Virtually all parts, particularly cylindrical parts, go through OD grinding to create a smooth, even and perfect look and feel. Not only is this done for aesthetic purposes for visible components and parts, but it is essential in parts such as automobile parts, aircraft and marine parts, or any other parts where there is a shaft or other component that needs to be completely smooth for effective and correct movement.
The term OD grinding stands for outer diameter grinding, and it refers only to the exterior surfaces of a component or piece. This type of grinding can be paired with ID or inside diameter grinding which grinds inside bores or holes in a component, such as a hollow shaft or tube.
This process can be completed on alloys and other suitable materials, including some plastics and rubbers, from very small rods and bars to up to just under fifteen inches in specialized grinding shops. Typically machine shops will not have that ability and will not be able to grind the larger diameter components on their equipment.
Concentricity and other Factors
When there is a need for concentricity or the three-dimensional tolerance zone for the median of a cylinder or sphere, OD grinding uses a specialized type of equipment that holds the part mounted between the centers. This ensures that the diameter through the program, the CNC program controlling the equipment, is using the same centerline.
Other options or techniques in OD grinding have been perfected to provide tight tolerances with all types of different parts and components. For instance, peripheral-longitudinal outer diameter grinding is used to create perfect surfaces even with the length of the piece is more than that of the grinding wheel. The grinding wheel actually moves parallel and at right angles to the actual component. This process may take several passes to create the perfect exterior size and shape.
Centerless Grinding
When the tight tolerances are a must, centerless grinding is the most common OD grinding technique used by the most qualified shops. With this grinding process, which can produce tolerances of plus or minus 0.0001inches, the actual component, or pieces is not constrained during the grinding process; rather the alloy is placed between two grinding wheels which can be adjusted for speed to create a faster or slower process.
With OD grinding, choosing the right grinding tools, the right equipment and understanding the correct process is essential in getting the final part you want and need.
