Free tool · no sign-up · works on your phone at the machine
CO₂ laser mirror alignment
Fire a pulse at the tape, tap where the spot landed, and the page tells you which screw to turn, which way and how far. One small test turn per screw shows the page how your mount really moves the beam, and every decision is made from fresh near and far marks.
- Print at 100 % (not “fit to page”) and measure the 50 mm square. Cut out a target for mirror 2 and one for the head entry. Rings are 1 mm apart, as on the screen.
- Stick masking tape over the opening in front of the mirror, never on the mirror itself, and the target on the tape, TOP up. Plain masking tape works too.
- Fire single short pulses with the Test / Pulse button at the lowest power that leaves a mark. Change the tape when it gets busy.
Beam back on track?Buy the cat a coffee, from $2. You get our “With Love” heart SVG as a thank-you, and a shop coupon from $5.
How it works
- Choose a routine check or a full alignment, tick the safety list, and tell the page where the adjusting screws sit on the mirror holder.
- Fire one pulse with the carriage near and one far, and tap where each burn mark landed on the target.
- After one small test turn per screw, the page tells you which screw to turn, which way and how far. Fire near and far again until the marks meet, then check at the head.
Tips
- Screws make the marks meet. Tilting a mirror moves the mark on the next mirror, more the further away it is. When the near and far marks sit on top of each other, the beam runs parallel to the axis.
- A mount move centres them. If the marks meet but off centre, do not chase the centre with the screws: shift the mount (slotted holes, shims) instead, then check near and far again.
- Mirror 1 rarely needs work. Mirrors 2 and 3 ride on the gantry and the head, so vibration moves them; mirror 1 usually only after a new tube.
- Fresh tape, single pulses, lowest power that leaves a mark. Never stick tape on the mirror itself.
- Then focus. After alignment run the focus test.
FAQ
Which lasers is this for?
CO₂ lasers with a glass tube and three mirrors on a moving gantry: K40 machines and the common 50–150 W machines with Ruida or similar controllers. Diode lasers have no mirrors to align. Galvo lasers steer the beam with motor-driven mirrors and need a different setup.
Why do I have to turn each screw once as a test?
Mounts differ, and which way the mark moves depends on how the mount sits in your machine and which side you look from. A small test turn per screw (1/8 turn, more only if the marks barely change) shows the real direction and size. You then fire near and far again, so the page always works from fresh marks. It keeps correcting itself after every pair.
Which screws are the adjusting screws?
The two or three screws on the back plate of the mirror holder, often with springs and lock nuts, that tilt the mirror. The bolts that hold the whole mount to the machine are different: loosen those only to shift the mount when you centre the beam. Loosen the lock nuts before turning and tighten them gently when you finish.
Why should I leave the corner screw alone?
On a holder with three screws in an L shape, the corner screw sits on both tilt axes. Turning it moves the spot diagonally and undoes what the other two set. The page works with the two side screws and keeps the corner screw as the reference.
Is it safe?
Wear CO₂ laser safety glasses rated for 10,600 nm, keep the lid closed when you fire, keep your hands out of the beam path, and switch the laser off or disable firing before you reach in to turn a screw. Use single short pulses at low power. Follow your machine manual; you are responsible for your machine.
Do I have to adjust mirror 1 every time?
No. Mirror 1 sits on the frame next to the tube and usually needs work only after a new tube or a knock. Mirrors 2 and 3 ride on the gantry and the head, so vibration moves them over time. Choose Routine check: the page fires near and far on mirror 2 once to confirm mirror 1 is still right, then goes straight to mirror 2. If that check fails, mirrors 2 and 3 cannot make up for it, and the page shows you how to fix mirror 1.
Where do I start: tube, mirror 1, mirror 2?
The tube to mirror 1 is set at the factory and rarely needs work; if it does, follow your machine manual. Then mirror 1 to mirror 2 (gantry near and far), then mirror 2 to mirror 3 (head near and far), then the check at the head. Always in that order: changing an earlier mirror changes everything after it, and the page marks the later steps “check again”.
How close is close enough?
When the near and far marks overlap: within about half a millimetre is good, and that is also about how exactly a mark can be tapped on a phone. After an adjustment, a stage counts as done only when you have tightened the lock nuts and a fresh pair of marks still meets. A routine check of mirror 1 turns nothing, so one pair decides there. The beam into the laser head should be close to the centre; on mirror 2 the mark only has to sit clear of the edge.
What does the final check at the head do?
You fire once with the head in the centre and in each corner of the bed, with tape over the head entry. If all five marks land on the same place, mirrors 1 and 2 are right across the whole bed. The beam from mirror 3 through the lens and straight down is set by your machine manual: the page does not check it.
Does the page send my data anywhere?
Your taps and settings stay in your browser. Like the rest of cutcatvector.pro, the page uses Google Analytics to count visits and downloads; it does not send the spot positions.