What wattage do I need?


The more, the better ?

You might think that more power is always better. Think again…

CO2 lasers are actually very power inefficient lasers. A 40 Watt laser tube actually uses a lot more power than 40 Watt to shoot out its beam. It is not uncommon for having tubes which are only 5 to 10% efficient, which means that a 40W tube consumes between 400 and 800 Watts to operate. That is also the reason why you have to cool laser tubes with water cooling, because most power does not go into the beam, but through the glass to your water cooling system.

Of course not all laser tubes are that inefficient. There are also high quality tubes, but these come at premium pricing.

It also depends what you want to do with your laser cutter. If you only want to engrave and maybe cut some thin pieces of plywood/acrylic, then it makes no sense to buy a very powerful laser. These tubes are not only very power inefficient, but they are also very difficult to set a particular power level for the beam.

In engraving, you need to be able to set accurate power levels. But the bigger the tube, the more difficult to do this.

Some math. (using very inaccurate rough guessing)

Suppose we want to shoot our laser tube at around 20 watt power (50% on a 40W tube). Because the tube is not so stable in power, we assume that there is +10% and -10% of deviation in power possible.

Result: A 40W tube at 50% gives pulses between 18 and 22 watts of power, but a 80W tube at 25% gives pulses between 16 and 24 watts. Which of the 2 systems would you like to use to engrave ?

For most hobby use we’ll stick with 40, 50 and 60 Watt. More is mostly overkill

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