Just a quick straw pole, who here thinks the main reason a fibre will directly engrave metal and a co2 won't (assuming low powers here) is the wavelength ?
Just a quick straw pole, who here thinks the main reason a fibre will directly engrave metal and a co2 won't (assuming low powers here) is the wavelength ?
L Squared Lasers UK
2 x Halo Lasers 20 watt fiber
1 x Halo CO2 Galvo System
1 x Shenhui 1512 80 watt
3 x Electrox D40
3 x electrox Scriba 2
1 x Electrox Scorpion 40 watt Fibre
1 x Epilog EXT36 75 watt.
My thoughts are it's a power @ wavelength issue Matt. That could be 100% wrong, I don't know. But it's my understanding that at "X" power, "Y" wavelength will not penetrate metal. I suspect there is a curve where the power hits a point that it will penetrate.
Is that incorrect?
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Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.
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I think many of us simply the statement by making comments like "It's the wrong wavelength, it won't penetrate", which a more accurate statement is "at 80W, that wavelength isn't going to penetrate".
Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
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Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.
It's really 3 things:
- more energy in the 1060-1070nm wavelength is absorbed by metals vs. 10600nm ("normal" CO2)
- the smaller spot size gives a much greater energy density
- for marking lasers (usually pulsed; not CW or continuous wave), short pulses concentrate the energy over a much shorter time period which makes for more effective power (1mJ over 100ns = 10kW! ; 1mJ times 20kHz = 20W average power)
I wrote an article on this topic for Engraver's Journal back in 2011 if you want to read some more detail. It was not intended to be a scientific article but more of a practical explanation.
Jon Colley
Trotec Canada
A product of Energy Vs Time Vs Absorption rate (or reflective index)My thoughts are it's a power @ wavelength issue Matt.
The G100 pulsed 100watt CO2 cuts steel quite well so I would guess that 10^6 watts square inch energy is about right
You did what !
Every one is kinda right except Jon , who is exactly right , the wavelength is not the biggest factor by a wide margin, a 100 watt continues wave fibre will not engrave metal , a 5 watt pulsed fibre will ! Its all about peak power and generally over 5kw for blasting metal. It's only a special type of fibre that's really 'good' at engraving , as it happens that's pretty much all that's ever used so it can be taken out of the equation. But I'm dealing with someone that has got hold of a 150watt yag and can't understand why it won't even cut thin aluminium when the job was done before on a 20 watt laser. It always seem the general consensus it's 'wavelength' is the key & it's not
Yeah, I think there's about about 4 of you on here that understand the pulsed side of the equation
Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
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Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.
As I said earlier, energy absorbed is the key. Instantaneous energy absorbed, for sure, but still energy absorbed (and, of course, add "per unit of material" to that if you want to be ultra-precise). I'm not sure I would label it as a "special type" of fiber, however. A YAG can do the job if it's Q-switched, but you're certainly going to see much better numbers with something that can build up a much higher peak power (e.g., MOPA/MOFA). Wavelength is often used as a deciding factor because it appears like you're matching apples to apples, like saying a 250hp car is faster than a 200hp car (which can also be quite false), but the generalization is a reasonable one for most cases. You just have to make sure the assumptions being used for the rule of thumb still apply.
Hi-Tec Designs, LLC -- Owner (and self-proclaimed LED guru )
Trotec 80W Speedy 300 laser w/everything
CAMaster Stinger CNC (25" x 36" x 5")
USCutter 24" LaserPoint Vinyl Cutter
Jet JWBS-18QT-3 18", 3HP bandsaw
Robust Beauty 25"x52" wood lathe w/everything
Jet BD-920W 9"x20" metal lathe
Delta 18-900L 18" drill press
Flame Polisher (ooooh, FIRE!)
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all true Dan, my point is the wavelength is NOT the most important factor, its a factor that has an effect but is genrally used as the deciding factor. its all semantics as even though the genralisation is wrong the outcome is right. fibres are better on metal and thats probably all that maters.
thanks for the feedback guys
L Squared Lasers UK
2 x Halo Lasers 20 watt fiber
1 x Halo CO2 Galvo System
1 x Shenhui 1512 80 watt
3 x Electrox D40
3 x electrox Scriba 2
1 x Electrox Scorpion 40 watt Fibre
1 x Epilog EXT36 75 watt.