The rise of high-power fiber lasers for sheet metal cutting

Starting from a 2006 market of less than a dozen units, the annual sales of fiber laser cutters has recently been estimated at about 3% of total 2009 sales of high-power laser sheet metal cutters. The total number of fiber laser cutters installed through 2009 is estimated at 170-175 units and is expected to double the total this year with growth next year projected at 50-60%.

Why does the fiber laser as an energy source for sheet metal cutting attract interest? The tightly focused spot size, resulting from high beam quality of the shorter wavelength fiber laser, offers faster processing speeds, with a larger working distance and higher depth of focus. The latter two advantages can ease workpiece tolerances.

The higher optical efficiency of this laser coupled with a more efficient use of wall-plug power reduces utility costs for electricity and cooling. The longer life of pumping diodes and the extended mean-time between maintenance make this laser an attractive option for small shops.

The compact cutting head facilitates simple integration into motion systems, reducing the complexity of large cutting tables; and these lighter components can be moved at higher speed with fewer components and lighter structures, reducing motion power while still maintaining accuracy. The fiber laser is the delivery device, eliminating the need for multi-mirror alignment procedures and, as the beam is contained in the fiber, the beam path is sealed to the cutting point.

What had first been suggested as a negative for fiber lasers was eye safety. All commercial lasers sold in North America and Europe must comply with safety standards, and equipment manufacturers have adapted their product designs for compliance. For sheet metal fabricating it is difficult to design to a Class I enclosure concept, as shuttle tables may need to access the cutting area for load/unload operations. So most flat sheet cutters powered by CO₂ lasers operate on a Maximum Permissible Exposure basis with the operators positioned far enough away from the beam/material interaction point so that reflective energy is dissipated. With the solid-state ytterbium fiber lasers, operating at 1.06 μm, it is necessary to restrict operator access to the beam interaction point behind safety enclosures. Most fiber laser cutter suppliers comply with this one way or another. Thus the safety situation has been mitigated.