The ability to grind with the help of machines was developed centuries ago and it was a giant leap forward in our growth and development. There are different types of grinding methods and mechanisms used for a variety of objectives. Some methods are useful for small-scale purposes, while others are useful for medium to large scale works. Surface grinding, cylindrical grinding, and centreless grinding are a few of the grinding types. The machines vary in their usage, size, operation, cost, precision and flexibility. Some grinding machines are portable but these are generally not heavy-duty ones. The commercial grinders use large vehicles to transport the heavier machines to the site. Transportation of these machines is costly and it is done only when the workpiece can't be brought to the factory.
What is centreless grinding?
Centreless grinding machines do not use a central spindle or a central axle. Though the individual wheels may have their own mechanism of rotation, they move independent of each other. However, when a workpiece is being worked upon, one of the wheels is fixed while the other is made to rotate. When needed, both the wheels can be made to rotate for grinding the workpiece. This type of grinding process has several advantages over other types of grinding mechanisms. Most of the machines are getting automated. Those used in heavy-industries or for precision-grinding are nearly always automated, that is, operated by a computer numeric control. These advanced machines can be programmed according to the requirement and the same process can be repeated endlessly.
One of advantages of centreless grinding is that the operator does not have to hold the workpiece in hand. When you involve men to directly work upon the parts, you run the risk of bringing in human error. This error can be completely eliminated if the job, from the start to the end, is performed by the machine itself. However, the operator can do things manually if need be. Second, the loading time is small as compared to that required in many other types of centered grinding. Then there are many other advantages like a smoother finish, heavier passes between the wheels, and a longer wheel life.
Different types of centreless grinding!
There are three types of centreless grinding machines. First is the through-feed type. In this type of grinding, the workpiece is passed completely between the wheels. The motion of the wheels is controlled in different directions to work on the workpiece. Second is the end-feed type. In this type, the workpiece is fed from different ends to give it the desired shape. The item has to be inserted and pulled out several times to complete the process. And the third one is the in-feed type. This type of grinding is suitable for giving complex shapes to workpieces. First the object is fed into the machine and then the wheels are adjusted. Once the task is done, the workpiece is pulled out from the machine. Each of the above types has its advantages and disadvantages. For example, the through-feed type is effective for items of cylindrical shape, while the end-feed type is useful for tapered items.