Superfast Machining for Superalloy Metals with Blue Arc
I’m Mike Lamphere, senior manufacturing engineer at GE Aviation’s Hooksett, New Hampshire facility. At our Hooksett’s manufacturing facility, we have started to use the new process GE calls Blue Arc technology. The Blue Arc machining process is a patented technology developed at GE Global Research in Niskayuna, NY and Shanghai, China, in conjunction with GE Aviation. The Blue Arc machining process has truly revolutionized the way we produce bladed disks or blisks for our jet engines, cutting our production time from days to hours. Let me tell you how.
Milling is used extensively in the aviation industry to hog out large amounts of material. The problem within aviation is that the nickel-based super alloys that we typically use are difficult to machine. These alloys also have material properties that approach the cutting tool’s properties, and this can significantly shorten the life on the cutting tools. All conventional machining processes, such as milling, require a tool with higher hardness than the material being machined so a chip can be generated. As material properties approach that of the cutting tool, the milling process is typically slowed to conserve tool life and prevent tool breakage. This substantially increases the component manufacturing cost.
The Blue Arc is changing this. What you can see in the video from our first BlueArc machine is that the machine configuration is similar to a milling machine and can be programmed to generate features that a typical milling machine can produce. But the cutting mechanism of the Blue Arc technology changes the game since it uses an electric discharge to machine the workpiece. Because the material removal mechanism is electro-thermal rather than mechanical, the process is not affected by the material properties of the workpiece. This allows low-cost tooling electrodes to be used instead of expensive carbide. The material is submerged to aid with cooling and help shield the arc discharge. High-pressure flushing is used to push the chips from the cutting zone.
The Blue Arc process reduces the cycle time to generate preforms on blisks from days to hours. It is about three times faster than milling, and we have a plan to achieve 4-5x faster time overall. Analysis at GE’s Global Research Center has shown approximately 30 percent net energy reduction with the Blue Arc process over conventional milling. Additionally, the Blue Arc process can be used for turn and grind applications.
Blue Arc is the future: It lets us rough machine faster with less energy consumption and realize significantly reduced cost. GE Aviation is very excited to among the first to use this technology for our engines.