Aerospace component prototyping, batch production, and mass production of extremely hard and exotic materials (such as Inconel, Hastelloy and other superalloys, powdered metal, and titanium alloys) are ideally suited to PEM technology. Contact-free machining means your parts are free of thermal and mechanical stresses with NO microcracks, white layers, or electrode wear.
- Turbine blades
- Turbine discs
- Fuel cells / heat exchangers
- Jet engines
- Full-form gear profiles
- Dynamic seals
- Oil flow features
PEM Technologies recently completed development of a machining and finishing process for ball valve components of the main fuel flow control for NASA’s new J-2X rocket engine. We worked closely with Aerojet Rocketdyne to produce a key part for the engine that will power the next-generation Space Launch System (SLS), the largest rocket ever built. NASA is commissioning the rocket to transport astronauts to the International Space Station and make exploration of the solar system’s outer reaches easier than ever. The SLS is capable of lifting up to 130 tons into orbit.
“The opportunity to support America’s space program by developing a fast, cost-effective machining solution is exciting,” says Don Risko, vice president of PEM Technologies. “The ability of our process to reduce a 19-step process to a single step exemplifies the advantages of full-form machining of metal components.”
Precision electrolytic machining (PEM) dislodges surface atoms with a pre-formed metal electrode that never touches the workpiece. A solution of deionized water and salt provide a conductive path between the electrode and workpiece while a precise DC voltage pulse produces an electrical current. The result of that electrochemical reaction is precise metal removal without any surface degradation occurring.
PEM Technologies’ contact-free electrolytic machining process can be used with most metals, including tool steels, superalloys such as Inconel and special alloys such as Nitinol. The company’s machining process also works well on many powder metallurgy steels.
quality gears for precision meters are machined burr-free, six at a time, in a standard PEMTec machine. Although surface finish is material dependent, many materials are machined to very smooth finishes, with some as good as 1-4 in Ra. PEM machining is a full form precision machining process that usually starts with a solid blank or a preform of the component geometry. The electrode used to machine the turbine wheels in this example is a negative of the turbine wheel geometry less the machining gap for electrolyte. Eight turbine wheels are machined in one 45-minute machining cycle.