24-09-2012, 12:47 PM
ABRASIVES
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Abrasives can be described as micro miniature cutting tools. It primarily consists small bits of hard mineral materials called grain. Grinding is a process that includes polishing, cutting , shaping and size reduction operations. Abrasive are a type of ceramic material which are characterized by their extreme hardness, high melting point and chemical inertness and are employed in grinding operation.
CLASSIFICATION OF ABRASIVES
The Abrasive can be classified based on the method of origin and the method of abrasive operation.
Based on Origin:
Abrasives are classified based on their origin as follows:
• Natural Abrasive - There are several minerals found in nature which are used for abrasive purpose. Some of them are diamond , emery , quartz , flint.
• Artificial Abrasive - Materials are prepared by electrical fusion of raw materials. Some of them are Silicon Carbide , Cubic Boron Carbide , Alumina and Zirconia.
Based on their mode of operation:
Abrasives are classified based on the operation as below:
• Bonded Abrasive - Abrasive grains are bonded to the matrix of bond either vitrified, or organic (rubber, resin) bond. The synonym for binded abrasive is grinding wheel.
• Coated Abrasive – Abrasive grains are glued on to a flexible backing made of cloth, paper or vulcanized fiber. These are used in the areas where flexibility is also needed in addition to grinding.
• Loose Grain - In this operation abrasive grains are used as such for grinding operation. The grinding of plate glass is one of the largest loose Abrasive grinding operations.
• Mounted Abrasive – Bonded abrasive are mounted on the iron or steel handle to make it comfortable handy tool.