REVIEW ON MICRO-MILLING OF HARD AND BRITTLE MATERIALS AND EXPERIMENTAL INVESTIGATION ON TCM USING MULTI SENSORS

Abstract

Miniaturisation of subtractive machining processes has received significant focus in its development of the production of high-precision and high-quality micro-components. There is an ever-pressing demand for micro-components in industries such as aerospace, pharmaceutical and biomedical, industries which require components with high-quality surface finishes and specialist mechanical properties produced by micro-machining processes, where most selected process is micro-milling, where hard and brittle materials are to be machined. Hard and brittle materials are considered difficult-to-machine materials due to their high hardness and tendency to fracture under machining. Tool condition and longevity defines output quality during micro-machining and is very unpredictable. The necessity to carry out Tool Condition Monitoring (TCM) is of paramount importance to high quality procedures. This article will provide an overview of machining requirements and considerations for machining of difficult-to-machine materials and focus work on optimum-process defining areas of micro-milling. It will review the current state of TCM and developments in Industry 4.0 technologies & methodologies and their implementation. Experimental work to support the research done has been performed implementing a TCM system to monitor the machining of glass and silicon using an Acoustic Emission Sensor. A TCM system has been configured from scratch connecting all the necessary hardware, and a program has been written to plot and extract data points individually, to be displayed for analysis. The configured system has produced characteristic results of micro-machining, corresponding with the literature studied and provides a strong platform for future refinement of the system.