ANALYSIS OF THE DIAMOND SAWING PROCESS

There are three methods in use for separating diamonds, i.e. by cleavi ng, by laser beam and by sawing. Sawing is one of the main methods use d for this purpose. This operation is carried out on special sawing ma chines equipped with a sawing disk blade, 0.04-0.14 mm thick and 76 mm initial diameter. The rotational velocity (n) of the disk is between 6000 and 12000 r.p.m. Diamond powder is embedded in the periphery of t he disk. The outcome surface of a diamond after the sawing operation m ust be flat and smooth. Whenever such a surface is actually obtained, the polishing time and the loss in size and weight of the diamonds are reduced. In the present work, the positioning of the diamond to be sa wed, with respect to an embedded particle in the disk, to create a fav ourable cutting angle is discussed. This would make it possible to red uce the range angle (gamma) to near-zero, and thereby the cutting forc es. Furthermore, a method to control the morphology and grain size of the diamond powder to be used in the cutting was developed. In the dia mond industry, two modes of sawing operations are in practice. One use s the periphery of the disk for the sawing while the other employs a c ircular hole in the centre of the disk. Analysis of the two modes show ed that the hole mode is more promising, as the design in that case re quires tensioning of the disk and makes for better lateral stability d uring the sawing process. In addition the tangential and the radial st resses, developed in both sawing methods, were calculated. To support the above, data was obtained from existing literature and analysed.