Burr Formation and Surface Quality in High Speed Micromilling of Titanium Alloy (Ti6Al4V)

Titanium and Ti alloys are popular materials used in aviation and biomedical field due to their excellent strength-to-weight ratio and corrosion resistance properties. Micromilling is a common mechanical machining process used in the production of microscale features. The micro-tool has very low stiffness and even small forces can lead to catastrophic tool failure. High speed micromachining can be used to address the issue because of lower chip loads at higher rotational speeds. Consequently, high speed micromilling can be used for micromachining of hard metals/alloys which are difficult to accomplish at lower speeds. Nowadays high speed micromilling is gaining popularity due to its high material removal rate and good surface finish. In many cases, the machined product does not need an additional finishing process. However, the burr formation in the mechanical machining process is the most important problem which becomes more critical for a microscale feature. Removal of micro-size burr is much more difficult than its macro counterpart. The current work is focused on the characterization of the burr formation in high speed micromilling. Influence of various process parameters, viz., spindle speed, feed rate, depth of cut, tool diameter and number of flutes of the micromilling tool has been analyzed on the burr size and on the quality of the machined surface via measuring the surface roughness.