Investigation In Machining Nanocomposite Ceramics By WEDM

Ceramics are used more and more in space technology,engineering industry andoil patch as a kind of materials for its high intensity,high hardness,low density,lowexpansion,et al. But they are very difficult to machine because of their low reliabilityand hard brittle. Nanocomposite ceramics have excellent mechanical properties at bothambint and elevated temperatures, they are called "omnipotence materials"or"materials of 21 century". So the investigation of machine nanocomposite ceramic bywire electrical discharge machining (WEDM) is very important.The relations between the process parameters and machining speed as well as theprocess parameters and surface roughness in WEDM machining the TiN/Si₃N₄nanocomposite ceramics are investigated by test. Through the comprehensive analysisof the test results, the effect law of the process parameters on the technical index ofWEDM is concluded, which provides the basis for parameters selection in WEDM.This paper presents an experimental investigation of the machining characteristicsof the TiN/Si₃N₄ nanocomposite ceramics in wire electrical discharge machiningprocess. During experiments, parameters such as open circuit voltage,pulse duration,pulse width and electric current were changed to explore their effect on the surfaceroughness and micro structure. Optical and scanning electron microscopy, SEM, X-Rayand microhardness tests were used to study the characteristics of the machinedspecimens. Taking into consideration of the experimental results, it is found that theintensity of the process energy does affect machining speed and surface roughness aswell as microcracking, but a slight degradation of shape recovery occurs due to thedepression of the re-cast layer.This paper presents an investigation on the effect and optimization of machiningparameters on the surface roughness and material removal rate (MRR) in wire electrical discharge machining (WEDM) operations. On the basis of math-physicsstatistics, design the orthogonal test sheet, the TiN/Si₃N₄ nanocomposite ceramics aremachined by WEDM. The experimental studies were conducted under varying pulseduration,pulse width,open circuit voltage and electric current. The settings ofmachining parameters were determined by using Taguchi experimental design method.and then, a team of test data are recorded. The level of importance of the machiningparameters on the surface roughness and material removal rate (MRR) is determinedby using analysis of variance. The optimum machining parameter combination wasobtained by using the analysis of range analysis method and variance analysis method.After analysis of the test data, The optimal search for machining parameters for theobjective of minimum surface roughness together with maximum material removalrate (MRR) is performed by using the established mathematical models.