Laser cutting ability tailing off over 45% power

Community Laser Talk
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1

I am reconditioning a 100w laser and I am surprised at some of the test results. When I do cut/engrave tests, I’m seeing cutting engraving power peaking at about 45% (using a myjg100c PSU). I’m not sure about the life of the laser tube, but I suspect it’s coming towards the end. So my questions are:

  • Is it normal for the power to be in a “hump” where the cutting power tails off after a certain percentage?
  • How does the power/speed performance compare to a fresh 100w tube?

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Notes:

  • The material is a 6mm (soft/light) poplar ply
  • I have set the DSP max laser power to 65% as this corresponds to 25-27ma read on analog amp meter and digital readout on laser PSU.
  • It’s unlikely to be caused by mirror misalignment - I see the same result across multiple locations of the laser bed (corners, middle etc)
  • It’s unlikely to be material-related. I see the same for acrylics
  • The fading of the “Cut Test” title is sanding, not lack of laser power.
2

My tube test at the beginning, right after I bought it, clearly showed me that the penetration effect of the tube (nominal 60Watt) becomes less deep, after about 70%, which corresponds to about 18mA at this time. The other insight I got was that the machine’s power settings are not linear/proportional between mA, %, and power effect, it looks more like a “dinosaur” curve.