Laser Power 100%

[Trevor Allison]

Hi Guys

So I have bought my laser cutter/engraver and spent the last few days re-arranging my workshop to fit it in. It's a Chinese-made Yellow/Grey 4060, which I bought from a small UK company. They supplied, delivered, set it up and gave me a brief training, which was a very good service and I would recommend them to any Brit looking to buy a machine. It came with an EFR F2 80W laser tube.

I have read enough on this and other sites to know that I need to be careful not to run the laser at a power level above 25 milliamps. My question is - will the machine manufacturer have set it up so that 100% power is less than or equal to 25mA? If I measure the cathode current and it exceeds 25mA (at say 80% power) is it possible to adjust anything on the HV power supply, or within RDWorks, to scale the power so that 100% stays within the manufacturers guideline? I have a 30mA meter on order but it won't be here for a couple of weeks.

Another question if I may - when I press the Pulse button, what power level is the Ruida controller firing the laser at 'out of the box'? Is it 100%? In your version of the RDWorks user manual (great job btw) it says ...set power to 14% or less and give it a quick pulse...' How do I do that exactly?

TIA

[Dave Vigness]

EFR F2 should top out at 24mA. If you don't have actual power output test capabilities, run it a hair lower. My 80W EFR F2 hits 80W at 23.5mA.

You can go into the Vendor Settings on the laser tab and set max percentages for the controller. For my 6445G, the 80W / 23.5mA equals 63% power.

Manufacturers will not cap the power, that's up to you. I run mine up past the 23.5mA twice a year when I get out my Dohicky and measure the actual output up to 100%. I compare it to the readings I got when the machine was new. When it starts dropping off I know it's time to start shopping for a new tube. Better to have it on hand and install it on your schedule, than to have to get one quick because it died in the middle of an important project.

As far as I know, PULSE will fire at what ever your current max power is for the job. Somebody correct me if I'm wrong. I mainly use pulse for verifying my registration edges more than anything.

[Jeffrey Aley]

My question is - will the machine manufacturer have set it up so that 100% power is less than or equal to 25mA?

No, they will not have done so.

If I measure the cathode current and it exceeds 25mA (at say 80% power) is it possible to adjust anything on the HV power supply, or within RDWorks, to scale the power so that 100% stays within the manufacturers guideline? I have a 30mA meter on order but it won't be here for a couple of weeks.

The HV supply MAY have an adjustment on it. Depends on your HV supply. Find the model number on it and then Google it.
RDWorks does have a max power limit (I think Dave already posted about this). Note that it's a "clamp" setting, not a "scale" setting. In other words, the way it works is it sets any power > the limit, equal to the limit. So if you set it at, say, 65%, values above 65% do nothing - they just set it to 65%. Ideally, we'd want a setting that would set "100% = xx mA". Then you'd be able to set 100% = 25mA, and 50% would be approximately 12.5mA, etc.

I'd use the laser at <50% or 60% until your meter arrives. It's only a couple of weeks; be patient, Grasshopper.

Another question if I may - when I press the Pulse button, what power level is the Ruida controller firing the laser at 'out of the box'?

You can set the Max power on the front panel of the laser by pressing (wait for it...) the MaxPower button. Whatever that is set to, that's what the Pulse button will use.

[Trevor Allison]

Thanks for the comprehensive responses. Who would have thought that the Max Power button sets the Max Power? Damn clever these Chinese

[Bob Marino]

Hi all,
I have a new 60W PS which is powering a 50W Laser. Max current on my laser is 19mA. This PS does have an adjustment on the side.
Note, this is a custom build. At full power, it is reading 24mA. I want to reduce to the manufacture spec of laser tube, 19mA

The question I have is this. Is the potentiometer a single turn or multi-turn? I don't want to start turning the screw and mess up the current setting.

Thanks in advance!

Be safe all!

[Dave Vigness]

You're best off to limit it in the controller, then you can uncap it for annual testing. Personally I left mine as is and know what percentage power I hit my 80W at, 23.5mA. You don't want to run at 100%, but you do occasionally want to test at 100%. Have you run the power curve with the new PSU to see where you hit your 60W?

[sebastien laforet]

At full power, it is reading 24mA. I want to reduce to the manufacture spec of laser tube, 19mA

you may get an answer, but my personal suggestion is to let as is. those machines are individual creatures... each one has its own set of power settings, and trying to "fix" this by setting your max power to 100% is not very useful.

different machines (even if quoted for the same power) will have different power curves, so you have to test materials, speed, power for each and have a reference grid. this is the only way to have regular results.

so, if your usable max power is 82%, for example, just note this, and act accordingly. for another machine, it might be another value. use the "library" of rdworks or lightburn to save the settings and stick to it, because even if you fix the max power at 100%, you will still have to remember the correct value for speed and min-power, that you can obtain only by trial&error.

[Bob Marino]

If i set 11% min and 35% max in the controller for the laser settings, will lightburn use these values when i set the power at 40% max?

[Dave Vigness]

I will back up Sebastian's comments.

The power percentage shown on the controller and set in the software is what would best be described as a fantasy number, for reference with that machine only.

It is a combination of the laser tube, the laser PSU, and the controller. I upgraded my controller... and had to adjust my power percentages to get the same mA. I had a laser PSU go bad and had to replace it... you guessed it, had to adjust my percentages to get back to my known mA for my laser tube.

There is nothing, I repeat nothing, that will take the place of an accurate power test / power curve for your particular laser tube. Then you know the corresponding mA for a particular power. If you ever change laser tubes, then you do it all over again, and that's not including the annual test to verify the health of your laser tube. Do an annual test, and you will know when to start shopping for a laser tube, instead of it dying in the middle of an important project and paying through the nose to get a replacement overnighted.

[Bob Marino]

I understand both of your expainations.

i'm really looking to limit the tube power, and staying under its max mA of 19. I have set min 0 and max 30%. This is a DIY build, so im looking to protect my tube as best as i can.

After running power tests the tube never receives more than 20mA.

https://www.dropbox.com/s/hfjif8nm92kw6 ... 1.mp4?dl=0

Thanks