Knowing the basics of centerless grinding is an important step to making it a successful operation in your shop. But first, why would you choose this process over another cylindrical grinding process? First, the operation eliminates the need for workpiece center holes, drivers or workhead fixtures that are required in the other two cylindrical grinding methods (center-type and chucking type). Also, centerless grinding, if set up properly, will achieve roundness, surface finish and dimensional tolerances that are among the best available in metalworking.
Parts can be ground using a continuous process called throughfeed, or the work can be fed to a predetermined point across the work blade to a fixed stop using the infeed process.
Traditionally, centerless grinding was found in shops involved in high volume production runs. Although this is still a critical segment, the process advantages can also be seen in shops that run shorter job lot sizes.
Centerless grinding is an OD grinding process where the workpiece is supported on its own outer-diameter by a work blade located between a high speed grinding wheel and a slower speed regulating wheel with a smaller diameter. The relationship between the grinding wheel, regulating wheel and work blade is what decides if the process will be successful to an application or if it will instead produce bad parts.
To achieve rounding action, the workblade must be set so that the centerline of the workpiece is above the centerline of the grinding and regulating wheels. The key is to set up an angled work blade so it slopes toward the regulating wheel so it can control the (regulate) the workpiece rotation against the higher speed grinding wheel so metal removal can take place. The angle of the work blade helps keep the workpiece in contact with and under the control of the slower rotating regulating wheel to resist any tendency to “spin up” to the speed of the grinding wheel, which is not good.
Finishing carbide inserts using EDM or grinding.
Automating the honing process is key to high-volume precision bore production with sub-micron accuracy.
As tooling complexity increases, one might expect in-house tool grinding to gradually fade away. In fact, though, more and more shops are taking advantage of CNC tool grinding’s increased capabilities to improve consistency, flexibility and productivity.