One of the most essential pieces of equipment in the manufacturing industry is the grinding machine. The grinding machine can be used to perform different operations. This is the reason why some special types of grinders are designed to specifically carry out some of the operations.
A grinding machine, popularly known as a grinder, is a power tool or machine tool used for grinding. Like other machine tools, it is a machining process that uses an abrasive wheel as the cutting tool. The abrasive grain on the wheel’s surface cuts a small chip from the workpiece through a shear deformation.
Well, in this reading, you’ll be learning what a grinding machine is, its parts, diagram, types, operations, advantages, disadvantages, & how it works.
Let’s begin!
What is a Grinding Machine?
A grinding machine or grinder is an industrial power tool that features an abrasive wheel for cutting or removing chips from metal surfaces. It can also be defined as a process of metal cutting by using a rotating abrasive wheel from the surface of the workpiece.
The grinding machine comprises a power-driven grinding wheel rotating at the necessary speed and a bed with a device to guide and hold the workpiece. The diameter of the wheel and the manufacturer’s rating define the speed. The grinding head may move over a fixed workpiece or remain stationary while the workpiece moves.
Using a grinder on a workpiece that shows low surface roughness will help to obtain high surface quality, accuracy, and dimension.
Parts of a Grinder
Grinding machine parts consist of the following parts:
- The base or bed is made of cast iron, which rests on the floor and carries all the machine parts.
- Tables are usually two in some types of grinders: the lower and the upper table. The lower table is designed to produce a transverse movement to the work by sliding one of the guideways on the bed, which is achieved by power or by hand.
- The headstock is positioned over the bed and supports the workpiece with the aid of a dead center and drives it.
- The tailstock can be adjusted and fixed in any required position to accommodate different lengths of the workpiece.
- The wheelhead consists of a grinding wheel and a driving motor.
Grinding Machine Diagram
How Does a Grinding Machine Work?
The working of a grinder or grinding machine is quite interesting and easy to learn and perform. It is widely used in different manufacturing companies, and it is available in different types. They are used for grinding workpieces at high surface quality and the accuracy of the shape and dimension.
A grinder features an electric motor that supplies motion power to the grinding wheel using a pulley and belt. For the portable grinder, the rotor is inside the grinding machine, and the power switch is located beside the handle of the grinder. So, the switch must be pressed before the grinder works.
For grinders that feature an electric motor, the motor rotates at a certain rpm (from 150 to 1500 RPM, it may change according to the type of grinding machine.) The grinder works with the help of a v-belt and cone pulley when it transfers to the grinder’s head.
Grinding Machine Operations
The following are the operations that can be performed on a grinding machine:
- Surface grinding operation.
- Cylindrical grinding operation (internal and external cylinder grinding.)
- Centerless grinding operation.
- Form grinding operation.
- Wet and Dry grinding operations.
Surface Grinding
Surface grinding is one of the most frequently performed grinding processes. It is a refining process that entails the removal of the oxide layer and impurities from the workpiece surface to achieve a planar surface on metallic or nonmetallic materials.
The workpiece is normally secured to the grinder’s worktable using a magnetic chuck, specialized vices, or vacuum chucks for nonmagnetic materials. The horizontal spindle is equipped with a straight wheel. The process is initiated by the table’s reciprocation.
This is done to obtain a flat surface as the rotating grinding wheel cuts off the material from the top surface of the workpiece and gives the flat look.
Cylinder Grinding
This grinding operation is carried out only on cylindrical jobs. It is of two types; external and internal cylindrical grinding, an external grinder is used to remove excess material from the outer surface of the workpiece. While the internal is done for smoothening the internal surface of a hole or any cylindrical workpiece.
Centerless Grinding
In this type of grinding operation, two grinding wheels are fitted parallel with a 5-10-degree angle, which is provided to obtain a longitudinal motion of the workpiece. A cylinder rod is placed between the two grinding wheels due to the tilted angle. This allows the workpiece to automatically pass through the wheels, and a smooth surface is obtained.
Form Grinding
In this type, the grinding wheel is maintained to maintain the shape of the final product. The job passes through the wheel, and automatically the pre-determined shape is formed on the workpiece.
Wet and Dry Grinding
The two methods of performing a grinding operation are wet and dry grinding. In the wet grinding, coolant like water or any other cooling substance will be sprayed to cool the surface so that the longevity of the grinding wheel increases and a fine surface finish is obtained. In dry grinding, coolant is not used, making it not a preferred method because the grinding wheel easily wears and an uneven surface finish is obtained.
Types Of Grinding Machines
The following are the types of grinding machines:
Belt Grinder
These machines often employ coated abrasives to treat metals and other materials during the machining process. From finishing to deburring to stock removal, belt grinding is a flexible technique fit for all kinds of projects.
Surface Grinder
A surface grinder is made up of a rotary table, an abrasive wheel, and a chuck for holding workpieces. To achieve a smooth finish, the material is held in place by the chuck as the wheel and item are revolved.
Bench Grinder
A bench grinder is often attached to a workbench or floor stand and contains two wheels, one for roughing and one for finishing operations. The wheels have varied diameters. Its applications include forming tool bits or other instruments needing manufacture or maintenance. Bench grinders are run by hand.
Cylindrical Grinder
A cylindrical grinder is used to shape the outside of a workpiece. Workpieces of any form may be fed into these machines as long as they have a central axis for rotation. The workpiece and grinding wheel spin in tandem in a cylindrical grinder.
Centerless Grinder
Two rotary wheels are used by centerless grinders to hold the workpiece firmly in position. A centerless grinder doesn’t utilize a spindle, contrary to a centered grinder. The pace at which the material is removed is determined by the wheel rotation speed.
Advantages and Disadvantages of Grinding Machine
Advantages
Below are the benefits of a grinding machine:
- High surface finish and accuracy are produced.
- Ability to machine hard material.
- Less pressure can be applied to work.
- Ability to work at high temperatures.
- Offers highly accurate dimensions.
- Ability to cut any type of metal at a speed rate.
- It can produce a smooth surface
Disadvantages
Below are the limitations of a grinding machine:
- The tools are highly expensive.
- Materials are removed little by little, making it a time-consuming process.
- Operation is carefully done to avoid damage.