Centreless grinding is a precision machining process that uses abrasive cutting to remove material from the chosen workpiece. It’s known as centreless grinding because unlike centred grinding, there is no fixture used to secure the workpiece. Instead, the workpieces will typically be secured between the two rotary grinding wheels. The rate at which material is removed from the workpiece will be determined by the rotation speed of the grinding wheels.

The centreless grinding process

A centreless grinding machine features a grinding wheel which acts as the cutting tool. This rotates at high speeds that remove materials from the workpiece. The speed of the rotations can be varied to suit different workpiece requirements.

A regulating wheel is positioned opposite the grinding wheel and this rotates at a slower speed. This regulates the removal process, enabling greater precision.

It’s important to remember that in centreless grinding the workpiece will be positioned between the grinding wheel and the regulating wheel. It isn’t fixed in place by a centre or a chuck. A work rest is used to hold the workpiece in place during the grinding process to maintain proper alignment and overall stability.

The interaction between the grinding wheel and the regulating wheel rotates the workpiece. While the grinding wheel removes material from the workpiece, the regulating wheel ensures consistency and helps to achieve the required precision. This added precision is what enables centreless grinding to achieve the tight tolerances required.

Two types of centreless grinding

There are two primary types of centreless grinding that are commonly used:

●      Thru-Feed Grinding

With this method of centreless grinding the workpiece is continuously fed through the grinding wheels with material being removed along its entire length.

●      In-Feed Grinding

During In-Feed grinding the workpiece is fed into the grinding for a specific length. Materials are only removed at the end of the workpiece.

Why use centreless grinding?

Centreless grinding is used across a range of industries from manufacturing to aerospace and healthcare equipment. It has a range of advantages that make it well-equipped for different applications.

The primary advantage of centreless grinding is its ability to achieve extremely tight tolerances. This kind of precision is essential in industrial applications where components have to meet exacting specifications, such as aerospace and automotive. Because centreless grinding can be used as a continuous process without the need for interruptions it’s able to cope with significant volumes and lowers production costs.

Centreless grinding is also able to process multiple workpieces simultaneously with high levels of consistency. This not only reduces the time required, it also reduces wastage and associated costs. Because of the smooth finish it produces, the need for additional finishing operations may be removed.

A wide range of materials can be processed using centreless grinding, including metals and plastics. This flexibility makes it a suitable choice for different applications, from manufacturing smaller precision parts to very tight tolerances for larger components. The process helps to minimise heat generation, which is particularly important when working with heat-sensitive materials. 

Because the process doesn’t require a centre hole, the setup process is simplified. It also allows for the machining of workpieces that may be more difficult to hold in place using other grinding methods. Centreless grinding also requires less operator input, largely removing the human element that may result in inconsistencies. This extra consistency is another factor why centreless grinding can reduce waste and associated costs.

Overall, centreless grinding is a highly effective method for achieving high-precision results at high production volumes without the need for specialised operator experience. This makes it a valuable tool across a range of industries and applications.

High-Quality Grinding Machines from Sparx

If you’re looking for a high-quality grinding machine then Sparx Machine Tools can help. Our range can help you enhance precision and productivity in your operations.

At Sparx, our experienced team are always on hand to advise about surface grinding machines and safe practice.

To find out more, call us on 01202 830840 or complete the contact form and we will get back to you.