Mahoney laser power probe

Does anyone here own and use a Mahoney laser probe? I purchased one a while back and finally got around to using it. I have an older 80watt Reci tube that has very low hours on it. It hasn’t been cutting great lately so I bought the probe to test it. The probe measured about 46 watts.
Looking for someone with some experience.

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I have one. Make sure that you are keeping it in the beam for the exact number of seconds that yours was calibrated for. Also, it will continue to climb for a little while after you shut off the beam. You also need to zero the meter using the adjustment screw on the back side before using.

Anthony, I laid the probe flat on my laser bed. I lined up the laser head to be in the middle of the black plastic piece( be careful to not focus on it). I then pushed the pulse button on my laser control panel for 17 seconds. I am not sure when you push the pulse button what the power is. Would a 95% power give you a different reading then say 50% power. Would I want to check the reading coming out of the laser to bypass mirrors?

The emitter power is measured just before the beam exits the emitter.
Then at the outlet of the nozzle. I would recommend unscrewing the nozzle and removing the lens. If the difference is 10-15%, this can be considered the norm. But if the difference is greater, measurements should be taken between the mirrors and the cause of the power loss should be found.

As for what power is used by the Pulse button, this depends on what controller you have. On my Ruida RDC6445G, the Pulse button uses the currently selected Max Power setting on the main screen and I can change it by pressing the Power button and typing a new value.

I usually measure at the 2nd mirror. You want the power set to 100% to measure the max output of the tube. If it is set to 50% you will not get an accurate reading.

Using 100% is not always “safe” for the tube. Many lasers are shipped with a power supply that is more powerful than the tube, and the power supply doesn’t “know” what rating of tube is connected.

Upon accurately measuring the current my laser power supply delivers to the tube, I found that a power setting of 80% already gives me my tube’s maximum (continuous) rating. Running it at 100% power setting would probably damage my tube (although the overdrive wouldn’t be so bad as to cause immediate damage).

I can’t recommend enough to place an accurate milliampere-meter in series with the tube and using it to finding what maximum power setting to use, especially with Chinese lasers that often don’t come with well-documented safe operation limits out of the box.

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Yes, I have a 0-100W Mahoney and used it to check my K40 and my NEJE M2+. It works well, but you need to expose for the duration that that particular probe was calibrated to. Each probe is unique and individually calibrated to a particular timed exposure. It should also be held isolated from any material that would draw heat away, so resting it on a surface will probably affect the reading to the low side. I would support the probe in the air with some insulated support.

As @Grumpy_Old_Man mentioned, the reading will continue to climb for a few seconds after the beam is turned off. That time is required to get an accurate reading. And, as he also pointed out, be sure to let the probe temperature stabilize and then zero the meter before running a test.

Finally, it’s ok to run the laser at 100% for the few seconds required for the test. If you turn down the power then you’re relying on the accuracy of your power control to determine the laser output power and I wouldn’t rely on any of these machines for that.

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I’m new to laser and trying to understand min/max settings. The tech guy who set my 100w machine up said its actually putting out 90w. He also said I’m bets to only run 50% as my max.
I’ve currently got 20min / 50max and I’m struggling to cut through 4.5mm acrylic.
Should I increase to a higher max %

The laser tube ignition unit supplies current to the tube. The maximum operating current for a 90-100 W tube is 21-28 mA. depends on the manufacturer.
RECI w2 = 25mA.
Yongli A2s = 21mA
Lasea f4 = 28mA
If you have a tube from another manufacturer, check the information for your model.

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Min / Max settings relate to the change in power output as the laser head accelerates / decelerates. Basically, as the laser head slows down when coming to a corner you are putting more energy into the material unless you put a lower value in the min settings. E.g. 30% max / 15% min.

I can cut 10mm clear acrylic with a 50 watt laser.

Check that you actually have a true 100 watt laser tube, there is a lot of marketing nonsense about laser power and when you think you have a 100w tube you actually have 75 ~ 90 watts.

Maximum power used should be the value that you achieve the manufacturers maximum operating current. For my 50W machine it’s just 58%.