Fiber laser cutting assist gas technology evolves. With AAG nitroboxes you can purchase compact units that can generate 40 bar or 200 bar, depending on your requirements.
“Assist gas generation for laser cutting has come a long way during the past decade. As more shops expand their laser cutting capacity, they often take another look at assist gas consumption. More operations are looking at alternatives for delivered gas, and this includes generating gas on-site, specifically nitrogen,” said Malcolm Moriarty of Metal Chip Machinery.
“Purity in on-site nitrogen generation has reached the so-called five-nines levels – 99.999+ per cent pure,” explained Moriarty.
“The latest nitrogen generation systems can be tuned to the flow rate and purity level an application requires. Five-nines nitrogen purity may be overkill for typical laser cutting assist gas applications, but certain machine elements can benefit from such purity. Some cutting heads on the market require a nitrogen purge gas that’s 99.999 per cent pure, and some smaller, dedicated nitrogen generation systems have been designed to supply that purge gas.”
“If you’re cutting thick stainless, 99.99 per cent purity (four nines instead of five) will help prevent discoloration on the cut edge. Some less critical applications, say, thin-gauge mild steel, probably wouldn’t need such a high purity level.”
“From what we’re seeing, 99.99 per cent would be a fairly standard purity requirement for most applications. But purity requirements do vary, depending on the laser machine and application.”
“What about oxygen? Oxygen generation systems are on the market, though they usually aren’t designed for laser cutting. Oxygen generators are ideal for oxyacetylene cutting and welding purposes.”
“In the days when CO2 lasers dominated, cutting with nitrogen assist gas became the norm for precision work that required a shiny edge, while oxygen cutting held its place for thick carbon steel, which benefited from oxygen’s exothermic reaction that stimulated the cut.”
“Early on the fiber laser’s nitrogen consumption was a rude awakening for some. This in turn gave a boost to nitrogen generation, a technology that has become increasingly accepted by more laser machine OEMs.”
“We have been appointed the South African agents of AAG Makina, a Turkish company that has been manufacturing air and gas filtration systems since 1986.”
“Nitrogen generation for consumption with fiber laser cutting is gaining popularity because of the cost savings. Up until now only small systems have been available, for example cutting pressure up to 16bar. Now with AAG nitroboxes you can purchase compact units that can generate 40 bar or 200bar.”
“Depending on your requirements with a 40 bar system you can easily cut 20mm stainless steel on a 6kW fiber laser machine. And the area taken up by the system is just under 5m², which is very minimal in a busy shop.”
“Laser machine OEMs have refined the laser parameters to reduce the required pressure. And when you reduce the pressure, you can reduce the flow rate, hence the savings on assist gas consumption.”
“For example, the AAG systems are accepted and used on most of the fiber laser OEM manufacturers.”
“The continual increase in fiber laser power is starting to have an effect on assist gas usage. The assist gas pressures have been able to be reduced as lasers have become more powerful.”
For more information contact Metal Chip Machinery on TEL: 011 476 7509 or 072 834 3164 or visit www.metalchipmachinery.co.za