An investigation on the top burr formation during Minimum Quantity Lubrication (MQL) assisted micromilling of copper

Abstract

Micromilling is one subtractive manufacturing process where excess material is gradually removed from the workpiece in the form of micro-chips with the help of a miniaturized cutting tool in order to fabricate three-dimensional micro-features. Burr formation in micromilling is one important problem as excessive burr hampers dimensional accuracy and functional requirements of the miniaturized features. Top-burr formation in micromilling is attributed to the lateral plastic deformation of the workpiece material when a rounded edge of the tool compresses it. This article explores the role of spindle speed and axial depth of cut on top-burr formation during micromilling of industrially pure copper samples using 0.5 mm TiAlN coated tungsten carbide micro end mills in MQL cutting environment. It is observed that down milling side top-burrs are significantly wider and larger as compared to that of the up milling side. For constant spindle speed, the average top-burr width is found to increase with axial depth for both up and down milling sides. However, the average top-burr width decreases marginally with the increase in spindle speed. In both up and down milling sides, the influence of depth of cut on top-burr width is more pronounced as compared to the influence of spindle speed. It was also observed that the difference between down milling top-burr width and up milling top-burr width does not vary appreciably with spindle speed.