A growing uncertainty in the global economy is forcing many manufacturers to reassess their corporate outlook towards the environment. Today there is a growing attention to sustainability in industry accompanied by a paradigm shift towards realizing a sustainable society. It is now very common to hear about Green Production and Green Systems, but few literature exist that deal with the relatively newer subject of Green Maintenance. The term green production is often used to describe production with a sustainable perspective. Also, lean production has been proposed as a means of achieving sustainability. Lean and Green production systems require efficient production and low use of resources such as energy, materials, etc. One major facilitator of this is effective maintenance. Sometimes regarded as the necessary evil, maintenance still has a negative image in the industry. But as the paradigm on manufacturing shift towards realizing a sustainable society, we should also begin to realize the changing role of maintenance. Still, the impact of maintenance on sustainability and Green production is not very well described in research.   This Master Thesis within the School of Innovation Design and Engineering at Mälardalen University presents a literature review on green maintenance by trying to identify and assess the key factors of maintenance effects on green production, life cycle assessment and sustainability of maintenance activities. In addition, a brief introduction to the greening of remanufacturing activity, part of a green process by itself, is provided. The research is based upon extensive literature study, questionnaire survey and interviews with relevant industry as well as academic personnel. A discussion of the results of the interview followed by a conclusion on the key factors of maintenance on sustainability is provided. Future research areas have also been suggested.       Keywords: Green maintenance, Production maintenance, Sustainable maintenance,     Total Productive Maintenance

This thesis reviews and analyses the potential impact of maintenance on the fulfilment of Green Production Systems. Overall aim is to highlight how maintenance may contribute to decreasing the environmental impact of production. The thesis is based on the combination of literature studies and set of qualitative interviews conducted in selected companies. Three Swedish manufacturers were interviewed about their way of working, as well as their views on sustainability within operation management including maintenance. The results of the research explains why some organisations fail to recognize maintenance’s role to achieve sustainability, and how maintenance has been characterized in these organisations, namely by: short term pressures, reactive approach, neglecting hidden costs, lack of teamworking between production and maintenance departments, and low focus (hierarchical low status) on maintenance importance, resulting in lack of skilled labor available in organizations. In contrast, practices and strategies to succeed found to be based on the following: long term thinking, structured way of working, a proactive approach to maintenance, aiming to integrate core values into operational work, and establishing an environment which fosters continuous improvement and employee development. Same study identifies areas and "effects of poor maintenance" to be dealt with in the journey toward sustainable production, these are: economic, quality, processes wastes, emissions, resource consumption, safety and work environment related. It is therefore suggested that organizations may choose a proactive approach to maintenance that is best suited to their needs, which allows efficient production and long-term profitability, while considering safety and environmental aspects. Various concepts are available, but the organisation has to optimise on the combination of various practices. Following to the findings, a proposal is made that proactive culture should be integrated into daily work in a practical way such as Safety-Quality-Environment becomes everyone's responsibility. Sustainable perspective and sticking to best course of proactive measures are prioritized against short term pressures. To support this proposal a toolkit is developed that can be used at team/level continuous improvement programs, based on the PDCA model. Finally, the thesis emphasizes what benefits the optimum maintenance can provide on the fulfilment of competitive and resource-efficient production systems.

Rapporten baseras på en litteratur- och intervjustudie kring underhållsstrategier och komponentutbyten i kärnkraftverk, med fokus på komponenter som tenderar till att påverkas av åldring i en högre grad. Exemplifiering sker genom en kompletterande fallstudie kring kabel- och rörgenomföringar av typen Brattbergare som har packbitar bestående av ett polymert material. Erhållet resultat av litteratur- och intervjustudien belyser vilka säkerhetsföreskrifter som råder för all kärnteknisk verksamhet i Sverige. Utöver det erhålls information om hur åldring påverkar ett materials egenskaper över tid och att detta ligger till grund för fastställandet av ett system eller en komponents kvalificerade livslängd. I takt med att majoriteten av världens kärnkraftverk närmar sig sin ursprungligt tilltänkta livslängd och planeras underhållas för fortsatt långtidsdrift finns det ett ökat intresse för effektiva underhållsstrategier. Åldershanteringen har en avgörande roll för anläggningens lönsamhet och driftsäkerhet. Fallstudien föreslår två olika underhållsstrategier som stöds av resultatet av litteratur- och intervjustudien. Deras ekologiska påverkan och ekonomiska omfattning beaktas för att utse den metod som har störst potential att öka resurseffektiviteten och minska kostnaderna för underhållsåtgärder. Vald metod går ut på att praktiska tillståndsmätningar tillämpas för att undersöka hårdheten av packbitar till Brattbergare. Hårdhetsmätningarna syftar till att ge indikationer på i vilken grad packbitarna harpåverkats av degraderande åldringsmekanismer under olika förutsättningar. Resultatet av fallstudien överensstämmer med de resultat som noterades i litteratur- och intervjustudien. Packbitarna hårdnar när de åldras. Två miljöbetingelser som tenderar till att påskynda åldringsprocessen är förhöjda temperaturer och stråldoser. Vald metod för fallstudien är praktiskt realiserbar trots vissa begränsningar i befintliga kärnkraftsanläggningar vid Forsmark. Presenterad strategi bör kunna bistå med en ekologisk och ekonomisk optimering av underhållsarbetet för kabel- och rörgenomföringar. / This report is based on a literature study and interviews regarding maintenance strategies and component replacements in nuclear power plants. Focuses of the study are on components which tend to more commonly be affected by degrading aging mechanisms. Exemplification is done with a complementary case study about cable- and pipe transits with packing pieces made of polymeric materials. A frequently used application for cable- and pipe transits in Swedish NPPs is manufactured by MCT Brattberg AB.  Result obtained from interviews with relevant personnel’s and the literature study providing knowledge about prevailing safety regulations at Swedish nuclear facilities. Moreover, information is gained about how aging affects the features of materials over time and that it is the basis for determining the qualified lifetime of systems and components. Further on this could be of specific interest considering that the majority of the worlds NPPs are close to its intended lifetime and soon entering a phase of LTO. A proper aging management is an important factor when it comes to a safe and reliable operation of an NPP.  The case study compares two different maintenance strategies which are supported by the obtained result from interviews and the literature study. Considering ecological and economic impacts of the strategies, the one with the greatest potential to reduce negative influences are exemplified. Chosen method included practical hardness measurement with a portable durometer at packing pieces for cable- and pipe transits. Measured hardness of the packing pieces indicates at what degree which they have been affected by degrading aging mechanisms given different circumstances.   The obtained result from the two different parts of the report is corresponding to each other. Packing pieces consisting polymers hardens as they age. Elevated temperatures and higher dose rates accelerates the aging process. Represented method of the case study is practically viable at existing NPPs at Forsmark. Presented strategy should be able to assist with an ecological and economic optimization maintenance work for cable- and pipe transits.

Cyber-Physical System (CPS) or Digital-Twin approach are becoming popular in industry 4.0 revolution. CPS not only allow to view the online status of equipment, but also allow to predict the health of tool. Based on the real time sensor data, it aims to detect anomalies in the industrial operation and prefigure future failure, which lead it towards smart maintenance. CPS can contribute to sustainable environment as well as sustainable production, due to its real-time analysis on production. In this thesis, we analyzed the behavior of a tool of Ringvalsverk 4, at Ovako with its twin model (known as Digital-Twin) over a series of data. Initially, the data contained unwanted signals which is then cleaned in the data processing phase, and only before production signal is used to identify the tool’s model. Matlab’s system identification toolbox is used for identifying the system model, the identified model is also validated and analyzed in term of stability, which is then used in CPS. The Digital-Twin model is then used and its output being analyzed together with tool’s output to detect when its start deviate from normal behavior.

The recharge is the focus of data analysis of the different situations with the integration of the system and development of the two-stage 2/2 proportional cartridge valve for the steel industry machine. Using the statistical analysis technique to visualize the valve signal data behavior identify the accuracy of the machine data and apply the statistical feature extracting model using classification and clustering algorithms of real-time data analysis for the manufacturing. The fundamental principles of data analysis with a particular emphasis on its key function in the collection, cleansing, and analysis of substantial amounts of data to develop significant insights. Moreover, we explore the importance of data visualization in effectively presenting intricate research outcomes. We get the data accuracy of 76 percent for train and test set data in the statistical analysis feature indicating the best accuracy in the early stage. Our model gives high accuracy of the recommendation data automation system of the steel industry. Analysis of the valve data in multiple ways for the predictive maintenance of conditional monitoring of the tubes mail production machine. PdM is used for data processing of predictive manufacturing, behavior patterns of machines data, and correlation of statistical model for decision making for the maintenance activity avoiding downtime.  The data consists of different channels in the steel industry machine. Some automation process is used for the feature combination of the analysis of valve data in industry between each feature and signals. Using a dataset comprised of sensor data, operation logs, and maintenance records industrial control data of machines and use of this predictive model has the potential to yield significant cost savings for the steel industry through the prevention of unplanned maintenance, while also enhancing operational safety manufacturing of machine in the industry.