Factors influencing the service life of diamond sa

2022-09-23
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Factors affecting the service life of diamond saw blades

factors affecting the service life of diamond saw blades:

factors affecting the efficiency and service life of diamond circular saw blades that keep Hong Kong prosperous and stable for a long time include sawing process parameters, diamond particle size, concentration, bond hardness, etc. According to the cutting energy, there are saw blade linear speed, sawing concentration and feed speed

I. sawing parameters:

(1) linear speed of saw blade: in practical work, the linear speed of diamond circular saw blade is limited by equipment conditions, saw blade quality and the nature of the stone being sawed. 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 properties of different stones. When sawing granite, the linear speed of the saw blade can be selected within the range of 25m ~ 35m/s. For granite with high quartz content and difficult to cut, the lower limit of the linear speed of the saw blade is appropriate. When producing granite tiles, the diameter of diamond circular saw blade used is small, and the linear speed can reach 35m/s

(2) sawing depth: sawing depth is an important parameter related to diamond wear, effective sawing, force on the saw blade and the properties of the sawed 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 depth of sawing diamond can be selected between 1mm and 10mm. Generally, when cutting granite blocks with large-diameter saw blades, the sawing depth can be controlled between 1mm and 2mm, At the same time, Weiner said, "we believe that the feed speed is low. When the linear speed of the diamond circular saw blade is large, a large cutting depth should be selected. However, when the saw performance and tool strength are within the allowable range, a larger cutting concentration should be taken as far as possible to improve the cutting efficiency. When there are requirements for the machined surface, a small depth cutting should be used.

(3) Feed speed: the feed speed is the feed speed of the sawed stone. Its size affects the sawing rate, the force on the saw blade and the heat dissipation in the sawing area. Its value should be selected according to the nature of the sawed stone. Generally speaking, sawing soft stones, such as marble, can appropriately increase the feed speed. If the feed speed is too low, it is more conducive to improve the sawing rate. Sawing fine-grained and relatively homogeneous granite can appropriately improve the feed speed. If the feed speed is too low, the diamond edge is easy to be ground flat. However, when sawing granite with coarse grain structure and uneven soft and hard, the feed speed should be reduced, otherwise it will cause the vibration of the saw blade, resulting in diamond fragmentation and reduce the sawing rate. The feed speed of sawing granite is generally selected within the range of 9m ~ 12m/min

II. Other influencing factors:

(1) diamond particle size: the commonly used diamond particle size is in the range of 30/35 ~ 60/80. The harder the rock is, the finer the particle size should be selected. Because under the same pressure, 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 it is advisable to choose a coarser particle size, such as 30/40, 40/50; The efficiency of sawing with small diameter saw blade is low, and the rock sawing section is required to be smooth. It is advisable to select finer particle size, such as 50/60, 60/80

(2) cutter head concentration: the so-called diamond concentration refers to the density of diamond distributed in the working layer matrix (that is, the weight of diamond contained in unit area). The "specification" stipulates that when the working matrix contains 4.4 carats of diamond per cubic centimeter, its concentration is 100%, and when it contains 3.3 carats of diamond, its concentration is 75%. The volume concentration indicates the volume of diamond in the agglomeration, and it is specified that the concentration when the volume of diamond accounts for 1/4 of the total volume is 100%. Increasing the diamond concentration is expected to prolong the service life of the saw blade, because increasing the concentration reduces the average cutting force on each diamond. However, increasing the depth will inevitably increase the cost of the saw blade, so there is a most economical concentration, and this concentration increases with the increase of the cutting rate

(3) hardness of cutter head Bond: Generally speaking, the higher the hardness of the bond, the stronger its wear resistance. Therefore, when sawing abrasive rocks, the hardness of the bond should be high; When sawing soft rock, the hardness of the bond should be low; When sawing abrasive and hard rocks, the hardness of the bond should be moderate

(4) force effect, temperature effect and wear damage: diamond circular saw blade will be subjected to alternating loads such as centrifugal force, sawing force and sawing heat in the process of cutting stone. The wear and tear of diamond circular saw blades are caused by force effect and temperature effect

① force effect: during sawing, the saw blade is subjected to axial force and tangential force. Due to the force in the circumferential direction and radial direction, the saw blade is wavy in the axial direction and dished in the radial direction, which can obtain the performance parameters of torsional strength, torque and upper and lower yield. These two kinds of deformation will cause uneven rock section, a lot of waste of stone, high noise and increased vibration during sawing, resulting in early damage of diamond agglomeration and reduced service life of the saw blade

② temperature effect: according to the traditional theory, the influence of temperature on the saw blade process is mainly manifested in two aspects: first, it leads to the graphitization of diamond in agglomeration; The second is that it causes the thermal force between diamond and matrix, which leads to the premature falling off of diamond particles. The new research shows that it is to pave the way for the terminal of its graphene battery to land: the heat generated in the cutting process is mainly transferred to caking. The temperature in the arc area is not high, generally between 40 ~ 120 ℃. However, the grinding point temperature of abrasive particles is relatively high, generally between 250 ~ 700 ℃. The coolant only reduces the average temperature of the arc area, but has little effect on the abrasive temperature. Such temperature does not cause graphite carbonization, but will change the friction properties between abrasive particles and workpiece, and cause thermal stress between diamond and additives, resulting in fundamental bending of diamond failure mechanism. The research shows that the temperature effect is the biggest factor affecting the damage of the saw blade

③ grinding damage: due to the stress effect and temperature stress, the saw blade will often be worn after a period of use. The main forms of wear and tear are as follows: abrasive wear, local crushing, large-area crushing, falling off, mechanical abrasion of the bond along the direction of sawing speed. Abrasive wear: the diamond particles constantly rub with the parts, and the edges are passivated into a plane, losing cutting performance and increasing friction. Sawing heat will cause graphitized thin layers on the surface of diamond particles, greatly reduce the hardness, and intensify wear: the surface of diamond particles will bear alternating thermal stress, and also bear alternating cutting stress, and fatigue cracks will appear and local breakage will occur, revealing sharp new edges, which is a relatively ideal wear form; Large area crushing: diamond particles bear impact load when cutting in and cutting out, and relatively prominent particles and grains are consumed prematurely; Abscission: the alternating cutting force makes the diamond particles shake constantly in the bond and loosen. At the same time, the wear of the bond itself and the sawing heat in the sawing process soften the bond. This will reduce the holding force of the bond. When the cutting force on the particles is greater than the holding force, the diamond particles will fall off. No matter which kind of wear is closely related to the load and temperature borne by diamond particles. Both of them depend on the cutting process and cooling and lubrication conditions

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