| Cutting is a key process during the production of granite slabs. It influences not only on the cost effectiveness of the current procedure, but also on the efficiency and quality of the subsequent procedure in production. At present, sawing granite with diamond tools is the most popular method, which consumes most of synthetic industrial diamond. Relative to early technique for granite machining, cutting with diamond circular saw-blade revolutionizes the whole sector both in reducing the cost and in improving the efficiency. However, the revolutionary meanings seem to embody in the processing of the marbles. The maximum cutting depth for granites, especially for hard granites, is much less than that for marbles.Based on the thorough analysis on the state of arts of granite sawing and the existing problem, the mechanism for sawing of granites under the conditions of large depth of cut is discussed in this thesis, and a new type of diamond saw-blade with short segments is developed to realize deep sawing of granites. The main work of this thesis can be summarized as follows:1. Make diamond saw-blade of normal structure with iron-base metal matrix; set up the platform for the experiment and test of the deep sawing of granites; during the sawing of the granite, monitor the sawing power and forces, observe and count the worn pattern of the grits in the surface of the diamond segments, and measure the protrusion height of the grits.2. Discuss the mechanism of the deep sawing of granites; build model of sawing loads; make statistic analysis of the worn pattern of the grits and the influence of protrusion height on the sawing loads.3. Analyze the stress distribution of the saw-blade during the sawing by Finite Element Method (FEM); study the influence of the thickness, rotary speed, clamping ratio and diameter of the saw-blade on its dynamic performance by modal and buckling analysis.4. Based on the analyses mentioned above, develop a new type of diamond circular saw-blade with short segments, and find out its sawing performance and the effect of processing parameters on its performance by sawing experiment.Through experimental study and theoretical analysis, the following achievements and conclusions can be obtained:1. From the fracture analysis, sawing experiment and observation of the grit state in the segments surface after sawing, it indicated that the segments which were made up of appropriate iron-base metal matrix and high grade coated diamond, can meet with the need of deep sawing, and carry out the experiment of deep sawing at 120mm depth of cut.2. During the sawing process, the total sawing forces acting on the saw-blade and average loads acting on each diamond grit increase with the depth of cut (ap) or the feed speed (vf). ap contributes more to the total forces than Vf, whereas Vf contributes more to the average loads than ap. When keeping ap and Vf constant, the sawing forces decrease with the peripherallinear speed vs in case of not increasing the vibration of the blade.3. The sawing energy is mostly consumed by the friction between the saw-blade and the swarf and by the scratch of the grits with the granite. The tangential force component has good corresponding relation with the bilateral surface area plowed by a diamond grit, and such relation also exists between the normal force component and the normal contact stress at the sawing arc zone. The force models that derived from these relations are quite identical to the experiment results.4. The worn pattern of the diamond grits have been subdivided into twelve states for the first time. Quantified analysis of the effect of the working state of the diamond segment surface on the sawing forces indicates that the average protrusion height of the grits is negatively correlated with the sawing forces. The larger the protrusion height is, the smaller the sawing forces are. The bigger the proportion of the whole, micro-fractured and flatten with little face grits are, the sharper the saw-blade is, and the smaller the sawing forces...
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