Dependence Of Forces On Segment Working State In Deep Sawing Of Granites

Sawing is one of the important working procedures in the production of granite slabs. Currently, sawing of granites is predominantly performed by the circular saw-blades with diamond impregnated segments. In sawing process, the working state of segments is synthetic reflection of all factors; therefore it is researched by many scholars at home and aboard who have expected to reveal the essence of sawing, however, the working state is still unable to be measured and evaluated effectively and quantitatively because of its inherent complexity and the limitation of research methods. Sawing forces, as important process parameters, have also been researched thoroughly; nevertheless, it is difficult to establish a uniform relationship between forces and sawing parameters due to the effect of the segment working state, which makes the results of these researches incomparable. Consequently, to evaluate the segment working state quantitatively and to research the dependence of forces on sawing parameters and on segment working state is one of the most significant tasks in research of diamond tools.In this thesis, segment working states is identified quantitatively to some extent by a video microscope, and the effects on forces of sawing parameters and of segment working state are evaluated respectively in deep sawing. Firstly, the relationship between forces and sawing parameters, saw-blade shapes, granite workpieces and sawing modes is researched by using of firebricks to keep the segment working state relatively stable; Secondly, the relationship between forces and segment working state is studied in tool wear progression by keeping the sawing parameters constant, and the effect on forces of diamond worn types and the mean height of protrusion of diamond grains is ultimately analyzed quantitatively.The main experiment results in this thesis are summarized as follows:1. The normal force and tangential force increase with the cutting depth or feeding speed in sawing of granites; while the effect of cutting depth is evidently larger than that of feeding speed; The normal force and tangential force decrease with the increase of peripheral speed at the constant cutting depth and feeding speed.2. In most cases, forces in down-cutting are lower than those of up-cutting at the constant sawing parameters in sawing of granites.3. In the sawing process, the bigger the proportions of whole and micro-fractured grains are, and the smaller the proportions of macro-fractured and pull-out grains are, the lower the forces; conversely, the larger the forces. Commonly, the higher the mean height of protrusion of diamond grains is, the lower the forces; otherwise, the larger the forces.4. In this thesis, the proportions of the whole, micro-fractured, macro-fractured, and pull-out grains are better correlated with sawing forces, the mean height of protrusion andthe proportions of the polished and new-emerged grains are less correlated with forces.5. In sawing of granites, the plowing and scratching interaction between diamond grains and granites is mainly related with the worn types of grains, while the friction between slurry (coolant together with sawing swarf) and segment surface is most related with the mean height of protrusion of diamond grains. In the wear experiment of chapter four, sawing forces expended for plowing and scratching are larger than those for friction.Overall, the results obtained in this thesis provide a reference for researching deep cutting of granites and the wear mechanism of segments, for improving segment performance, for instructing the manufacture of diamond saw-blades and for optimizing sawing parameters.