Granularity
The commonly used diamond grain size is in the range of 30/35 to 60/80. The harder the rock, the finer grain size should be selected. Because under the same pressure conditions, the finer the diamond, the sharper it is, which is conducive to cutting into hard rocks. In addition, generally large-diameter saw blades require high sawing efficiency, and a coarser particle size should be selected, such as 30/40, 40/50; small-diameter saw blades have low cutting efficiency and require a smooth rock cutting section. Choose a finer particle size, such as 50/60, 60/80.
Tip concentration
The so-called diamond concentration refers to the density of diamonds distributed in the matrix of the working layer (that is, the weight of diamonds per unit area). "Specifications" stipulate that the concentration of 4.4 carats of diamond per cubic centimeter of the working matrix is 100%, and the concentration of diamonds of 3.3 carats is 75%. The volume concentration indicates the volume of diamond in the agglomerate, and stipulates that the concentration is 100% when the volume of diamond occupies 1/4 of the total volume. Increasing the diamond concentration is expected to extend the life of the saw blade, because increasing the concentration reduces the average cutting force experienced by each diamond. But increasing the concentration will inevitably increase the cost of the saw blade, so there is a most economical concentration, and the concentration increases as the sawing rate increases.
Hardness of cutter head
Generally speaking, the higher the hardness of the binder, the stronger its wear resistance. Therefore, when sawing abrasive rocks, the bond hardness should be high; when sawing soft rocks, the bond hardness should be low; when sawing abrasive and hard rocks, the bond hardness should be moderate.
Effect
In the process of cutting the stone, the diamond circular saw blade will be subjected to alternating loads such as centrifugal force, sawing force, and sawing heat.
Due to the force effect and temperature effect, the diamond circular saw blade is worn and damaged.
Force effect: During the sawing process, the saw blade is subject to axial force and tangential force. Due to the force in the circumferential and radial directions, the saw blade is wave-shaped in the axial direction and dish-shaped in the radial direction. These two kinds of deformation will cause uneven rock cutting surface, waste of stone, loud noise and increased vibration during sawing, resulting in early damage to diamond agglomeration and reduced blade life.
Temperature effect: The traditional theory believes that the influence of temperature on the saw blade process is mainly manifested in two aspects: one is to cause the graphitization of the diamond in the agglomeration; the other is to cause the thermal stress of the diamond and the matrix to cause the diamond particles to fall off prematurely. New research shows that the heat generated during cutting is mainly transferred to agglomerates. The arc zone temperature is not high, generally between 40 and 120°C. The grinding point temperature of the abrasive grains is higher, generally between 250 and 700 ℃. However, the coolant only reduces the average temperature of the arc zone, but has little effect on the temperature of the abrasive particles. Such a temperature will not cause the graphite to be carbonized, but will change the friction properties between the abrasive particles and the workpiece, and cause thermal stress between the diamond and the additives, which will lead to a fundamental change in the failure mechanism of the diamond. Studies have shown that temperature effect is the biggest factor influencing saw blade damage.
Wear and damage: Due to the force effect and temperature, the saw blade will often be worn and damaged after a period of use. The main forms of wear damage are as follows: abrasive wear, partial crushing, large area crushing, shedding, and mechanical abrasion of the bonding agent along the cutting speed direction. Abrasive wear: The diamond particles are constantly rubbing against the workpiece, and the edges are passivated into a plane, which loses cutting performance and increases friction. The heat of sawing will cause a thin layer of graphitization on the surface of the diamond particles, which will greatly reduce the hardness and aggravate the wear: the surface of the diamond particles is subjected to alternating thermal stresses, and at the same time, it is also subjected to alternating cutting stresses, and fatigue cracks will appear and partially broken, revealing A sharp new edge is an ideal wear pattern; large area crushing: diamond particles are subjected to impact load when cutting in and out, and the more prominent particles and crystal grains are consumed prematurely; shedding: alternating cutting forces make the diamond The particles are constantly sloshing in the binding agent to produce looseness. At the same time, the wear of the bond itself and the heat of sawing during the sawing process soften the bond. This reduces the holding force of the binder, and when the cutting force on the particles is greater than the holding force, the diamond particles will fall off. No matter what kind of wear is closely related to the load and temperature of the diamond particles. Both of these depend on the sawing process and cooling and lubrication conditions.
