Does the water temperature going thru the laser tuber have a direct affect to the efficiency of the burn. I know you dont want your water temp toexceed 70 F, but is there a limit to how cold?
You don’t want it below the dew point temperature, which can allow condensation on the tube.
The laser tube temperature will affect the gas ignition point, which is most obvious at the lowest power. At normal power levels the temperature likely won’t make much difference.
For example, a test pattern on a scrap CD-R started with the coolant at 20.5 °C, which meant the Min power of 7.1% didn’t quite fire:
Running the test pattern over the whole CD-R raised the coolant to 20.7 °C by the end and the Min power was firing somewhat better:
Raising the Min power to 7.5% produced a complete pattern on another CD-R, although with some thin sections:
The chiller has a water-cooled pump, so when the Basement Shop gets cold I run it for a while to raise the water temperature into the normal 20±1 °C operating range.
Which is another reason why normal cut settings should have more power than the absolute minimum required to get through the material. 