1,721,024 research outputs found
Design and simulation of CONWIP in the complex flexible job shop of a Make-To-Order manufacturing firm ,
Full text linkThis paper presents a methodology for the design and integration of CONWIP in a make-to-order firm. The approach proposed was applied directly to the flexible job shop of a real manufacturing firm in order to assess the validity of the methodology. After the description of the whole plant layout, attention was focused on a section of the shop floor (21 workstations). The CONWIP system deals with multiple-product families and is characterized by path-type cards and a pull-from-the-bottleneck scheme. The cards release strategy and a customized dispatching rule were created to meet the firm’s specific needs. After the simulation model of the present state was built and validated, the future state to be implemented was created and simulated (i.e. the CONWIP system). The comparison between the two systems achieved excellent results, and showed that CONWIP is a very interesting tool for planning and controlling a complex flexible job shop
Design and simulation of multi-CONWIP into a Make-To-Order firm with general job shop configuration
No full textThis paper presents a general approach for designing and implementing a multi-loop CONWIP system in a complex make-to-order (MTO) firm (i.e. multi-product and multi-routing). The approach was illustrated and then directly simulated in the general job shop of an Italian manufacturer of oil hydraulics products. Firstly, the approach was briefly described, and a case study follows to depict the steps of the implementation. The chosen system consists of a dual-loop CONWIP with cluster type cards and pull-from-the-bottleneck method. Also, a customized dispatching rule and the common unit to measure WIP were chosen according to the firm’s needs and strategy. After designing, this system was simulated and compared with the performances of the current one; it shows lower average values and standard deviations of WIP and flow times, without affecting throughput rate. Finally, the simulated system will also have much lower weighted lateness, to the slight detriment of job tardiness and wait-to-match times for purchase orders. However, multi-CONWIP is an appealing solution for job shop MTO environments
Strategic fit of the Italian supply chains: An experimental Study
No full textAlmost 20 years ago, Marshall L. Fisher asked on the Harvard Business Review "What is the right supply chain for your product?" To search for an answer, he proposed a matrix to understand if the nature of a company's products and the priority of its supply chain match or not. The aim of this work is to determine quantitatively the level of strategic fit of Italian companies from different sectors (e.g. automotive, rubber and plastics, fashion and apparel and machineries and equipment). To achieve our goal, we built a multiple-choice questionnaire with 11 questions on a company's supply chain and 9 questions on its products, to determine products characteristics and supply chain priorities. Also, the questionnaire is provided with some general questions to describe the characteristics of the company. The questionnaire was sent to around 2,000 companies, and we received 172 answers. Firstly, we built the Fisher matrix, and found out that around 61% of companies resulted to match supply chain priorities with product's characteristics. Around 27% of companies, instead, presented a responsive supply chain with functional products, and another 12% of companies have an efficient supply chain with innovative products: both these solutions present criticalities. Finally, we investigated the degree of coherence of the different sectors, and this produces interesting suggestions, both for researchers and practitioners
Design and simulation of multi-CONWIP into a Make-To-Order firm with general job shop configuration
No full textThis paper presents a general approach for designing and implementing a multi-loop CONWIP system in a complex make-to-order (MTO) firm (i.e. multi-product and multi-routing). The approach was illustrated and then directly simulated in the general job shop of an Italian manufacturer of oil hydraulics products. Firstly, the approach was briefly described, and a case study follows to depict the steps of the implementation. The chosen system consists of a dual-loop CONWIP with cluster type cards and pull-from-the-bottleneck method. Also, a customized dispatching rule and the common unit to measure WIP were chosen according to the firm’s needs and strategy. After designing, this system was simulated and compared with the performances of the current one; it shows lower average values and standard deviations of WIP and flow times, without affecting throughput rate. Finally, the simulated system will also have much lower weighted lateness, to the slight detriment of job tardiness and wait-to-match times for purchase orders. However, multi-CONWIP is an appealing solution for job shop MTO environments
A new perspective on Workload Control by measuring operating performances through an economic valorization
Full text linkWorkload Control (WLC) is a production planning and control system conceived to reduce queuing times of job-shop systems, and to offer a solution to the lead time syndrome; a critical issue that often bewilders make-to-order manufacturers. Nowadays, advantages of WLC are unanimously acknowledged, but real successful stories are still limited. This paper starts from the lack of a consistent way to assess performance of WLC, an important burden for its acceptance in the industry. As researchers often put more focus on the performance measures that better confirm their hypotheses, many measures, related to different WLC features, have emerged over years. However, this excess of measures may even mislead practitioners, in the evaluation of alternative production planning and control systems. To close this gap, we propose quantifying the main benefit of WLC in economic terms, as this is the easiest, and probably only way, to compare different and even conflicting performance measures. Costs and incomes are identified and used to develop an overall economic measure that can be used to evaluate, or even to fine tune, the operating features of WLC. The quality of our approach is finally demonstrated via simulation, considering the 6-machines job-shop scenario typically adopted as benchmark in technical literature
Developing a new framework for value added indicators enabled by RFID data in the fashion and apparel sector
No full textThe aim of this paper is to develop a novel framework of Value Added Indicators (VAIs), based on RFID data, that can be used specifically in the fashion and apparel sector. We use the acronym VAIs, instead of the more common Key Performance Indicators (KPIs) already used to monitor all operational parameters, because of the intrinsic goal of our key metrics, that is to increase the value of the fashion and apparel supply chain by using RFID technology. After a preliminary literature review phase, aimed at addressing Business Intelligence literature as well as sets of KPIs available for different industries and different supply chain areas, we developed a framework that illustrate how to leverage KPIs to generate value. Then, we integrated the results of the literature review with new VAIs based on end users voice: we set up two panels of experts, both from different industries and from the academia, to validate the framework and integrate it with additional indicator sets relevant for the end users. The study has produced a set of 60 different VAIs that use, or might use, RFID technology to produce, monitor and increase the overall value of the fashion and apparel supply chain. These VAIs are organised in a structured framework, built and validated by more than 10 experts from the field. The results of the paper are promising both for researchers and practitioners. The first, in fact, could use this list of VAIs to set benchmarks for different market segments of the fashion and apparel retail sector. Practitioners, on the other hand, could use the results of this study to evaluate which use case of RFID could fit and, also, which VAI could be handy for their company
Process parameter optimization in the design of a pasteurizer for fresh filled pasta
No full textOne of the process optimization basic principles is a correct Design of Experiments (DOE). In this work a DOE Taguchi approach has been applied to the optimization of a pasteurizer for fresh filled pasta. The three considered factors are pasteurizing time, vapour pressure and product load on the pasteurizer frame. Each factor presents three levels and two replications have been carried out in every trial condition, by means of an L9 orthogonal array. The results have then been evaluated on the basis of 9 different response variables, as well as with an Overall Evaluation Criterion (OEC), all of them based on the Signal to Noise (S/N) ratio. An Analysis of Variance (ANOVA) has been performed for each variable and for the OEC; and this very last parameter has been used to find out the optimum state. Finally, the expected improvement in the optimum condition has been calculated, in terms of S/N ratio and from the economical point of view
EXPERIMENTAL ANALYSIS AND PRODUCT COMPARISON OF THREE DIFFERENT APPLE PUREE EXTRACTION TECHNIQUES
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Addressing Supply Chain’s Circularity Through Simulation: Textile Waste Separate Collection Models
No full textEvery year, the textile industry produces vast quantities of textile waste, leading to environmental deterioration. This is primarily due to its conventional supply chain approach, marked by excessive production of virgin fibres and inefficient waste management practices favouring landfill disposal or incineration. Hence, a fundamental requirement for widespread adoption of sustainable practices by all stakeholders in the textile supply chain, including consumers, is the development and validation of circular models. These models should incorporate innovative systems for collecting, sorting, reusing, and recycling textiles, along with resilient configurations for circular supply chains in the textile industry. Given these premises, this paper aims to assess the effect, measured in terms of environmental performance, achievable by adopting advanced waste management models in the textile supply chain. Specifically, two agent-based simulation models of a "standard" and "innovative" collection system of household textile waste are presented and compared. Benefits of the innovative model are finally provided, along with possible managerial insights
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