| Certain materials such as steels, nickel, and titanium alloys cause rapid thermo-chemical tool wear and poor surface finish during conventional diamond turning (DT). Optical quality surface finishes on these materials are possible when vibration-assisted machining (VAM) is incorporated. It is theorized that VAM reduces tool wear by reducing tool temperatures and forces. The goal of this research is to observe and measure tool wear during VAM and identify how this wear is related to process parameters, and how it is mitigated with VAM.;Baseline conventional DT tests on thermo-chemical wearing material were carried out in conjunction with finite element (FE) simulations of the DT process to develop a thermo-chemical wear model. To relate this model to VAM, kinematic calculations were made identifying related parameters; namely relative tool tip velocity and uncut chip thickness. FE simulations of the elliptical vibration assisted machining (EVAM) process are carried out that vary input EVAM parameters. Tool temperatures are extracted from FE data and supplied to the thermo-chemical wear model. These predictions are used to identify optimal EVAM conditions to minimize thermo-chemical wear.;Finally, several EVAM and LVAM experiments are carried out to test the hypotheses devised from the parametric study and FE simulations. In addition, comparison is made between conventional DT surface finish and VAM. The complex relationship between VAM parameters and reduced tool wear are discussed in terms of the thermo-chemical wear model and predictions made based on the FE simulations. |
