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More and more machines are increasing their flexibility so as to be able to produce different products with the same tooling. In this context, it is necessary to have fast and accurate methods to evaluate the system performance. This paper presents an approximate analytical method for the performance evaluation of production systems in which Z different types of products are produced. The proposed method is based on the decomposition of the complex system into a set of simpler building blocks, each one formed by two machines and Z homogeneous buffers. The set of building blocks models the whole behavior of the original system. The performance of each building block is evaluated by using the aggregation technique applied to two-machine lines in which the behavior of several products is modeled by an aggregate product, thus simplifying the complexity of the analysis. The numerical results reported in this paper prove the method provides accurate results. Keywords: Flow lines, multi-product, aggregation, decomposition, 1. Introduction A frequent solution to the problem of increasing shop floor productivity is to use flexible machines. These are machines that are equipped with general purpose tooling allowing different [...]

This paper presents an analytical method for evaluating the performance of production systems, jointly considering in a unique framework quality and production logistics performance measures. In the literature, quality and production logistics have traditionally been investigated using independent approaches. Thus far, only a few recent contributions have focused on their mutual inter-relation, showing that benefits can be achieved from an integrated analysis. This paper contributes to this growing research by considering, for the first time, production systems in which the behaviour of the machines is monitored by statistical control charts. The control action performed by the quality control system on the machines is directly modeled. Moreover, the impact of the quality control action on the logistic flow of parts in the system is taken into account. In order to estimate the performance of such systems, an approximate analytical method based on the system decomposition technique is developed. The accuracy of the method is assessed by comparing the results with those obtained by simulation. Analysis of the results provides new insights into the relations among the quality and production logistics performance measures and paves the way to the development of integrated design techniques for improved configurations of the system as a whole. [ABSTRACT FROM AUTHOR]

Considerable effort is usually devoted by companies to ensure the competitiveness of their manufacturing systems. This makes continuous improvement a central topic in production management activities. Less attention is given to the methods that drive improvement and to the way actions are defined and selected. In the literature, analytical models and simulation are the most widely used tools for manufacturing systems' performance evaluation and improvement. In practice, simple approaches, mainly based on experience, seems to be the best compromise to face this problem. In a collaboration project between Politecnico di Milano (Milano, Italy), Kungliga Tekniska hogskolan (Stockholm, Sweden) and Scania CV AB (Sodertalje, Sweden) within the European Network of Excellence VRL-KCiP we proposed a new methodology, based on analytical methods, to support the company in manufacturing system productivity improvement through re-configuration. The application of this approach to the Scania six-cylinder engine-block machining line enabled a remarkable increment in throughput by selecting analytically the most suitable improvement actions. [ABSTRACT FROM AUTHOR]

The automotive industry can be described as a backbone in many developed countries such as Japan, Korea, USA, and Germany, while being an enabler for economic prosperity in developing countries like China, Brazil, Eastern Europe, and Russia at the same time. However, the dynamics and uncertainty are increasing heavily by market changes, regulations, customer behavior, and new product technologies. Manufacturing research has to find answers to increase quality of products, flexibility of plants, and supply chain networks, to manage complexity in technologies and variants and overall to stay competitive even in high wage countries. In this paper, major technological challenges are discussed and the current state of manufacturing technology and research is presented. Moreover, for each technological and organizational area, future industrial, and research challenges are highlighted.

Despite the growing global interest in 3D printed carbon fiber reinforced polymers, most of the applications are still limited to high-performance sectors due to the low effectiveness-cost ratio of virgin carbon fibers. However, the use of recycled carbon fibers in 3D printing is almost unexplored, especially for thermoset-based composites. This paper aims to demonstrate the feasibility of recycled carbon fibers 3D printing via UV-assisted direct ink writing. Pyrolyzed recycled carbon fibers with a sizing treatment were firstly shredded to be used as a reinforcement of a thermally and photo-curable acrylic resin. UV-differential scanning calorimetry analyses were then performed to define the material crosslinking of the 3D printable ink. Because of the poor UV reactivity of the resin loaded with carbon fibers, a rheology modifier was added to guarantee shape retention after 3D printing. Thanks to a customized 3D printer based on a commercial apparatus, a batch of specimens was successfully 3D printed. According to the tensile tests and Scanning Electron Microscopy analysis, the material shows good mechanical properties and the absence of layer marks related to the 3D printing. These results will, therefore, pave the way for the use of 3D printed recycled carbon fiber reinforced polymers in new fields of application.

Nowadays, Lithium-ion batteries are widely used in advanced technological devices and Electric and Hybrid Vehicles, due to their high energy density for weight, reduced memory effect and significant number of supported charging/discharging cycles. As a consequence, the production and the use of Lithium-ion batteries will continuously increase in the near future, focusing the global attention on their End-of-Life management. Unfortunately, wasted Lithium-ion batteries treatments are still under development, far from the optimization of recycling processes and technologies, and currently recycling represents the only alternative for the social, economic and environmental sustainability of this market, able to minimize toxicity of End-of-Life products, to create a monetary gain and to lead to the independence from foreign resources or critical materials. This paper analyses the current alternatives for the recycling of Lithium-ion batteries, specifically focusing on available procedures for batteries securing and discharging, mechanical pre-treatments and materials recovery processes (i.e. pyro- and hydrometallurgical), and it highlights the pros and cons of treatments in terms of energy consumption, recovery efficiency and safety issues. Target metals (e.g. Cobalt, Nickel and Lithium) are listed and prioritized, and the economic advantage deriving by the material recovery is outlined. An in-depth literature review was conducted, analysing the existing industrial processes, to show the on-going technological solutions proposed by research projects and industrial developments, comparing best results and open issues and criticalities., Competing Interests: Declaration of competing interest The authors declare no competing interests. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)