The intense heat generated during the machining of these next-generation materials can deform, chip and break ordinary cutters. “It is like slicing butter with butter,” says Michael Petracci, president of GE Ventures Licensing. “You won’t get very far.”
As a result, parts from the most advanced metals are taking longer to make and getting more expensive. Since GE uses them inside jet engines, gas turbines and other machines, “we needed a better tool for the job,” Petracci says. “Since there was nothing on the market, we invented one.”
Cue the Blue Arc, the superfast machine that can slice through an aerospace-grade titanium alloy in just three minutes — the job normally takes 45 (see top image). GE estimates that it could save $200 million over five years using the technology.
The company first introduced it in 2011. Since then, a number of customers and GE businesses have taken it for a spin. They used it to make parts from Inconel, a tough alloy used in jet engines, and titanium, which softens at 1,649 degrees Celsius. “When people see this technology in action, they are amazed,” Petracci says.
Blue Arc uses a high-speed beam of electrons to erode and remove metal. The design eliminates the need for high-powered spindles, expensive cutters and other devices. “Cutting tools have been around since the Stone Age and hard tungsten carbide tools, which have been around since the 1950s, have been their latest iteration until Blue Arc came along,” Petracci says.
Blue Arc can work for an entire shift without a bit change. Since it doesn’t deform or break, it can cut machine-tool capital costs by 30 percent and the cost of cutter tools by 70 percent.
The list of advantages goes on. Compared to traditional tools, Blue Arc machining reduces the stress on aerospace blisks, compressor blades and other components. The machine also has a smaller footprint on the factory floor, wastes less material and generates less dust and contaminants in the air, Petracci says.
He says the technique is especially useful now, when engineers prefer to machine large parts from a single piece of metal, which allows them to retain the strength of the metal while minimizing the weight of the completed part. “We had to figure out new ways to cut super-alloys into unique geometries more efficiently,” Petracci says.
GE invented and refined the technology, drawing on scientists at its Global Research Center and expertise from GE businesses including Aviation, Power and Oil & Gas. GE partnered with Mitsui Seiki, a Japanese manufacturing-machine maker, to produce the prototype Blue Arc machine. It is now seeking licensing partners to learn how they would use it. Interested companies can test it at GRC’s Detroit campus.
Petracci says using Blue Arc won’t require a complete retooling of factories. Instead, cutting machines can be retrofitted to work with the new technology. “Blue Arc will take us into the modern era of machining,” he says.
Superalloy components before and after Blue Arc machining: