What does a normal laser tube look like when in use?
Looks pretty normal to me. Are you having a problem?
It always seems as if people’s 40k’s are cutting better. I guess I’m second-guessing my self.
Alignment of the mirrors can make a huge difference even if you are only off center by a mm. Other reasons for peoples success can be from replacing the mirrors and lens with higher quality ones, the cheap lenses actually absorb quite a bit of the lasers energy. I tested one K40 that had 35W at the tube, by the time it got to the lens it was down to 25W due to cheap mirrors.