Reply with QuotePower and wavelength(and price)
best wishes
Dave
Laser Head
What is the difference between the laser head on a kern laser (that can cut metal) and a regular run of the mill 150 watt laser system ? I know that the Kern laser is not a glass tube type laser but why can it cut metal ?
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Power and wavelength
best wishes
Dave
It's mostly power.
Here is a chart of the materials lasers can cut and the power required.
I don't how reliable the info is. Laserable Materials
I dont know, the Kern laser is 150 watt system and they claim it can cut thru 1/8 mild steel, yet a 150 watt run of the mill laser cant cut 1/8 steel. It must have something to do with the laser head or the lenes
Also the laser must be properly focused - just like we used to do with a magnifying lens and some paper when we were kids.
Oxygen assist,
Pretty much any laser over 80 watts can cut steel if you introduce oxygen.
I'm not going there though at risk of somebody thinking they can just pump oxygen into their cheap Chinese machine and cut metal.
Ever seen the devastation caused by an Oxygen tank explosion?
best wishes
DAve
Not wavelength. Power is different. And price.Originally Posted by Exsecratio
Power and wavelength
best wishes
Dave
CNC lasers, constructions, service
That is nonsense.
Even 150W RF does not cut mild steel. Even with Oxygen.
There are mostly two types of low power Co2 lasers (up to 400W)
DC excited and RF excited.
RF can cut mild steel starting from 200W
Synrad's Laser Processing Calculator
DC laser don`t.
CNC lasers, constructions, service
The whole reason I brought this up is that Kern lasers (the 150 watt) does not cut metal as a stock unit, if you pay the extra 10K they will install the metal cutting option, but they stated that it must be done in the factory. What is the metal cutting option ? 10K dollars ?
Just curious
"Nonsense" is such a strong word
That's without Oxygen and cutting 1mm into stainless steel on an 80Watt DC excited EFR tube.
With the addition of Oxygen it cuts 1.6mm mild steel but covers the machine in ablated particles.
Focal length of lens 38.1mm GaAs and Moly mirrors.
I've also never never been to India however I have no doubt that it exists
best wishes
Dave
Bundy, it's the addition of high pressure Oxygen gas into the cut to promote cutting the same way that many Oxy Acet torches work
The laser itself is providing heat, the Oxygen provides the cutting ability.
best wishes
Dave
Any chance the difference can be accounted for because one is talking about a continous wave laser vs a pulse laser. It may be a case of talking about apples and oranges. Output power will probably be higher with a pulse laser. Of course I am really just speculating. Wish I knew more. FanFan
There are differences between RF excited and DC excited laser sources, however none of them have any real bearing on what they can cut.
RF lasers have positive dynamic resistance
DC have negative
DC has high constant power and bad short pulse preformance
RF has 5% less but good short pulse performance
Wavelength (not applicable here,an RF source and DC tube generate the same wavelength) Power output and power density are what affects a lasers ability to cut along with the assisting gas (or the reaction the assisting gas generates).
best wishes
Dave
OK, You got me interested and confused. So is the beam being focused to a very small tight spot ( high energy densisty) and the oxygen is used solely to clear the area ( of slag , smoke and debris, etc) where the beam is being focus ( tightly controlled) or is the oxygen being used to support or accelerated/ boost the cutting process. Could another inert gas be used with the same results?
FanFan
Recently I have seen some laser systems and just trying to make sense of the whole thing. Just trying to learn. Learning the whole processs could be helpful. Thanks for any info. Like I said it is interesting.
Hiya FanFan,
First you will need to understand power density, have a read of this and see if it makes sense.
Once metal of any kind reaches "white heat" the introduction of Oxygen starts a highly exothermic reaction causing the metallic substrate to turn from a metal to an oxide, this oxide is blasted away from the surface by the pressure of the gas.
Oxygen is used to allow lasers to cut materials that a beam alone wouldn't have the power to cut or to increase the efficiency of the cut allowing much thicker materials to be processed.
Argon / Nitrogen and other Nobel gasses can be used in place of Oxygen to remove the blue/black colouration caused by oxidation of the metal. (the blue line around the cut) a cheaper way is to use C02 but it is less effective (although a LOT cheaper).
There are a few other limiting factors with metal cutting such as Pierce powers and linear rates but these tend to be a product of raw power rather than methodology
best wishes
Dave
Dave, Thank for posting that link with explanation of power density. I have been a little under the weather so I didn't get a chance to read it until today. The explanation was quite clear and well written. The only part that was a bit confusing was the metric dimensions used. It is a little tricky putting the realtive dimensions in prespective.It is just something that I am just not use to using and visualizing metric dimensions. It just takes a little processing/ translating. I have seen a variety of types lasers. Still trying to sort out the differences. Difference such as Yags and CO2. There seem to be several types of C02. Ones with blowers and those with out. Like I said I am just starting to get an exposure. A bit here and there. All interesting. Thanks again for the explanation. FanFan
No problem my friend
If you have a look in the section on the forums where Depth Of Field is explained you will find quite a few other bits from Tubes to Mirrors to compressors
best wishes
Dave
ps: Todays useless bit of information? A yard can be defined as the length of a pendulum that causes its arc to swing in exactly 1 second.
Last edited by Exsecratio; 03-05-2012 at 08:13 PM.
