Characteristics Of Force And Energy In High-speed Circular Sawing Of Granite With A Thin Diamond Blade

As rapidly ascending of stone capacity and trade, the problem of waste is more and more concerned, especially for the top-grade granite. The circular saw-blades with diamond impregnated segments are extensively applied in sawing of granite, the conventional saw-blades, owing to the thickness, decreases cutting rates and restricts the development of industry for top-grade granite slab. So decreasing the thickness became to a trend of development for diamond circular saw-blades. But with the saw-blade thinning, it will cause a series of problems during the sawing process, such as stiffness reduction, easy deformation under the external force and heavy vibration, which will induce loss of the life of saw-blades, bad production quality and noise pollution to the environment. To solve this issue, the technique of high periphery speed sawing was put forward. And the past investigation have proved that the high periphery speed help to improve dynamic stiffness, axial rigidity and ultimate load.In the conventional Circular Sawing of granite, the periphery speed is about 30m/s-50m/s. In this paper, a circular diamond saw-blades of 2mm thickness is used to saw granite in high periphery speed (80m/s). In these trials, the net consumed power, horizontal and vertical force components acted on the sawblade were measured. According to the acquired data and machining parameters, the specific energy (which is the energy expended in removing a unit volume of material), normal and tangential force components were calculated and their relations were illustrated, then mathematic and physical models were preliminarily established. These provided basic data and guideline for the quantificational description of the sawing process of granites, for the manufacture of diamond segments and for the designation of sawing machine. In addition, the relation between the sawing forces and the surface of the diamond segments is investigated.Through experimental study, the following achievements and conclusions can be obtained:(1) In the high speed sawing, the effect of cutting depth on sawing forces is larger than feeding speed, the process parameter of larger feeding speed and smaller cutting depth should be selected. The sawing forces and the force ratio decrease with the periphery speed, material is easier to be removed in the high speed sawing compared to normal speed.(2) In the high speed sawing, the effect of cutting depth and feed speed on special energy is same to the normal speed. In cases at the constant removal rate and maximum undeformed chip thickness, the special energy increase with the periphery speed, especially for low removal rate and small maximum undeformed chip thickness.(3) The sawing energy expended in brittle fracture and swarf kinetic energy represent a negligible portion, the energy consumed by slurry and its interaction with matrix is about 30%.The sawing is mostly consumed by the friction by the scratch of the grits with the granite. Sawing power per unit width monotonously increases with the grain plough area per unit width.(4) There is correlation between sawing forces and worn pattern of the diamond grits in high speed sawing. The worn particles occurring on the segment surface are mainly of the macro-fractured crystal and pull-out hole type. And proportion of the two types are more than 50%.