External Cylindrical Grinding
Primarily performed on external cylindrical grinding machines, used for grinding the outer cylinders, outer cones, and shoulder end faces of shaft-like workpieces. During grinding, the workpiece rotates at a low speed. If the workpiece simultaneously moves longitudinally back and forth, and the grinding wheel feeds laterally relative to the workpiece after each single or double stroke of longitudinal movement, this is called longitudinal grinding. If the width of the grinding wheel is greater than the length of the surface being ground, the workpiece does not move longitudinally during grinding; instead, the grinding wheel continuously feeds laterally relative to the workpiece, which is called plunge grinding. Generally, plunge grinding is more efficient than longitudinal grinding. If the grinding wheel is dressed to form a shaped surface, plunge grinding can machine shaped external surfaces.
Internal Cylindrical Grinding
Mainly used on internal cylindrical grinding machines, universal external cylindrical grinding machines, and coordinate grinding machines for grinding cylindrical holes, conical holes, and hole end faces of workpieces. Longitudinal grinding is generally used. Plunge grinding can be used when grinding shaped internal surfaces. When grinding internal holes on a coordinate grinding machine, the workpiece is fixed on the worktable. The grinding wheel rotates at high speed and also performs planetary motion around the center line of the hole being ground. In internal cylindrical grinding, due to the small diameter of the grinding wheel, the grinding speed is often less than 30 m/s.
Surface Grinding
Mainly used for grinding planes, grooves, etc., on a surface grinding machine. There are two types of surface grinding: peripheral grinding, which uses the outer cylindrical surface of the grinding wheel, is generally performed on a horizontal spindle surface grinding machine; various shaped surfaces can also be machined using a profile grinding wheel. End face grinding, which uses the end face of the grinding wheel, is generally performed on a vertical spindle surface grinding machine.
Centerless Grinding
Generally performed on a centerless grinding machine, it is used to grind the outer diameter of the workpiece. During grinding, the workpiece is not centered or supported by a center, but is placed between the grinding wheel and the guide wheel, supported by a support plate below, and rotated by the guide wheel. When the axis of the guide wheel is adjusted to be oblique to the axis of the grinding wheel by 1° to 6°, the workpiece can rotate while automatically making longitudinal feed motion along the axial direction; this is called through grinding. Through-feed grinding can only be used for grinding external cylindrical surfaces. When using centerless plunge grinding, the guide wheel axis and the grinding wheel axis must be adjusted to be parallel to each other, ensuring the workpiece is supported on the support plate without axial movement, and the grinding wheel continuously feeds laterally relative to the guide wheel. Centerless plunge grinding can machine shaped surfaces. Centerless grinding can also be used for internal grinding. During machining, the outer circle of the workpiece is supported on rollers or support blocks for centering, and an eccentric electromagnetic suction ring drives the workpiece to rotate. The grinding wheel extends into the hole for grinding. In this case, the outer circle serves as a positioning reference, ensuring that the inner and outer circles are concentric. Centerless internal grinding is commonly used on specialized bearing ring grinding machines to grind the inner grooves of bearing rings.