Robert Fothergill, EDM Applications Specialist with Poco Graphite, recently published an article in Mold Making Technology discussing that understanding all the electrode parameters can improve EDM efficiency. I can’t agree more.
As discussed, sinker EDM machining technology has improved significantly over the years. These changes effect the processes and decisions an EDM machinist will face when running the machine. But, some performance factors remain the same even with the advanced technology:
• Machinability – a balance between easy to machine and resilient enough to withstand the machining process
• Metal Removal Rate – achieving the proper electrode material/work metal/application combination rate so the MRR can be maximized
• Wear Resistance – maximizing the electrode to produce and maintain detail related to its wear and machinability
• Surface Finish – surface finish is obtained with a combination of the proper electrode material, good conditions and appropriate power supply. The final surface will be a mirror image of the electrodes surface
• Material Cost – fabrication time, cutting time, labor and electrode wear are all factors that depend on the electrode material
By far, the electrode material used in the EDM process has a direct correlation to the performance and efficiency of the EDM burn. So, the electrode material must be matched to the application to guarantee success at the highest rate of productivity. Graphite grades, particle size, tensile strength, isotropy and uniform structure all are important considerations in material selection.
Unlike the other performance factors, material choice is a performance process you can directly control. You can chose to work only with quality materials that offer consistent profiles. While quality materials cost more, they eliminate the costs associated with inconsistency and machine wear.
I would also add that your relationship with your material provider should also be considered a performance factor. A relationship with a supplier can enhance your overall EDM efficiency. Consistent quality, reliable supply, reasonable price and proper advice are all tangible parts of your overall results.
Regardless of the machine that is being used, each of these performance factors will be impacted by the electrode material. Whether the job calls for a specific surface finish, electrode wear or MRR, a consistent effective electrode material is critical to achieving the desired result.