The production of nitrogen and oxygen is achieved by a process separating air-borne gases. Indeed, there is a very high concentration of nitrogen in the air (71%) and 21% of oxygen.
A nitrogen/oxygen generator is a production unit that manufacturers can place near their laser cutting workshop, to produce the gas required for their fibre laser cutting machines. A system of molecular sieves captures the desired gas in the air and lets the other gases escape. This is known as Pressure Swing Adsorption (PSA) technology.
Charly Zenou - Novair explains that "the aim of this solution is to fill the racks with a pressure of 300 bars, thus supplying the machines in the same conditions as with conditioned gas. This solution also makes it possible to optimise the sizing of the installation while meeting peak production levels.”
According to Johan Elster – Bystronic, "generators are an interesting solution, particularly from an environmental viewpoint. They are used a lot in countries where gas procurement is complicated.”
Frédéric Thiollier - Linde France comments that "a generator can be an interesting solution in specific cases, as long as the supplier undertakes to strictly comply with the laser machine manufacturer’s requirements in terms of purity, pressure, volume, etc. We also provide generators, but often this is not the most cost-effective solution to supply laser machines.”
For David Debources (Air Liquide), "nitrogen generators have lots of constraints compared with rack or bulk gas: a lower level of purity, which could cause oxidation on the cutting edges, limited pressure and flow rates which mean that the laser can only cut a thickness below 15mm, as well as high power consumption that should not be overlooked in the overall profitability calculation.”
Jean-Luc Marchand (Messer France) notes that "the generator solution is attractive, but it is difficult to get a clean cut because of the oxygen impurities in nitrogen. The overall cost (acquisition, maintenance and electricity) is also high and, in most cases, exceeds the cost of gas supply via a tank and cylinder rack.”
Charly Zenou – Novair explains that "when supplying a generator, there is a firm commitment to a purity of 5.0. The solution is sized according to the volume and pressure expected. A rack filling system provides the manufacturer with a backup and the ability to absorb production peaks. The overall cost is very competitive. Generators are also simple and environmentally-friendly solutions that don’t require procurement. Users produce gas on-site in complete autonomy, without any risk of shortages.”