Mopa & Color - Speed Increases?

Community Laser Talk
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60W Mopa - Color Sample
60W Mopa - Color Sample1371×1308 290 KB

Hey all, very new to Mopa here (under a week)

So I have just upgraded from a 5w Diode to a Monport 60w Mopa specifically for color marking.

Working with Stainless Steel, getting colors, but wanting to speed up the process.

After spending days researching and 10hrs+ testing different Power / Speed / Freq / Pulse / Line Spacing settings, I have kind of tuned it in enough to get a broad range of colors on SS ..

The issue though, is that I can only get color if I am running ranges of: Speed 20-150mm/s.. Power 8-10% .. Freq 50-200khz .. Pulse 150-250 … (attached image is the best I have achieved so far)

Which in turn means even small projects can take several hours to complete.

I’ve tried all settings of each adjustable parameter from 5-1000, but as soon as I go past 150 speed, or power over 10% it washes out or burns and I loose all color.

Am I missing something ? .. I see a lot of folks on YouTube, saying they are using speeds of 300+ even up to 1500-2000 but then Line Spacing of as tight as 0.002 which make it take just as long anyway.

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Whats the exact model? You mention going up to 200kHz, but dont forget the frequency range goes up to 3000kHz (or 4k, depending). Try a q-pulse nearer 8-16, and frequencies around 1k at 1000mm/s, power 50%ish.

MOPA colour hunting is pretty frustrating. I’ve spend 1000+ hours on the problem, only now making some breakthroughs by writing a software stack from scratch.

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Monport GPro 60W Mopa

Monport GPro 60w
Monport GPro 60w624×237 36.2 KB

I have done tests with Freq 10 - 2500, Q-Pulse 5 - 350, Speed 10 - 1500, Pow 2 - 75%, Line Space 0.002 - 0.04 and multiple combinations of each ..

Gone through about 20 sheets of ‘304 Stainless Steel’ 200x200x0.5mm sheets, with around 10 test pattern ranges on each side.

Anything outside of: Speed 20-150mm/s.. Power 8-10% .. Freq 50-200khz .. Pulse 150-250 .. Simply result in Silver / White - Brown / Burnt .. There is ZERO hint of any colors ..

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Ok, so now I am completely lost ..

I created a Color Wheel test in Lightburn, matching up the test pattern colors as close as possible to the button colors in Lightburn ..

Then did another test run, on the same sheet as the sample I did, and pretty much ZERO matched up.

I also tried it on a coin and got different results again.

Yes I understand different materials get different results, but both the ‘Test Sheet’ and ‘Coin’ are 304 Stainless Steel 0.5mm thick.

Color Wheel Test
Color Wheel Test849×831 155 KB

The Lightburn color wheel settings, match the shown Material Test exactly.

Power 8.0, Pulse 200, Int 0.04 .. Black - 128SP / 32.5FR .. Red - 74SP / 100FR .. and so on

But nothing marked as it did in the Material Test, on the same sheet of SS and the coin got different results again.

I expected as much with the coin, as it would be from a different batch of metal. But why is the sheet so different ?

Finally I did another Material Test, using the same settings as the 1st one and it perfectly matches the original color test …

5

That’s the problem with doing color. The fiber laser heats up the surface causing an different oxidation layer depending on the heat. Same settings over a larger are will cause the surface temperature to become lower as the fiber takes more time to cover the area. Keep in mind that metal is very good at conducting the heat away.

Any change, such as material thickness and overall size will cause the color to shift or turn gray.

I spent lots of time attempting this, but I don’t have the patience or money to make it worth the trouble. I just don’t attempt it anymore.

I have a M60 JPT M7 MOPA. I’ve had it for a couple of years.

Good luck.

:grinning_cat:

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I looked some of my parameters and you are correct about 1 thing, I’m either running really fast with 0.00X spacing or slow with 0.0X spacing. Frequencies up to 1200KHz. Q-Pulse from 8 and up. Seems like you can spend hours testing but really need to do it on an identical material to what your final product is going to be or you are just burning up time.

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{7E7312A0-E837-438D-8BD7-E1CF08481934}
{7E7312A0-E837-438D-8BD7-E1CF08481934}762×120 13.4 KB

Taking this into account for my tests, I have run another this morning and here is the outcome ..

Color Test 2
Color Test 21287×844 203 KB

Sorry for the poor photo, its very difficult to get the lighting and angle to match what I actually see ..

The Lightburn Wheel (Right) is matched up with the Lightburn Material Test (Left) as close as possible to the results. But when burned (Center), most of the colors are significantly different.

I did 4mm squares, to match the 4mm Material Test, which show this is not a ‘Size / Shape’ issue.

This is a ‘Lightburn Material Test’ references do not match ‘Lightburn Layer’ settings issue.

Anyway …. I guess I will just have to keep testing with the ‘Layers’ settings until I get what I want :frowning:

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