Centerless grinding describes a technique that holds the workpiece in the center between two grinding wheels, which rotate in the same direction (usually clockwise). The left side grinding wheel is held in position as it rotates. The direction of force applied to the workpiece by the left side grinding wheel is downwards towards the platform that holds the workpiece in place.

The secondary grinding wheel to the right is called the regulating wheel. It has the flexibility to move in response to the pressures applied to the workpiece between the two grinding wheels. The regulating wheel keeps the workpiece in place and turns it for grinding by the grinding wheel. This allows the grinding wheel to remove any excess material that remains after grinding in the first pass.

Precision CNC Centerless Grinding Machine 0.8-60mm

Forms of Centerless Grinding
The three forms of centerless grinding are through-feed, end-feed, and in-feed. Here is an explanation of the differences:

• Through-Feed Centerless Grinding – In this process, the workpiece is fed through the center of the two grinding wheels. This technique is best used for parts that are cylindrical in shape. The regulating wheel can be set at such an angle that it pulls the material through the grinding process, without the need for any separate feeding mechanism.
• End-Feed Centerless Grinding – In this process, the workpiece is fed into the grinding system until it hits an end stop. After that, the grinding process happens and then the workpiece goes back out in the opposite direction it was fed. This process works well for workpieces that are tapered.
• In-Feed Centerless Grinding – The process is most useful for workpieces that have an unusual shape, such as an hour-glass shape. To start the process the workpiece is put into the grinding apparatus by hand. Then careful attention is paid to the contours required for grinding to make sure the piece stays in place and the complex grinding is a success.

Summary
Centerless grinding is a really an interesting process and is the technique used to have the exact amount of material removed to make a perfectly finished workpiece. It is a technique used in many manufacturing processes and it is extremely useful.