Laser 101 · Troubleshooting
Why your laser cutter is losing power.
If your laser is cutting slower or struggling with materials it used to handle, it is losing power. Here are the symptoms, the common causes, and how to test for them safely.
Power loss is usually gradual
Most laser power loss is not sudden — it creeps in. Cuts that used to go through in one pass start needing two. Engraving looks shallower. Materials that were easy become a struggle. Because it happens slowly, it is easy to miss until the machine is clearly underperforming.
The good news: the causes are a short list, and several are simple fixes, not a new tube.
The usual causes
Power loss comes from one of five places: a dirty lens or mirrors absorbing energy instead of passing it; misalignment losing power at every bounce; incorrect focus spreading the beam; a failing power supply; or an aging tube at the end of its working life.
They are worth checking roughly in that order — cheapest and easiest first.
How to test for power loss
Two simple tests tell you a lot. The pulse test: fire a short, low-power pulse onto a piece of masking tape or scrap and look at the burn mark — compare it to what the machine used to do, and compare pulses at different bed positions to spot alignment loss.
The ramp test: cut a line across a piece of material while stepping power down, and see at what power it stops cutting through. Run the same test over time and a declining machine shows itself clearly.
Isolating the cause
Start simple. Clean the lens and mirrors and re-test — this alone restores a surprising amount of lost power. Confirm the focus is set correctly. Check alignment, especially if cuts are uneven across the bed.
If the optics are clean, focus is right, and alignment is good, and the machine is still weak everywhere, the cause is the power supply or the tube.
When the tube is simply old
A CO₂ tube has a finite life and slowly loses output as it ages — eventually no amount of cleaning or alignment brings it back, and it needs replacing. If you would like a clear answer rather than a guess, we test and diagnose CO₂ lasers on-site across Southern California and remotely by Zoom anywhere in the US.
Common questions
Why is my laser cutter losing power?
Usually one of: dirty optics, misalignment, incorrect focus, a failing power supply, or an aging tube. Check the cheap, easy causes — optics and focus — first.
How do I test my laser's power?
Use a pulse test (fire a low-power pulse onto tape and read the burn) and a ramp test (cut a line while stepping power down to see where it stops cutting through). Repeat over time to track decline.
Can dirty optics really cause power loss?
Yes — a film of residue on a lens or mirror absorbs energy instead of passing it. Cleaning the optics often restores a surprising amount of lost power.
How do I know if I need a new tube?
If the optics are clean, focus is correct, and alignment is good, and the laser is still weak across the whole bed, an aging tube is the likely cause.
Can you test my laser for me?
Yes — we test and diagnose CO₂ lasers on-site across Southern California and remotely by Zoom anywhere in the US, and tell you honestly whether it is a fix or a part.
Laser down? We can help.
Industrial CO₂ lasers, beds up to 46 by 58 inches, in downtown Los Angeles. A real person checks every job.
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