Centerless / OD Grinding
Centerless grinding and O.D. grinding are effective methods of surface grinding for round/cylindrical parts and for grinding non-round parts to achieve better roundness. Petersen Precision are experts at both centerless and O.D. grinding, using these processes to finish parts and to prep materials for further machining and/or finishing.
Centerless Grinding Service
In centerless grinding, no spindle or fixture is used to hold the workpiece; instead, the workpiece is secured between two rotary grinding wheels. One wheel is stationary, while the other is movable to accommodate different part sizes and to apply appropriate pressure to the workpiece to achieve the desired finish. The workpiece is fed between the wheels from end to end to grind the entire length of the workpiece.
With our centerless grinding capabilities, we can maintain a tight outside diameter with an excellent surface finish. However, by its nature, centerless grinding does not control the centrality of the axis from the beginning to the end of the part; instead, the workpiece is allowed to “float” so that the O.D. can be tightly and uniformly controlled.
Centerless grinding produces a naturally round diameter that is often round to less than 50 µ-inches or better. Through feed centerless grinding can be applied to work pieces of .050 to 2.0” in diameter and lengths of up to 12 ft.
O.D. Grinding Service
In O.D. (outer diameter) grinding, the workpiece is held either on its O.D. or on a center feature to hold it on center, and the grinding wheel is maneuvered into contact with the part to grind its outer surface. The workpiece is allowed to rotate, with the grinding wheel rotating in the same direction. The two surfaces are therefore moving in opposite directions when they contact each other, which provides smoother operation with less chance of chatter.
The O.D. grinding process can also be used for plunge grinding, in which the workpiece is held in place and the grinding wheel is moved to contact the part. With plunge grinding, the whole part can be processed, or specific sections of the part can be ground separately (such as a bearing journal). Specialty grinding wheels can be utilized to contact multiple points on the workpiece simultaneously, or to produce different finishes on different sections. Plunge grinding is often a quicker way to work with parts being held on centers.
Centerless & O.D. Grinding from the Experts
Both grinding methods can be used to produce very round parts with uniform finishes around their entire outer surface. Depending on the process and the material being worked, outside diameters can be finished to within ±0.000050”.
Though a good portion of Petersen Precision’s work with centerless and O.D. grinding is dedicated to part production, we primarily use these processes to prepare parts or materials for further processing, including CNC machining, CNC turning, and cylindrical lapping operations.