Thermal and force modeling of CGI drilling

This paper presents a validated temperature distribution model that allows the prediction of temperature increase on a compacted graphite iron (CGI) workpiece during the drilling process. The thermal modeling procedure begins with the geometric modeling of inclination, rake, helix, and effective rake angles. Then, force models are evaluated for the chisel and cutting lip. The force model incorporates mechanistically calculated thrust force and torque values for varying inclination and rake angles on each divided tool segment. Divided segments are obtained by sectioning of the cutting edge, and they are named elemental cutting tools (ECTs). Force results are used to predict heat flux on the chisel, cutting lips, and the margin of the drilling tool. The heat flux values at the margin are optimized through numerical iteration between measured and calculated temperature values. The developed model is also verified experimentally. There is only a negligible difference between the measured and calculated temperature results. Finally, the temperature distribution on the workpiece is successfully obtained using numerical analysis.