The results of Turn while Burn technology from Charmilles.
Shops looking to increase wire EDMing speed and flexibility had a lot to see at Charmilles' (www.charmillesus.com) Westec booth. The company showcased its Robofil 240cc/440cc wire EDMs with cutting speeds of 42 square in. per hour in tool steels and special "turn while burn" capability.
To achieve such speed, Charmilles kicked up the maximum amplitude from 400 to 1,200 amps and increased maximum ignition voltage by 25 percent for the machines' new CC generators. The digital generators are zero voltage to protect parts against electrolytic effects during roughing and finishing.
For handling a wide range of workpieces, the machines can rotate workpieces while burning in the X and Y axes. While other turning units basically index parts, Charmilles' system provides true simultaneous B-axis action through servo controls for complex 3D part shape burning.
The machines achieve fine surface finishes with fewer skim cuts, and their generators are designed for cutting materials, including titanium and titanium alloys, for the medical industry. CC generators prevent oxidation on titanium and maintain surface integrities free of brass and zinc that originate in the wire electrode during the cutting process. In carbide applications, the machines minimize cobalt depletion, the effect of which is to hold tungsten together, and thus ensure high bearing capacities for punches and dies. Additionally, the new generators excel in cutting PCD form tools, leaving surface finishes and edge sharpnesses competitive with grinding.