Electro Discharge Machining (EDM) is a very efficient machining process widely used in manufacturing components of complicated geometry. Based on its nature, i.e. material removal by electric discharge, the process induces thermal stresses that in turn result in generation of wide spread micro-cracks on the surface of the machined part. In this paper the influence of EDM characteristic parameters on the surface microstructure in CK45 alloy steel which is suitable for manufacturing of forging dies has been extensively investigated. An extensive experimental programme has been carried out to explore the role of various EDM parameters on the quality of the machined surface. The relation of EDM parameters has been evaluated quantitatively using the test results and regression analysis. Predicting the impact of EDM parameters on the surface quality as the outcome of this study provides means to appropriately decide on the adjustment of parameters to their optimum values and achieve the desired die surface quality at reasonable manufacturing time and cost. پرونده مقاله

The aim of this research work is to evaluate the effects of coolant including nano- powder material for the cooling purpose in milling process and comparing the results with the conventional coolant. Generation heat and weak heat transfer reduces the tool life and also deteriorate surface roughness during milling operation. To overcome this problem, it is necessary to use coolant for cooling as well as lubrication purposes. Due to limited heat removal rate from the work piece through the conventional coolant, some nano powder material is added to coolant, to improve the heat transfer coefficient. The added nano powder also increases machinability, decreases production time and improve surface roughness. In this paper nano fluid of copper with 99 percent purity added to Z1 coolant for machining of St37 work piece in milling machine. In this research, some factors such as rotational speed, feed and depth of cut in the three states of machining, with different coolant including Z1 and nano fluid and dry condition were investigated and finally temperature of machined work piece and its surface quality were evaluated. By comparing the obtained results it is evident that the heat removal rate and surface quality in the case of nano fluid are improved and furthermore the tool life as well as machining efficiency increases. پرونده مقاله