Tech Talk
What is “EDM Dressing Metal Bond Systems”?
Metal bond wheels have been manufactured in crush dressable matrices. However, the great majority are sintered in copper/bronze materials and even cast iron. Truing and dressing these types of wheels to accurate forms and with a periphery open enough to cut is most effectively done using Electro-discharge Machining (EDM). The electric arc readily erodes the matrix as well as the abrasive, and, depending on the current density, the wheel surface can be prepared with coarse pits, which allow chip clearance and cutting fluid application. EDM dressing of metal-bonded wheels is usually performed off the grinding machine and on an EDM machine. There has been a ceramic grinding machine produced which combines the whole EDM process in the grinding machine. The CNC control forms a carbon electrode, and, using the cutting fluid as the electrolyte, EDMs the profile in the wheel. Over the period of time, however, the electric current will cause detrimental pitting of the spindle bearing. It is therefore better to perform EDM dressing off the grinding machine.
