[rossandmarita]

We have one at work, I'm the get it working guy. I have no laser experience, got all other materials cutting and piercing nice. Just aluminium piercing.
How do you pierce aluminium? On a 4000W co2, it makes a lot of noise, lots of plasma and then a nice white plop on top when it finally blasts through. Especially bad on 3/16 and up using a 7.5" lens.

[MonoNeuron]

From what I have read the CO2 laser wavelength is reflected by aluminium so it's going to be very hard to cut anyway.

YAG lasers are supposed to be very good for this due to the different wavelength. I use Al mirrors on my laser but it is only 30 watts and the mirrors don't heat up any detectable amount.

Copper is also hard to cut with a CO2 laser. A lot of industrial lasers use copper as the end reflector inside the tube.
Just my 2 cents worth.
Rich.

[quazga]

In addition, you also have the oxidation problem with aluminum. When heated with shop air an aluminum oxide layer forms and aluminum oxide is a refractory that is able to withstand very high temperatures.

[BuzzFuzz]

What cutting gas are you using for the pierce, aluminum is usually cut using nitrogen in the 10-20 bar range but you will need to use oxygen as the piercing gas, set your piercing power to 90% and set piercing gas to oxygen at around 2 bar and it will pierce straight through. Trying to Pierce with nitrogen will destroy your cutting lens, the beam can also reflect back up all the way to the output window doing damage to all the optics, I have been running co2 lasers for 15 years now so you can trust me on this one.

[Rigsby]

I can only second the last posting, You need to use (relatively low pressure)Oxygen for the piercing and Nitrogen for the cutting, that way you won't get any splatter on the lens and that's it really.:bat:

[TheMadEtcher]

I use a Mazak Hypergear 4k watt laser at work. What settings are you using? Maybe I can help