Stability criteria and break out of grains of super-hard of grinding tools

Failure of grinding tools may be the result of the continual wear, although their productivity can also be loosen due to hack, fracture, break out of grains from bond or other causes, so generally because of breakage. The productivity of the honing, grinding tools and other tools with bound grains (regulating rollers, band grinders, etc.) depends significantly on the cutting productivity of the active grains. The cutting productivity—beside other factors—depends also on the clamping stability of the grains into the binding material. The quantity and direction of the force that is necessary for the individual grains to break out of the binding material should be examined. The objective of the research summarized in the paper is to outline the process of fracture and its mechanical criteria. In this paper the new results, obtained so far, will be presented.