The factors that affect the efficiency and life of diamond saw blades include sawing process parameters, diamond particle size, concentration, and bond hardness. Sawing parameters include blade line speed, sawing concentration and feed speed.
Sawing parameters
1）Linear Speed of Saw Blade
In practice, the linear speed of the diamond saw blade is limited by the equipment conditions, the quality of the saw blade 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 linear speed of the saw blade can be selected in the range of 25m～35m/s. For granite with high quartz content and difficult to saw, the limit value 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.
2）Cutting Depth
The cutting 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 sawing 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. At the same time, the feeding 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 allowable 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.
3）Feeding Speed
The feeding speed is the feeding 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 cutting soft stone, such as marble, the feed speed can be increased appropriately. If the feed speed is too low, it will be more conducive to increase the sawing rate.
When sawing fine-grained granite with a relatively homogeneous structure, 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.
Other Influencing Factors
1）Diamond Size
The commonly used Diamond Grit 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 helpful for cutting into hard rocks. In addition, generally large-diameter saw blades require high cutting efficiency, and coarser particle size should be selected, such as Industrial Diamond Mesh 30/40, 40/50; small-diameter saw blades have low cutting efficiency and require a smooth section of rock sawing. Choose a finer particle size, such as Mesh Synthetic Diamond 50/60, 60/80.
The Diamond Grain size of commonly used diamond size ranges from 30/35 to 60/80. The harder the rock, the finer particle size should be selected. Because under the same pressure, the thinner the diamond is, the sharper it is, which makes it easier to cut into hard rock. In addition, the general large diameter saw blade requires high cutting efficiency, it is appropriate to select the use of coarser particle size, such as 30/40, 40/50. The sawing efficiency of small diameter saw blade is low, and the sawing section of rock is required to be smooth, so it is advisable to choose a finer particle size, such as 50/60 and 60/80.
2）Concentration of Cutter Head
The concentration of cutter head is the diamond concentration, which refers to the density of diamonds distributed in the matrix of the working layer (that is, the weight of diamonds contained in a 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 3.3 carats of diamonds is 75%. The volume concentration indicates the volume of the diamond in the agglomerate and stipulates that the concentration is 100% when the volume of the diamond occupies 1/4 of the total volume. Increasing the diamond concentration can prolong the life of the saw blade, because increasing the concentration reduces the average cutting force experienced by each diamond. However, increasing the depth will inevitably increase the cost of the saw blade, so there is a most economical concentration, and the concentration increases as the sawing efficiency increases.
3）Hardness of Cutter Head Binder
In general, the higher the hardness of the binder, the stronger its anti-wear ability. Therefore, when sawing abrasive rocks, the hardness of the binder should be high; when sawing soft rocks, the hardness of the binder should be low; when sawing abrasive and hard rocks, the hardness of the binder should be moderate.
4) Force Effect, Temperature Effect and Wear Damage
In the process of cutting 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.
Force Effect: During the sawing process, the saw blade is subject to axial force and tangential force. Due to the force in the circumferential direction and the radial direction, 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, large waste of stone, high noise during sawing, and increased vibration, which will cause early damage to diamond agglomeration and reduce the life of the saw blade.
Temperature Effect: Studies have shown that the heat generated in the cutting process is mainly transferred to agglomerates. The arc zone temperature is not high, generally between 40~120C. 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 particles and the workpiece, and cause thermal stress between the diamond and the additives, which leads to the fundamental bending of the failure mechanism of the diamond. Therefore, the temperature effect is the biggest factor influencing the damage of the saw blade.
Wear Damage: Due to the force effect and temperature effect, 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.
Crownkyn Superhard Company provides Diamond Abrasives with different strengths and models to meet the practical needs of diamond saw blade customers and improve the control of diamond particles.
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