production and operations management
Morteza Saeidi; Mostafa Ebrahimpour Azbari; MohammadRahim Ramazanian
Abstract
The purpose of this Article is to Designing a model for improving the Sustainable Performance of Small and Medium Food Companies in Guilan Province so that in the current environment, managers and decision makers by recognizing the factors, challenges and consequences to improve the sustainable performance ...
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The purpose of this Article is to Designing a model for improving the Sustainable Performance of Small and Medium Food Companies in Guilan Province so that in the current environment, managers and decision makers by recognizing the factors, challenges and consequences to improve the sustainable performance of Small and Medium Food Companies. The present Article is in the category of applied research from the perspective of purpose, in the category of exploratory-descriptive research in terms of nature and in the field of field studies based on data collection.This Article is in the category of qualitative research. A paradigm model was created by the Grounded theory method through three stages of open, axial and selective coding. The Results of data Analysis using Grounded Theory led to the formation of 13 main floors, 29 main categories and 248 concepts. The six main classes of paradigm model of the Grounded theory using theoretical coding in the form of: pivotal phenomenon (sustainable performance improvement), causal conditions (organizational survival, social and environmental obligation, gaining competitive advantage), contextual conditions (environmental factors, organizational factors), Interfering Conditions (environmental factors, organizational factors), strategies (macro level, organizational level). Finally the Economic, Social and Environmental consequences of achieving Sustainable Performance Improvement were achieved by implementing the strategies.
production and operations management
fahimeh tanhaie
Abstract
The mix model assembly line has attracted the attention of many industrial manufacturers due to its special features and the ability to adapt to market changes. This article has discussed and investigated a new approach in relation with customers, the results of which indicate the proper management of ...
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The mix model assembly line has attracted the attention of many industrial manufacturers due to its special features and the ability to adapt to market changes. This article has discussed and investigated a new approach in relation with customers, the results of which indicate the proper management of demand. The proposed model pays more attention to priority customers, and a parallel production line is defined that is faster than the main line and has workers with special skills. According to the rapid process of environmental changes, one of the things that can be considered to increase flexibility in the make to order environment is to set the conditions for rebalancing the line. In this article, the rebalancing of the line is also considered and included in the modeling, and the minimization of its costs is considered as another goal. Therefore, in this article, a multi-objective line balancing problem is proposed by examining rebalancing and vertical balancing problems. Benders decomposition algorithm is used to solve this problem. The results show that exact methods do not have the ability to solve large-sized problems in a reasonable time, but the solution time for Bander's decomposition method, considering the size of the problem, shows the appropriate efficiency of this algorithmIntroductionMix model assembly lines, known for their ability to adapt to changing market demands with minimal adjustments, are currently employed in active industries worldwide. The findings of this article also hold potential for reducing assembly line waste in the country's manufacturing sector. Drawing from the principles of lean production and the theories of Scholl and Becker, achieving an optimal production line balance can lead to the reduction of at least five out of the ten types of waste. While the topic of line balancing is crucial in itself, this research sheds light on a significant aspect often overlooked in most studies on planning mixed model assembly lines: the order-based environment. Many previous studies have focused solely on the 'make-to-order' environment and its assumptions, often neglecting balance issues. Given the paramount importance of customer roles in industries, it is imperative to introduce a framework for managing customer orders within line balancing problem models. The aim of this article is to enhance cost management and productivity in mixed assembly lines across various industries, ensuring that demands are met and assembly process constraints are addressed. To achieve this, we first develop the necessary mathematical models for each component and subsequently devise algorithms for their solutions.Materials and MethodsAn express line is defined in parallel and faster than the main line, as well as having workers with special skills. Considering the rapid process of environmental changes, another thing that can be considered to increase flexibility in the base order environment is to create conditions for rebalancing the line so that both the workload and the cost can be balanced at the same time. This reduced the reassignment of duties. From this point of view, in the proposed model in this part, rebalancing of the line is also desired and it is included in the modeling, and the minimization of its costs is considered as another goal of this model. Also, the goal of balancing the assembly line, which is to distribute the total workload between the stations as smoothly as possible, is also included in the proposed model of this part, which is also called vertical balance, so that each station has a balanced amount of work. Be in a work shift. Therefore, in this model, a multi-objective problem of determining the balance is designed by examining the problems of rebalancing and vertical balance. The orders coming into the organization are prioritized first, because in the order-based production environment, the delivery time of orders is very important, especially for high-priority orders, because customers expect an appropriate response in a short period of time. This prioritization can be done by any method, the output of which determines regular customers and priority customers. After determining the priority of the orders and paying attention to the main line and the designated vanguard, priority orders can be entered into the Parallel line, which operates faster and has multi-purpose operators.Discussion and ResultsIn order to validate the model and ensure the correct performance of the combined benders algorithm with the LP metric method, first the mathematical model in a small size is solved and a comparison between the results and the proposed algorithm is done. Finally we used the proposed algorithm in the large size that the gams software is not able to determine the answer. The L-P metric method obtains the optimal solution in small sizes, but in large sizes, when we give 3600 to 10800 seconds to the solver, it cannot obtain the optimal solution and requires another method to solve. The results of the comparisons show that the LP-metric method does not have the ability to solve large-sized problems in a reasonable time, but the solution time for the benders decomposition method, considering the size of the problem and the obtained answers, shows the appropriate efficiency of this algorithm.ConclusionsFlexibility in the production lines is very important and it should be able to respond to the demand when customer orders change. Therefore, the definition of a mix model line provides flexibility in responding to customer demand and reducing the delivery time for priority orders. When we are faced with a large volume of orders, it can be useful to do things in parallel line. This issue, which is rarely seen in research, is presented in the balance model of this article in the form of two parallel lines. This issue is especially effective in industries such as automobile manufacturing.
production and operations management
abolfazl Kazazi; Mohammad Taghi Taghavifard; reza kianimavi; mohsen hooshangi
Abstract
Companies, as one of the most prominent features of today's societies, are rapidly changing and evolving, and in the current situation, improving the innovation capabilities is one of the main goals of any living and active organization. The purpose of this study is to investigate the effect of social ...
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Companies, as one of the most prominent features of today's societies, are rapidly changing and evolving, and in the current situation, improving the innovation capabilities is one of the main goals of any living and active organization. The purpose of this study is to investigate the effect of social capital on innovation capabilities in supplier-buyer relationships by of opportunistic and intellectual property risks. The statistical sample in this study contains 95 of supply chain managers which are active in the escalator and elevator industry. The collected data were analyzed by using partial least squares method and Smart PLS software. The findings illustrate positive and significant effect of social capital on innovation capabilities (and indirectly through intellectual property risk). Opportunistic and intellectual property risks also have a significant negative impact on innovation capabilities. The results of this study for managers reveal the fact that investing in social capital in a buyer-supplier relationship not only does not hurt but also achieves a competitive advantage through innovation capabilities.
production and operations management
yousef shamsi; houshang ta; soleiman Iranzadeh
Abstract
The purpose of this article is to develop a model of manufacturing flexibility in the food industry. The present research is a mixed qualitative and quantitative research method. In qualitative research, the Grounded theory method is a tool for building a conceptual model of manufacturing flexibility. ...
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The purpose of this article is to develop a model of manufacturing flexibility in the food industry. The present research is a mixed qualitative and quantitative research method. In qualitative research, the Grounded theory method is a tool for building a conceptual model of manufacturing flexibility. The statistical sample of this section includes 20 experts familiar with the subject of manufacturing flexibility. The sampling method in the qualitative section is the Snowball Sampling method. The method of data collection in this part of the interview is semi-structured. The method of data analysis in the qualitative part is a three-step process of open, axial and selective coding. The results of this section show the model of manufacturing flexibility paradigm. The data collection tool in the quantitative part is a researcher-made questionnaire based on sub-categories and concepts obtained from the qualitative stage. The method of data analysis in this section is confirmatory factor analysis and structural equation modeling. The statistical sample in this section is 201 managers of food industry companies in East Azerbaijan province. The results show that environmental dynamics, increasing competitiveness and access to new markets are among the reasons for the need for manufacturing flexibility, in which automation and timely production are considered as industry strategies to achieve manufacturing flexibility; These factors have a direct effect on increasing organizational performance and customer satisfaction as a consequence of flexibility. The results also show that intervenors such as managerial factors, financial capability, etc. can influence strategies.
production and operations management
Majid Shakhsi-Niaei; Fateme Ghayoor
Abstract
Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ...
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Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ball-valves manufacturing company. In the first phase, preferences of various product groups have been determined via a multiple-attribute-decision-making method which is used as an input for the second phase. To do this, one of the outranking methods has been used because of the variety in the dimension and the nature of different attributes. In the second phase, a deterministic multi-objective mixed-integer mathematical model has been designed considering the needs of the company. This model not only concentrates on the benefits, but also considers the preferences of the products. The third objective function is decreasing work in process. To solve this model, ϵ-constraint method has been used leading to a set of Pareto-optimal solutions, enabling the decision-maker to choose the best solution by trading off between the three objective functions. So top managers are able to decide how to provide product preferences and how to decrease WIP products while the benefits remain reasonable. The results show that using the proposed approach in the case study has improved 35%, 28%, and 56% total benefit, total utility, and WIP products, respectively.
production and operations management
Mahsa Sobhi shojaa; Parvaneh Samouei
Abstract
In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely ...
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In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely employed in many industries due to their efficiency and flexibility . In these lines, a worker can be assigned to multiple stations located at entrance and exit sides. However, in many realistic situations, robots may be unavailable during the scheduling horizon for different reasons, such as breakdowns. This research deals with line balancing under uncertainty The Objective in this research is minimizing the cycle time for a given number of workstations and minimizing robot cost.This research deals with line balancing under uncertainty and presents one robust optimization model for balancing and sequencing of u-shaped robotic assembly line with considering set up times between task, failure robot times and preventive maintenance times for every robot. Since the NP-hard nature of the problem, multi-objective harmony search is developed to solve it. Numerical experiments also demonstrated that by increasing uncertainty level, the objective function values, cost and cycle times (minimum, maximum and average) increased. performance of the robust approach by the results, shows that in real conditions, considering the probability of event failure, values of cycle time and cost change significantly, which indicates the need to consider uncertainty, especially failure in robotic assembly lines.
production and operations management
Hadi Mokhtari; Hossein Shirani
Abstract
Today, in order to maximize the productivity, sales and profits of factories, variousfactors must be considered. One of these factors is energy saving, which leads tosuccess in any businesses. Another important factor is rework in the productionprocess, which reduces waste and optimal use of resources. ...
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Today, in order to maximize the productivity, sales and profits of factories, variousfactors must be considered. One of these factors is energy saving, which leads tosuccess in any businesses. Another important factor is rework in the productionprocess, which reduces waste and optimal use of resources. In this research, a linearmathematical programming model has been developed for a multi-stage productionsystem considering energy consumption and the possibility of rework. The objectivefunction of the model is calculated from a combination of energy costs and rawmaterial costs, and the proposed model has three categories of balance constraints,demand constraints and time constraints. The balance constraints, the task ofcalculating the number of raw materials required and the amount of input materialsto each part of the production stage, the demand constraints are the task ofcalculating the number of final products, and the inventory and time constraints arealso the task of calculating the time available to the production of each product.A hypothetical production system is flow shop. To understand the proposed modelbetter, a logical example is designed and solved and analyzed using GAMS software. In the current situation , energy consumption is one of the concerns of policy makers in the fields of production and industry , and therefore this research with the proposed model , helps decision makers in manufacturing industries to ensure optimal energy consumption , optimal decisions in adopt multi -stage rework and production condition
