Centerless grinders are unique in that they do not require a cutting surface to be attached to in order to grind. Instead, the abrasive material is placed in a rotating cylinder and rotated at extremely high speeds. The use of such high speed grinding allows the machine to create very smooth surfaces and the quality of the grinding output depends largely on the quality of the grinding wheel. Due to the nature of the grinding process, it is important to use high quality grinders. In addition to this, there are specific considerations that need to be addressed when selecting a grinder.
Cast-iron centerless grinders are considered the most durable of all centerless grinders. Although the cost of the cast iron design varies significantly, they are generally made of the best metal and also have the longest service life. They are also most efficient when compared with their aluminum and steel counterparts.
Centerless grinders are commonly used in applications where accuracy is paramount. This type of machine is particularly suited to precision machining applications because they are devoid of a stationary spindle or housing. In other words, all of the cutting, grinding, etc. occurs through the use of a fixed, or adjustable drum.
For the most reliability and accuracy, it is often necessary to install two independent grinding wheels. Two separate grinders can provide greater accuracy and prevent chatter or burrs from forming. Typically two separate, sealed ceramic grinding wheels are used in centerless machines; however, some manufacturers have developed hybrid models that incorporate both types of ceramic stone media in their construction.
A common feature among grinders that utilize centerless technology is the presence of a Lagrange point. A Lagrange point is a geometric region in which the material is mounted on the inside surface of the lathe. The grinding wheel passes through this area without interruption. Most notably, migraines do not form in areas where the lathe’s spindle is positioned inside a Lagrange point. Because a centerless grinder relies on the use of a fixed housing and spindle system, they may be more prone to material damage than those with a stationary spindle assembly. However, since all of the cutting, grinding, drilling, etc. can occur entirely through the use of a ceramic tile, there is no need for a Lagrange point.
One other benefit of centerless grinders is that they typically incorporate automatic balancing systems. The use of automatic balancing systems allows these units to maintain accurate internal balances at all times. In addition, these units typically include taper wheels that allow for greater accuracy and greater ability to perform in high-demand situations.