Recently I’ve noticed my laser (red/black 100W CO2) has been engraving weaker and weaker on the front right corner (furthest point from the first mirror).
I did a bit of investigating, and found that the bed was level, so unfortunately the focal distance isn’t the issue.
My only other idea is a weak tube, which causes the laser to be weaker at further distances - however, it cuts just fine in the top left corner using my ‘original’ settings.
Is there any other tests I can run to try and diagnose this? I’ve read numerous posts after searching, and most seem to be bed-height related - unfortunately, mine is not. To rule it out (after measuring) I placed an item in the top left, manually focused it, and then ran it - did the same thing in the bottom right, and the engraved material is noticably lighter.
I don’t see any difference in my milli-amp power output at any time, it stays steady based on the power I’m requesting, so I don’t believe it’s a power supply issue.
Mirrors are cleaned and focused using a focus tool and verified, hitting center and consistent across the bed.
This is almost certainly due to beam misalignment and divergence over distance. The farther a beam has to travel, the more it will diverge, which does reduce power at the corner farthest from the laser output. I saw a 2-3% drop in power on my 130w machine from corner to corner.
All laser sources are consumables. So yes, even sitting on the shelf a tube has a shelf life.
What Colin was referring to is alignment issues causing beam diffraction - over simplified - and this means the same power setting will have different power output on different parts of the bed. Should be not massive though, single digit %.
So you might have some other compounding issues.
Colin’s recommendation of beam misalignment is solid. Realignment of the gantry mirrors would be the first thing I’d attempt. I’ve fixed the same issue similarly.