Forms of Cylindrical Grinding:
1. Center cylindrical grinding
2. Centerless cylindrical grinding
3. Cylindrical grinding of end face
The method of cylindrical grinding:
1.Longitudinal grinding method:
Longitudinal grinding method is the most commonly used grinding method. During grinding, the worktable is fed longitudinally and the grinding wheel is fed periodically horizontally. The grinding allowance of the workpiece must be ground in multiple reciprocating strokes.
Features of longitudinal grinding method:
a.Over the entire width of the grinding wheel, the working conditions of the abrasive grains are different. The sharp corners of the left end face (or right end face) of the grinding wheel bear the main cutting action. Most of the abrasive grains are responsible for reducing the surface roughness value of the workpiece. The longitudinal grinding method has small grinding force and good heat dissipation conditions, and can obtain higher machining accuracy and smaller surface roughness value.
b.Labor productivity is low.
c.Low grinding force, suitable for grinding slender, precision or thin-walled workpieces.
2.Plunge grinding:
Plunge grinding is also known as lateral grinding. The length of the outer circle of the workpiece to be ground should be less than the width of the grinding wheel. During grinding, the grinding wheel performs continuous or intermittent lateral feed motion until all the allowance is removed. There is no longitudinal feed movement when grinding the grinding wheel. A higher cut-in speed can be used during rough grinding; a lower cut-in speed can be used during fine grinding to prevent workpiece burns and thermal deformation.
Plunge grinding method features:
a.The working conditions of the abrasive grains are the same throughout the width of the grinding wheel, and the grinding effect of all the abrasive grains is fully exerted.
b.The radial grinding force is large, and the workpiece is prone to bending deformation, which is generally not suitable for grinding finer workpieces.
c.Large grinding heat is generated during grinding, and the workpiece is easily burned and deformed by heat.
d.The morphology of the grinding wheel surface (dressing marks) will be copied to the workpiece surface and affect the surface roughness of the workpiece. In order to eliminate the above defects, a small longitudinal movement can be made at the end of the cutting method.
e.Due to the limitation of the width of the grinding wheel, the plunge method is only suitable for grinding the outer surface with a short length.
3.Segment grinding:
The segmented grinding method is also called the comprehensive grinding method. It is a comprehensive application of the cut-in method and the longitudinal method, that is, the workpiece is roughly ground in sections by the cut-in method, leaving a margin of 0.03~0.04mm, and finally the longitudinal method is used for fine grinding to size. This grinding method not only utilizes the advantages of high production efficiency of the plunge method, but also has the advantages of high machining accuracy of the longitudinal method. When grinding in sections, there should be an overlap of 5~10mm between two adjacent sections. This grinding method is suitable for workpieces with better grinding allowance and rigidity, and the length of the workpiece should also be appropriate. Considering the grinding efficiency, a wider grinding wheel should be used to reduce the number of segments. The best condition is when the length of the machined surface is about 2~3 times the width of the grinding wheel.
4.Deep grinding method:
This is a more commonly used grinding method, which uses a large amount of back cut to grind off all the grinding allowance of the workpiece in one longitudinal feed. Since the basic grinding time is shortened, the labor productivity is high.
Features of deep grinding method:
a.Suitable for grinding rigid workpieces.
b.The grinder should have greater power and stiffness.
c.When grinding, use a small unidirectional longitudinal feed. The longitudinal feed direction of the grinding wheel should face the headstock and lock the tailstock sleeve to prevent the workpiece from falling off. The hardness of the grinding wheel should be moderate and have good grinding performance.
