Factors Affecting Diamond Saw Blades

Granularity

Commonly used diamond particle sizes are 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 and sharper the diamond 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 sawing efficiency, requiring smooth rock sawing section, and should be Use a finer granularity, such as 50/60, 60/80.

Blade concentration

The so-called diamond concentration refers to the density of diamonds distributed in the working layer matrix (ie the weight of diamonds contained in a unit area). The "Specification" states that the concentration of 4.4 carats of diamond per cubic centimeter of working matrix is 100% and that of 3.3 carats of diamond is 75%. The volume concentration indicates the volume of diamond in the agglomerate, and it is stipulated that when the volume of diamond accounts for 1/4 of the total volume, the concentration is 100%. Increasing the diamond concentration is expected to prolong the life of the saw blade because increasing the concentration reduces the average cutting force per diamond. However, increasing the concentration will inevitably increase the cost of the saw blade, so there is a most economical concentration, and the concentration increases with the increase of the sawing rate.

Blade hardness

Generally speaking, the higher the hardness of the bond, the stronger its wear resistance. Therefore, when sawing abrasive rocks, the binder hardness should be high; when sawing soft rocks, the binder hardness should be low; when sawing abrasive and hard rocks, the binder hardness should be moderate .

Effect

In the process of cutting stone, the diamond circular saw blade will be subjected to alternating loads such as centrifugal force, sawing force, and sawing heat.

Grinding and breakage of diamond circular saw blades due to force and temperature effects.

Force effect: During the sawing process, the saw blade is subjected to the action of axial force and tangential force. Due to the force in the circumferential and radial directions, the saw blade is wavy in the axial direction and dish-shaped in the radial direction. These two kinds of deformation will cause uneven rock section, waste of stone material, loud noise and intensified vibration during sawing, resulting in early damage of diamond agglomeration and shortening of saw 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 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 the cutting process is mainly transferred to the agglomerates. The arc zone temperature is not high, generally between 40 and 120 °C. The abrasive grinding point temperature is relatively high, generally between 250 ~ 700 ℃. 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 carbonization of graphite, but will change the friction properties between the abrasive particles and the workpiece, and cause thermal stress between the diamond and the additive, resulting in a fundamental change in the failure mechanism of diamond. Studies have shown that temperature effects are the biggest factor in breaking saw blades.

Wear and tear

Due to the force effect and temperature, the saw blade is often worn and damaged after a period of use. The main forms of abrasion damage are as follows: abrasive wear, local crushing, large-scale crushing, falling off, and mechanical abrasion of the binder along the direction of the sawing speed. Abrasive wear: The diamond particles are constantly rubbed against the workpiece, the edges are passivated into a flat surface, the cutting performance is lost, and the friction is increased. The heat of sawing will cause a graphitized thin layer on the surface of the diamond particles, the hardness will be greatly reduced, and the wear will be aggravated: the surface of the diamond particles is subjected to alternating thermal stress and alternating cutting stress, and fatigue cracks will appear and partially break, revealing A sharp new edge is an ideal wear pattern; large-scale crushing: diamond particles are subjected to impact load when cutting in and out, and the more prominent particles and grains are consumed prematurely; falling off: alternating cutting forces make diamond The particles are constantly shaken in the binder to loosen. At the same time, the wear of the bond itself during sawing and the heat of sawing soften the bond. This reduces the holding force of the bond, and when the cutting force on the particles is greater than the holding force, the diamond particles will fall off. Either type of wear is closely related to the load and temperature to which the diamond particles are subjected. Both of these depend on the sawing process and cooling and lubrication conditions.