Optimal batch quantity models for a lean production system with rework and scrap

In an imperfect manufacturing process, the defective items are produced with finished goods. Rework process is necessary to convert those defectives into finished goods. As the system is not perfect, some scrap is produced during this process of rework. In this research, inventory models for a single-stage production process are developed where defective items are produced and reworked, where scrap is produced, detected and discarded during the rework. Two policies of rework processes are considered (a) First policy: rework is done within the cycle, and (b) Second policy: rework is done after N cycles of normal production. Also, three types of scrap production and detection methods are considered for each policy, such as (i) scrap is detected before rework, (ii) scrap is detected during rework and (iii) scrap is detected after rework. Based on these inventory situations, the total cost functions for a single-stage imperfect manufacturing system are developed to find the optimum operational policy. Some numerical examples are provided to validate the model and a sensitivity analysis is carried out with respect to different parameters used to develop the model

A Decision Making Framework for Reverse Logistics Network Design

The main objective of this research is to answer the following research question “How should a company design their reverse logistics network in a more efficient or responsive way?” In this research, a conceptual framework has been developed based on several key factors for network design. Through the analysis of each key factor affecting network design decision, we have built a conceptual framework for reverse logistics network for companies to decide on whether to centralize versus decentralize their reverse logistics operations, and whether to outsource or insource some of their operations? Some existing studies are able to fit well in our proposed framework, giving us better insights to decision making in reverse logistics network design. The proposed conceptual framework is helpful for the companies or organizations to make better decisions when designing their reverse logistics operations to achieve a lean or responsive network

Determining Process Target Value and Ordering Policies in Two-Echelon Hierarchy Production System.

Selection of the mean (target value) for a production process is a classical problem in quality control. Basically, a process mean is selected based on a balance between production cost and economical consequences associated with conforming items and nonconforming items. The process mean affects many production decisions. In particular, because it determines the process conforming and yields rates, it affects the production setup policy. These production decisions also affect the raw material requirement and, thus, its procurement policy when the raw material is supplied by outside vendors. Consequently, process mean, production and raw material procurement policies should be jointly determined to minimize the total related costs. Furthermore, in practice, quantity discounts may be available in raw material purchasing. Because of the interaction between the process mean determination and the raw material ordering policy, quantity discounts will affect all of the related decisions. This dissertation consists of three parts. In the fist part, a two-echelon model is formulated to incorporate the issues associated with production setup and raw material procurement into the classical process mean problem for a single-product production process. In the second part, quantity discounts in raw material purchasing are incorporated into the model. The quantity discounts policy under study is known as all-unit quantity discounts. In the third part, we consider a situation in which the supply rate of the raw material is finite and constant. Three cases in terms of quantity discounts in the raw material purchasing are considered: no discounts, incremental quantity discounts and all-unit quantity discounts. Mathematical models are formulated for all the cases discussed above. Analytical properties are derived and efficient solution algorithms are proposed. Examples are used to illustrate the solution procedures and sensitivity analyses are performed to study the effects of model parameters on the optimal solutions

Optimizing productivity by eliminating and managing rejection frequency using 5s and kaizens practices: case study

The worldwide demand of ceramic tiles market is projected to spread about 21,000 million square meters by 2020. The rising infrastructure progress activities in emergent countries is expected to motivate the trade growth throughout the estimated period. The industry has fascinated a number of new competitors owing to the fast demand progress, thus executing the business extremely reasonable. The production of ceramic tiles involves two different stages: pre bisque firing kiln processes and post bisque firing kiln processes. Rejection encountered in pre bisque firing kiln processes can be recycled deprived of much damage to the environment however the post bisque firing kiln rejection cannot be reprocessed. On the other hand, greatest amount of thermal energy is consumed in the bisque firing kiln process. This research paper highlights a case study of frontier ceramic ltd to diminish the post bisque firing kiln rejections frequency during the production of ceramic wall tiles. In this perspective, 5S methodology is used to reorganize the workstations and process flow while the application of kaizens philosophy of continuous improvement has directed to 40% decrease in post bisque firing kiln rejection consequently saving energy and damage to environment

Economic design of multistage systems for screening inspection by attributes

Ph.D.Lynwood A. Johnso

Embalagens de vidro pós-consumo no sistema de coleta seletiva: o caso da cidade de Londrina

Purpose:  This article presentes the results of an in-depth and contextualized study on the problems in the commercialization of glass containers sent to the selective collection system of the city of Londrina-PR, Brazil.Design: The methodological strategy was the triangulation of sources of evidence desiring to understand the situational characteristics, as well as the operational and environmental challenges faced by the local actors involved, especially the cooperatives. Quantitative and qualitative study case using primary and secondary data collection from multistakeholders.Findings: The data collected here allow us to conclude that vitreous materials have demonstrated difficult commercialization processes and are among those materials that are economically less interesting for cooperatives, intensifying the high social fragility of cooperates.Practical implications: The search for solutions to environmental and economic problems caused by the high generation of municipal solid waste in Brazil still have strong deficiencies in methodologies and technologies. Social implications:  How the reverse logistics of vitreous packaging is operationalized has increased public financing with this type of material, since the sales price obtained by waste pickers does not corroborate the economic support of cooperative enterprises.Originality/value: This study allows to advance in the explanation and description of the way of structuring the reverse chain of vitreous packaging, especially in medium-sized municipalities in the inland.Keywords: post-consumption; packaging; glass; recycling; selective collectionFinalidade: Este artigo apresenta os resultados de um estudo aprofundado e contextualizado sobre os problemas na comercialização de embalagens de vidro enviadas para o sistema de coleta seletiva da cidade de Londrina-PR, Brasil.Metodologia: Utilizou-se como estratégia metodológica a triangulação de fontes de evidências almejando uma compreensão detalhada das características situacionais, bem como dos desafios operacionais e ambientais enfrentados pelos atores locais envolvidos, em especial, as cooperativas. O estudo de caso de âmbito quantitativo e qualitativo abarcou dados primários e secundários advindos de multistakeholders.Constatações: Os dados permitem concluir que materiais vítreos possuem dificuldade para serem comercializados e estão entre aqueles economicamente menos interessantes para as cooperativas, intensificando a elevada fragilidade social dos cooperados.Implicações Práticas: No Brasil, a busca por soluções aos problemas ambientais e econômicos causados pela geração elevada de resíduos sólidos urbanos ainda apresentam fortes deficiências quanto às metodologias e tecnologias.  Implicações Sociais: A forma como está operacionalizada a logística reversa das embalagens vítreas tem elevado o financiamento público com este tipo de material uma vez que o preço de venda obtido pelos catadores não corrobora com a sustentação econômica dos empreendimentos cooperativos.Originalidade/valor: Este estudo permite avançar na explicação e descrição sobre o formato de estruturação da cadeia reversa de embalagens vítreas, em especial em municípios de médio porte do interior do país

End-of-Waste Criteria for Glass Cullet: Technical Proposals

This report is the JRC-IPTS contribution to the development of the end-of-waste criteria for glass cullet in accordance with Article 6 of Directive 2008/98/EC of the European Parliament and of the Council on waste (the Waste Framework Directive). This report includes a possible set of end-of-waste criteria and shows how the proposals were developed based on a comprehensive techno-economic analysis of glass recycling and an analysis of the economic, environmental and legal impacts when glass cullet ceases to be waste. The purpose of end-of-waste criteria is to avoid confusion about the waste definition and to clarify when certain waste that has undergone recovery ceases to be waste. Recycling should be supported by creating legal certainty and an equal level playing field and by removing unnecessary administrative burdens. The end-of-waste criteria should provide a high level of environmental protection and an environmental and economic benefit.JRC.J.5-Sustainable Production and Consumptio

A DESIGN OF OPTIMUM SCREENING PROCEDURE USING SURROGATE VARIABLE

[[abstract]]In this article, a new profit function based on a surrogate variable of its performance variable is provided to develop an optimum screening procedure for manufacturing. The optimum screening procedure helps producers set up the mean level of manufacturing and the screening limits of a surrogate variable to reach a maximum expected profit per unit. The proposed method is useful when the products in the manufacturing process are classified into different grades and sold in two alternate markets. A cement-packing example is used to illustrate the proposed method, and a numerical study is conducted to evaluate the effects of cost components and distribution parameters on the expected profit per unit. The proposed screening procedure provides a significant improvement over existing methods in term of higher expected profit per unit.[[notice]]補正完畢[[journaltype]]國外[[booktype]]紙本[[countrycodes]]SG

Best Environmental Management Practice for the Waste Management Sector

The way communities generate and manage their waste plays an absolutely key role in their ability to use resources efficiently. While making European economy more resource efficient and circular requires a large spectrum of actions, a huge potential for saving resources lays in improving waste management at local level in Europe. On the basis of an in-depth analysis of the actions implemented by frontrunner organisations in the waste management sector, this report describes a set of best practices with high potential for broad uptake. They are called Best Environmental Management Practices (BEMPs) and aim to help local authorities in charge of waste management and waste management companies move towards circular economy. The BEMPs, identified in close cooperation with a technical working group comprising experts from the sector, cover the waste management areas which determine the most the overall waste management performance: setting a waste management strategy, promoting waste prevention, establishing an efficient waste collection that supports re-use and recycling, and stimulating waste and product re-use. Certain areas of waste treatment are also covered. The BEMPs address mainly the management of municipal solid waste, but also of construction and demolition waste and healthcare waste. Additionally, the report provides a set of environmental performance indicators that organisations can use to assess their waste management performance and monitor progress as well as benchmarks of excellence that give an indication of the levels achieved by best performers. The report presents a wide range of information (environmental benefits, economics, case studies, references, etc.) for each of the best practices and aims to provide inspiration and guidance to organisations of the sector. In addition, the report will be the technical basis for the development of an EMAS (EU Eco-Management and Audit Scheme) Sectoral Reference Document on Best Environmental Management Practice for the Waste Management sector according to Article 46 of Regulation (EC) No 1221/2009 (EMAS Regulation).JRC.B.5-Circular Economy and Industrial Leadershi