Amada FO 3015 Aluminum cutting

[FabproHelp]

I just was looking for some help with cutting .060 Aluminum. We have tried using the shop gas and nitrogen neither has been successful. Usually I can cut one or two good parts then they start to become "welded" in to the sheet. It seems as though it only happens the final inch before reconnecting with the pierce. What could be causing this problem?? I have been messing with the laser for days with nothing to show for it.

 

[laserdog]

Aluminum is just like stainless this is what I do. Try it and let us know what happens because you could have contaminated nitrogen or it could be as simple like a focus or gas problem. You may need to do a focus test to check the lens. So many things could cause this problem so lets start with the easiest thing the conditions.

Cut Conditions

5" lens
Gas kind 4
Gas press .6 to .7
Nozzle 3.0
Nozzle gap .02
Focus -.02
Set on Clean cut

Pierce conditions

power 2000 - 4000
Freq 100
Duty 100
Gas kind 4
Nozzle gap .15

 

[FabproHelp]

We are going to try those settings in the morning. What would you recommend using for cut conditions with gas kind 5. shop air?

 

[evans1089]

I would suggest looking/cleaning your lense. Then adjust the focus.

 

[laserdog]

I never used shop air because if you don't have a good dryer it can cause some problems if water gets into the system.

 

[LaserSpyder]

try cutting it with the 7" lens and .120 Aluminum cutting conditions, I do this with all thin material now to not loose cut time swapping lens

 

[FabproHelp]

Thank you all for the help. We have the .060 aluminum cutting well (most of the time). Now when we are cutting .080 aluminum we cant get any consistency. The first part comes out near perfect. Minimum dross and we can flake off what is left over. The second, third, fourth, and so on never seem to cut well. What would you suggest ??

 

[Foostrap]

If you stop after the first part, and let the machine sit for 5 minutes, then cut another part, how is the cut of that next part?
You may have a cooling issue, or a stressed optic somewhere (lens would be first one to try). If it's not the lens, then it could be the output coupler inside the resonator (best to call service for that one). How many hours do you have since the last maintenance on the resonator?

 

[LASERNINJA]

http://www.eng-tips.com/viewthread.cfm?qid=356114

 

[FabproHelp]

Thanks for the tip foostrap. We did find that the lens was no good. How long does a standard 5 inch lens last?

 

[Foostrap]

That depends on a lot of things; power used; gas pressure; piercing type (spatter getting back to the lens or not). Cutting at full power and full nitrogen gas pressure is the most stressful for the lens. If you cut at 4kW (or more), 20 bar non stop, then the lens could get stressed after just 500 hours or less. If you cut mild steel with low power and low oxygen pressure, it could last up to 3000 hours (assuming it remains clean).