Accuracy and quality of micro-holes in vibration assisted micro-electro-discharge drilling of Inconel 718. (March 2019)

• Record Type: Journal Article
• Authors: Unune, Deepak Rajendra; Nirala, Chandrakant Kumar; Mali, Harlal Singh
• Is Part Of: Measurement. Volume 135(2019)
• Page Start: 424
• Page End: 437
• Publication Date: 2019-03
• Subjects: Micro electro discharge drilling -- Low-frequency vibration -- Micro-holes -- Accuracy -- Surface quality; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2018.11.067
• Languages: English
• ISSNs: 0263-2241

Abstract

Graphical abstract: Highlights: Role of vibration assistance in μEDD process performance was investigated. The quadratic models for responses of vibration assisted μEDD were established. Micro-holes with good quality and accuracy were obtained with vibration assistance. Abstract: Achieving micro-features on superalloy like Inconel 718, with dimensionally high accuracy, has never been easy using a conventional machining technique. Micro-electro-discharge drilling (µEDD) has emerged as one of the key machining technique for fabrication of micro-holes in such superalloys. Although the process has the proven potentials, quality and accuracy of micro-holes deteriorate due to high tool wear and process become unproductive due to the impasse of debris and unsteady machining conditions, especially for high aspect ratio hole drilling. To overcome such issues, anticipating a better performance, a low-frequency vibration assisted µEDD is proposed for machining of Inconel 718. Performance measures, such as material removal rate ( MRR ), electrode wear ratio ( EWR ), overcut, and taper angle are analyzed as results of the µEDD operation performed by choosing gap-voltage, capacitance, electrode rotation speed (ERS), and vibrational frequency (VF) as control factors. The Box–Behnken design was used to plan the experiments. The effect of low-frequency vibration on accuracy and surface quality of fabricated micro-holes was also discussed and compared with those achieved by without vibration assistance to the process. An enhancement in the performance of low-frequency vibration assisted µEDD due to improved flushing, debris evacuation, and stable machining conditions is noticed.