Puzzled.
Fixed mirror sorted, fixed mirror to Y mirror aligned.
Y to X mirror sorted and aligned. So the laser hits virtually the same mark in top left, bottom left and bottom right but it’s high by a couple of mm in the top right. Cannot get it to line up properly.
Also, can I get the damn thing to cut 3mm acrylic any faster than 3mm/s
Suggestions please.
Only thing I can see happening is your beam is hitting the inside of your cone on you air assist
What power level are you using for your 3mm acrylic? I can cut it smoothly at 7.5mm/s with 29% power.
I am having to go to 20ma (it’s the anologue meter type) and 2-3mm per second. Air assist head not fitted yet and waiting for new mirrors and lens.
Is your focal length correct have you done a slanted board test?
How far is the material from the laser cutter? (mine is ~50mm)
I did manage to cut through at 6mm per second using the slanted board method but when I tried to do it again, I couldn’t. Need some physical help.
Did you adjust your bed to the middle of the cut through heigh
http://www.floatingwombat.me.uk/wordpress/wp-content/uploads/2015/02/K40-Alignment-Instructions.pdf the best guide I’ve read. The thing is you have to adjust the mirror to hit the same spot on the next part and then move next mirror to be hit in the center. A little counterintuitive at first but very logic. I can explainmore when at the computer, now I’m mobile 
Wait you just said - I did manage to cut through 6mm per second using the slanted board method… but now you cannot - is your mirror dirty?
Slant method helps determine best focal length - if you remove the lens itself you should still burn paper…if it is coming through the center that will tell you first if all the other alignments are good… as you indicated it goes up as it gets further away from the second mirror you will want to angle that mirror down a little to hit right in the center (this deflection will be more than up next to the mirror). This will effect your cut. Then once that is aligned - if you take out the lens itself you should have a paper burn right in the middle otherwise you will still want to make sure it is aligned all the way across perfect (as close to the center as physically possible).
It sounds like you are possibly dealing with a dirty lens and still a slight alignment issue
We can chat more if needed…
From what you say, it is just 1 corner that the beam is hitting too high, the TopRight.
What this makes me wonder is on the CentreRight, is the beam hitting too high (but slightly lower) than the TopRight? It could be that the entire Right hand rail is not level.
Matter resolved. The laser tube was not level. It was 2mm off on the opposite end to the mirror. Also, all mirrors now aligned correctly and the lens was in the wrong way! Sorted and now she cuts 3mm at 6mm/s at about 13ma!!
perfect!!.. glad to hear that