Disk grinding

Resinoid-bonded wheels find wide use in heavy-duty snagging operations where large amounts of metal must be removed quickly, in cutting-off operations, portable disk grinding (as for weld-beads), roU grinding, and vertical spindle disk grinding. 

Nankov, M.M. Supersonic activation or cup-shape diamond disk grinding. ISEM-9, Proceedings of the Symposium for Electro Machining. The Japan Society of Electro-Machining Engineers, Nagoya, Japan, S397-399,1989. 

Another example of a type of process where water is used is disk grinding. The rubber is ground by friction created by it being passed between two grinding wheels. Water can be added to the process to both remove heat and improve its efficiency. The particle sizes generated by this process can be down to around 500 pm, without water, and down to 250 pm, or less, with water. 

Crushing and grinding uses mechanical force to break larger particles into smaller ones. A variety of tools are used depending on the particle s size and hardness. Large particles are crushed using jaw crushers capable of reducing particles to diameters of a few millimeters. Ball mills, disk mills, and mortars and pestles are used to further reduce particle size. 

Bonded abrasive products are made as wheels, disks, cylinders, sticks, blocks, and segments, all of which are defined n.yiSyi-B74.2-1974, "USA Standard Specifications for Shapes and Sizes of Grinding Wheels." This bulletin is sponsored by the Grinding Wheel Institute it is obtainable from most wheel manufacturers. 

Zirconium oxide is fused with alurnina in electric-arc furnaces to make alumina—zirconia abrasive grains for use in grinding wheels, coated-abrasive disks, and belts (104) (see Abrasives). The addition of zirconia improves the shock resistance of brittle alurnina and toughens the abrasive. Most of the baddeleyite imported is used for this appHcation, as is zirconia produced by burning zirconium carbide nitride. 

Pin MiUs In contrast to peripheral hammers of the rigid or swing types, there is a class of high-speed mills having pin breakers in the grinding circuit. These may oe on a rotor with stator pins between circular rows of pins on the rotor disk, or they may be on rotors operating in opposite directions, thereby securing an increased differential of speed. See also the Mikro-ACM pulverizer described later. 

The pellet (pressed-disk) technique depends on the fact that dry, powdered potassium bromide (or other alkali metal halides) can be compacted under pressure in vacuo to form transparent disks. The sample (0.5-1.0 mg) is intimately mixed with approximately 100 mg of dry, powdered KBr. Mixing can be effected by thorough grinding in a smooth agate mortar or, more efficiently, with a small vibrating ball mill, or by lyophili-... 

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