EDM, or Electrical Discharge Machining, is a process used to machine hard metals and other conductive materials by eroding them with sparks of electrical discharge. Some of the top manufacturers of EDM machines include:

1. Makino: A Japanese company that produces a wide range of machine tools, including EDM machines, milling machines, and machining centers.
2. Fanuc: A Japanese company that produces a wide range of EDM machines, as well as CNC systems, robotics, and machine tools.
3. Mitsubishi Electric: A Japanese company that produces a wide range of EDM machines, including wire EDM and sinker EDM machines.
4. Sodick: A Japanese company that produces a wide range of EDM machines, including wire EDM, sinker EDM, and high-speed graphite machining centers.
5. Chmer: A Taiwanese company that specializes in the production of EDM machines, including wire EDM, sinker EDM, and CNC control systems.
6. Charmilles: A Swiss company that produces a wide range of EDM machines, including wire EDM, sinker EDM, and high-speed graphite machining centers.
7. Agie: A Swiss company that produces a wide range of EDM machines, including wire EDM, sinker EDM, and high-speed graphite machining centers.
8. GF Machining Solutions: A Swiss company that produces a wide range of EDM machines, including wire EDM, sinker EDM
9. Tungsten Electrode
10. Brother Industries
    
    This list is not exhaustive and in no particular order. and it is based on market share and reputation, but also industry standard in specific countries and industries.