Micromilling high aspect ratio features using tungsten carbide tools

Abstract

This article presents experimental studies on micromilling thin walls to explore process capabilities in direct manufacturing of high aspect ratio features using tungsten carbide micro-end milling tools for two different materials: aluminium and brass. This study has been conducted in two phases. At first, the effects of micromilling parameters on the surface roughness have been investigated and most suitable machining conditions in obtaining highest surface quality have been identified. In the second phase, the effects of machining strategies have been explored in order to optimize final quality of the thin walls in terms of straightness of the machined thin walls, uniformity of wall thickness and burr presence. As a result of this experimental study, optimized machining parameters and strategies are presented. In the case of micromilling brass (CuZn36Pb3), a down-milling cutting direction with a Z-step milling strategy at a spindle speed of 35,000 r min−1, an axial depth of cut of 150 µm and a feed rate of 150 mm min−1 provided the best overall thin-wall quality. In the case of micromilling aluminium (Al6061-T4), a down-milling cutting direction with a ramp milling strategy, a spindle speed of 25,000 r min−1, an axial depth of cut of 150 µm and a feed rate of 200 mm min−1 yielded the best results.