We consider tools whose cutting action occurs by cleavage. The cutting part is made up of natural or synthetic diamonds retained by a mixture of tugsteno powders and copper-based alloys which, by melting in an oven infiltration process, make the diamonds clinging to the cutting surface. During the drilling operation, each diamond penetrates the material to be drilled and a certain amount of material is removed by the rotary effect. This category of products differentiate in terms of quality and size of the diamond.
NEXUS uses both natural and synthetic diamonds. Natural diamonds have a generally roundish and quite irregular shape while synthetic diamonds have a more regular and pointed shape. The magnitude of the diamond identifies the size of the individual stones and is expressed in parts per carat; for example a 20/30 ppc diamond (carat stones) means that a carat of this size counts between 20 and 30 stones, that is, 25 stones. The smaller is the size, the larger are the stones that make it up. This technology is applicable to drill materials with variable hardness from 50 to 150 MPa. Obviously larger diamonds are more protruding and can remove larger quantities of material for each revolution, but large stones cannot penetrate hard materials unless they are subjected to high pressures. To better adapt the operativity to the variability of the hardness of the rocks, are available tools with different diamond sizes. In general, hard materials will be worked with small stones while softer materials with larger stones. It is not enough to define the type of rock to be drilled to identify the most suitable diamond size because in the hole making there are other variables that have a decisive influence on the cutting efficiency. The depth and direction of the drilling, the level of fracturing of the rock, the variability of materials within the same hole, the characteristics of the probe (number of revolutions, torque, thrust on the tool), have a decisive influence on the choice of the more suitable size and therefore must be evaluated carefully in order to make the best a choice. Over the standard size range, NEXUS may implement special tools focused on specific customer's requests. These tools can be used with water or air as drilling fluid for tool cooling and debris removal.