What are the factors that affect the life of diamond saw blades?

The factors affecting the efficiency and life of diamond circular saw blades include cutting parameters, diamond size, concentration and binder hardness, etc. The number of cutting can be saw blade line speed, saw cutting concentration and feeding speed.

I. Sawing parameters

（1）Saw blade linear speed: In practice, the linear speed of diamond circular saw blade is limited by equipment conditions, saw blade quality and the nature of the sawn stone. In terms of the best service life and cutting efficiency of the saw blade, the linear speed of the saw blade should be selected according to the nature of different stones. When sawing granite, the linear speed of saw blade can be selected within 25m ~ 35m/s. For granite with high quartz content and difficult to sawing, it is advisable to take down the limit value of linear velocity of saw blade. The diameter of diamond circular saw blade used in the production of granite face brick is small and the linear velocity can reach 35m/s.

（2）Sawing depth: Sawing depth is an important parameter related to diamond abrasion, effective sawing, force of saw blade and the nature of sawn stone. Generally speaking, when the linear velocity of diamond circular saw blade is high, a small cutting depth should be selected. According to the current technology, the depth of diamond can be selected between 1mm ~ 10mm. Usually when cutting granite waste with a large diameter saw blade, the cutting depth can be controlled between 1mm ~ 2mm, and the feeding speed should be reduced at the same time. When the linear velocity of diamond circular saw blade is large, the cutting depth should be large. However, in the scope of the performance and strength of the sawing machine, a larger cutting concentration should be taken as far as possible to improve the cutting efficiency. Small depth cutting should be used when machining surfaces are required.

（3）Feeding speed: Feeding speed is the feeding speed of the sawn stone. Its size affects the cutting rate, the blade stress and the heat dissipation in the cutting area. Its value should be selected according to the nature of the sawn stone. Generally speaking, sawing softer stone, such as marble, can be appropriate to improve the feeding speed, if the feeding speed is too low, more conducive to improve the sawing rate. Sawing fine grain structure, more uniform granite, can appropriately improve the feeding speed, if the feeding speed is too low, diamond blade is easy to be polished. However, when sawing coarse grained granite with uneven soft and hard texture, the feeding speed should be reduced, otherwise the blade vibration will lead to diamond fragmentation and the cutting rate will be reduced. The feeding speed of sawing granite is generally selected within 9m ~ 12m/min.

2.Other influencing factors

（1）Diamond size: The commonly used diamond size ranges from 30/35 to 60/80. The harder the rock, the finer the granularity should be chosen. The thinner and sharper the diamond, the easier it is to cut into hard rock at the same pressure. In addition, generally large diameter saw blades require high cutting efficiency, it is appropriate to choose a coarser grain size, such as 30/40, 40/50; Small diameter saw blade sawing efficiency is low, requires smooth rock sawing section, it is appropriate to choose a fine particle size, such as 50/60, 60/80.

（2）Tip concentration: the so-called diamond concentration refers to the density of diamond distributed in the working layer (i.e. the weight of diamond contained in the unit area). According to the “specification”, the working matrix containing 4.4 carats of diamond per cubic centimeter has a concentration of 100% and 3.3 carats of diamond a concentration of 75%. The volume concentration represents the amount of volume occupied by diamond in the caking, and specifies that the concentration is 100% when the volume of diamond accounts for 1/4 of the total volume. An increase in diamond concentration may prolong the blade’s life because the increase in diamond concentration reduces the average cutting force per diamond. However, increasing the depth will inevitably increase the cost of the blade, so there is an economic concentration, and this concentration increases with the increase of osmium rate.

（3）Hardness of tool head binder: Generally speaking, the higher the hardness of the binder, the stronger the abrasion resistance. Therefore, when sawing large abrasive rock, the binder hardness should be high; When sawing soft rock, the hardness of binder should be low. The hardness of the binder should be moderate when sawing hard and abrasive rocks.

（4）Force effect, temperature effect and grinding damage: In the process of stone cutting, diamond circular saw blade will be subjected to the alternating load of centrifugal force, saw cutting force, saw cutting heat, etc.

The abrasion damage of diamond circular saw blade is caused by force effect and temperature effect.

Force effect: During sawing, the blade is affected by axial and tangential forces. Due to the presence of forces in the circumferential direction and radial direction, the saw blade is wavy in the axial direction and dished in the radial direction. These two kinds of deformation will cause uneven rock cutting surface, excessive stone waste, loud noise and intensified vibration during sawing, resulting in early diamond caking damage 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°C. The coolant only lowers 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, and cause the diamond failure mechanism to fundamentally soften. Studies have shown that temperature effect is the biggest factor influencing saw blade damage.

Wear damage: Due to the force effect and temperature effect, the blade will often wear damage after a period of use. The main forms of wear damage are as follows: abrasive wear, local crushing, large area crushing, shedding, mechanical abrasion along the direction of the cutting speed of the binder. Abrasive wear: diamond particles and workpiece friction, edge passivation into a plane, loss of cutting performance, increase friction. The saw cutting heat will lead to the appearance of graphitization thin layer on the surface of diamond particles, which will greatly reduce the hardness and aggravate the wear: the surface of diamond particles is subjected to alternating thermal stress and cutting stress, and then fatigue cracks will appear and local breakage will reveal sharp new edges, which is a relatively ideal wear form. Large area crushing: the diamond particles bear the impact load when they are cut in and out, and the outstanding particles and grains are consumed prematurely; Shedding: Alternating cutting forces cause diamond particles to be shaken in the binder and become loose. At the same time, the wear and heat of the binder in the process of sawing soften the binder. This makes the binder holding force down, when the cutting force on the particles than the holding force, diamond particles will fall off. Any kind of wear is closely related to the load and temperature of diamond particles. Both depend on the osmium technology and cooling and lubrication conditions.