Reduction of drilled-hole fracture and burr by rotary ultrasonic machining technology

Abstract

Abstract In this paper, rotary ultrasonic machining (RUM) is introduced to process the micro-drilling on graphite and brass. The best combinations of process parameters are presented as the experimental results on this research. On the basis that graphite offers efficient electrical conductivity and low hardness, and that brass as copper-zinc alloys provides convenience for processing, fractures or edge collapses are often evident after machining. This research focuses on proposing improvements by cooperating RUM with Taguchi method, from which the optimizations of process parameters and parameter verifications can be conducted. Control factors include spindle speed of the drill-bit, peck drilling, processing feed rate, and ultrasonic power. Each factor is inspected by three levels. Quality features are determined by the fracture area. This research reveals that the difficulty in removing shavings leads to the breakage of machining tools inside the drilled holes. Incorrect process parameters cause failure at processing the micro-drilling on graphite and brass.