Difference between centerless grinder and cylindrical grinder

A grinding machine, as a type of industrial power processing equipment, is characterized by the use of a grinding wheel to cut or remove chips from a metal surface. It can also be defined as the process of cutting metal from the surface of a workpiece using a rotating grinding wheel.

There are many types of grinding machines, including cylindrical grinding machines, internal grinding machines, centerless grinding machines, and surface grinding machines, etc. Here we will focus on the differences between cylindrical grinding machines and centerless grinding machines.

Cylindrical grinding machine

An external cylindrical grinder is a grinder used to shape the outside of an object. Cylindrical grinders can machine a variety of shapes, but the object must have a central axis of rotation. This includes, but is not limited to, shapes such as cylinders, ellipses, cams, or crankshafts.

Cylindrical grinding machines are a special form of grinding machine used to machine cylinders, rods and other similar workpieces. The cylinders are located between two centers and rotate in one direction, while the grinding wheel or wheels are close together and rotate in the opposite direction.

What is the centerless grinding process?

Centerless grinding is the process of removing material from the outside diameter of a workpiece using a grinding wheel. In its simplest form, centerless grinding consists of a machine base, grinding wheel, regulating wheel and working insert.

Centerless grinding has a short loading time, no margin for deflection, and allows for a large amount of grinding. Centerless grinding wheels have a longer life. The workpiece is rigidly supported by the regulating wheel, which presses the workpiece against the grinding grain on the wheel, enabling grinding of brittle materials and deformed parts.

Difference between centerless grinding machine and cylindrical grinding machine

1. Grinding principle: When grinding on an external cylindrical grinder, it is used to grind the outer cylinders, outer cones and end faces of the shaft shoulders. When grinding with a centerless grinder, there are two grinding wheels, a guide wheel and a grinding wheel. The guide wheel drives the cylindrical workpiece to rotate on the angle, and the grinding wheel acts as a grinder for the workpiece.

2. Processing method: The workpiece of the cylindrical grinder must be centered during processing, centered with the center of the head and tailstock or clamped with the center of the chuck, etc. Centerless grinders rely on external rotation for processing. Since they cannot be centered, their roundness depends on the roundness of the workpiece itself. Therefore, the accuracy of machining into a circle is not as good as that of cylindrical grinding machines. Therefore, workpieces with high roundness requirements are processed on centerless grinders before. It is best to process the circle with an external grinder first, and then use a centerless grinder.

3. Machining accuracy: Centerless grinders and cylindrical grinders should not be judged arbitrarily if they are more accurate than the two types of grinders. Both types of grinding machines are very accurate, depending on the origin and manufacturing accuracy of the grinder. Centerless grinding is mainly used for batch shafts. The product is processed by grinding wheels and introduced for squeezing and grinding. The part rotates without a fixed center of rotation, while cylindrical grinding requires the part to be fixed with an ejector pin so that it can rotate around the axis for grinding.

4. Grinding machine characteristics: The grinding wheel spindle bearing of cylindrical grinding machine adopts tapered oil wedge dynamic pressure bearing, and the grinding wheel spindle still has high bearing rigidity at low speed. The main features of centerless grinding machines are good versatility, high modularity, high precision and rigidity, and high efficiency of centerless grinding machines.

The major difference between centerless and cylindrical grinding machines is that centerless grinding machines do not require fixtures, only inserts for supporting the workpiece and additional guide wheels to drive the workpiece for grinding, but cylindrical grinding does not require inserts and uses centers and fixtures. For clamping the workpiece for grinding, cylindrical grinding machines are equipped with only grinding wheels and no guide wheels.

5. Concentricity of workpiece: Centerless grinding machines and cylindrical grinding machines grind external cylinders. Cylindrical grinding machines can guarantee the concentricity of the workpiece, while centerless grinding machines cannot guarantee the concentricity requirements of the workpiece under normal circumstances.

6. Grinding machine structure: Cylindrical grinding machines consist of the bed and table, grinding wheel holder, headstock, grinding frame, longitudinal feed handwheel, transverse feed handwheel, reversing stop, and other components. Centerless grinders are mainly composed of the main body, grinding wheel holder, guide wheel, headstock, spindle unit structure, spindle rod automatic tool mounting system, etc.

7. Grinding machine use: Cylindrical grinding machines are mainly used for precision grinding of end faces, external circles and tapered surfaces of batch shaft parts. It is suitable for military, aerospace and general-purpose precision machining workshops with small batch and high precision requirements. Shaft parts processing. Main application range of centerless grinding machine: For polishing cylindrical surfaces of various rings, shafts, and tube-type parts. For various steps, cones, centerless grinding machines are mainly used for grinding through holes of various cylindrical parts and ring parts, as well as tapered parts for plunge grinding, etc.

This article describes the similarities and differences between centerless grinding machines and cylindrical grinding machines. Centerless grinders and cylindrical grinders, which are also grinding machines, both use grinding wheels for grinding operations, but there are also major differences in the processing of various types of workpieces. While they are suitable for mass production, cylindrical grinding is suitable for high-precision single-piece processing.