Advances in Materials Processing Technologies, 2006

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Authors: Hector Siller, C. Vila, Ciro Rodríguez
Abstract: This study shows a methodology for characterizing high speed machining centres, in terms of their capabilities, to reach programmed feed rates while the machining of complex sculptured surfaces. The impact on the cycle time of the whole operation has been evaluated making a parametric variation of the geometries to be machined. Therefore, for a distributed and simultaneous characterization of machining centres located in different places, tools for Collaborative Engineering have been used (PLM and CAD/CAM/CAE).
Authors: P. Gilles, J.M. Redonnet, P. Lagarrigue, R. Beceril, B. Fraysse, V. Boucharessas
Abstract: To allow for enhanced quality while reducing machining time, machines have become increasingly complex, thus leading to an increase in purchase, running and operator training costs. In what follows in the present paper, we shall firstly show how a virtual machine tool can be developed. Secondly, we shall study the influence this tool can have on teaching methods..
Authors: Pedro Jose Núñez López, Jorge Simao, E.M. Rubio Alvir, J.L. Rincón
Abstract: During turning operations, the workpiece clamping system and the selection of the cutting conditions are of prime importance. They both have a significant influence on workpiece roundness error ER, due to the dynamic behaviour of the chuck-axis-workpiece system. This dynamic behaviour is conditioned by selected machining parameters (cutting speed v, depth-of-cut d, feed rate f) and the design of the workpiece (length L and diameter φ). The main aim of the work was to evaluate the influence of the aforementioned parameters (v, d, f, L/φ) on workpiece roundness error ER during turning AISI-1045 steel material, for a range of machining conditions (v=150, 200, 250 m/min, f=0.15, 0.20, 0.25 mm/rev, d=1, 2, 3 mm). Furthermore, the cutting force signals were monitored throughout the tests in order to control the process and the correlation of the three force components (depth Fd, tangential Ft, feed Ff) with workpiece roundness error ER was analysed. Of all the various operating process parameters that were evaluated, the machined workpiece length L and the depth-of-cut d were shown to have the most significant influence on ER variation. The highest ER values were obtained when the highest depth-of-cut d, feed rate f, cutting speed v and length L values were employed and combined. Little effect on the output measure ER was observed when cutting speed v and feed rate f parameters were individually increased. Moreover, an increase in the cutting force (Fd, Ft y Ff) values showed to produce a significant increase in workpiece roundness error ER.
Authors: Wen T. Chien, W.C. Hung
Abstract: The purpose of this study is to develop two predictive models for burr height in cutting titanium alloy plates by using Nd:YAG laser. Firstly, Taguchi method has been used to arrange the experimental scheme and analyze the results via analysis of mean . The important laser cutting parameters affecting burr height can be found. It shows that the pressure of assistant gas, the focusing position and the pulsed frequency are the most important cutting parameters in order. Then they have been chosen as the input variables for response surface methodology and used to construct a mathematical equation for predicting burr height. Secondly, the laser cutting parameters and experimental results obtained from conducting the schematic arrangement using Taguchi method and response surface methodology have been treated as training patterns and recalling patterns for the back-propagation neural network. As a result, a predictive model for burr height prediction in laser cutting titanium alloy has been established. To verify the accuracy of above two prediction models, there are 9 sets of experiment have been performed. It shows that the average error for predicting burr height by the mathematical equation derived from response surface methodology is 5.52% and by the predictive model established by back-propagation neural network is 4.51%, respectively. Obviously, both predictive models are good enough for the relational research and practical applications. It can be concluded that the procedure used in this research and the obtaining predictive models can be used practically in correlate industry.
Authors: Alfredo Sanz, E.M. Rubio Alvir, Carmen Martínez Murillo, M.A. Sebastián
Abstract: Present work shows many of Virtual Reality (RV) developments carried out in manufacturing processes field by the collaboration between Aerospace Materials and Production Department at the UPM University and Manufacturing and Construction Engineering at the UNED university. Most of them have been directed towards Numerical Control Machine Tools field and towards equipment that configure automated manufacturing systems like Flexible Manufacturing Systems (FMS).
Authors: P. Pereira Navaza, E. Ares, Jose L. Diéguez, A. Pereira
Abstract: In the present consumer, the personalization and originality of the made polymeric products it is one of the area in which dwells efforts of investigation take it pleases. Many companies uses plastic recipients that dog be painted or wrapped with to plastic but to however, the development of artistic relief plows not developed. The biggest problem was obtaining an artistic process out. In manual a way, it is very complicated, and there was not specific software to develop this kind of work because they were designed to carry out tech-line pieces. The aim of this work is to develop to method to produces to 3-D relief, an artistic appears and some letters, in a mould.
Authors: Ignacio Puertas, C.J. Luis-Pérez
Abstract: In this work, a surface roughness study on the die-sinking electrical discharge machining (EDM) of siliconised silicon carbide (SiSiC) has been carried out. The selection of the abovementioned conductive ceramic was made taking into account its wide range of applications in the industrial field: high temperature gas turbines, bearings, seals and lining of industrial furnaces. This study was made only for the finish stages, due to the enormous importance that a good surface quality has over such important properties as, in the case of ceramic materials: corrosion, fatigue and wear resistance. The present study has been carried out on the influence of five design factors: intensity supplied by the generator of the EDM machine (I), pulse time (ti), duty cycle (η), opencircuit voltage (U) and dielectric flushing pressure (P), which are the most relevant parameters to be controlled by the EDM process machinists, over two roughness parameters such as Ra and Rq. The study of the behaviour of the two previously mentioned parameters has been done by means of the technique of design of experiments (DOE), which allows us to carry out the previous analysis performing a relatively small number of experiments. In this case, a 25-1 fractional factorial design, whose resolution is V, has been selected due to the number of factors considered in the study.
Authors: G. Petropoulos, N. Vaxevanidis, A. Iakovou, Kostas David
Abstract: This study concerns the formulation of a multi-parameter surface texture model in EDMachining of AISI D2 tool steel. The model is developed in terms of pulse current and pulse-on time which are the dominant machining conditions, via factorial design of experiments. By applying analysis of variance and statistical multi-regression analysis to the experimental data close correlation is proved between certain surface finish parameters and the machining conditions, with pulse current exerting the strongest influence. By applying this model the appropriate conditions for successful finish can be selected, as well as functional surface characteristics can be quantified.
Authors: Daniela Herman, J. Plichta, K. Nadolny
Abstract: A new type of ceramic abrasive tools prepared of aluminium oxide (alumina), designed to realise the one-pass process of inside diameter grinding. Distinctive feature of these tools is the gradient distribution of the abrasive grain zones with different sizes and structure which enables to carry out the rough (efficient) and finishing grinding in one pass. An influence of the grinding speed vS and the quantities of the working engagement ae on the worksurface roughness and the grinding power were determined.
Authors: Roberto Jiménez Pacheco, R. Villagrasa, J.A. Albajez, Juan-José Aguilar-Martín
Abstract: This paper shows a solution to the problem of finding an optimum sheet metal bending sequence using Genetic Algorithms (GA). First it shall be explained how the problem can be modelled, previous to its solution by GA. Secondly the method for optimization, under different criteria, is described. Finally the results obtained and the advantages of using the GA are shown.

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