma water, and antifreeze has certain weak corrosion and can only be used for a short period of time. Long-term use will cause damage to the laser and cutting head optics, causing unnecessary losses. After winter, the pipeline must be cleaned with distilled or deionized water, especially the filter screen of the water cooler, the filter element and the filter element of the laser water inlet, and the distilled water or deionized water should be used as the cooling liquid.

If the machine is shut down for a long time, such as the Spring Festival shutdown or before the laser is transported, the cooling water in the chiller must be drained, and the residual water in the equipment including the laser and the chiller must be blown out with compressed air to prevent internal icing or water leakage from causing device damage.

Drain the cooling water in the chiller