Stress State in the Cutting Zone when Machining Synthetic Granite with a Cutting Tool
At present, one of the advanced construction materials used for the production of housing elements of high-precision machines is synthetic granite. Synthetic granite is a composite material consisting of a polymeric binder and high-strength mineral grains. Although production engineers and design engineers strive to manufacture products from this material by casting without further machining, in some cases it is necessary to mill, turn and grind them. At the same time, the behavior of the synthetic granite is not sufficiently studied when it is machined by a cutting tool. The process of chip removal when machining synthetic granite greatly influences the machining results. The cutting forces, energy consumption, precision and surface quality depends on this process. This paper deals with the problems of chip formation when machining synthetic granite. On the basis of the theory of elasticity, the stress state in the cutting zone is determined. The Flamant solution is used to determine distribution of the normal and shear stresses in the cutting zone. As a result of the study it was found that the maximum stresses are formed below the cutting surface. Consequently, the main crack will travel into the depth of the material. Thus, the surface roughness of the synthetic granite is not a trace of the tool and does not reflect the roughness of the cutting edge, but is completely determined by crack propagation. Also, this type of chip formation leads to instability of the cutting operation and the generation of vibrations, which reduces the machining accuracy.