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Showing 15 results for Subject: Manufacturing Process & Systems

Abbas Dideban, Maysam Zareiee, Ali A. Orouji, Hassan Rezaei Soleymanpour ,
Volume 24, Issue 1 (2-2013)
Abstract

This paper deals with the problem of forbidden states in discrete event systems modeled by Petri Net. To avoid the forbidden states, some constraints which are called Generalized Mutual Exclusion Constraints can be assigned to them. Enforcing these constraints on the system can be performed using control places. However, when the number of these constraints is large, a large number of control places must be connected to the system which complicates the model of controller. In this paper, the objective is to propose a general method for reducing the number of the mentioned constraints and consequently the number of control places. This method is based on mixing some constraints for obtaining a constraint verifying all of them which is performed using the optimization algorithms. The obtained controller after reducing the number of the control places is maximally permissive.
Hadi Mokhtari , Ashkan Mozdgir,
Volume 26, Issue 2 (7-2015)
Abstract

Assembly lines are special kinds of production systems which are of great importance in the industrial production of high quantity commodities. In many practical manufacturing systems, configuration of assembly lines is fixed and designing a new line may be incurred huge amount of costs and thereby it is not desirable for practitioners. When some changes related to market demand occur, it is worthwhile to re-balance an existing line rather than balancing a new one. Hence, in this paper we suggest a re-balancing model of an existing assembly line in which a new demand related cycle time (CT) is embedded to the traditional assembly line balancing problem (ALBP) as a new parameter. It does not focus on balancing a new line instead it considers a more realistic problem which is re-balancing an existing line. The objective is to re-schedule the tasks in order to reduce the current CT to the new required one such that two criteria are optimized: (i) minimization of the incurred costs and (ii) minimization of non-smoothing of reconfigured line. To solve the considered problem, an effective differential evolution algorithm is developed. Furthermore, to enhance the performance of algorithm, its parameters are optimized by the use of Taguchi method which is a conventional statistical technique for parameter design. The obtained results from computational experiments on benchmark instances show the effectiveness of suggested algorithm against other methods.

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Rassoul Noorossana, M. Nikoo,
Volume 26, Issue 2 (7-2015)
Abstract

In many manufacturing processes, the quality of a product is characterized by a non-linear relationship between a dependent variable and one or more independent variables. Using nonlinear regression for monitoring nonlinear profiles have been proposed in the literature of profile monitoring which is faced with two problems 1) the distribution of regression coefficients in small samples is unknown and 2) with the increasing complexity of process, regression parameters will increase and thereby the efficiency of control charts decreases. In this paper, wavelet transform is used in Phase II for monitoring nonlinear profiles. In wavelets transform, two parameters specify the smoothing level, the first one is threshold and the second one is decomposition level of regression function form. First, using the adjusted coefficient of determination, decomposition level is specified and then process performance is monitored using the mean of wavelet coefficients and profile variance. The efficiency of the proposed control charts based on the average run length (ARL) criterion for real data is compared with the existing control charts for monitoring nonlinear profiles in Phase II

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Javad Rezaeian, Masoud Shafipour,
Volume 28, Issue 3 (9-2017)
Abstract

This research deals with a hybrid flow shop scheduling problem with parallel batching, machine eligibility, unrelated parallel machine, and different release dates to minimize the sum of the total weighted earliness and tardiness (ET) penalties. In parallel batching situation, it is supposed that number of machine in some stages are able to perform a certain number of jobs simultaneously. Firstly, with respect to the proposed problem a mixed integer linear programming model is developed. Since the problem is NP-hard, for solving large size problems, a hybrid meta-heuristic algorithm which combines artificial immune system and simulated annealing is proposed. The performance of hybrid algorithm is tested by some numerical experiments and the results show its superiority to the other two algorithms.


Bardia Behnia, Iraj Mahdavi, Babak Shirazi, Mohammad Mahdi Paydar,
Volume 28, Issue 3 (9-2017)
Abstract

Nowadays, the necessity of manufacturers’ response to their customers’ needs and their fields of activities have extended widely. The cellular manufacturing systems have adopted reduced costs from mass-production systems and high flexibility from job-shop manufacturing systems, and therefore, they are very popular in modern manufacturing environments. Manufacturing systems, in addition to proper machinery and equipment, workforces and their performance play a critical role.

Staff creativity is an important factor in product development, and their interest in cooperating with each other in the work environment can help the growth and maturity of this factor. In this research, two important aspects of cellular manufacturing take into consideration: Cell formation and workforce planning. Cell formation is a strategic decision, and workforce planning is a tactical decision. Practically, these two sectors cannot be planned simultaneously, and decision making in this regard is decentralized. For this reason, a bi-level mathematical model is proposed. The first level aims to reduce the number of voids and exceptional elements, and the second level tends to promote the sense of interest between the workforces for working together, which will result in synergy and growth of the organization.


Bahman Esmailnezhad, Mohammad Saidi-Mehrabad,
Volume 29, Issue 1 (3-2018)
Abstract

This paper deals the stochastic cell formation problem (SCFP). The paper presents a new nonlinear integer programming model for the SCFP in which the effect of buffer size on the grouping efficacy of cells has been investigated. The objective function is the maximization of the grouping efficacy of cells. A chance constraint is applied to explore the effect of buffer on the SCFP. Processing time and arrival time of the part for each cell are considered stochastic and are following exponential probability distribution. To find out the optimal solution in a reasonable time, a heuristic approach is used to linearize the proposed nonlinear model. This problem has been known as an NP-hard problem. Therefore, two metaheuristic methods, namely; genetic algorithm and particle swarm optimization are employed to solve examples. The parameters of the algorithms are calibrated using Taguchi and full factorial methods, and the performances of the algorithms on the examples of various sizes are analyzed against global solutions obtained from Lingo software’s branch and bound (B&B) in terms of quality of solutions and computational time.
Mangesh Phate, Shraddha Toney, Vikas Phate,
Volume 30, Issue 1 (3-2019)
Abstract

In the Wire EDM of oil hardening die steel materials is a complicated machining process. Hence to find out the best set of process parameters is an important step in wire EDM process. Multi-response optimization of machining parameters was done by using analysis called desirability function analysis coupled with the dimensional analysis approach. In the present work, based on Taguchi’s L27 orthogonal array, number experiments were conducted for OHNS material. The WEDM process parameters such as, pulse on time , pulse off time, input current, wire feed rate and the servo voltage are optimized by multi-response considerations such as material removal rate and surface roughness. Based on desirability analysis, the most favorable levels of parameters have been known. The significant contribution of parameters is determined by dimensional analysis. The experimental results show that the results obtain by using DA approach has a good agreement with the measured responses. The correlation up to  99% has been achieved between the developed model and the measured responses by using dimensional analysis approach. 
In the Wire EDM of oil hardening die steel materials is a complicated machining process. Hence to find out the best set of process parameters is an important step in the wire EDM process. Multi-response optimization of machining parameters was done by using analysis called desirability function analysis coupled with the dimensional analysis approach. In the present work, based on Taguchi’s L27 orthogonal array, number experiments were conducted for OHNS material. The WEDM process parameters such as pulse on time, pulse off time, input current, wire feed rate, and the servo voltage are optimized by multi-response considerations such as material removal rate and surface roughness. Based on desirability analysis, the most favorable levels of parameters have been known. The significant contribution of parameters is determined by dimensional analysis. The experimental results show that the results obtain by using DA approach has a good agreement with the measured responses. The correlation up to  99% has been achieved between the developed model and the measured responses by using dimensional analysis approach. 
Amir-Mohammad Golmohammadi, Mahboobeh Honarvar, Guangdong Guangdong, Hasan Hosseini-Nasab,
Volume 30, Issue 4 (12-2019)
Abstract

There is still a great deal of attention in cellular manufacturing systems and proposing capable metaheuristics to better solve these complicated optimization models. In this study, machines are considered unreliable that life span of them follows a Weibull distribution. The intra and inter-cell movements for both parts and machines are determined using batch sizes for transferring parts are related to the distance traveled through a rectilinear distance. The objectives minimize the total cost of parts relocations and maximize the processing routes reliability due to alternative process routing. To solve the proposed problem, Genetic Algorithm (GA) and two recent nature-inspired algorithms including Keshtel Algorithm (KA) and Red Deer Algorithm (RDA) are employed. In addition, the main innovation of this paper is to propose a novel hybrid metaheuristic algorithm based on the benefits of aforementioned algorithms. Some numerical instances are defined and solved by the proposed algorithms and also validated by the outputs of exact solver. A real case study is also utilized to validate the proposed solution and modeling algorithms. The results indicate that the proposed hybrid algorithm is more appropriate than the exact solver and outperforms the performance of individual ones.
Mangesh Phate, Shraddha Toney, Vikas Phate,
Volume 31, Issue 2 (6-2020)
Abstract

In the present work, a model based on dimensional analysis (DA) coupled with the Taguchi method to analyze the impact of silicon carbide (SiC) has been presented. The wire cut electrical discharge machining (WEDM) performance of aluminium silicon carbide (AlSiC) metal matrix composite (MMC) has been critically examined. To formulate the DA based models, total 18 experiments were conducted using Taguchi’s L18 mixed plan of experimentation. The input data used in the DA models are a pulse on time, pulse off time, wire feed rate, % SiC, wire tension, flushing pressure etc. According to these process parameters, DA models for the surface roughness and the material removal rate was predicted. The formulated DA models have shown a strong correlation with the experimental data. The analysis of variance (ANOVA) has been used to find out the impact of individual parameters on response parameters.  
 
Reza Rostami Heshmatabad, Mohammadreza Shabgard,
Volume 31, Issue 3 (9-2020)
Abstract

In this study, the electrochemical machining (ECM) of the 304 stainless steel with the response surface methodology (RSM) approach for designing, analyzing and mathematical modeling was used. The electrolyte type, concentration and current parameters were considered as the machining parameters. The mathematical model for the responses was presented and based on the type of electrolyte including NaCl, NaNO3 and KCl. The results showed that the current has the highest effect on Surface Roughness (SR) and Material Removal Rates (MRR) and respectively it improves them to 0.465μm and 0.425gr/min. The electrolyte concentration has the highest effect on Over Cut (OC) and causes to increase its values. Under the conditions of NaCl electrolyte, 1 molarity concentration and 55 A current, the optimum condition 0.4006 gr/min MRR, 0.75 mm OC and 0.465mm SR was achieved. 
Bhanudas Bachchhav,
Volume 32, Issue 1 (1-2021)
Abstract

The present work aims to investigate Abrasive Water Jet Machining parameters for machining of Al-Al2O3 Metal Matrix Composite. Plan of experiments, based on Taguchi’s analysis technique were performed using L9 orthogonal array. A correlation was established between concentration of Al2O3, Stand-off distance, pressure and Transverse feed with Metal Removal Rate, Surface Roughness, Over-cut and Taper angle by regression analysis. On the basis of experimental results and S/N ratio analysis, ranking of the parameters has been done. The analysis of variance (ANOVA) has been used to find out the impact of individual parameters on response parameters. Al2O3 concentration plays a very significant role in determination of MRR and surface roughness. Also overcut is largely influenced by stand off distance. Furthermore,  multi-objective optimization can be carried out using advanced optimization techniques.  This work helped to generate technical database for industrial applications of MMC.
Hadi Mokhtari, Aliakbar Hasani, Ali Fallahi,
Volume 32, Issue 2 (6-2021)
Abstract

One of the basic assumptions of classical production-inventory models is that all products are of perfect quality. However, in real manufacturing situations, the production of defective items is inevitable, and a fraction of the items produced may be naturally imperfect. In fact, items may be damaged due to production and/or transportation conditions in the manufacturing process. On the other hand, some reworkable items exist among imperfect items that can be made perfect by additional processing. In addition, the classical production-inventory models assume that there is only one product in the system and that there is an unlimited amount of resources. However, in many practical situations, several products are produced and there are some constraints related to various factors such as machine capacity, storage space, available budget, number of allowable setups, etc. Therefore, we propose new constrained production-inventory models for multiple products where the manufacturing process is defective and produces a fraction of imperfect items. A percentage of defective items can be reworked, and these products go through the rework process to become perfect and return to the consumption cycle. The goal is to determine economic production quantities to minimize the total cost of the system. The analytical solutions are each derived separately by Lagrangian relaxation method, and a numerical example is presented to illustrate and discuss the procedure. A sensitivity analysis is performed to investigate how the variation in the inputs of the models affects the total cost of the inventory system. Finally, some research directions for future works are discussed.
M Kaladhar, Vss Sameer Chakravarthy, Psr Chowdary,
Volume 32, Issue 3 (9-2021)
Abstract

Surface quality is a technical prerequisite in the field of manufacturing industries and can be treated as a quality index for machined parts. Attainment of appropriate surface finish plays a key role during functional performance of machined part. It is typically influenced by the machining parameters. Consequently, enumerating the good relation between surface roughness (Ra) and machining parameters is a highly focused task. In the current work, response surface methodology (RSM) based regression models and flower pollination algorithm (FPA) based sparse data model were developed to predict the minimum value of surface roughness in hard turning of AISI 4340 steel (35 HRC) using a single nanolayer of TiSiN-TiAlN PVD-coated cutting insert. The results obtained from this approach had good harmony with experimental results, as the standard deviation of the estimated values was simply 0.0804 (for whole) and 0.0289 (for below 1 µm Ra). When compared with RSM models, the proposed FPA based model showed the least percentage of mean absolute error. The model obtained the strongest correlation coefficient value of 99.75% among the other models values. The behavior of machining parameters and its interaction against surface roughness in the developed models were discussed with Pareto chart. It was observed that the feed rate was highly significant parameter in swaying machining surface roughness. In inference, the FPA sparse data model is a better choice over the RSM based regression models for prognosis of surface roughness in hard turning of AISI 4340 steel (35 HRC). The model developed using FPA based sparse data for surface roughness during hard turning operation in the current work is not reported to the best of author’s knowledge. This model disclosed a more dependable estimation over the multiple regression models.
Sundaramali G., Santhosh Raj K., Anirudh S., Mahadharsan R., Senthilkumaran Selvaraj,
Volume 32, Issue 3 (9-2021)
Abstract

One of the goals of the manufacturing industry in the globalisation era is to reduce defects. Due to a variety of factors, the products manufactured in the industry may not be defect-free. Six Sigma is one of the most effective methods for reducing defects. This paper focuses on implementing Six Sigma in the automobile industry's stator motor shaft assembly. The high decibel noise produced by the stator motor is regarded as a rejected piece. Six Sigma focuses on continuous improvement and aids in process optimization by identifying the source of the defect. In the Six Sigma process, the problem is measured and analysed using various tools and techniques. Before beginning this case study, its impact on the company in terms of internal and external customer cost savings is assessed. This case study was discovered to be in a high-impact area. The issue was discovered during the Core and Shaft pressing process. Further research leads to dimensional tolerance, which reduces the defect percentage from 16.5 percent to 0.5 percent.
Chaymae Bahtat, Abdellah El Barkany, Abdelouahhab Jabri,
Volume 34, Issue 2 (6-2023)
Abstract

The productivity and flexibility of current manufacturing systems (dedicated and flexible production systems) are no longer competitive as products are developed and brought to market in increasingly shorter cycles. As a result, a new generation of reconfigurable manufacturing systems (RMS) has emerged that should be responsive enough to cope with sudden market changes while maintaining excellent product quality at low prices. These systems could also leverage technologies at the heart of Industry 4.0, such as artificial intelligence and machine learning, the Internet of Things (IoT), and digital twins, to create a smart, dynamic, and most importantly, reconfigurable factory, dubbed the Reconfigurable Factory 4.0. This study provides an organized and up-to-date systematic review of the literature on reconfigurable manufacturing systems, from design to simulation, and from automation to the fourth industrial revolution (Industry 4.0) highlighting the application areas as well as the significant approaches and technologies that have contributed to the development of a Reconfigurable Factory 4.0.
 

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