Modulating power on a CRS 355-15 laser

Community Laser Talk
1

I came across a forum post where someone had a laser engraver and was confused about why the power was greyed out in Lightburn.

I am in a different situation where I bought this same engraver (15 W version), but I have stripped the galvo from the box and laser, and just want to use the JZC LMCV4 to turn the laser on and off while modulating the power from 15 W down to a few mW for alignment purposes. Not exactly a LightBurn post… but this fellow had a similar problem of wanting to adjust the power output of the source.

I am having lots of trouble finding documentation about this laser, and was wondering if anyone understands how LightBurn achieves the power modulation of this specific laser.

LLM’s have suggested using PWM modulation of the GATE signal on the laser, but before I write some code with the balor library, I wanted to see if this was actually a valid approach. I know that I can bump up the repetition rate to decrease the efficiency of the output, but that will probably only get me down to 5W or so. Looking to bring this even lower to the mW range.

Any help is appreciated!

2

You need to get a manual on the uv source. That will tell you what’s available. I have a manual for my fiber, but it has power setting inputs.

The manual should tell you how to manipulate the source.

Check out this thread.. if you need to ask questions, then do so… @Colin is one of the Lightburn people and can probably assist you better than I.

:grinning_cat:

3

I have not got clue as to what your asking. i’m just a dumb lorry driver, if it’s not got wheels on forget it.lol

4

Diode lasers do not have such complexity. None of it applies to our machines, so no need to worry about it. :joy:

5

I can only add that I talked to a UV laser manufactuerer and he told me that UV lasers can be controlled with a PWM signal as most other lasers as well. It’s not that linear as with other diodes, but the pump diodes can be power controlled as well.

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6

** What you’re seeing is pretty normal for galvo fiber lasers with JZC (LMCV4) :+1:

In LightBurn, the “power” control can be greyed out because power modulation isn’t handled like PWM on diode lasers — it’s controlled internally by the laser source (via frequency, pulse width, and current settings in EZCad config).

Using PWM on the GATE signal usually won’t give proper analog-style power control and can be unreliable or unsafe for the source.

If you want very low output (mW range), the usual approach is:

  • Lower frequency + pulse width + current in the source settings
  • Use test grids to find minimum stable output

For deep control, you may need to adjust parameters in EZCad configs or the laser source itself rather than relying on LightBurn alone.**

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