Diamond grinding wheels production study with the use of the finite element method

AbstractResearch results on 3D modeling of the diamond grain and its bearing layer when sintering diamond grinding wheels are provided in this paper. The influence of the main characteristics of the wheel materials and the wheel production process, namely the quantity of metallic phase within diamond grain, coefficient of thermal expansion of the metallic phase, the modulus of elasticity of bond material and sintering temperature, on the internal stresses arising in grains is investigated. The results indicate that the stresses in the grains are higher in the areas around the metallic phase. Additionally, sintering temperature has the greatest impact on the stresses of the grain-metallic phase-bond system regardless of the type of the bond. Furthermore, by employing factorial design for the carried out finite element model, a mathematical model that reflects the impact of these factors on the deflected mode of the diamond grain-metallic phase-bond material system is obtained. The results of the analysis allow for the identification of optimal conditions for the efficient production of improved diamond grinding wheels. More specifically, the smallest stresses are observed when using the metal bond with modulus of elasticity 204GPa, the quantity of metallic phase in diamond grain of not higher than 7% and coefficient of thermal expansion of 1.32×10−51/K or lower. The results obtained from the proposed 3D model can lead to the increase in the diamond grains utilization and improve the overall efficiency of diamond grinding

Friction and Material Modelling in Finite Element Simulation of Orthogonal Cutting

In the present paper the influence of the friction and material modelling on the results of the Finite Element simulations of machining is investigated. An orthogonal cutting model is proposed, which incorporates Coulomb’s friction law. The validity of this model is tested against similar experimental and numerical results from the relevant literature and the influence of the friction coefficient is investigated. Then, a second model, with a friction model based on Zorev’s stick-slip theory, is prepared and compared to the first one. Furthermore, simulations with Johnson-Cook material model for both kinds of friction modelling are presented and compared to the other models. The results of the different kinds of models although exhibit small discrepancies between models’ results such us cutting forces, affect temperatures and chip morphology

Friction in Orthogonal Cutting Finite Elements Models with Large Negative Rake Angle

In this paper, orthogonal cutting finite elements models are built for the investigation of the impact of large negative rake angles on the friction coefficient in the tool-chip interface in machining. The simulation results give an insight on the mechanism of chip formation in processes with large negative active rake angle, such as machining with chamfered tools, grinding and micromachining. For the present analysis, cutting conditions resembling the qualitative and quantitative characteristics of the aforementioned processes were selected. More specifically, tool rake angles varying from -10o to -55o and Coulomb friction with constant friction coefficient were considered. The results indicate that friction coefficient is greatly affected by the negative tool rake angle, exhibiting values well above 1 for the high extreme of the examined rake angle spectrum