The factors that affect the efficiency and life of diamond circular saw blades include sawing process parameters, diamond particle size, concentration, and bond hardness. The sawing parameters include saw blade line speed, sawing density and feed speed.
1. Saw blade linear speed: In actual work, the linear speed of diamond circular saw blades is limited by equipment conditions, saw blade quality and the nature of the sawn stone. From the perspective of the best saw blade service life and sawing efficiency, the linear speed of the saw blade should be selected according to the properties of different stones. When sawing granite, the saw blade linear speed can be selected in the range of 25m～35m/s. For granite with high quartz content and difficult to saw, the lower limit of the saw blade linear speed is appropriate. In the production of granite tiles, the diameter of the diamond circular saw blade used is small, and the linear speed can reach 35m/s.
Sawing depth: Sawing depth is an important parameter related to diamond wear, effective sawing, the force of the saw blade and the properties of the sawn stone. Generally speaking, when the linear speed of the diamond circular saw blade is high, a small cutting depth should be selected. From the current technology, the cutting depth of diamond can be selected between 1mm and 10mm. Generally, when large-diameter saw blades are used to cut granite blocks, the cutting depth can be controlled between 1mm and 2mm, while the feed speed should be reduced. When the linear speed of the diamond circular saw blade is large, a large cutting depth should be selected. However, when the sawing machine performance and tool strength are within the permissible range, a larger cutting concentration should be used for cutting to improve cutting efficiency. When there are requirements for the machined surface, small depth cutting should be used.
Feed speed: The feed speed is the feed speed of the sawn stone. Its size affects the sawing rate, the force of the saw blade and the heat dissipation of the sawing area. Its value should be selected according to the nature of the stone being sawn. Generally speaking, when sawing soft stone, such as marble, the feed speed can be appropriately increased. If the feed speed is too low, it is more conducive to increase the sawing rate. For sawing fine-grained, relatively homogeneous granite, the feed speed can be appropriately increased. If the feed speed is too low, the diamond blade will be easily ground. However, when sawing coarse-grained granite with uneven softness and hardness, the feed speed should be reduced, otherwise it will cause the vibration of the saw blade and cause the diamond to break and reduce the sawing rate. The feed speed of sawing granite is generally selected in the range of 9m to 12m/min.
二、 Other influencing factors：
Diamond particle size: The commonly used diamond particle 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 grain size should be selected, such as 30/40, 40/50; small-diameter saw blades have low cutting efficiency and require a smooth cutting section for rock. Choose a finer particle size, such as 50/60, 60/80.
Tip concentration: The so-called diamond concentration refers to the density of diamond distribution in the matrix of the working layer (that is, the weight of diamond contained in a unit area). The "Specification" stipulates 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 accounts for 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 depth 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 cutting rate.
3. Hardness of the binder of the 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
4. Force effect, temperature effect and wear damage: During the cutting of stone, diamond circular saw blades 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.
① 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 wavy in the axial direction and dish-shaped in the radial direction. These two kinds of deformation will cause uneven rock cutting surface, a lot of waste of stone, loud noise during sawing, and aggravated vibration, resulting in early damage to diamond agglomeration and reduced blade life.
② 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 heat 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. However, the grinding point temperature of the abrasive grains is relatively high, generally between 250 and 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 the graphite to be carbonized, but will change the friction properties between the abrasive grains and the workpiece, and cause thermal stress between the diamond and the additives, which leads to the fundamental bending of the diamond failure mechanism. Studies have shown that temperature effect is the biggest factor influencing saw blade damage.
③Wear and damage: Due to the force effect and temperature, the saw blade tends to be worn and damaged after a period of use. The main forms of wear damage are as follows: abrasive wear, local crushing, large area crushing, shedding, and mechanical abrasion of the bonding agent in the direction of the sawing speed. Abrasive wear: The diamond particles are constantly rubbing against the parts, and the edges are passivated into a flat surface, 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 wear: the surface of the diamond particles is subjected to alternating thermal stresses, while also undergoing alternating cutting stresses, fatigue cracks will appear and localized fractures will appear, 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 sawing heat during the sawing process soften the bond. This reduces the holding force of the binder. 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 cutting process and cooling and lubrication conditions.
