The modern practice in precision grinding particularly when using superabrasive grinding wheels is to employ a motorized rotary dressing tool. The tool usually consists of a diamond-faced disc with a narrow cutting edge. A rotary disc is far more durable than a single-point diamond and a precision disc allows excellent rotational accuracy for precision dressing. The runout of the dressing disc is likely to be approximately 2 pm.
Typically, the disc is arranged when dressing to have a surface speed vd = 0.4 to 0.8 times the surface speed of the grinding wheel vs. This means the dressing tool has to rotate at high speed for high-speed grinding. The dressing tool assembly must be capable of low vibration operation at these speeds. The dressing tool rotational speed nd should not be a multiple of work rotational speed nw. For similar reasons, the dresser rotational speed should not be a simple multiple of the grinding wheel rotational speed ns.
If it is decided to perform dressing at reduced grinding wheel speed, it is important not to excite machine resonance from the dressing tool system or the grinding wheel drive system.
19.14.4 Speed Rules
Summarizing the requirements outlined in this discussion, the following general rules may be concluded: [12]
The same principle of avoiding multiple speed relationships that directly affect workpiece roundness can be extended to other machine elements in the system, such as the control wheel, drive motors, and gears.