This work analyses how ergonomics and assembly system design techniques are intimately related. It also develops a new theoretical framework to assess a concurrent engineering approach to assembly ...systems design problems, in conjunction with an ergonomics optimization of the workplace. Its purpose is to provide professionals with a new and detailed approach to assembly system design procedures that includes ergonomics issues.
The methodological framework offered takes into account technological variables (related to work times and methods), environmental variables (i.e. absenteeism, staff turnover, work force motivation) and ergonomics evaluations (i.e. human diversity) to create a comprehensive analysis.
At conclusion of the study, the work reports data and insights from two real industrial cases, where an advanced simulation software is used, to validate the procedure and support methodology applicability.
This work provides an extremely valuable methodological framework to companies who recognize the link between assembly and ergonomics. The methodology underlines the necessity to analyze and classify the assembly system layout configuration in relation to both technological and environmental parameters- as reported in the framework.
•We provide a novel DSS based on decision trees to support PdM implementation.•The approach is based on context-aware information and on maintenance costs.•We outline the profitability domain of CM ...and PdM based on ML.•We provide a very intuitive and easy methodology based on ML.•We include a real industrial case to illustrate the robustness of the method.
Nowadays, the industrial environment is characterised by growing competitiveness, short response times, cost reduction and reliability of production to meet customer needs. Thus, the new industrial paradigm of Industry 4.0 has gained interest worldwide, leading many manufacturers to a significant digital transformation. Digital technologies have enabled a novel approach to decision-making processes based on data-driven strategies, where knowledge extraction relies on the analysis of a large amount of data from sensor-equipped factories. In this context, Predictive Maintenance (PdM) based on Machine Learning (ML) is one of the most prominent data-driven analytical approaches for monitoring industrial systems aiming to maximise reliability and efficiency. In fact, PdM aims not only to reduce equipment failure rates but also to minimise operating costs by maximising equipment life. When considering industrial applications, industries deal with different issues and constraints relating to process digitalisation. The main purpose of this study is to develop a new decision support system based on decision trees (DTs) that guides the decision-making process of PdM implementation, considering context-aware information, quality and maturity of collected data, severity, occurrence and detectability of potential failures (identified through FMECA analysis) and direct and indirect maintenance costs. The decision trees allow the study of different scenarios to identify the conditions under which a PdM policy, based on the ML algorithm, is economically profitable compared to corrective maintenance, considered to be the current scenario. The results show that the proposed methodology is a simple and easy way to implement tool to support the decision process by assessing the different levels of occurrence and severity of failures. For each level, savings and the potential costs have been evaluated at leaf nodes of the trees aimed at defining the most suitable maintenance strategy implementation. Finally, the proposed DTs are applied to a real industrial case to illustrate their applicability and robustness.
•Environmental sustainability through the reprocessing of end-of-life products.•Traditional perspective and social responsibility perspective analysis.•Critical aspects for sustainability in supply ...chain design are analysis.•Transportation efficiency maximization through closed loop transportation system.
Every item produced, transported, used and discarded within a Supply Chain (SC) generates costs and creates an impact on the environment. The increase of forward flows as effects of market globalization and reverse flows due to legislation, warranty, recycling and disposal activities affect the ability of a modern SC to be economically and environmentally sustainable. In this context, the study considers an innovative sustainable closed loop SC problem. It first introduces a linear programming model that aims to minimize the total SC costs. Environmental sustainability is guaranteed by the complete reprocessing of an end-of-life product, the re-use of components, the disposal of unusable parts sent directly from the manufacturers, with a closed loop transportation system that maximizes transportation efficiency. Secondly, the authors consider the problem by means of a parametrical study, by analyzing the economical sustainability of the proposed CLSC model versus the classical Forward Supply Chain model (FWSC) from two perspectives: Case 1, the ‘traditional company perspective’, where the SC ends at the customers, and the disposal costs are not included in the SC, and Case 2, the ‘social responsibility company perspective’, where the disposal costs are considered within the SC. The relative impact of the different variables in the SC structure and the applicability of the proposed model, in terms of total costs, SC structure and social responsibility, are investigated thoroughly and the results are reported at the conclusion of the paper.
All manufacturing companies define their business strategies and competitive priorities based on several factors related to their production systems, like flexibility, productivity and quality. As a ...consequence, maintenance plays a crucial role in guaranteeing availability and reliability of production facilities; hence, designing proper maintenance policies allows companies reach their goals.
In the last decade, while some scientific contributions have developed qualitative frameworks to help choosing optimal maintenance policy, others have introduced different quantitative cost models related to each maintenance policy.
The purpose of this paper is to introduce a new quantitative framework to develop optimal maintenance policies, using several cost models, based on simple but relevant costs, like spare parts, labor, missing production costs and other indirect costs. A very simple, user-friendly abacus has been developed to guide the researchers and professionals to choose the optimal maintenance policies for their needs. The application on a real case study demonstrates the validity of the presented framework, and opens the field to several considerations about the possibility of new models and future research.
► Maintenance policy design process is investigated in order to influence in positive way on competitiveness. ► A quantitative framework is developed, introducing new economical formulations for maintenance policy evaluation. ► Several easy to use graphical tools are defined to help researchers and practitioners to design the correct maintenance policy. ► The application on a real case study demonstrates the validity of the framework and its graphical tools.
An intense positron sources is a demanding element in the design of future lepton colliders. A crystal-based hybrid positron source could be an alternative to a more conventional scheme based on the ...electron conversion into positron in a thick amorphous target. The conceptual idea of the hybrid source is to have two separate objects, a photon radiator and a photon-to-positron converter target. In such a scheme an electron beam crosses a thin axially oriented crystal with the emission of a channeling radiation, characterized by a considerably larger amount of photons if compared to Bremsstrahlung. The net result is an increase in the number of produced positrons at the converter target. In this paper we present the results of a beam test conducted at the DESY TB 21 with 5.6 GeV electron beam and a crystalline tungsten radiator. Experimental data clearly highlight an increased production of photons and they are critically compared with the outcomes of novel method to simulate the number of radiated photons, showing a very good agreement. Strong of this, the developed simulation tool has been exploited to design a simple scheme for a positron source based on oriented crystal, demonstrating the advantages in terms of reduction of both deposited energy and the peak energy deposition density if compared to conventional sources. The presented work opens the way for a realistic and detailed design of a hybrid crystal-based positron source for future lepton colliders.
The increasing rate of hospital admissions has resulted in a commensurate increase in the number of treatments and surgeries performed, as well as resource and material usage, and requires planners ...to improve hospitals' internal logistics. Logistics modelling of internal goods and corresponding material handling systems and simulating future scenarios can provide planners with necessary decision support. Introducing an agent-based simulation model using historical data generated by an automated guided vehicle (AGV) in a case hospital facilitates analysing the goods delivery system's current status and potential countermeasures to improve internal logistics. In comparison with other industries, such as manufacturing, AGVs utilised in hospitals have to interact with persons, patients and elevators, transport several different types of goods and cover a sizeable multi-floor area. By including these factors, the simulation model represents an appropriate method to test different scenarios and improve delivery performance and AGV utilisation. The study highlights the constraints related to operating AGVs in dynamic environments, such as those encountered in hospitals.
Purpose
– The paper aims to focus on in-house part logistics design and management for assembly systems in which supermarket storage is adopted and coupled with an automated transportation system. In ...this context, this work aims to assess the transportation mode selection problem to speed up the preliminary design phase.
Design/methodology/approach
– The paper is divided into two main parts. The first one provides and discusses a new conceptual framework derived from the authors’ experience in the field and from previous published works. The framework aims to support managers in problem comprehension by setting three problem sub-phases, key input parameters and qualitative guidelines without losing sight of the big picture. The second part focuses on the transportation mode selection sub-phase by assessing an analytical study followed by a multi-scenario analysis.
Findings
– The final outcome of this work is a decision support matrix capable of setting technical guidelines that are helpful to managers and practitioners to speed up the transportation mode selection problem in the preliminary phases.
Originality/value
– This work is beneficial for supporting managers in understanding the main decisional steps involved in the design of a part-feeding system with a supermarket by discussing the three problem sub-phases and key input parameters and providing both qualitative and quantitative guidelines. Moreover, this study explores the transportation mode selection problem, which is not yet largely explored in the published literature.
PDF
