Bar Centerless Grinding

Centerless grinding is a high-precision machine operation to grind the outside of cylindrical bars to precise diameters and surface finishes. Unlike conventional cylindrical grinding, there is no center or chuck that holds the bar in place. Two rollers—a guiding and driving bar—hold the bar clamped and through which bars can be ground continuously at high speeds. The operation is widely used in the automobile, aviation, and manufacturing industries to produce high-precision bars with close tolerances.

Arrangement: Bar is between regulating wheel (rotating workpiece) and grinding wheel (actually grinding). Rotation speed and bar position are controlled by regulating wheel, and grinding wheel grinds away at the surface.

Grinding: Fed continuously into grinding wheels, bar is worn away. Grinding wheel wears away a very thin layer of the bar's surface for the sake of achieving the optimum diameter and surface finish.

Adjustment: Wheel speed and position can be controlled to achieve the desired grinding depth and surface finish. The process can be fine-tuned using different grit sizes of grinding wheels for a given application.

Finish: Once the desired diameter and finish are achieved, the bar is pulled back and inspected for accuracy.