Actuellement, les matériaux collectés à partir de produits en fin de vie sont recyclés en matière première pour être réutilisés dans un nouveau cycle de production. Cependant, la consommation énergétique des filières de recyclage reste importante. Le processus du recyclage fait aussi perdre la valeur ajoutée et l’énergie utilisée durant la fabrication de pièces originales. Aujourd’hui, les techniques de fabrication additive sont suffisamment performantes et permettent une fabrication de produits avec un matériau compatible avec l’usage. La prise en compte des performances de ces nouvelles techniques dans une stratégie soutenable peut ouvrir des pistes pour modifier les pièces et les réutiliser directement sans retourner au niveau de matière première. Cette thèse a pour objectif de développer une stratégie soutenable, qui permet de donner une nouvelle vie à une pièce en fin de vie (ou une pièce existante) en la transformant directement en une nouvelle pièce destinée à un autre produit. Afin de développer une telle stratégie, les travaux menés de la thèse visent à résoudre les verrous scientifiques suivants :Le premier verrou scientifique est lié à la faisabilité technologique : est-il possible de déposer de la matière sur une pièce existante en utilisant les techniques de fabrication additive pour obtenir la nouvelle pièce avec une bonne santé de matière ? Cette question a été résolue en réalisant une étude expérimentale sur l’observation de microstructures et de propriétés mécaniques des éprouvettes, qui sont fabriquées par ajout de nouvelles entités sur une pièce existante en EBM. Le deuxième verrou scientifique est lié à l’étude de la chaîne complète de fabrication d’un point de vue technologique. Comment concevoir des gammes de fabrication en combinant intelligemment des opérations additives et soustractives pour obtenir la pièce attendue à partir de la pièce existante ? Une méthode de conception des gammes de fabrication combinant les procédés additifs et soustractifs a été proposée en s’appuyant sur le concept d’entités de fabrication additive et soustractive. Le troisième verrou scientifique est lié à la soutenabilité et la stratégie présente-t-elle des avantages par rapport à la stratégie conventionnelle en termes de soutenabilité ? Une approche s’appuyant sur la méthode d’Analyse du Cycle de Vie (ACV) a aussi été développée pour évaluer des impacts environnementaux. Des critères permettant de qualifier le domaine de la stratégie proposée vis-à-vis de la stratégie conventionnelle ont été identifiés / Currently, materials collected from end-of-life (EoL) products are recycled into raw material for reusing in a new production cycle. However, energy consumptions of recycling sectors remain important. The added values and energy used in the manufacture of original parts are also lost during the material recycling process. Nowadays, additive manufacturing techniques are sufficiently efficient and allow the manufacture of products with a material compatible with the use. Taking into account the performances of these techniques in a sustainable strategy can open the ways to modify parts and reuse them directly without returning to the raw material level. This thesis aims to develop a sustainable strategy, which allows giving a new life to an EoL part (or an existing part) by transforming it directly into a new part intended for another product. In order to develop such a strategy, the works of the thesis aims to solve the following scientific issues : the first scientific issue is related to the technological feasibility : is it possible to deposit material on an existing part using additive manufacturing technologies to obtain the new part with good material health ? This question is solved by carrying out an experimental study on the observation of microstructures and mechanical properties of the samples, which are manufactured by adding new features into an existing part in EBM. The second scientific issue is related to the study of the complete manufacturing chain from a technological point of view. How to design the process planning for additive and subtractive manufacturing combination to manufacture the expected part from the existing part ? To solve this question, a methodology to design the process planning for combining these manufacturing processes has been proposed based on the concept of additive manufacturing and machining features.The third scientific issue is linked to the sustainability and does the new strategy have advantages in comparison to the conventional strategy in terms of sustainability ? An approach based on the Life Cycle Assessment (LCA) method has also been developed to assess environmental impacts. The criteria for qualifying the domain of the proposed strategy vis-a-vis the conventional strategy were also identified

Les produits avec des phases d'usage multiple sont de plus en plus pris en considération a du fait des pressionséconomiques et environnementales. Ces produits aux cycles de vie complexes, utilisent des process tels que leremanufacturing. Ces process doivent être modélisés et évaluée par des équipes de conception. Cette thèse montrecomment représenter, modéliser et évaluer des produits en cycle de vie à boucle fermées. L'étude montre commentétablir des évaluations environnementales pour ces produits et les comparer aux évaluations environnementales decycles de vie classiques.Les modèles ont été développés sur des travaux antérieurs, tels que la méthodologie de Gehin et al. basée sur leconcept du brique du cycle de vie produit. La première approche proposée sert pour évaluer les bénéficesenvironnementaux des opérations et des activités autour du cycle de vie de produit en boucle fermée(remanufacturing scénario de fin de vie et systèmes de produit-service comme stratégie de vente des services).L'introduction de systèmes produit-service vise à réduire les impacts environnementaux de produits parl'intensification de l'utilisation. Ainsi, la thèse propose un modèle pour évaluer les éléments de systèmes produitsserviceet leur cycle de vie du point de vue environnemental. La thèse se concentre sur l'élaboration d'un modèle quiintègre le cycle de vie d’un produit-service système et ses paramètres, en tenant en compte des éléments physiques,ainsi que de l'infrastructures, la conception des unités de services, les acteurs dans la logistique et leurs interactions.Les modèles permettent d’identifier et de distinguer les différentes phases du cycle de vie du produit et de réajuster ladécision des concepteurs dans le processus de conception du produit. De plus, le modèle cherche l'intégration desparamètres du process de remanufacturing et des systèmes produit-service dans l'ensemble du cycle de vie duproduit. Les modèles visent à aider la conception de produits et de processus, ainsi que les acteurs de la chaîneapprovisionnement et les personnes chargées de la prise de décision sur la conception du produit et deschangements dans le système.Les résultats peuvent être utilisés, afin d'évaluer la performance environnementale des différents scénarios de fin devie des produits, fournissant un outil pour les concepteurs qui permet de quantifier les avantages environnementauxliés à l'utilisation des produits en cycle de vie en boucle fermée. / Products with multiple use phases have to be considered regarding new economic and environmental pressures.Therefore, the related complex life cycles of (re)manufactured products have to be modeled and assessed by designteams for a better understanding of their performance. This thesis presents methodologies to represent, model andassess closed-loop product lifecycle (focused on remanufacturing strategies). The study shows how to establishenvironmental assessments for remanufactured products life cycles and how to compare them to environmentalassessments for classical life cycles.The present study shows how to establish the models and how to compare the environmental assessments ofremanufactured products life cycles vs. classical life cycle scenarios. The objective is to provide easy to use methodsand tools for designers to allow them quantifying the environmental benefits related to the use of a closed loopstrategy. In this project, a life cycle assessment, life cycle bricks, and a parametric model of the products are used toevaluate and compare the environmental benefits provided by the remanufacturing. The methodologies and modelshave been developed based on previous works, such as the the life cycle bricks concept developed by Gehin et al.[2007].On the other hand, the thesis proposes a model to assess the product-service systems elements and their respectivelife cycle from an environmental point of view. Here, the thesis focuses on the development of a model whichintegrates the product lifecycle within those parameters by a product-service system strategy, taking into accountphysical elements, as well as the infrastructures network, unit services design, supply chain actors and theirinteractions.Finally, a model has been developed to assess from an environmental point of view the data of the operations andactivities around product life cycle of the products with final non classic disposition scenarios (remanufacturing asend-of-life scenario and multiple uses by the disposition of the service offers system as a business strategy). Themethodologies and models proposed allow identifying and distinguishing impacts between the different product lifecycle stages and readjust the designers’ decision at the product design stage. The results can be further used insimulation, to evaluate the environmental performance of different product life cycle end-of-life scenarios.

Das praxisorientierte Forschungsprojekt widmet sich den Grenzen und Potenzialen der Wiederaufarbeitung von Bekleidung – einer Nischenlösung der Circular Economy. Im Mittelpunkt der Forschungsarbeit steht die Frage, wie die Wiederverwertung von Abfallmaterialien aus der Textilindustrie als Teilflächen mit Hilfe von digitalen Technologien nach-haltig und effektiv gestaltet werden kann. Zudem wird erforscht, welche damit verbundenen ästhetischen Potenziale für den Entwurf neuer Bekleidung entstehen.

Remanufacturing is an important product recovery option that benefits our sustainable development. Cores, i.e. the used products/parts, are essential resources for remanufacturing. Without cores, there will not be any remanufactured products. Challenges in the core acquisition process are mainly caused by the uncertainties of: return volume, timing and core quality. Core Acquisition Management actively attempts to reduce these uncertainties and achieve a better balance of demand and return for the remanufacturers. The aim of this dissertation is to extend the knowledge of Core Acquisition Management in remanufacturing, by investigating the current status of research and industrial practice, and developing quantitative models that assist the decision making in the core acquisition process. In the dissertation, a literature review is firstly conducted to provide an overview about the current research in Core Acquisition Management. Possible further research interests, for example, more studies based on non-hybrid remanufacturing systems and imperfect substitution assumption are suggested. Through an industrial survey carried out in a fast developing remanufacturing market - China, environmental responsibility and ethical  concerns, customer orientation and strategic advantage are identified as the most important motives for the remanufacturers, while customer recognition is their most serious barrier at present. Suggestions for further improving the Chinese remanufacturing industry from the policy-makers’ perspective are provided. After the above investigation, mathematical models are then developed to assist the acquisition decisions in two aspects: to deal with the uncertainties of return volume and timing, and to deal with the uncertainties of core quality. Acquisition decision about volume and timing is firstly studied from a product life cycle perspective, where the demands for remanufactured products and the core availability change over time. According to industrial observations, the remanufacturing cost decreases with respect to its core inventory. Using optimal control theory, core acquisition and remanufacturing decisions are derived to maximize the remanufacturer's profit. It is found that besides a simple bang-bang type control policy (either collecting as much as possible, or nothing), a special form of synchronizing policy (adjusting the core collection rate with demand rate) also exists. Furthermore, the acquisition decision depends greatly on the valuation of cores, and Real Option Valuation approaches are later used to capture the value of flexibility provided by owning cores when different aspects of remanufacturing environment are random. More specifically, the value of disposing a core earlier is investigated when the price of remanufactured product is uncertain, and the impact of the correlation between stochastic demand and return is also studied. To deal with the uncertainties of core quality, refund policies with different numbers of quality classes are studied. Under the assumption of uniformly distributed quality, analytical solutions for these refund policies are derived. Numerical examples indicate that the customers’ valuation of cores is an important factor influencing the return rates and the remanufacturer’s profit. Refund policies with a small number of quality classes could already bring major advantages. Credit refund policies (without deposits) are included for comparisons. In addition, within a game theory framework, the trade-off of two types of errors of the quality inspection in a deposit-refund policy is studied. The salvage values of different cores show great influences on the remanufacturer’s policy choices. The value of information transparency about the inspection errors are studied under different conditions. Interestingly, the customer may actually return more low quality cores when the inspection accuracy is improved.

This research focuses on improving the remanufacturing process efficiency by estimating the workstation utilization through identifying percentage of %Blocking and %Waiting on individual workstations within a remanufacturing flow line. It attempts to achieve this aim such that improved use of methods to overcome the effect of variability can be employed. Extensive literature review revealed the requirement of strategies to recover End of Life products due to the introduction and implementation of legislative directives demanding manufacturers to recover the End of Life resources. Upon analyzing the range of product recovery strategies, End of Life product remanufacturing has emerged as an appropriate and suitable strategy to be used since it extends the operational life of existing products without the need for the new resources required when making products. Remanufacturing is a process in which a product is disassembled to component level. Each of the components will be thoroughly examined for defects. Upon identifying defects, they will either be repaired or components will be replaced. This process in turn increases the product life span. However, remanufacturing is not widely used process applied into various industry sectors due to the fact that it is labour intensive and expensive process compared to new products. Although remanufacturing process is in infancy where small number of industry such as Automotive and Aerospace are deriving benefit from it by making effective use of remanufacturing. Ideally, the suitable manufacturing methods i.e. flow processing system, should be used to remanufacture products. However when flow processing is deployed, it is found that there are a number of factors affecting the process that if not tackled, will result in poor performance and poor efficiency of the overall remanufacturing system. This inefficiency is primarily due to the number of sources of variation found in terms of supply, product design, parts specification, operation and demand variability. Further investigation led to the characterizing the remanufacturing variability and identified ways the effect of this variability can be removed or reduced using Lean principles e.g. Single Minute Exchange of Dies and use of an appropriate manufacturing system. Based on the information revised in literature and experimental design, novel equations were developed along with a set of rules that accurately measures the workstation utilization in terms of %Blocking and %Waiting on individual workstation.

published_or_final_version / Mathematics / Master / Master of Philosophy

Syfte – Syftet med detta examensarbete är att bidra med kunskap om hur kvalitetsstyrning av inkommande returflöde kan generera en effektivare återtillverkningsprocess. För att uppfylla syftet har följande två frågeställningar formulerats: Vilka faktorer i returflödet påverkar effektiviteten i en återtillverkningsprocess? Hur kan dessa faktorer kontrolleras för att erhålla en effektivare återtillverkningsprocess? Metod – För att uppnå examensarbetets syfte har en fallstudie genomförts hos återtillverkningsföretaget Recyctec AB i Jönköping. Empirisk data har samlats in med hjälp av intervjuer, observationer och benchmarking. Utöver fallstudien har en litteraturstudie genomförts där ett teoretiskt ramverk skapats. Det teoretiska ramverket har sedan analyserats tillsammans med empirin för att slutligen generera examensarbetets resultat. Resultat – De osäkerhetsfaktorer som författarna identifierat är: drivkrafter för ett återtillverkningsnätverk, osäkerheter i returnerade produkter och kvalitetsbedömning av returnerade produkter. Genom att arbeta med åtgärder för returproduktanskaffning och kvalitetsstyrning för dessa tre osäkerhetsfaktorer kan en effektivare återställningsprocess erhållas. Genom att kombinera olika drivkrafter kan samarbetsviljan i återställningsnätverket ökas. Vidare kan osäkerheten i returnerade produkter minskas genom att dela in kvalitet i olika tydligt definierade och standardiserade kvalitetsklasser. Implikationer – I detta examensarbete föreslås återtillverkande företag skifta fokus från kvalitetskontroller till kvalitetssäkring och lägga resurser där problemen uppstår. Vidare föreslås även en kombination av olika drivkrafter för returproduktanskaffning för att därigenom skapa incitament för returer av bättre kvalitet. Begränsningar – Befintlig teori har fått tolkas och anpassas av författarna för examensarbetet då specifik teori för aktuell analysenhet inte funnits att tillgå. Problemställningarna i återtillverkningsbranschen har visat sig vara branschspecifika och därmed olika. Examensarbetets generaliserbarhet hade därmed kunnat stärkas av ytterligare fallstudier. / Purpose – The purpose of this thesis work is to contribute with knowledge about how quality management can generate a more efficient remanufacturing process. In order to fulfill this purpose the following two questions were formulated: 1.     Which factors in the return flow affects the efficiency of a remanufacturing process? How can these factors be controlled to obtain a more efficient remanufacturing process? Method – In order to achieve the purpose of this thesis, a case study has been conducted at Recyctec AB in Jönköping. Empirical data has been collected through interviews, observations and benchmarking. In addition to the case study a literature study has been carried out in order to create a theoretical framework. The theoretical framework has been analyzed together with the empirical data in order to generate the result of the thesis. Findings – The uncertainties identified by the authors are: driving forces for the remanufacturing network, uncertainties in returned products and quality assessment of returned products. By working with measures on return product acquisition and quality management for these three uncertainties, a more efficient remanufacturing process can be achieved. By combining different driving forces a higher level of cooperation in the remanufacturing network can be achieved. Furthermore, dividing quality into different clearly defined and standardized quality classes can reduce the uncertainties in returned products. Implications – This thesis proposes remanufacturing companies to shift focus from quality control to quality assurance and to address resources where the problems arise. Furthermore, the authors suggest remanufacturing companies to combine different driving forces for product return in order to create incentives to return products with higher quality. Limitations – Existing theory has been interpreted and adapted by the authors to the thesis, as specific theory for the current unit of analysis has not been available. The problems in the remanufacturing industry have proven to be industry specific and thus different. The thesis generalizability could therefore been strengthened by further case studies.

This project investigates how remanufacturing of robotic lawn mowers can be incorporated into an existent forward supply chain. The project is conducted as a single case study on Husqvarna where an interview study and a literature study provide the empirical data and theory, respectively. Alternatives are proposed for potential remanufacturing cases at various locations, where different parties ranging from original equipment manufacturers to independent manufacturers perform the remanufacturing process. SWOT analyses are conducted to identify the most promising alternatives for a further economic analysis. The economic evaluation is based on net present values and a sensitivity analysis which together determines the feasibility of the alternatives. The results of the project answer three research questions. The first concludes that out of seven defined production systems there are only two that are not suitable for remanufacturing in a general case mainly due to the low flexibility of these systems. The results of the second identifies labor, logistics, and operational prerequisite factors that must be considered when implementing remanufacturing for case specific alternatives. The conclusion of the third research question lists the feasibility of the alternatives from which the recommendations for Husqvarna are presented. This project recommends Husqvarna to implement a remanufacturing process for their robotic lawn mowers either by enlisting their current dealers or by themselves at a location nearby the spare parts warehouse in Torsvik. Which alternative is the most profitable depends mainly on the expected quantity of the acquired cores, i.e. Husqvarna as a centralized remanufacturer benefits more from higher quantities while the decentralized dealer alternative would comparably be more profitable if the quantities were lower. As it is perceived that initial collected quantities will be low, and possibly even somewhat higher for the dealers, a decentralized remanufacturing process could be the most profitable alternative to start with. Using a third-party remanufacturer is also feasible but considered risky and therefore not recommended as they could have the same core acquisition problem as Husqvarna while having lower profitability.

Majority of the products get discarded at end-of-life (EoL), causing environmental pollution, and resulting in a complete loss of all materials and embodied energy. Adopting a closed-loop material flow approach can aid preventing such losses and enable EoL value recovery from these products. Design and engineering decisions made and how products are used impact the capability to implement EOL strategies such as disassembly and remanufacturing. Some underlying factors affecting the capability to implement these EOL strategies have been discussed in previous studies. However, relevant metrics and attributes are not well defined and comprehensive methods to quantitatively evaluate them are lacking. This study will first identify key lifecycle oriented metrics affecting disassemblability and remanufacturability. Then a methodology is proposed for the quantitative evaluation of these strategies considering the quality of returns, product-design characteristics and process technology requirements. Finally, an industrial case-study is presented to demonstrate the application of the proposed method.

Adapting a circular system through business model experimentation can generate profit and sustainable growth for fashion firms. Business model experimentation explores novel opportunities to be at the forefront of transforming existing markets. Remanufacturing is one circular strategy that entails the process of recovering both raw material and value from end-of-life products for the production of new items. Remanufacturing in the context of business model experimentation is a promising solution in the fashion and textile industry to drive the transition into a circular economy. Through case study research the phenomenon of remanufacturing business model experimentation within the fashion and textile industry is investigated. The case phenomenon is investigated by means of the Re:workwear project, in which the brand Cheap Monday uses discarded workwear for a remanufactured collection next to its common collection. The focus of the study is on remanufacturing business model experimentation alongside the brand’s business-as-usual and decisive factors of this phenomenon. The processes and -steps within experimentation were analysed through semi-structured interviews with various involved parties of the supply chain. A framework combining the Business Model Canvas and the stepwise approach of business model experimentation by Bocken et al. (2017) is developed and applied throughout the research. It is found that (1) motivation and scope, (2) input material, (3) flexibility, (4) stakeholder collaboration and (5) system development are decisive factors for remanufacturing business model experimentation. Further research is necessary to investigate the phenomenon in other settings and within a variety of other firms in the industry in order to test the findings and validate the generalisability.