Grinding Theory
Grinding is a machining process involving the use of an abrasive wheel to remove material from a workpiece in order to shape and finish it. It is commonly used in machining metals, plastics, and composites. It is usually performed by grinding wheel or belt and can be either manual or machine operated.
Grinding can be further divided into different categories such as surface grinding, cylindrical grinding, jig grinding and creep-feed grinding. Each type of grinding is used for different applications, such as metalworking and woodworking.
The basic principle of grinding is that when a force is applied to a material, particles will be removed from its surface in a predictable manner. The amount of grinding forces applied is controlled by the type of the grinding wheel and its shape, size, and distribution. The diameter of the wheel depends on the amount of material to be removed from the workpiece.
Grinding force is generated by the abrasive particles in the grinding wheel. The particles remove material from the workpiece surface in the form of tiny chips, at a rate depending on the relative speed of the grinding wheel with respect to the workpiece. The grinding wheel also contains cooling fluids that help keep the grinding wheel and workpiece cool during grinding operations.
The grinding wheel that has been specifically designed for any particular application is known as the grinding wheel specification (GWS). This includes the shape and size of the wheel, its hardness, the type of abrasive particles present in it, the coolant and the bonding material used to bind the particles.
To obtain a good finish on the workpiece, it is of utmost importance to select a good GWS and also to use the right grinding parameters such as the cutting speed, feed rate, and depth of cut. Additionally, the workpiece materials and the cutting tool need to be chosen carefully to ensure a smooth grinding operation.
While grinding operations have been used for many years and can be considered an effective and time-efficient method of machining, it is not the most suitable for applications which require high precision. For these applications, CNC machining is more suitable because it allows for variations in the cutting speed, feed rate and depths of cut for more precise cutting, as well as consistent surface finishes. Additionally, CNC machining requires less post-processing, which makes it more cost-effective than manual grinding.
