Research On The Surface Natur Of Nanocomposite Ceramics Machined By WEDM

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