I’m confused on what power and speed my Ruida should be set on when. I’m trying to do another material test. It worked a week ago now nothing is cutting through. I have a 60w Omtech.
Although many things can contribute to this, let’s eliminate LightBurn by checking for possible machine failures.
Your laser: OmTech
Your controller/ firmware: Ruida KT332N
I have what may be an identical machine with the same controller.
The high voltage laser power supply has a digital display:
If yours has the same display, then you can report the current for each test pulse. If not, then read through this for background and we’ll find a different way to verify the beam output.
First test: does the power supply work at all?
- With the machine turned off remove the larger connector (the lower green block in the picture) from the power supply
- Turn the power on
- Put something disposable, like a block of wood, under the laser head
- Press the small red
TESTbutton on the power supply
If the power supply works, the display will read about 14 mA and the laser beam will poke a hole in the wood. If not, the supply is dead and you need a replacement.
Assuming it works, with the power off, plug the green connector back into the power supply.
Second test: does the power supply obey the controller?
Set the KT332N controller for manual pulses (page 35 of the manual). Press MENU → Laser → Laser mode: Continue, Enter on the console to save, then Esc back the normal display. When you press the Pulse button on the controller display the laser beam will turn on and stay on until you release the button.
Set the controller pulse power (page 27 of the manual). Press Enter on the console, move the selection to Power, go through the agonizing process of changing it to 25%, press Enter to save it.
Put something disposable under the laser head, press and hold the Pulse button, and the meter on the power supply should read 7 mA (more or less).
If it does not, then something is wrong between the controller and the HV supply, which will require more testing.
If it does, then the controller behaves as expected.
Third test: does the tube current vary predictably?
On the controller console, set other power levels and verify the current changes roughly in proportion to the setting. For example, if 50% produces 14 mA, then 25% should be about 7 mA and 75% should be about 18%. All those numbers are rubbery, but should give you the idea.
Don’t run the laser at more than about 75% for more than a few seconds while testing, but you can try 99% to find the maximum current the power supply will put out. The tube or its accompanying paperwork may have a maximum current written on it, although the power supply will probably produce far more current than that; OMTech seems to over-promise the laser power by abusing tubes rated for lower power output.
If the power levels vary as expected, then we can proceed to figure out which LightBurn settings changed.
Hello ednisley,
Here are my readings:
TEST 12mA
25% power 6 mA
50% power 15 mA
75% power 21 mA
Janis
What speeds are you running and how do they compare to the start speed?
You might want to adjust the lps so 100% is the maximum current limit. I actually use 50% to adjust the lps.
It’s an easy check, if you have and can use a voltmeter. Just measure the pwm to see if the percentages match.
That would identify the component where the anomaly is occurring…
Using his values, at 50% control, you read 15mA, that would indicate a maximum current availability of 30mA from the lps. This is pretty hot for a 60W glass tube…
The percentage power he lists don’t really figure… 75% should be ~22.5mA. It being co2, I guess this maybe close enough… but I’ve never been off that far on mine. Maybe just too picky.
Yeah, you’d think so, right? 
I formerly believed a supply sold for a 60 W machine would arrive pre-adjusted for a reasonable current, along the lines of that chart you whip out every now and again. The two (three, counting the deader) I have top out in the 25 to 30 mA range, which is definitely over the top for a 60 W tube and absurd for the 50 W tube actually in the machine.
Soooo, I’ll just go with the flow, say 50% will probably be around 15 mA, and by golly, that’s what it turns out to be.
FWIW, the tube in my laser has no trace of any current ratings, but while packing it up I found the machine summary sheet with “21 mA” scrawled into one square. Maybe 21 mA really produces 60 W output, but I have my doubts.
Looks good to me!
At this point we’ve established the controller works, the power supply works, the tube (probably) works, so we can eliminate all of that and move on with finding the real problem.
Assuming for the moment that the tube is lasing properly, the next step is to verify the beam hits (roughly) at the center of all three mirrors and goes out through the middle of the nozzle.
Note that a new machine should be properly aligned, but experience shows assuming it’s in good shape is a bad assumption. 
Using the machine console , change the Continue setting to Laser (IIRC. It might be Pulse or something like that, but it’s the other choice) and set the time to 50 ms. Set the power level to 30%, which should be close to the right value.
Then stick a piece of masking tape on the entrance to Mirror 1 (at the output end of the laser tube) and fire a pulse:
- If it burns a hole right through the tape, reduce the time until it doesn’t (using fresh tape each time)
- If it doesn’t do anything, increase the time until it does (more fresh tape)
- When you get a nice toasty mark, you’re done
The mark should be in the middle of the circular aperture. If not, then there’s a problem.
Repeat for Mirror 2 on the left end of the gantry. You may need to increase the power to maintain a toasty mark.
Repeat for Mirror 3 on the laser head, again increasing the power as needed.
If all three marks are pretty close to centered, that’s good. In any case, upload pictures to show off your work.
Squash a piece of tape on the nozzle and fire another pulse. It should produce a hole pretty much in the middle of the circular dent in the tape; if not, that’s a problem. Again, pix to show off the results.
If all that worked, then we can be reasonably sure:
- Controller works
- HV supply works
- Laser tube works
- Mirrors are aligned
- Beam comes out the nozzle
Report back on what you find!
While you’re there, check the tube resonance is TEM00…
My 50W came with a 60W supply… even though the tube was actually a little over 40W.
Does this mean you don’t believe this anymore?
I think they have the pot manufactured and set to the highest current level and it’s assembled this way. It’s then tested for response time… This should increase the chances of it passing when tested…
I don’t live there, so I don’t know … just that mine was turned all the way up.
Here is the chart I think you’re referring…
And my lps… 60W
I have aligned and clean all mirrors. I loss my original test cut files so I created new ones with the settings from the ones that cut last week. Well of course the same settings are not cutting, only engraving lines. Trying hard not to scream. This is by far the hardest thing I have encounter in all of my crafty life. OMG!!!
Also, I was told that the settings in Lightburn overrides my controller setting. Is this correct?
No it doesn’t.
If there are settings like power/speed Lightburn will use your setting here, but you have to manually go into the Machine settings to actually change things that relate to controller configuration issues.
Did you check your tubes resonance mode when you did M1?
Hey, I try to learn from my mistakes. 
I want to think they set it for the maximum current corresponding to the nominal power level on the sticker, but you’re probably right. AFAICT, 30-ish mA seems only 10% excessive for anything over 100 W, so that explains what’s going on.
We’ll assume the beam looks OK and comes out the middle of the nozzle, but if the machine continues to not cut, you’re gonna need to show your work.
Combining that bit of new information with the results so far suggests that, despite what you think, the settings are not the same, because the machine passes all the straightforward tests.
Upload the *lbrn2 files in your reply so we can take a look at it.
The first time you do something, you ask “How can anyone possibly do this?” The second time, you say “Hey, that was straightforward!” The third time, you wonder “Why doesn’t everybody know how to do this?”
You just passed stage 1: welcome aboard!