Laser and abrasive waterjet cutting methods have evolved over the past decade to overtake stamping and EDM in fabrication and welding job shops.

“Customers look at ways to cut various materials, and many choose laser, a good tool for production on parts up to ½-in. thick,” Nick Giannotte, vice president of MC Machinery Systems' Waterjet & EDM sales and marketing, said.

“Thicker parts and hardened steel can't take the heat, so in many applications, abrasive waterjet is most versatile. It cuts all types of materials with no heat and high-precision,” Giannotte added. His company is owned by Mitsubishi Corp. (www.mitsubishi-world.com), which also manufactures EDM/laser systems.

Laser and abrasive waterjet cutting are alternative cutting methods that have been developed to go beyond cutting ordinary metals and metal alloys. Today, these cutting tools are used to cut exotic metal and composite materials, and because of their increased use in industrial applications, they have limited the uses of CNC machining and metal stamping in some applications.

LAI International, a provider of precision engineered components and assemblies for aerospace, power generation, defense and other advanced technology industries, said CNC-based industrial laser and abrasive waterjet can be important tools for cutting the high-tech materials its customers require.

Tom Sterner, operations support manager in LAI's Westminster, Md., facility, said when it comes to determining the best cutting method application, there are several factors to take into consideration besides price.

The other factors are:

Material type

“Generally, just knowing the material that is to be used eliminates one or the other process,” Sterner said.

For example: Laser light can be absorptive with some materials and reflective with others.

Material thickness

“There's a definite limit to how thick lasers can cut. High-powered lasers that have their cutting power at their focal point can cut up to 1-in.-thick materials, but a ½-in. thickness is more usual for practical applications,” Sterner said.

“We've cut very thick materials — up to 14 in. — with waterjet technology, which has a much less defined threshold. If the material is too thick, it eliminates laser as a process right away,” he added.

Material shape

Nesting parts in a large sheet can be accomplished with sophisticated controls for either laser or waterjet cutting machines. Well-nested parts cut from a single sheet provide economic operations and take advantage of the small kerfs that both laser and waterjet cutting technologies produce. That can be a significant cost saving for expensive materials.

Compared with a kerf of 0.875 mm (0.035 in.) for waterjet cutting, the typical kerf for laser is 0.250 mm (0.010 in.).

“Complexity of geometry can also come into play as a factor when deciding which process to use,” Sterner said. If a part has a complex geometry, either a laser or a waterjet cutting system may be picked to cut it to get the precision that the complexity demands. Both abrasive waterjet and laser machines are capable of cutting geometric shapes, but as thicknesses approach the ½ in. threshold that represents lasers' upper operating line, thermal conduction can become a consideration because edge finishes may develop problems.

Heat-affected zones

For applications in which a heat-affected zone can't be tolerated, waterjet cutting is the choice because it produces no heat-affected zone.