A grinder or grinding machine consists of various machine or power tools used for grinding. It is a kind of machining that is done using an abrasive wheel as a cutting equipment. Every piece of abrasive on the surface of the wheel cuts a little chip from the workpiece.
Grinders are used to complete workpieces that must show a high surface quality and premium accuracy of dimension and shape. There are also several roughing applications in which grinders are used to remove high volumes of metal rapidly. Meaning that grinding is a broad field.
Grinders remove materials from the workpiece via abrasion, which can result in the emission of substantial amounts of heat. So in order to cool the workpiece (to avoid overheat and exceed its tolerance), grinders incorporate a coolant. This coolant may also benefit the technician as the heat generated can cause burns. Note that in high-precision grinders; the final grinding steps are set up in a way that removes about 200 nm per pass. The result of this is that very little amount of heat is generated that even without a coolant, the rise in temperature is negligible.
From the simplest to the most complex grinders, grinding machines are classified in three different variations namely cylindrical grinders, utility grinders, and surface grinders. Note that these are just categories of grinding machines there are several grinders under each of these varieties. Read on and see the different uses of the variations of grinders.
A utility grinder is used for offhand grinding where a workpiece is supported with the hand and brought to bear the rotating abrasive wheel. What determines the level of accuracy of this kind of grinding machine depends wholly on the operator's skill, dexterity, and knowledge, of the capabilities of the machine and the kind of job it is used for. The utility grinder comes with a horizontally mounted motor and a grinding abrasive wheel at every end of the motor.
Cylindrical grinders include both center and the center-less types. This type of grinders come with multiple grinding wheels. When using cylindrical grinding machines, the workpiece is rotated past the wheels till it forms a cylinder shape. It is used to create precision rods, bearing races, bushings, tubes, and many other parts.
Surface grinders are used to grind flat surfaces. Here the workpiece is supported on top a rectangular table that moves back and forth and reciprocating beneath the grinding wheel. This type of grinding machine has a head that is lowered toward a workpiece which moves back and forth beneath the grinding wheel on top a table that has a controllable magnet used with a magnetic stock. It can also have a vacuum chuck or some other fixturing means. The common surface grinders come with a grinding wheel that rotates horizontally cutting through the circumference of a grinding wheel.
Some types of surface, cylindrical, and utility grinders include;
A floor-mounted utility grinder stands waist-high secured to the floor with bolts. This utility grinding machine has two grinding abrasive wheels. This two wheel arrangement allows for installing a coarse wheel (for roughing) on an end of the shaft as well as a fine grain wheel (meant for finishing ) at its other end. This system saves the time that may have been consumed in changing wheels.
Just like it is with a floor mounted utility grinder, a coarse grinding wheel and a fine grinding wheel are mounted on the machine (this is meant for convenience of an operation). Each of the wheels are provided with a table tool rest (adjustable) with an eye shield (for protection). This machines motor comes with a thermal overload control to stop the motor if to much wheel pressure is applied. There by preventing the motor from burning out.
A rotary surface grinder (also known as a Blanchard style grinder), has a grinding head that rotates the grinding wheel via a vertical axis cutting through the end face of its grinding wheel. While a table rotates a work-piece in the opposite position (underneath). This kind of grinding machine removes large sums of material and can grind flat surfaces with spirial grind marks. It can be used to sharpen and make metal stamping die sets, fixture bases, flat shear blades, or parallel and flat surfaces. These type of surface grinders can also be manually operated.
A tool and cutter grinder is usually used to perform the minor functions of a drill bit grinder, or any other specialized tool-room grinding operations.
A jig grinder as its name implies has different uses when it comes to finishing jigs, fixtures, and dies. However, its primary function is grinding holes and pins. This grinding machine may also be used for difficult surface grinding.
A gear grinder is usually employed as a final machining process during the manufacturing of a high-precision gear. Its primary function is to remove the remaining few thousands of material left after other manufacturing methods (like gashing or hobbing).
A die grinder is a high-speed rotary tool that is hand-held. It has a small diameter grinding bit. This grinding machine is typically air driven (it uses compressed air). However, it can be driven by a small electric motor or with a flexible shaft.
This grinder is a machine attachment designed to mounted to the tool part of engine lathes. Tool post grinders can be used for external and internal grinding of cylindrical workplaces.