A SEM and EDS insight into the BUL and BUE differences in the turning processes of AA2024 Al-Cu alloy

When a Built-Up Edge (BUE) and a Built-Up Layer (BUL) are formed on the rak e face of a tool, the surface finishing of the workpiece, the tool geometry and other output parameters can be affected. Till a few years ago both eff ects were considered as two forms of the same phenomenon. More recently, so me authors have established differences between BUL and BUE, those related to thickness. The mechanism of BUL and BUE formation is not taken into acco unt by these authors. This work reports on the results of a study using the SEM and EDS of the microstructural features of BUL and BUE formed over TiN turning inserts in machining of an Al-Cu alloy. The results obtained in th is study have allowed the establishment of a first hypothesis about the dif ferences between the mechanisms of BUL and BUE formation. (C) 2001 Elsevier Science Ltd. All rights reserved.