The water chiller in top condition.
All the essential everyday knowledge about the water chiller to keep it in good condition so your laser source will be in top shape too!
Why is cooling water so important?
The water chiller must contain sufficient clean cooling water. This is necessary to cool the laser source. During laser cutting, the laser source produces a lot of heat, but the laser source itself cannot cope with heat very well. The cooling water transfers the heat from the laser source through the hoses to the water chiller near the machine. The water chiller cools the water to the right temperature and pumps it back to the laser source.
Because of the electromagnetic activities inside the laser source, the water must be demineralised, so everything that happens inside the laser source is not affected by the water flowing through it. Any kind of pollution will reduce the demineralised effect of the water and will have a bad influence on the laser source. This might even cause the laser source to break down or the machine to go into short-circuit protection, as the high voltage in the laser source might come out through the water.
This can lead to very unusual but undesirable and dangerous scenarios as shown in the picture below.
Proper cooling water is of vital importance.
How can you tell if there is enough cooling water?
The CW-3000 water chillers do not have a fill level gauge, so you will have to change the cooling water in these water chillers to be sure that the right amount of water is in them.
On the CW-5000 and CW-5200, look on the back of the water chiller for the fill level gauge, if it is between the values ‘Full’ and ‘Normal’, the water level is fine.
Please note that when the machine has run once or more, the water is not only in the tank but also in the laser source and the hoses. So it is only normal for the level not to be at ‘Full’ when the machine is running, which is why it is more important to monitor the ‘Normal’ level than the ‘Full’ level.
Is your cooling water clean?
If there is sufficient cooling water in the chiller, it is important to check that this water is clean. Do you see some dirt in the laser source or at the fill level gauge? Then you have to empty the water chiller, clean it and replace the water. Be careful to not touch anything when checking the laser source!
When to replenish, when to renew?
When to replenish, when to renew? Advantages of one over the other?
In theory, the water chiller doesn’t ever need to be replenished. The water chiller will beep and set off an alarm if there is a real shortage. However, this is usually a result of a larger defect (leak) so it is advisable to check why it is empty.
How much cooling water do you need and where do you buy it?
About 7 liters of demineralised water goes into the water chiller. You can buy the demineralised water at the hardware store.
How to empty the water chiller
What you need:
- A 10 L bucket
- A table or other place where the water chiller can be placed
- A socket wrench (22)
Mark the hoses with a permanent marker so you can keep them apart, in order not to confuse the inlet and outlet later. The easiest way is to name one hose ‘in’ and one hose ‘out’. Disconnect the water hoses from the chiller but not from the laser machine. Hang the outlets of these hoses high so no water will run out. Carefully lift the water chiller onto the table, keeping in mind the open hose connections where a small amount of water may come out.
On the back of the water chiller, in the bottom left-hand corner (viewed from the back), is the drain cap. Place the bucket under the drain cap and unscrew it completely using a socket wrench (22). Empty the entire water chiller into the bucket. When no more water comes out, grab the front handle and raise the front so the last bit of water will come out. Now screw the drain cap back on the water chiller.
Place the bucket behind the machine and put the hose that was connected to the outlet of the water chiller into the bucket, making sure it is completely submerged. Take the air pump from the machine and connect it to the other water chiller hose inlet. Start the air pump and let it blow the hoses and the laser source entirely empty. This might take a while, so continue for about 5 minutes. Turn off the air pump and disconnect the air hose. Now disconnect both hoses and take the water to a chemical waste disposal site following what is stated in the MSDS.
How to fill the water chiller?
What do you need:
- 7 liters of demineralised water
- A funnel that fits a 35 mm hole
Make sure the water hoses are connected to the chiller correctly. Both the output and input hoses should be attached in the right places.
Please note! For the BRM Original, the water chiller inlet must be on the laser machine outlet and the water chiller outlet on the laser machine inlet. For the other machines, it depends on how you have labelled the hoses. (Check the section ‘How to empty the water chiller’.)
Check if the drain cap is properly closed. Unscrew the cap on top of the water chiller and place the funnel in it to fill the water chiller with 7 L of demineralised water. Screw the cap on top of the water chiller back.
Start the water chiller and verify that the water flows in the right direction in the laser source. It should flow from left to right (if you are standing behind the laser machine). If this is not the case, reverse the hoses on the inlet and outlet. Now keep the water chiller running for a few hours until you see no more air bubbles in the laser source. If after about three hours you still see some air bubbles, you can pinch the hose a little to give a jolt to the water to release them. As soon as the water, without air bubbles, circulates well with the water chiller on, the laser machine can be used again.
Air bubbles in the laser source
Air bubbles in the laser source can cause irreparable damage. Air is a very poor heat conductor, especially compared to water. Therefore, if there are too many or too large air bubbles at one place, that area can become hotter than the rest of the laser source. This can cause thermal stress on the glass, slightly distorting it, but enough to cause the laser to not cut as well as it should. There can also be so much heat that the laser source breaks because the glass can no longer handle the stress. That is why it is crucial to check the laser source for air bubbles.
