Basic Characteristics of CBN Grinding Wheel Internal Grinding

1. Due to the limitation of the inner hole diameter of the workpiece, the diameter of the inner grinding wheel is small, and the rotation speed is also limited by the spindle speed of the inner grinder (usually 10000~20000r/min). The peripheral speed of the grinding wheel generally does not reach 30~35m/. s. Therefore, grinding surface roughness and productivity are not as good as cylindrical grinding

2. When the inner circle is ground, the diameter of the grinding wheel is small, and the rotation speed is much higher than that of the cylindrical grinding wheel. Therefore, the number of times each abrasive grain participates in grinding per unit time increases correspondingly as compared with cylindrical grinding, and the grinding wheel easily becomes blunt. Dressing and replacement (frequent dressing, rapid wear of the grinding wheel), increased auxiliary time, affecting production efficiency

3. When the inner circle is ground, the smaller the workpiece hole diameter is, the smaller the diameter of the long axis of the attachment grinding wheel is, but the larger the overhang length is, so the rigidity is poor, bending deformation and vibration are easily generated during grinding, and the size and shape of the workpiece are affected. Accuracy and surface roughness, but also limit the amount of grinding and not conducive to productivity

4. When the inner circle is ground, the grinding wheel is in contact with the workpiece in an inscribed circle, the contact arc is longer than the outer circle, and because the inner circle grinding is in a semi-closed state, the coolant is less likely to enter the hole and it is more difficult to directly inject into the grinding zone. Internally, therefore, the grinding temperature is high, the abrasive particles are liable to be blunt, the grinding wheel is easy to be clogged, and the workpiece is easily burned to affect the surface quality