Showing papers on "Taguchi methods published in 2002"

Prediction of surface roughness in CNC face milling using neural networks and Taguchi's design of experiments

Abstract: In this paper, a neural network modeling approach is presented for the prediction of surface roughness (Ra) in CNC face milling The data used for the training and checking of the networks’ performance derived from experiments conducted on a CNC milling machine according to the principles of Taguchi design of experiments (DoE) method The factors considered in the experiment were the depth of cut, the feed rate per tooth, the cutting speed, the engagement and wear of the cutting tool, the use of cutting fluid and the three components of the cutting force Using feedforward artificial neural networks (ANNs) trained with the Levenberg–Marquardt algorithm, the most influential of the factors were determined, again using DoE principles, and a 5×3×1 ANN based on them was able to predict the surface roughness with a mean squared error equal to 186% and to be consistent throughout the entire range of values

Optimisation of the EDM process based on the orthogonal array with fuzzy logic and grey relational analysis method

Abstract: In this paper, the use of the grey relational analysis based on an orthogonal array and fuzzy-based Taguchi method for optimising the multi-response process is reported. Both the grey relational analysis method without using the S/N ratio and fuzzy logic analysis are used in an orthogonal array table in carrying out experiments for solving the multiple responses in the electrical discharge machining (EDM) process. Experimental results have shown that both approaches can optimise the machining parameters (pulse on time, duty factor, and discharge current) with considerations of the multiple responses (electrode wear ratio, material removal rate, and surface roughness) effectively. It seems that the grey relational analysis is more straightforward than the fuzzy-based Taguchi method for optimising the EDM process with multiple process responses.

Efficient statistical tolerance analysis for general distributions using three-point information

Abstract: The experimental design technique in the literature, which has been limited only to normally distributed random variables, is extended to handle non-normal cases. It is easy to implement and provides good results for the moments of system response functions compared with other traditional methods. It is based on the three-level Taguchi method, and optimum levels and weights to handle non-normal distributions are derived. A systematic procedure for tolerance analysis is then proposed by using the Pearson system. Numerical results for non-linear examples are shown to be very accurate in comparison with those from Monte Carlo simulations and the first-order reliability method.

Design of Experiments Using the Taguchi Approach: 16 Steps to Product and Process Improvement

Abstract: (2002). Design of Experiments Using the Taguchi Approach: 16 Steps to Product and Process Improvement. Technometrics: Vol. 44, No. 3, pp. 289-289.

A study on shrinkage compensation of the SLS process by using the Taguchi method

Abstract: This paper proposes the test pieces of the X, Y, and Z axes to compensate for the distortion of the SLS parts resulting from the phase changes during the sintering process. In the case of the test pieces proposed for the compensation of the X and Y axes, the accurate rates of shrinkage can be measured with the reduction of curling that is obtained from the adjustment of the building orientation. A set of basic equations is suggested as a useful scale factor to adapt the shrinkage rate. The scale factors of the X, Y, and Z axes generated by the build-up of the compensation test pieces of each axis are required to satisfy the dimensional accuracy, even if there is any change in the build position and the size of the SLS parts in the chamber. A new approach is investigated that enables the operator to determine the optimal scale factors for an actual SLS process applying the Taguchi method.

Optimisation Technique for Face Milling Stainless Steel with Multiple Performance Characteristics

Abstract: An optimisation technique for face milling stainless steel based on the Taguchi method with multiple performance characteristics is proposed in this paper. Three cutting parameters namely, cutting speed, feedrate, and depth of cut, are optimised with consideration of multiple performance characteristics including removed volume, surface roughness, and burr height. In this study, not only are the multiple performance characteristics improved, but also the optimal cutting parameters and the weighting factor that significantly affect the multiple performance characteristics are obtained. Experimental results are provided to illustrate the effectiveness of this approach.

Optimizing multi‐response problem in the Taguchi method by DEA based ranking method

Abstract: Looks at the Taguchi method, a traditional approach that seeks to obtain the best combination of factors with the lowest societal cost solution to achieve customer requirements, and also principal component analysis (PCA). States that the Taguchi method can only be used to optimize single response problems and not multi‐response problems and that PCA, although it has been considered to solve multi‐response problems, itself has shortcomings. Proposes a data envelopment analysis ranking (DEAR) approach as an effective means of optimizing the multi‐response problem. Includes a series of steps from the proposed approach which are capable of decreasing uncertainty caused by engineering judgement in the Taguchi method and overcoming the shortcomings of PCA. Concludes that the DEAR approach is more powerful for practical applications.

Robust fuzzy controlled photovoltaic power inverter with Taguchi method

Abstract: This paper presents design and implementation of a robust fuzzy controlled photovoltaic (PV) power inverter with Taguchi tuned scaling factors. To achieve fast transient response, small steady-state error and system robustness, a robust fuzzy controller is adopted, in which its input and output scaling factors are determined efficiently by using the Taguchi-tuning algorithm. The proposed system can operate in different modes, grid-connection mode and stand-alone mode, and can accommodate wide load variations. Simulation results and hardware measurements obtained from a prototype with a microcontroller (Intel 80196KC) are presented to verify the theoretical discussions, and its adaptivity, robustness and feasibility.

Optimization of a Roller Levelling Process for Al7001T9 Pipes with Finite Element Analysis and Taguchi Method

Abstract: This paper is concerned with the optimization of process parameters for a roller leveller that is an indispensable piece of equipment to eliminate the undesirable curvature of a thin-walled aluminum pipe. Optimization of process parameters has been carried out for a multi-staggered-type 14-roller leveller. A finite element model of a multi-staggered 14-roller leveller was constructed for numerical analysis. The analysis is carried out with the fractional model and the Taguchi method for evaluation of the effect of process parameters such as the intermesh and the slanted angle of rollers. The response variable is set to the plastic strain along the pipe length. The optimum combination of process parameters is determined from the numerical result and confirmed by experiments. The comparison of the numerical result with the experimental one shows good coincidence for its validity and reliability.

Parametric optimization of magnetic‐field‐assisted abrasive flow machining by the Taguchi method

Abstract: Some hybrid-machining processes have been developed in the recent past with a view to devising composite machining processes, which are able to overcome the limitations of one process with the help of advantageous features of another similar process. The present paper identifies the parameters of abrasive flow machining (AFM) that significantly affect the material removal when a magnetic field is applied around the workpiece. The Taguchi method has been adopted for studying the effect of magnetic-field-assisted AFM parameters, individually, on the abrasion rate of work materials. Optimization of the process parameters has been carried out for the purpose of off-line monitoring of the process. Copyright © 2002 John Wiley & Sons, Ltd.

Determination of optimal ball-burnishing parameters for plastic injection moulding steel

Abstract: The objective of this study is to determine the optimal plane ball-burnishing parameters for plastic injection moulding steel PDS5 on a machining centre by utilising the Taguchi's orthogonal array method. The design and manufacture of a burnishing tool are described. Four burnishing parameters, namely the ball material, burnishing speed, burnishing force and feed, were selected as the experimental factors in Taguchi's design of experiments to determine the optimal burnishing parameters which have the dominant influence on surface roughness. The optimal burnishing parameters were found after carrying out the experiments specified by Taguchi's L 18 orthogonal table, by the analysis of variation, and by a full factorial experiment. The optimal plane burnishing parameters for the plastic injection moulding steel PDS5 were a combination of a tungsten carbide ball, a burnishing speed of 200 mm/min, a burnishing force of 300 N and a feed of 40 μm. The surface roughness R a of the specimen can be improved from about I μm to 0.07 μm by using the optimal burnishing parameters for plane burnishing.

Determination of the optimum conditions for ion nitriding of AISI 5140 steel

Abstract: AISI 5140 low alloy steel was ion nitrided under different process parameters including time (1, 4, 8 and 12 h), temperature (400, 450, 500 and 550 °C) and gas mixture ratio (0.05, 0.33, 1 and 3 N 2 /H 2 ). By determining the fatigue strength, surface hardness, compound layer thickness and case depth, the optimum working conditions were determined by using a Taguchi design of experiment. After ion nitriding process, it is aimed to maximize fatigue strength, surface hardness and case depth as well as to minimize compound layer thickness. While the optimum conditions were determined, due to the goals (above aims) more than one being, the trade-off among goals was considered. First of all, each goal was optimised, separately. Then, all the goals were optimised together, considering the priority of the goals, and the optimum results were obtained at 0.05 N 2 /H 2 gas mixture ratio, at the temperature of 450 °C and for 12 h process time.

A robust process optimization for a powder type rapid prototyper

Abstract: Rapid Prototyping (RP) technology is being widely used in diverse areas including mold manufacturing. However, the quality of RP parts is significantly affected by the property of adopted material and process parameters of the rapid prototyper. The aim of this paper is to investigate the powder material and to optimize the process parameters for Zcorp 402 3DP rapid fabricator. Taguchi's method was employed to investigate the possible process parameters including binder setting saturation value (shell & core), layer thickness, and location of made‐up parts. The experimental result shows that these optimal parameters can shorten parts building time and reduce the use of powder and glue about 20 per cent for ZP100 and 10 per cent for ZP11. Additionally, the quality of RP parts is also improved dramatically. The observation of experiments also shows that the parts made by ZP11 powder is difficult to clean up because of its starch‐based property.

Statistical process design for robotic GMA welding of sheet metal

Abstract: A statistical process design method is proposed for robotic gas metal arc (GMA) welding of sheet metal. The proposed method has the objective of minimizing weld cycle time by maximizing welding travel speed, while maintaining predictable weld quality over a range of worst-case processing conditions. This formulation offers a coherent alternative to Taguchi signal-to-noise ratios that permits the use of classically designed experiments that have potential advantages in experimental cost savings. The method is based on recommended choices of independent variables that place all experimental points in the region of interest. Also, so relatively simple weld evaluation approach was included for sheet metal applications. The method was applied on 16-gauge, 409 stainless steel lap joint welds in the horizontal position. The optimization revealed interesting dependencies of achievable travel speeds on root opening and welding gun positioning factors.

Influence of forming parameters on static recrystallization behaviour during hot rolling aluminium alloy 5083

Abstract: In this paper, the influence of rolling parameters (i.e. rolling temperature, roll speed, roll temperature, friction and the ratio of the mean thickness to the contact length in the roll gap Hm/L) on static recrystallization (SRX) behaviour is studied by the combination of the finite element method (FEM) with the Taguchi experimental method. The FEM is first applied to simulate a single pass laboratory rolling experiment by the use of both empirical and physical models. A new approach is used to generate the mean value of the Zener-Hollomon parameter, which is necessary for the prediction of the volume fraction recrystallized (XV) when the empirical SRX model is used. A physical model which considers the density of recrystallization nuclei and the total stored energy is also applied based on the prediction of internal dislocation density, subgrain size and misorientation. The predicted XV and the recrystallized grain size at the centre and subsurface fit well with experimental measurements from the literature. Then, the Taguchi method is applied to design an orthogonal experimental table, L9({34}), which indicates that there are four parameters, each parameter has three levels and a total of nine test runs need to be conducted. These nine virtual experiments are analysed by the use of FEM. The predicted results are then analysed by the use of the Taguchi method from which the influence of each rolling parameter on XV is given. The studies show that rolling temperature has the greatest influence on XV for the centre point whilst friction is the most important parameter on the determination of XV within the surface region. The roll temperature and roll speed have little influence on XV for both the centre and subsurface point.

Optimization of the aluminium die casting process based on the Taguchi method

Abstract: Porosity in the die casting process causes costly scrap loss and limits the use of die-cast parts in critical high-strength applications. The amount of porosity is closely related to the die casting process parameters. Consequently, the mechanisms of porosity formation in relation to die casting parameters have to be studied in detail. A considerable reduction in porosity formation can be obtained by Taguchi technique implementation in the die casting process. Through simple multifactorial experiments in the foundry, controllable factors can be isolated to provide centring and variance control for a process variable. The primary objective of this paper is to investigate the effects of process parameters on porosity formation in the pressure die casting process to improve casting quality. Examples of the off-line technique used in a Greek aluminium die casting company are given for the purpose of illustrating the practicality and ease of use by industry engineers and managers.

3D surface characterisation of electropolished EDMed surface and quantitative assessment of process variables using Taguchi Methodology

Abstract: The electro discharge machining (EDM) process produces surfaces that require some form of finishing operation This is done in order to improve the surface texture and appearance of the component’s surface However, it is also desirable to remove the white uppermost recast layer (produced by the EDM process) so as to improve the functional performance of the surface Electropolishing or electrochemical polishing (ECP) is one technique that is used mainly to improve the appearance of steels as well as for passivation of stainless steels However, this process is very complex in nature, and it is not well understood how the different process parameters influence the surface integrity of the component in salt solutions The aim of this paper is to present the results of a preliminary design of experiment of an EDM+ECP process sequence using Taguchi methodology 3D characterisation of the surfaces has been done and ANOVA technique has been used to assess the quantitative influence of the different process factors of ECP The results have shown that the direct current is the most dominant factor in modifying the surface texture, especially the Sq and Sm 3D parameters The interaction effect between current and distance between electrodes is relatively important as compared to the individual effect of the latter variable

Analysis of parameter design experiments for signal-response systems

Abstract: Robust parameter design experiments for signal-response systems (Taguchi's dynamic characteristics) have received an increasing amount of interest over the last few years. The development of methodology to analyze data from such experiments is still in the formative stages. This paper covers three approaches for analysis, including the use of Taguchi's dynamic signal-to-noise ratio. A new graphical technique, the joint effects plot, is introduced, and its usefulness is demonstrated.

Optimization of filling process in RTM using a genetic algorithm and experimental design method

Abstract: In the resin transfer molding (RTM) process, preplaced fiber mat is set up in a mold and thermoset resin is injected into the mold. An important issue in RTM processing is minimizing the cycle time without sacrificing part quality or increasing the cost. In this study, a numerical simulation and optimization process for the filling stage was conducted in order to determine the optimum gate locations. The control volume finite element method (CVFEM), modeled as a 2-dimensional flow, was used in this numerical analysis along with the coordinate transformation method to analyze a complex 3-dimensional structure. Experiments were performed to monitor the flow front to validate the simulation results. The results of the numerical simulation corresponded with that of the experimental quite well for every single, simultaneous, and sequential injection procedure. The optimization analysis for the sequential injection procedure was performed to minimize fill time. The complex geometry of an automobile bumper core was chosen. A genetic algorithm was used to determine the optimum gate locations in the 3-step sequential injection case. Taguchi's experimental design method was also used for determining the pressure contribution of each gate. These results could provide the information on the optimum gate locations and injection pressure in each injection step and predict the filling time and flow front.