It's kind of like the way moving air cools something faster than still air, but if air is moving faster that the materials ability to transfer heat into the air then the airs velocity "energy " generates friction and imparts energy from it's velocity in the form of heat by exciting the molecules of the material.
Like a spacecraft re entering earths atmosphere, in this case moving air is not able to cool, rather it heats.
When a laser imparts its energy into the material in a way that it exceeds the materials flashpoint it is not always focused at it's tightest.
Sometimes less is more, for cooling moving air is good, but way too much fast moving air is counter productive, not all things are linear and material science is amazing, pressed titanium connecting rods ....but I digress.
Look at this video, where the beam gets tightest ( where the pensile is pointing ) it stops imparting energy into a large surface area and cuts through a thin area without exceeding the flashpoint of the material adjacent to the thin cut line. When the wood is moved into a less concentrated beam of the same energy it imparts heat into more surface area and exceeds the materials flashpoint before penetrating, but if focused needle thin all that energy would just punch through a small spot.
Sometimes less is more in a sense and some tools work better for different jobs, 10400nm will cut clear looking glass but 1040nm will mostly pass through.
