Effect of Contact Time on Forces, Power and Metal Removal Rate

In precision grinding, if the normal force is low, the abrasive grains will develop wear flats, dulling the wheel and reducing its cutting capability. Under fixed infeed rate conditions, forces and power will rise, while during controlled force operations, the grinding rate will decrease. If the force is high enough, grain fracture will compensate for grain dulling and a steady state can exist. At high forces, grain fracture will dominate and the wheel can sharpen and actually cut faster, presuming the dressing conditions were moderate. The transition between dulling and sharpening for various wheels was investigated while external grinding in both fixed feed rate and controlled force modes.