Electro-Discharge Machining of Aluminum Alloy with Nickel Powder-Mixed Dielectric

Powder-mixed dielectric fluid is one of the innovations of electrode-discharge machining (EDM) which seeks to improve the process outputs by addition of Nickel powders to the dielectric during machining. In the present study, the influence of Nickel powder in kerosene dielectric fluid on EDM process outputs was investigated.  Experiments were conducted with the outputs as material removal rate (MRR) and surface roughness(Ra). During the EDM, the discharge current was varied between 3 and 15 A, while powder concentration ranges between 2 and 10 g/l.  Results indicate that the highest MRR of  39.888 mm3 /min was obtained with Nickel powder concentration of 6 g/l at the current of  9A, where as the lowest SR of  3.397 μm was obtained with Nickel concentration of 3 g/l at the current of 3A

Prediction of cutting forces developed during hard turning of hard chrome plated surfaces on EN24 substrate / K. N. Mohandas, C. S. Ramesh and Eshwara Prasad Koorapati

This paper investigates the development of cutting forces during the hard turning of hard chrome plated surfaces on EN24 substrate. The hard turning operation disproves the Merchant's theory of cutting force development during the machining as the hard turning is only a small stock material removal. Various forces produced such as cutting force, feed force and thrust force have been measured during the finish turning. The experimental results have indicated that the feed force is the predominant force out of three different forces developed. This is in good agreement with the available literature. The results obtained from the experimentation were used to predict the optimum cutting conditions in terms of cutting forces. The optimized cutting parameters are feed of 0.08mm/rev, cutting speed of 500rpm and depth of cut of 40jum. The developed mathematical model exhibited satisfactory goodness of the model fit in regression with different PcBN cutting tool inserts. A maximum of 5% variation in the experimental results of the cutting forces when compared with the mathematical model has been observed. This suggests that the developed mathematical model could be employed to predict the cutting forces during hard turning of hard chrome plated surfaces

Study of the Surface Integrity and Heat Measurement of Hard Turning of Hard Chrome Coated EN24 Substrate

AbstractThe principal aim of this paper is to hard turn the hard chrome plated EN24 substrate using TiAlN coated PcBN inserts. The variables used for the experimentations are the spindle speed, feed, depth of cut, nose radius and cutting edge angle. EN24 substrate was coated with hexavalent chrome to a thickness of 170μm. The surface hardness before and after hard turning of hard chrome plated surfaces were studied. The temperature developed on the insert, workpiece and chips were studied in the present investigation. An experiment was carried out to determine the maximum heat development on the insert. The experimental results revealed that the maximum heat was observed at 2mm from the cutting edge on the top diagonal. The images obtained from the confocal microscope and scanning electron microscope discovered the nature of fracture of the chips from the work surfaces

Prediction of residual stresses in roller burnished components : a finite element approach

Surface finish is an important factor in creating the durable metal components, and fatigue strength can be improved if compressive residual stresses are produced in the surface. Burnishing is a finishing process and compressive residual stresses are induced during the process. The present study of minimizing the surface roughness based on the experimental work, and finite element model was developed to evaluate the analytical results. Commercial purity Mild Steel and Aluminium were selected as work specimens and a high carbon high chromium roller was used as a tool for the burnishing process.<br /