What Is Laser Optical Power?
When buying a diode laser engraver you will often see that manufacturers often state the power of the laser engraver with big numbers, like 20W, 40W or even 80W. Some manufacturers claim that this is the machines cutting effect equivalent to the comparable CO2 laser power. Which it is not!
Other manufacturers claim that that number represents the machines electrical power consumption.
But definitely that is never the true power of the laser engraver machine! The thing you need to look for is the term called optical power. This is the true energy that laser module emits in a tiny spot which causes the material to burn away under the intense energy of this light.
In terms of optical laser power, the vast majority of the currently popular laser engravers fall in only two major categories – the 5W and 10W optical power. The first category features one single laser diode inside the module, while the 10W modules have clever optics inside that merge laser light from two laser diode sources, resulting in double the output power.
What We Wanted To Find Out?
If you read through all our laser engraver reviews on this website, you probably saw saw that between the machines, the cutting and engraving performance differs a lot despite the fact that their claimed optical output power is very similar (5W or 10W plus or minus 1W).
In this test we wanted to see, if the cutting performance differences are due to the manufacturers claiming wrong optical power values of their machines, or the difference in cutting performance might be due to some other factors.
Which Laser Engravers Did We Measure in This Test?
We have tested the following popular laser engravers:
We have also tested if a moderate use of the laser will degrade the modules output power, as we will compare a brand new Sculpfun S9 module to the one we have used extensively for approximately 50 working hours, with more than half of them being at full power.
How Did We Measure The Laser Optical Power?
We measured the optical power with a Fieldbest optical power meter, that measures by the principle of the heat produced by the laser light. The beam has to be unfocused in order not to damage the measuring probe. So we “focused” all the modules 20mm above the optimal focus for consistency, although the height does not affect the measurement all that much. It is more to ensure that the beam is unfocused.
Check the video below that shows the entire testing process:
What Did We Find Out?
As we can see, some of the laser modules are above specification, but some are below the specified output.
So, what can we conclude from this experiment? If you have read some review articles of different laser engravers on our website, probably saw that their cutting performance differs much more than the difference in output power that we have measured here could suggest.
So, what makes a good laser cutter if it is not the output power? The answer is inside the laser optical system. If a laser can focus the beam in a very small square shaped spot, it will perform much better at cutting compared to a laser with the same optical power but with a bigger focus spot size. A great example for this is the Sculpfun S9, which produces very clean cuts compare to similar machines with bigger focus spot size.
So, when buying a new laser engraver, you should not only look at the power output, but also at focus spot size. But the problem is that the advertised focus spot size is often nowhere near the real one. This is why this website was born, so you can have all the necessary objective information needed to purchase the best laser engraver for your needs!