Fundamental study of exit burr formation mechanisms during orthogonal cutting of AlSi aluminium alloy

Abstract

Burr formation during machining is an important issue in industry. It causes an additional deburring operation, which is time consuming and has a negative economic impact. This study aims to analyse burr formation mechanisms and its accumulation in successive passes during orthogonal cutting of a cast aluminium alloy. A customized experimental setup was developed, which includes a high speed imaging system and a laser profilometer. A design of experiments using the setup mentioned previously is carried out and a methodology for geometric burr characterization is developed and applied. Furthermore, statistical representation of the obtained results is performed, which allows the understanding of the geometric heterogeneity influence associated to burr formation mechanisms and to work material microstructure. Based on the exit burr analysis, new geometrical criteria are proposed for the characterisation and the definition of two main burr formation mechanisms. The influence of cutting parameters on burr morphology along the workpiece exit edge is investigated in depth. The results show that two types of burrs can be produced simultaneously along the workpiece exit edge due to the work material microstructure heterogeneity. The results present as well the influence of low uncut chip thickness that leads to a higher proportion of burrs without chamfer. This type of burr is higher and more propice to burr accumulation. After performing several cutting passes, these burrs may be eliminated and replaced by a burr with chamfer.