Customized metal-spinning machines fix out-of-round engine lip skins

Customized metal-spinning machines fix out-of-round engine lip skins

Machine builder MJC Engineering supplies equipment to GKN for operations in Camarillo, California, and Orangeburg, South Carolina, for Boeing 777 and 737 engine housings.

MJC Engineering is a custom machine tool builder in Huntington Beach, California, specializing in metal-spinning machines for applications such as sheet spinning, flow forming, wheel spinning, and rotary forging. Recently, the company was commissioned to build a series of metal-spinning machines for GKN for use at its plants in Camarillo, California, and Orangeburg, South Carolina. These machines are currently in use, producing lip skins for the engine housings on Boeing 777X and 737MAX aircraft. Using advanced computer numerical control (CNC) from Siemens and robotic handling technology, plus its proprietary servopump-controlled Green Power hydraulic power unit, the team at MJC Engineering solved an engineering challenge brought to them by GKN.

Finding a solution

The key to the solution was how to spin-form production run components out-of-round by 8.5″ to 9″ in various aluminum alloy blanks measuring up to 270″ diameters and 5/8″ thickness, while holding tight tolerances to be verified by thermo-imaging cameras and fed back by the CNC for accuracy tracking, plus integrate the heating torch for in-process adjustments. Carl Lorentzen, president, MJC Engineering, Per Carlson, vice-president and general manager, and Don Hebert, electrical engineer, were up to the task.

Each day at MJC, Lorentzen and his team combine metal-spinning with modern CNC controls and robotics to create state-of-the-art manufacturing processes producing laminar-flow lip skins for Boeing’s 737MAX and 777X aircraft. The lip skin is the highly engineered aerodynamic structure that makes up the leading edge of jet engine nacelles.

Metal-spinning is a forming process in which a blank of material is rotated on a spinning machine similar to a lathe. The blank of material is clamped onto a spin-forming mandrel and rotated by servo-controlled motors and drives. During rotation, heat is applied by a gas torch affixed to a robotic armature and a roller on the spinning machine makes contact with the part blank, forcing the part blank to flow over the spin-forming mandrel surface.

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