1. Antifreeze measures for laser cutting machines

Basic principles and methods of antifreeze

Liquids all have a "freezing point", and when the temperature of the liquid is below this "freezing point" temperature, it will solidify and form a solid. During the solidification process of deionized water or purified water, the volume will increase, which will "damage" the pipeline and sealing connection of the water cooling system and cause damage. To avoid damage to the laser, output head, and chiller caused by solidification of the cooling liquid, there are three solutions:

1）If there is absolutely no power outage in the local area, the water cooler should not be turned off at night. In order to save energy, the temperature of low temperature and normal temperature water should be adjusted to 5-10 ℃ to ensure that the coolant is in a circulating state and the temperature is not lower than the freezing point.

2）After daily use, drain the cooling liquid from the laser, laser output head, and water cooler.

3）Use antifreeze as the coolant.

2. Cooling water evacuation method and pipeline design reference

1）Schematic diagram of waterway connection:

2）Valve status during normal use (red closed and yellow open):

When the chiller is turned on, close the red valve and open the yellow valve. At this time, the chiller will actively pump the water from the internal water tank into the water storage bucket until there is no large amount of water flowing out, and turn off the power supply of the chiller.

4) Emptying residual water with low-pressure air:

Close the red marked valve as shown in the diagram, open the yellow marked valve, and inject clean compressed air or nitrogen of no more than 0.4Mpa (within 4kg) into point A until no water is blown out from the outlet at point B.

5) Water cooler drain outlet is normally open

Finally, open the drain outlet of the water cooler to drain the remaining water in the final water tank.

Attention: All cooling water in the laser, laser output head, processing head, and water-cooled machine must be drained thoroughly to effectively protect the entire water-cooled pipeline and related components.

3. Using antifreeze

When the operating environment frequently experiences power outages and does not have the conditions for daily coolant evacuation, antifreeze must be used. The basic liquid of antifreeze is generally composed of alcohols and water, requiring high boiling and flash points, high specific heat and conductivity, low low-temperature viscosity, less foaming, and no corrosion of metal parts, rubber hoses, etc. When selecting or mixing antifreeze, its freezing point should be 5 ℃ lower than the minimum temperature of the usage environment.

1) Use ethanol for short-term antifreeze:

If there is a power outage and the cooling water cannot be drained, temporary short-term antifreeze measures are required. Ethanol (alcohol) can be added to deionized or purified water, with an amount not exceeding 40% of the water tank volume. Ethanol has strong corrosiveness and can corrode grease, paint, rubber parts, and metals. Therefore, it cannot be used for a long time. It must be drained and cleaned with purified or deionized water within a week. If there are still antifreeze requirements, special antifreeze must be selected.

2)Use specialized antifreeze from a professional brand:

1) Antirogen-N ethylene glycol water type (industrial product, toxic to humans)

2) Antirogen-L propylene glycol water type (food grade, harmless to human body)

Using Clariant's Antifreeze N antifreeze, the minimum addition ratio is 3:7 [30% antifreeze, 70% water]. After adding antifreeze, it can resist -12~-15 ℃ without freezing. It is generally recommended to add in a 1:1 ratio, which can reach -25 ℃ without freezing. It should be noted that adding antifreeze only ensures that the water does not freeze within -25 ℃, but it does not mean that the water cooler can operate normally at very cold temperatures. The normal operating temperature of our water cooler should be above 5 ℃. The temperature for cold start should be above 10 ℃.