Date of this Version
Avinash Deshmukh, "MODELLING OF ANODE CRATER FORMATION IN MICRO-ELECTRICAL DISCHARGE MACHINING" University of Nebraska-Lincoln, Master's Thesis, 2013.
With rapid technology development in the fields of biomedical devices, aerospace, automobile, energy, semiconductors, biotechnology, electronics and communication, the use of micro parts and devices with micro-features has become indispensable. Micro-Electrical Discharge Machining (micro-EDM) because of its inherent characteristics is capable of fabrication of three-dimensional complex micro components and microstructures. However, due to difficulty in fully understanding of material removal mechanism, limited knowledge of process characteristics, lower material removal rate compared with other micromachining technique, the micro-EDM is only used in niche application. Therefore, in order to fully utilize the potential of micro-EDM, focused studies are needed to understand the fundamentals of process mechanism through crater formation, tool wear, debris formation, relationship between process parameter and process performance measures.
The aim of this research work is to develop a predictive thermal model for the simulation of single-spark micro-EDM at anode surface. Finite Element Analysis was performed to solve this model using commercial available software COMSOL. This model assumed a Gaussian distribution heat flux, constant heat flux radius, constant fraction of total energy transferred to anode, temperature dependent material properties to perform transient thermal analysis to predict single discharge crater geometry and temperature distribution on the workpiece for different discharge energy levels (less than 1μJ). The simulated part whose temperature was higher than melting temperature considered as removed part. The experiments were performed for single discharge spark using a Resistor-Capacitor (RC) with titanium alloy Ti-6Al-4V (Grade 5) as workpiece material and tungsten as tool electrode. The experimental crater dimensions were measured by using atomic force microscope (AFM).The simulated craters dimensions were compared with experimental craters. Results showed close agreement between simulated crater radii and experimental crater radii for the discharge energy range up to 1μJ.
Adviser : Kamlakar P. Rajurkar