Removing bubbles from laser tube

Laser tubes should not be operated with air trapped within cooling piping as this can cause temperature hotspots and compromise integrity of the tube.

In ideal world, stream of water would remove all the bubbles but in our reci tube there are some welding spots where water becomes turbulent and traps pretty large air bubbles. This trapped air is very hard to remove.

To remove those you can:

Wait

If you wait long enough they will disolve themselves, but it can take hours!

Tilt

You can turn off chiller and tilt entire cutter, all you need to do is get bubbles moving couple of inches away from blocking spot. Obviously this method is only feasable if you have small cutter or someone really strong  (like Vladimir Putin) in your workshop.

Pump cycle

Turn pump on and off, quite often bubbles will move slightly from the deadlock place if you turn off the pump, catch this moment and turn pump again to remove the bubbles. This is quite tricky and does not work all the time.

Turbulences in water flow

Best way we found is to cause turbulences in water flow, all what needs to be done is to pinch and release incoming [from laser tube perspective] water hose once or twice, pinch will cause pump to build up pressure and when you release that pressure is going into the tube causing strong turbulences and removing bubbles. Our CW-5200 chiller pump is connected to coolant pipes using soft silicone joints, those can be easily pinched by hand.

Be careful when pinching, start gently, turbulences and overpressure caused by this are quite strong, if we pinch ours all the way we can almost feel cutter to vibrate on release. It can damage laser tube.

Rear of chiller