Adjusting mirrors and focus on my K40. All mirrors beam shows as a dot and I have that centered in all mirrors. But when the beam leaves the focal lens it is a line instead of a dot. Why? Is the focal lens bad?
make sure it isnt being clipped by the end of your laser head nozzle, this can cause beam deformation.
No air nozzle installed. Not hitting the inside of focal tube either.
Cracked lens or mirror.
I get perfect dots al the way through the mirrors
Then it’s a bad focus lens
Also check that the beam is coming into and out of the lens holder parallel and in the center. If not the beam can be deflected and loose power.