I am stumped trying to align this k40. I get good and aligned burn marks from the fixed mirror to the y axis mirror and from the y axis mirror to the laser head mirror. But there’s nothing going from the focus lens to the bed??? If I put masking tape directly on the bottom of the laser head, I see a small burn mark…kind of skewed. But when I put the tape directly on the bed, there are no burn marks.
Any ideas would be appreciated…
Are you sure your lens is the right way round?
No lens?
Very very dirty lens?
Lens mounted but not flat to base surface and or upside down?
More than one lens? I know crazy…
Piece of paper, tape, ash, spiderweb or something occluding the beam in the head?
Mirror in head upside down, cocked, cracked, dirty, broken, ect…
Head plate rotated or bent to the point of casting the beam out of field.
If your still getting a good burn at the entry point, then I would think it has to be something on that list.
No mirror in head :)…
If you take out the lens do you then get a burn mark on the bed?
@Andy_Shilling yes I even took the lens out of another k40 I have that was the right way up and still nothing 
Yes lens
Did clean the lens
Getting same result with a different lens, but I can double check if it’s flat to the base
Only one lens
I agree, it has to be something with the lens…just have no idea what?
Yeah double checked that as well
I took out the lens and got the same result…no burn marks
You don’t have a cracked mirror and your laser is being split by the crack? Hence a weaker spot hitting your head and not doing anything
@Andy_Shilling I’m dumbfounded. I took it off earlier to double check the alignment and it hasn’t engraved since.
Did you remove the mirror in the head? I remember taking mine out and putting that back the wrong way. Cost me a new mirror, well one made from a HDD lol
Yes I did.
How did moving the mirror cost you a new one…did you drop it?
No put it in backwards and the laser broke it.
It actually cracked it right through but it took a few minutes to do it. I’m presuming the back of the mirror stores up the lasers heat until it’s too late, whereas if the orientation is correct it will just reflect it.
Mine isn’t cracked but I’m wondering if something similar is going on because once the beam leaves the mirror it sure isn’t hitting the table
I’m not sure how to tell if the mirror is the right way out not other than just swapping it around. If you do try make sure the laser is on very low power and just test for a split second at a time.
Got it figured out finally. In case anyone comes across this at a later date with the same issue.
It was an alignment issue. I was getting a good beam from the fixed mirror to the y axis mirror and from the y axis mirror to the laser head mirror. But wasn’t getting any marks from the laser head to the lens. To solve this I had to reposition all of the mirrors…not re align, reposition to get a straight beam going into the laser head and down at a 90 degree angle. I wasn’t getting that before even though the burn marks indicated I was. Once all the mirrors were repositioned and then realigned all was well.
I’m not sure I understand the problem yet? Any way you can explain it differently?
@Nathan_Thomas glad you got it sorted 
