Help cutting SS 10mm - 3 kw Rofin Laser (New to the Laser World)

[AndreCarneiro]

Hello Laser community,

I'm a new-born graduated Mechanical Engineer, with two years in HVAC industry and now i've been challenged in a different but attractive world of manufactaring equipments to HVAC.

Well as you can see I'm new to this World, and I'm trying to find my way around the path of the Laser cutting mechanism.
Its hard to me to understand every parameter and how they interact with each other. So I'm here to ask for your help in this case.

I'm trying to cut SS 10mm thick, with a 3kw fiber laser from ROFIN. The head Laser is a Precitec ProCutter with a 200mm Focal Lens.

I already did some changes with the gas pressure and with velocity and even the nozzle diameter, but the "best" result is the one I will show you in the pictures.

Now I will show you some photos of the "quality" (yes "quality", because its look like it appeared from the darkest sea with tons of sea grass attached ).

Bottom of the cut (Sea-grass) -

Pierce (kind of good)-

Cut "Quality" -

Table Parameters:

With this, what you think I can do to have a good cut?

By the way, with this table parameters I've tried to cut a square and i couldn't , just a solid big .

Well thank you for reading, and hoping for awesome help

 

[AndreCarneiro]

Guys can someone help me?

I've already "destroyed" a litle of the material. Doing a lot of tests, i started changing the focus point, starting with +3 and ended with -10 (intervals of 0,5) and the best i had was with -4,5 , but never a clean cut, it ended like the one i've showed in the previews pictures.

The tests result -

Anyone has any idea?

Thank you.

 

[LaserEngine]

Can you upload a better picture of the table parameter? Have to focus abit to much to read it.

 

[AndreCarneiro]

The table parameter its different now but the results are the same (unfortunately ), so the new one is:

Gas Type : N2
Pierce Focal Lenght : 0 mm
Pierce Power : 2800 W
Pierce Duty Begin : 100 %
Pierce Duty End : 100 %
Pierce Delay : 700 ms
Pierce Height : 2 mm
Pierce Pressure : 4 bar
Delay Pierce Cut : 700 ms
Cut Focal Length : - 4.5 mm
Cut Power : 3000 W
Min Cut Power : 2000 W
Cut Duty Cycle : 100 %
Cutting Height : 0.7 mm
Cut Pressure : 8 bar
Speed : 600 mm / min

 

[gotpho]

Andre,

Not sure if you figured it already but if you have then let us know what you did. My first guess is that your pressure is way too low to be cutting 10mm. I suggest going to at least 21 bar or 300 psi. I also suggest try bringing the focus even further down to around -8mm and -10 to see whether or not the increased pressure helps.

 

[AndreCarneiro]

Hello Gotpho.

Well unfortunately i was not able to continue the tests so I could have a clean cut, but I will take your suggestion and in the next test i will let you know the result.

Thank you for the suggestion.

"Nothing is true, everything is permitted."

 

[IvanBr]

gotpho get it right,focus -5.5,-6,maybe even lower,with that kind of resonator you can do about 700 mm/min ,probably no more....nozzle stand off 0.5 mm not lower,with pressure you can start with 11 bars and go higher and higher.....for piercing you its litle bit to close to material that 2 mm also you dont use pulsed for SS NEVER.....duty cycle you have for good reason so you can not pierce with same power through hole ciycle of piercing,also dont use diferent focal lenght for pierce and cut....if you need more info my mail is kr733ac@hotmail.com

8 years cutting steel on lasers

 

[AndreCarneiro]

Thank you for the answers, so you think with this resonator I can manage to achieve a clean cut? I didn't had time to experiment, but i've contacted my Machine support, and they said it would be very hard to have a clean cut because i'm using the full capacity of the laser. In my opinion, I think they just don't want to "waste" time and help me to achieve the cut.

So you are saying I have to be 2mm away from the sheet on pierce and in SS its better to do 100% pierce than pulsed one? Can you tell me why?

"Nothing is true, everything is permitted."

 

[IvanBr]

hay

you must think when you work with that kind of machine

SS AND AL ARE HIGH REFLECTIVE MATERIALS

if you come with the pulse on that kind of material with lens so close to the surface ,you risk rupture off lens


Every buyer of 2kw fiber have been told that this power is like 4kw CO2 ....well that not truth.....with fiber you get lots of horse power with litle consumption....with CO2 you get lot of ccm3 with great consumption

with fiber you cut thin materials wizj great speed but not the thick materials,for that you also need 4kw

so with yours machine cut max 8mm SS ,15mm mild steel and maybe 8mm al

good luck

 

[AndreCarneiro]

Hello guys,

Well thank you all for the feedback.
I've had a litle time to do more experiences and I've to say that it was hard to get the results. But here they are:

1-

2-

3-

4- PARAMETER -

The parameter are the ones identified with Q1, the Q2 are other that aren't defined.

It was hard, but i'm happy with the result. I have always to take off the gross, but its better to do that and having a cut, than not haveing a cut at all.




"Nothing is true, everything is permitted."