The factors affecting the efficiency and life of the diamond insert are cutting process parameters, diamond sand, concentration, and bond hardness.
The cutting parameters are the blade speed, the cutting concentration and the feed rate.
1. Cutting parameters:
(1) Line speed of the blade: In actual work, the line speed of the blade is limited by equipment conditions, blade quality and stone quality. From optimal blade cutting life and cutting efficiency, to the blade's line speed based on different stone properties.
When cutting granite, the linear velocity of the blade should be selected from 25m to 35m / s.
For high quartz content and hard cut granite, the line speed of the blade should be at the lower limit.
For the production of granite bricks, used blades should be small in diameter and line speeds up to 35 m / s.
(2) Depth of cut: The depth of cut is related to diamond wear, effective cutting, blade stress conditions, stone properties and more important parameters. In general, when the linear speed of the diamond saw blade is high, a smaller cutting depth is selected. From the prior art, the depth of the cutting blade should be selected between 1 mm and 10 mm.
Usually, large-diameter blades cut granite blocks, and the cutting depth should be controlled between 1mm and 2mm, and the feed rate is reduced. When the linear speed of the diamond blade is large, a larger depth of cut is selected.
However, when saw performance and blade strength are within the allowable range, a large depth of cut is selected to improve cutting efficiency.
A small depth of cut should be used when required on the machined surface.
(3) Feeding speed: The feeding speed is the feeding speed of the cutting stone. Its size affects the cutting efficiency of the blade area, blade stress and cooling conditions. Its value should be chosen according to the nature of the stone. In general, cutting soft stones like marble should increase the feed rate, and if the feed rate is lower, it will improve the cutting efficiency.
To cut fine grain structure and homogeneous granite, the feed rate should be increased. If the feed rate is low, the segments are subject to wear. However, to cut coarse grain structure and uneven soft and hard granite, the feed rate should be reduced, otherwise the blade may be vibrated, resulting in diamond fracture and reduced cutting efficiency.
The feed rate of the cut granite is usually selected in the range of 9m-12m / min.
2. Other influencing factors
(1) Diamond grit: The range of ordinary diamond grit is 30 / 35-60 / 80.
If the stone is hard, choose fine sand. Because the diamond is finer under the same pressure conditions, it is more conducive to cutting hard stone. In addition, it is generally required that the cutting efficiency of large-diameter blades is high, and coarse sand should be selected, such as 30 / 40, 40 / 50; the cutting efficiency of small-diameter blades is low, and the cross-section of the stone is required to be smooth, and fine sand should be selected, such as 50 / 60, 60 / 80.
(2) Segment concentration: The segment concentration is the distribution density of the diamond in the working layer is the bond (the average unit area includes the weight of the diamond). The standard stipulates that the working adhesive per cm is 4.4 carats of diamonds, the concentration is 100%, and when it contains 3.3 carats, the concentration is 75%.
The volume concentration represents the percentage of diamond in the segment volume and provides a concentration of 100% when the diamond volume is 1/4 of the total volume. Increasing the diamond concentration is expected to extend the life of the blade, because the increased concentration reduces the average cutting force per diamond, but increasing the depth will definitely increase the cost of the blade. Therefore, the higher the concentration, the higher the concentration. The cutting efficiency is higher.
(3) Hardness of the segment key: Generally speaking, the higher the hardness of the key, the higher the wear resistance. Therefore, when cutting high-stone, the bond hardness should be higher; when cutting soft stone, the bond hardness should be reduced; when cutting high-abrasive and hard stone, the bond hardness should be medium.
(4) Force effect, temperature effect and grinding damage: Diamond circular saw blade will receive the load of centrifugal force, cutting force and cutting heat alternately in the process of cutting stone. Loss caused by force and temperature effects caused by wear of the diamond saw blade.
(a) Force action: During the sawing process, the blade is subjected to axial and tangential forces. There is a radial force in the circumferential direction such that the saw blade is in the axial corrugated disk in the radial direction. Both of these deformations lead to a rock cross section that is not straight, stone waste, cutting noise, and increased vibration, leading to early diamond agglomeration and reduced saw blade life.
(b) Temperature effect: Traditional theory: The effect of temperature on the cutting process is mainly manifested in two aspects: first, the aggregation of diamond graphitization; secondly, the heat caused by diamond and matrix and diamond particles is too early.
New research shows that the heat generated during the cutting process is transferred to the aggregate. The arc temperature is not high, generally between 40-120 degrees Celsius. Abrasive grinding points are relatively high, typically between 250 and 700 degrees Celsius. The coolant can only reduce the average temperature of the arc zone, and the abrasive temperature is less affected.
Therefore, the temperature does not cause carbonization of the graphite, but it causes a change in the frictional properties between the abrasive and the workpiece, as well as thermal stress between the diamond and the additive, resulting in a substantial bending of the diamond failure mechanism.
It shows that the temperature effect is the biggest cause of blade breakage.
(c) Grinding damage: Due to excessive force and temperature, the saw blade will wear after cutting for a while. There are several types of grinding damage: abrasive wear, partial crushing, large area crushing, shedding, and the cutting speed of the binder along the mechanical wear.
. Abrasive wear: Diamond particles and style pieces are constantly rubbed, the edges are passivated into a plane, loss of cutting performance, and increased friction. The heat of cutting causes a thin layer of graphitization on the surface of the diamond particles, which greatly reduces the hardness and increases the wear: the surface of the diamond particles is subjected to alternating thermal stress, and can also withstand the stress of alternating cutting, and some of the fatigue cracks are broken and exposed. Sharp new edge is an ideal wearing pattern; large area broken: cut diamond particles with impact load, premature particle and particle premature consumption; close: alternating cutting force causes the diamond particles in the adhesive to vibrate Then it leads to looseness. At the same time, the adhesive during the sawing process wears and cuts heat to soften the adhesive. This causes the retention of the adhesive to decrease, and the diamond particles will fall off when the cutting force on the particles is greater than the holding force. Regardless of which type of worn diamond particles are subjected to loads and temperatures, they are closely related. Both depend on the cutting process as well as the cooling and lubrication conditions.