Power meter only showing ~ 5mA usage in a 100% cut?

Hey y’all, new to Lightburn. I picked up a Redsail clone machine 20X28 bed size - 60W. Having some questionable results…

I can pulse the control panel laser (power 80%) and get ~ 25mA output from my ammeter.

I create a box and set it to 6mm / sec and 100% power, and the ammeter is only showing ~ 5mA power but it’s cutting through the material.

Any suggestions or ideas? I don’t have auto Z and don’t know if the machine can sense material height and adjust cut power automatically? I am still trying to school myself on proper machine settings in LB software

New here too. I would make sure both min and max power on your layer settings is set to the power you want.

That was the first thing I checked. I have it set to 15% min and 100% max and it’s still only showing 5mA at the meter. It should be higher than that, no?

When I create a cut layer, I set my min and my max to the same %.

On my machine if I’m cutting say 3mm ply I set my min to 100% and my max to 100%. 100% on my machine is still in the safe ma range for my tube.

Your % will vary based on ma.

25 ma is high for a 60 watt tube. It should only be around 16 to 18 ma. 25 ma will quickly burn the tube out.

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I would try setting both min and max to 50% and check the ma.

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Check out Rdworks:learning lab on youtube.
everything you need to know about Co2 lasers.

Power can also be capped in the controller. Don’t remember where it’s at, but it overrides anything sent to it via the software. Possible the previous owner capped it for the material he was working with.

I also read somewhere that at low speeds the controller automatically uses the min power setting. Hope that helps.

Thanks for that! Yea, turns out if you have a max @ 100% and a min @ 15% it will cut the square out at a low setting. I upped it to both 65% (showing ~ 18 mA at the meter) and it cut through no problem.

Thanks for everyone’s help today!

Read about Min Power and the ‘Start Speed’ setting here:
https://lightburnsoftware.github.io/NewDocs/CutSettingsWindow.html#shared-basic-settings

It’s entirely dependent on the speed you run.

25mA is pretty high for a 50-60W tube. An SPT 850mm tube rated at 40W achieves 40W at ~16mA.

If you can find the tube spec and adjust your LPSU trim pot to ~2mA below the maximum, you will get consistent results and the tube will last longer than 100 hours, which is about the life you will get pushing it to 25mA.

I limit my 130W to 25mA, by way of comparison.

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