Cryogenic Machining System Cuts F-35 Part Cost By 30%

Lockheed Martin has purchased an Okuma MA-600HII horizontal machining center featuring a cryogenic machining system, which it believes will help to lower the cost of producing large titanium parts for its F-35 aircraft by 30 percent.

The 5ME liquid nitrogen-based cryogenic machining system will be used for roughing and finishing work on the titanium airframe parts that go into the F-35.

Prior to the purchase, Lockheed Martin and 5ME conducted test cuts using 5ME cryogenics on 6AI4V titanium. The cuts took 21 hours, a significantly faster rate than the coolant, which takes 44 hours. Despite the difference in speed, the cutter consumption during the test cuts was the same. Pete Tecos, 5ME’s executive VP of marketing and product strategy, said that the tests showed the value of using cryogenic machining for tough-to-cut materials.

“This has a significant impact on cost savings for initiatives like the F-35 program, not only in increased cutting speeds, but also through lower energy consumption, improved worker safety, and the elimination of the infrastructure and disposal required with flood coolants,” he said.

The 5ME cryogenic machining system supports cooling by permitting liquid nitrogen to flow through its spindle and inside the tool located below the cutting edge. Put simply, the lowered temperature allows for increased cutting speeds. Power consumption is reduced because the self-pressurized system diminishes the need for pumps or other parts that require more energy.

An exposure to cryogenic temperatures would be harmful to critical components. To protect the parts from this danger, the systems, which feed -321 degree liquid nitrogen at a set pressure and flow rate, uses insulated lines between the liquid nitrogen and sub-cooler, and also feeds to the spindle. The insulated lines are vacuum-jacked. Pressure- generated heat is taken away from the subsystem using a sub-cooler, which also changes liquid and gas back to 100 percent liquid. The conversion to complete liquid stops the formation of gases caused by pressure drops and downstream heat leaks.

The operator of the system can use the integral Cryo Controller to set the appropriate flow rate.

According to 5ME, the liquid nitrogen-based cryogenic machining system can be retrofitted to nearly any OEM spindle, and features a number of available tool interfaces. The cryogenic tooling includes turning and groove tools, solid carbide mills and drills, holders, indexable mills, drills, and boring tools.

The horizontal machining center will be used at Lockheed Martin’s Dallas/Fort Worth production facility.