Modeling the property variation of diamond composite and its impact on the reliability of cutting tools

Picks are commonly used cutting tools for mechanical excavation. Diamond composite is replacing tungsten carbide as cutting tips of the picks in hard rock cutting. Tips made of Thermal Stable Diamond Composite (TSDC) have high potential for improving tool life because of its high wear resistance, high hardness, high compressive strength and high thermal stability. However, as TSDC is a type of new material, the technology for its production is still unstable, which often results in considerable variations in the material properties of cutting tips. These variations can significantly affect the optimization of tip design. The conventional design approach based on mean values or extreme values cannot effectively optimize the design of cutting tip due to over or underestimation of tip failure risks. To address this issue, in this study, a probabilistic approach is proposed to model the property variations of TSDC tips and estimate tip failure risks under a given operational circumstance using reliability theory. The new approach enables designers and operators to estimate the failure risks of cutting tips with a specified confidence level.