Demanding high dimensional accuracy of finished work pieces and reducing the scrap and production cost, call for devising reliable tool condition monitoring system in machining processes. In this paper, a tool wear monitoring system for tool state evaluation during hard turning of AISI D2 is proposed. The method is based on the use of wavelet packet transform for extracting features from vibration signals, followed by neural network for associating the root mean square values of extracted features with tool flank wear values of the cutting tool. From the result of performed experiments, coefficient of determination and root mean square error for the proposed tool wear monitoring system were found to be 99% and 0.0104 respectively. The experimental results show that wavelet packet transform of vibration signals obtained from the cutting tool has high accuracy in tool wear monitoring. Furthermore, the proposed neural network has the acceptable ability in generalizing the system characteristics by predicting values close to the actual measured ones even for the cutting conditions not encountered in the training stage. Manuscript profile

In this paper, a real-time intelligent adaptive control with optimization methodology is proposed to produce parts with uniform surface roughness in finish turning of hardened AISI D2. Unlike traditional optimization approaches, the proposed methodology considers cutting tool real condition. Wavelet packet transform of cutting tool vibration signals followed by neural network was used to estimate tool flank wear. Intelligent models (artificial neural networks and genetic programming) were utilized to predict surface roughness and tool wear during machining process. Particle swarm optimization algorithm determined optimum feed rate that resulted in desired surface roughness. Performed confirmatory experiments indicated that the proposed adaptive control method not only resulted in parts with acceptable uniform quality, but also decreased the machining cost up to 8.8% and increased material removal rate up to 20% in comparison with those of traditional CNC turning systems. Manuscript profile

Production of lightweight metals with a higher strength to weight ratio is always the main goal of researchers. In this article, equal channel multi angular pressing (ECMAP) process as one of the most appealing severe plastic deformation (SPD) methods on production of ultra-fine grained (UFG) materials studied. Two main routes A and C investigated by FEM and compared with each other from different aspects of view. ABAQUS commercial software used to evaluate the maximum strain, maximum required force and strain inhomogeneity index in both routes and obtained results of FEM verified by both theoretical calculations and experimental tests. It is inferred that although equivalent plastic strain (PEEQ) in route A is higher than that in route C, the strain homogeneity as a quality factor for route C is higher. So, route C selected for more investigation and optimization. Grey relational analysis used as the optimization method. Geometrical parameters taken as input variables and both inhomogeneity index and maximum required load taken as objectives. Then, the suggested tests by full factorial method were simulated by FEM. After optimization, it was concluded that the best set up belongs to experiment number 20 which the values of Φ1, ψ1 and ψ2 are 165°, 0° and 15°, respectively. Also, it is inferred that among geometrical parameters, die channel angle (Φ1) is the most effective parameter. Manuscript profile

Equal channel multi angular pressing (ECMAP) process is the efficient method to enhance the productivity of ultra-fine grained (UFG) materials, by increasing process continuity and as a result decreasing process required time. Comparing repetitive ECAP method, in the same period, the number of passes can be done by ECMAP. In this article, ECMAP of AL strips in two typical annealed and as received conditions studied, and route C was selected as multi pressing route. Values of equivalent plastic strain (PEEQ) and micro-hardness in the cross section of ECMAPed strips obtained both by FE simulations and practical tests, correspondingly. These values also used for obtaining the inhomogeneity of produced ECMAPed strips. Furthermore, mechanical property for both as received and annealed strips before and after pressing, studied experimentally. Also, load-displacement curve during ECMAP process obtained by FEM. For FEM results validation, PEEQ calculated by the analytical method, too. Results show that there is good conformity between FE, analytical and practical results. Manuscript profile