Guide to Centerless Grinding Machine: Advantages, Working Principle and Parts

The grinding wheel rotates at high speed for grinding, while the guide wheel rotates in the same direction at a slower speed, thereby driving the workpiece to rotate and perform circumferential feed. During penetration grinding, axial feed is achieved by adjusting the inclination angle of the guide wheel axis, and during penetration grinding, radial feed is achieved by moving the guide wheel frame or grinding wheel frame. When centerless grinding, the center of the workpiece must be higher than the center line between the grinding wheel and guide wheel, which makes it impossible for the contact points between the workpiece and the grinding wheel and guide wheel to be symmetrical. Therefore, some raised surfaces on the workpiece can gradually be rounded during multiple rotations. If the top surface of the supporting plate is horizontal and the center of the workpiece is adjusted to be at the same height as the center of the grinding wheel and guide wheel, when there is a raised point on the workpiece that contacts the guide wheel, the opposite side of the raised point is ground into a concave pit, and its depth cannot be reduced to the height of the raised point. After the workpiece rotates 180 degrees, the raised points come into contact with the grinding wheel. At this point, the concave hole is exactly at the angle of the guide wheel, and the raised points cannot be ground flat. At this point, the outer surface of the workpiece is an equal-diameter edge circle. So, the key to rounding the workpiece is that the center of the workpiece is higher than the centerline between the grinding wheel and the guide wheel, but the higher distance should not be too large, otherwise, the vertical component of the guide wheel on the workpiece may cause the workpiece to jump and affect the surface quality of the machining. Generally, h=(0.15-0.25) d, where d is the diameter of the workpiece. A centerless cylindrical grinder does not have a headstock or tailstock but is supported by a support plate and a guide wheel, and is ground with a grinding wheel. The upper surface of the support plate is tilted by 30 ° to 50 ° so that the workpiece is tightly pressed against the guide wheel by cutting force. The axis of the guide wheel has a tilt angle relative to the axis of the grinding wheel α （1~5°）. The guide wheel rotates at a low speed and relies on friction to drive the workpiece to rotate. Due to the existence of an inclination angle, the velocity direction at the contact point between the guide wheel and the workpiece is oblique, which can be divided into two velocity components: one is to rotate the workpiece, and the other is to generate axial feed motion of the workpiece.