The grinding process consists of removing material from the workpiece by the use of a rotating wheel that has a surface composed of abrasive grains. Grinding is considered to be the most accurate (Marinescu 2006) of the existing machining processes.
Grinding processes are used when high accuracies, close dimensional tolerances, and a fine surface finishes are required. Grinding processes also allow for high production rates.. This allows for a lowered cost of production.Hard materials can also be machined.
Types of grinding processes
Selecting which of the following grinding operations to be used is determined by the size, shape, features and desired production rate.
- Surface grinding is most common of the grinding operations. A rotating wheel is used in the grinding of flat surfaces. Types of surface grinding are vertical spindle and rotary tables.
- Cylindrical grinding is also called center-type grinding and is used in the removing the cylindrical surfaces and shoulders of the workpiece. Both the tool and the workpiece are rotated by separate motors and at different speeds. The axes of rotation tool can be adjusted to produce a variety of shapes.
- Internal grinding is used to grind the inside diameter of the workpiece. Tapered holes can be ground with the use of internal grinders that can swivel on the horizontal.
- Centerless grinding is when the workpiece is supported by a blade instead of by centers or chucks. Two wheels are used. The larger one is used to grind the surface of the workpiece and the smaller wheel is used to regulate the axial movement of the workpiece. Types of centerless grinding include through-feed grinding, in-feed/plunge grinding, and internal centerless grinding.
- Creep-feed grinding is used for high rates of material removal. Depths of cut of up to 6 mm (0.25) inches are used along with low workpiece speed. Surfaces with a softer-grade resin bond are used to keep workpiece temperature low and an improved surface finish. up to 1.6 microns Rmax
- Pre-grinding is when a new tool has been built and has been heat-treated then to be pre-ground before anymore welding or hardfacing commences,this usually involves grinding the OD slightly higher than the finish grind OD''' to ensure of the correct Finnish size.