The tribological state test in metal forming processes using experiment and modelling

Purpose: of this paper is test of the tribological state in metal forming processes with main aims the determination of state on the tool contact surface (contact stresses and friction coefficient) friction coefficient modelling and simulation and to present the original method of defining contact stresses tf and pn and coefficient of contact friction mi. Design/methodology/approach: of this research is review of contact stresses determination methods, general principles of stochastic modelling, experimental friction test and modelling, examples tribological state test and simulaton by deep drawing and drawing processes. Main achievement are: original experimental identification of contact stresses, original experimental of tools for measurement of contact stresses, mathematical model for defining the tribological state. Application methods of this research are: experimental, tribological state test in forming processes by means of experiment and modelling, statistical and direct contact stresses determining method. Findings: experimental and stochastic modelling of tribological parameters of the forming processes and verification of mathematical model. The tribological state test is performed on the basis of experimental investigations and stochastic modelling. Research limitations/implications: modelling and optimization of tool geometry and selection of optimal lubricators, development experimental methods in the determination of contact stresses, etc. Practical implications: Results of investigations in processing conditions show that the desired effects can be achieved: increased durability of tools 20-40%, reduced stagnation time in the machining process 20-30%, increase on the productivity of the forming process 15-30% and less energy consumption up to 15%. Originality/value: of this paper is obtained original mathematical model for defining coefficient contact friction and contact temperature on the contact surface of tool. Also, is obtained original experimental tool for measurement of contact stresses.