On-site nitrogen generation provides significant savings at ABi Laser

Having invested in ‘state of the art’ laser equipment that would allow faster production and 24hr operation, Oldham-based ABi Laser found that achieving the equipment’s full potential was hampered by the supply, specification and costs of ‘delivered’ nitrogen, which is essential for the process.

The situation was remedied, along with significant cost savings, by the installation of an Atlas Copco on-site nitrogen generation ‘skid package’.

Abi says laser-cutting metal relies on a continuous supply of nitrogen gas as a blanket to prevent burning during the process. Purity of the gas is an important factor in overcoming the tendency for discolouration of laser-cut edges and to provide a high-quality finish. As well as meeting these key process requirements, the company wanted to achieve savings on the cost of delivered bottled nitrogen supplies.

Arran Reader, ABi’s managing director, said: “We made a major capital investment in order to increase output and cut a wider range of metals, including 25mm mild steel, stainless steel and aluminium.

“The installation of an Amada 6kW Ensis laser, together with an ASF EU pallet loader, meant we could offer our services at a more competitive price as we could run throughout the day with minimum manpower — and operate ‘lights out’.”

Mr Reader decided that installing on-site nitrogen generation would deliver significant cost savings, maintain supply independence, and ensure a continuous, reliable source of high purity nitrogen.

Hemel Hempstead-based Atlas Copco subsequently installed an HPN2 Skid 7 all-in-one nitrogen generation assembly on a trial basis which convinced Mr Reader that this was the route to follow; it also helped to establish the appropriate nitrogen purity level for ABi’s applications.

The delivery rate of 99.99%-purity nitrogen generation from the unit was established as 19Nm³/hr (normal cubic metre per hr) at 300 bar to charge the onboard 16 bottle manifold cylinder pack (MCP), thereby producing 408Nm³ over a 12hr period.

When running flat out, that equates to 57 MCPs a month. The average cost of ABi’s high-pressure nitrogen supply now produced on site by the HPN2 skid is £0.09 per m³, compared with £0.68 per m³ for delivered gas. Abi estimates a return on investment in two to three years.