Making a faster mild steel cut - Amada

[kltex]

I was cutting 6mm mild steel the other day, and the cut was good enough.
Power was only 1100 and speed was 1500.
This was the maximum speed I could run at this power level.
I figured I could rise the power and gain some more speed, but no matter what i did, I could not get a clean cut with higher speeds.

Cutting parameters are:
Feed rate 1500
Power 1100
Freq 2000
Duty 95
Gas Pressure 0.1
Gas Kind 2
Nozzle gap 1.5

Focus 0.0
Lens 5"
Nozzle 2.00

Attached is one picuture with the clean cut at 1500mm/min

And the other picture with 3 tests at 2500mm/min Power 1500, 1750 and 2000

 

[laserdog]

What laser do you have? 6mm is like cutting .25 and we use a 7.5" lens with a 1.4mm nozzle. A rule we use is 10 ga (.134) or less use a 5" lens with a 1.2mm nozzle and a nozzle gap of.060. Anything over that is a 7.5" lens, 1.4mm double flow nozzle and a nozzle gap of .028.

 

[ausman]

Feed 1800mm/m
Power 3000w
Freq 2000Hz
Duty 72%
Gas Pres 0.05
Gap 1.5mm

Lens, 5.0 F/L
Focus 0.0mm
Nozzle 2.0mm

Try that, then bump it up if it's cutting easily.

 

[evans1089]

I thought a 5" lens was for material up to 4mm?

 

[laserdog]

You can use a 5" up to .179 when the optics are clean but it's more forgiving if you stop at .134 with the 5".

 

[kltex]

My laser has 2000W, but I will try to replace the lense with a 7.5" and use smaller nozzle

 

[LASERNINJA]

I think that feed rate is respectable, 1500mm / min. The fastest I have seen for a 2kw is 65 ipm.

I have never tried a 1.4mm on a machine with out an adaptive optic. It might work but it also may complicate matters. My opinion, moving the focal point around has the biggest effect on the cut. Usually I move it 0.020". Or 0.5mm +/- untill there is significant improvement. With the 7.5" I change it by 1mm increments.

Food for thought. I have seen a 1500w pulsar cut 1/2" 12mm with a 5" lens. It was beautiful. It just takes time.