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High quality information is essential for the efficient decision making. Road condition is, together with traffic frequency, commonly used as input for classifying road status. Road condition is al ...

The research work done for improvement in carbon weighing compliance of mixing system of banburry machine is presented in this paper. As the carbon is one of the essential raw agents used in process of tire manufacturing. The carbon handling and transporting system used in banburry machine mixing process is one of the critical processes. Carbon weighing compliance is also known as efficiency of carbon usage. Plant optimization pillars are used for process improvements, new product developments, reducing breakdowns and improving product quality. This research work is mainly focused on the application of DMAIC phases (Define, Measure, Analyze, Improve, Control) along with terotechnology to improve the value of carbon weighing compliance of mixing system by reducing the carbon breakdowns which occur repetitively. The top five carbon breakdowns were identified by analyzing the data of carbon breakdowns of year 2017 thoroughly. Application of DMAIC phases helped in creating new inspection checklists for the effective preventive maintenance of the carbon handling and transporting system of banburry machine. The average value of carbon weighing compliance is increased by 7.5542% (from 89.35 to 96.91%) and the reduction in average downtime is 16.92% (from 490.33 to 407.33 min).

Hard competition forces companies to reduce uncertainty in production planning through, e.g. reducing the probability of failures. In this paper, more accurate data analysis through reducing random ...

Key performance indicators (KPI) are necessary for regulating maintenance performance, setting goals as well as for follow up and improvement. Several standards and models for measuring maintenance performance exist today, but these are mainly developed for in-house maintenance. For outsourced maintenance, which is regulated in a service contract, other kinds of KPIs are needed. The procurement of maintenance and contract forms is also changing; an alternative to the traditional maintenance contract based on fixed price and predetermined activities are the performance-based contracts. Cooperation contracts based on mutual trust and fairness for all parties are also available. New KPI models for regulating maintenance service contracts are therefore needed. In this paper, a KPI framework for maintenance contracts based on the concept of modular maintenance offerings is proposed. Modular maintenance offerings is a way to classify maintenance services offerings with increasing integration of the offering, and increasing focus on utility for the customer and the business ecosystem. The KPI framework proposes indicators for regulating contracts on three levels (resource, performance and utility level) and includes six categories of indicators: economic, technical, organisational, quality, safety and health, and relationship between actors.

Traditionally, procurement of maintenance has been based on fixed price on defined work. These types of contract forms can lead to negotiations on everything not included in the price, which may result in delays and a sense of distrust when all parties primarily look after themselves. Recently, forms for cooperation based on mutual trust and fairness for all parties have been developed; partnering. Partnering is characterized by common objectives and project organization, and risk analysis. The project is created and operated in cooperation with customers, contractors, suppliers and consultants. Transparency is a cornerstone of partnering and openness is what mainly differentiates partnering from traditional contractor projects. The Swedish railway uses traditional and very detailed contracting principles. This leads to several problems, such as lack of information and knowledge transfer between parties and life cycle phases, and no incentives for quality and productivity improvements. Is applying the concept of partnering for railway maintenance a solution to these problems? If so, why is the concept not already commonly applied and what are the barriers? This paper introduces the concept of partnering and reviews current research within the area. Thereafter, the possibilities in using partnering-based maintenance in Swedish railway are discussed.

Predmet je završnog rada životni ciklus broda s pogleda terotehnologije. Cilj je završnog rada analizirati životni ciklus broda, odnosno tri faze u životnom ciklusu broda kao poslovnog sustava s pogleda terotehnologije. Terotehnologija je multidisciplinarni pristup koji uključuje korištenje svih potrebnih tehnika kojima se osigurava da korisnik broda smanji ukupne troškove tijekom cijelog životnog vijeka broda te da poveća prihode koji nastaju eksploatacijom broda. Životni ciklus broda prema terotehnološkom pristupu može se analizirati kroz tri temeljne faze, a to su nabava, komisija te odlaganje. Nabava obuhvaća razvoj, dizajniranje i proizvodnju sustava, komisija se odnosi na rad sustava, odnosno na eksploataciju broda, a odlaganje na dekomisiju sustava, odnosno otpis broda. U sve tri faze životnog ciklusa broda javljaju se planirani i neplanirani troškovi koji bi se trebali uzeti u obzir od samog početka investicije brodara, odnosno od trenutka kada se pojavi potreba za nabavom novog ili rabljenog broda te kontrolirati tijekom cijelog životnog vijeka broda. The subject of this paper is the life cycle of the ship from a view of terotechnology. The aim of this paper is to analyze the life cycle of the ship, that is, the three phases in the life cycle of the ship as a business system from a view of terotechnology. Terotechnology is a multidisciplinary approach which involves the use of all the necessary techniques to ensure that a ship user reduces total cost over the lifetime of a ship and increases the revenue generated by ship exploitation. The life cycle of the ship according to the teretehnological approach can be analyzed through three basic phases: procurement (system development, design and production), commission (system operation) and disposal (system decommission). The procurement involves the development, design and production of the system, the commission refers to the system operation, ie to the exploitation of the ship, and the disposal to the system decommission, ie the ship's write-off. Planned and unplanned costs occur in all three phases of the life cycle of the ship, which should be taken into account from the very beginning of the ship's investment, ie from the moment when the need for the purchase of a new or used ship occur and should be controlled throughout the lifetime of the ship.

Maintenance has been treated as a cost-center although it has obvious direct impact on company production, delivery on time, product quality and consequently company business. In this paper we develop and test a new system (EcoCon) for monitoring and assessing the economic impact of maintenance on a production process. EcoCon is tested using real industrial data collected over 3 years. The main findings are that by using EcoCon it is possible to assess maintenance economic impact on a production process. Also, EcoCon provides data for analyzing causes behind deviations in maintenance and production performance. It can be applied on companies of similar production process/machine. But, in some cases, the system demands marginal accommodation to suit the differences in the maintenance economic related factors among companies. EcoCon provides production and maintenance mangers reliable overview of maintenance importance through monitoring maintenance economic impact by linking technical production performance, e.g. downtime, to economic savings/losses generated due to maintenance performance and other activities.

In today’s market, companies strive to achieve the competitive advantages. Failing in achieving these goals could threaten the companies’ existence. Failures in the operative level impact negatively on achieving these goals. In order to record these failures for better actions planning, special systems are often used for counting the number of failures, the duration of machines downtime and uptime for assessing the total downtime and classifying problems/failures in categories that are decided in advance. In this study, we develop a model to break down the contents of a company failure databases, prioritize failures, assess economic losses due to failure impact on the competitive advantages and suggest a method of how maintenance actions should be rank-ordered cost-effectively. The model is tested using real data. The major results showed that losses are mainly due to two categories i.e. “Bad quality” and “Less profit margin”, where failures of “Gear”, “Bearing” and “Raw materials quality” cause most of the losses. It is concluded that this model will enable the user to quickly identify and prioritize maintenance and improvement efforts cost-effectively.

Measuring maintenance performance is important for companiesto monitor whether their planned objectives are achieved or not. It isessential to have a good overview about the performance of maintena ...

Purpose: The purpose of this paper is to apply an analytic hierarchy process (AHP) for the evaluation/selection of maintenance policy. Methodology/Approach: The paper adopts a case study approach of selecting most appropriate maintenance policy in the case of Slovenian paper mill company. Several steps of the AHP method are used in order to structure the decision-making process. Five possible alternatives are considered: failure based maintenance, preventive maintenance, total productive maintenance, reliability centered maintenance and total quality maintenance. Findings: This paper proposes a framework for maintenance policy selection based on the AHP methodology. The framework was applied to select the most appropriate maintenance policy in a paper mill company. The results suggest that total quality maintenance is the most suitable concept for a paper machine. By performing a sensitivity analysis, it was revealed that the final outcome remained stable in all cases when the weights of the main criteria were increased for 25 percent. Originality/value: The paper contributes to the literature by providing a framework for decision-making process regarding the maintenance policy selection. In addition, this paper utilizes an exponentially weighted moving average (EWMA) chart for performing a consistency test. Moreover, a sensitivity analysis also presents an important implication of this study.

PurposeThe aim with this paper is to describe current IT practices within maintenance in Swedish industry, and to outline the future possible developments.Design/methodology/approachThe study is performed as a web‐based questionnaire survey consisting of 71 participants. A systems perspective is applied for capturing the most relevant aspects of IT utilisation.FindingsThe IT practices are characterised by high use of business‐specific IT solutions, low use of company‐wide IT solutions, low IT intensity and the client‐server architecture is dominating. The purchase decision and ownership of IT is to high extent tied to the maintenance function. Moreover, IT systems are apprehended as beneficial and connected to real needs. The findings imply a decentralised IT governance form and a mainly vertical (functional) IT support.Research limitations/implicationsThe socio‐technical approach suggested in this paper helps us to identify which areas to study, and also shows the tight interrelationship between different factors, layers and systems.Practical implicationsThe study results could be used for benchmarking purposes or to highlight state‐of‐the‐art of IT utilisation in maintenance, and thereby set the topic on the corporate agenda.Originality/valueStudies describing IT utilisation within maintenance in the form of case studies and surveys exist, but they mainly focus on one aspect. This study approached the problem from a socio‐technical perspective, covering several aspects connected to IT utilisation.

PurposeTo develop and test a model and software‐based support system for better understanding of the interactions between man‐machine‐maintenance‐economy (MMME), and enable cost‐effective decisions.Design/methodology/approachThe study is based on published knowledge and experience within maintenance, maintenance organization and production, and a case study.FindingsDevelopment of a model describing interactions between man‐machine‐maintenance‐economy interactions and MMME software module. MMME test shows its ability to identify, quantify, assess and follow up losses in production time which is necessary when planning effective maintenance actions.Research limitations/implicationsIn the paper the focus is to quantify production time losses in order to identify the root causes of the problem. The case study is performed at a manufacturing plant for truck engines.Practical implicationsA systematic approach of how to quantify and evaluate losses in production time in order to identify problems and problem areas within the production. This approach is discussed and motivated with the aim of achieving more cost‐effective decisions in maintenance.Originality/valueThe model and software application developed enables a structured way of analyzing production time losses in order to find cost‐effective solutions to the problems. The model is very flexible enabling it to be customized for a wide spectrum of branches.

Up until 2001 the operation and maintenance of Swedish railway, both the railway infrastructure and the rolling stock, was basically the responsibility of Statens Jarnvagar. At this year the operation and maintenance of the Swedish railway was deregulated and as a result the number of actors increased dramatically. Also, during the period from 1990 to 2012 there was an increase in the railway transports of 42 % in train-kilometres. This put great demands on the railway infrastructure operations and service, and indications were seen that the infrastructure was deteriorating leading to delivery quality problems. In order to solve the situation several governmental investigations were initiated. In a governmental report the situation of the railway maintenance is described as problematic due to several technical as well as organisational factors, of which the lack of competition is seen as the most important. Despite several investigations, the desired delivery quality is still not reached. This paper focuses on the Swedish railway infrastructure and describes the background and current state of the Swedish railway service management by utilising a business ecosystem perspective, which lets you capture the complexity and dynamics of the surroundings. By applying this perspective, looking outside the traditional framework of suppliers and customers, important areas in need of investigation or development can be singled out. As a part of the result, the Swedish railway infrastructure industry is modelled as an ecosystem, and directions for future development is pointed out.

Transportation systems are complex with respect to technology and operations with involvement in a wide range of human actors, organisations and technical solutions. For the operations and control of such complex environments, a viable solution is to apply intelligent computerised systems, such as computerised traffic control systems for coordinating airline transportation, or advanced monitoring and diagnostic systems in vehicles. Moreover, transportation assets cannot compromise the safety of the passengers by applying operation and maintenance activities. Indeed safety becomes a more difficult goal to achieve using traditional maintenance strategies and computerised solutions come into the picture as the only option to deal with complex systems interacting among them trying to balance the growth in technical complexity together with stable and acceptable dependability indexes. Industry 4.0 is a term that describes the fourth generation of industrial activity which is enabled by smart systems and Internet-based solutions. Two of the characteristic features of Industry 4.0 are computerization by utilising cyber-physical systems and intelligent factories that are based on the concept of “internet of things”. Maintenance is one of the application areas, referred to as maintenance 4.0, in form of self-learning and smart systems that predicts failure, makes diagnosis and triggers maintenance by making use of “internet of things”. This paper discusses the possibilities that lie within applying the maintenance 4.0 concept in the railway transportation industry and the positive effects on technology, organisation and operations from a systems perspective.

Asset Management as a field of science is relatively new, starting only in the late 60s/early 70s as terotechnology. In its existence it developed from tools and concepts to improve profitability towards a more holistic and integral management system orientation, formalized by ISO55k. Asset management is highly quantitative, in systematically comparing cost, performance and risk of decision options to find the best balance. Yet, no absolute measure exists for determining asset optimality. It is also hard to find any quantification at all justifying the implementation of asset management or even certification. This seems a strange omission. In this paper, it is demonstrated that for assets some form of absolute optimality can be defined. This asset optimality can be expanded to express the optimality of the asset portfolio, and thus the optimality of the asset management system, though barriers exist to do so, like subjective value judgments, uncertainties in the assumptions and complexity of the portfolio. Neither of these barriers however seems fatal to the applicability of the concept on asset management systems. Suggestions for further research include a more precise specification of optimality and research with regard to the applicability on diverse types of assets. This could be beneficial in the debate on the value of asset management.

It is about 50 % of the activities in the housing sector in the EU region are related to maintenance. According to several publications, building management systems are still quite rare and efficient methodologies for service life prediction of building parts still need to be developed. Also, recent studies show difficulties in finding comprehensive answers concerning, e.g. identifying risks and preventive maintenance actions. Incomplete information can easily lead to incorrect maintenance actions. The problem addressed is: How to improve performance and cost-effectiveness of the maintenance applied on real estate facilities especially buildings to reduce maintenance and management costs and increase company profit? The study’s objectives are to analyse maintenance; techniques, costs, weaknesses and potentials, and compare it with manufacturing industry experience. Also, to investigate whether there is a need for a DSS for planning and follow up cost-effective CBM. The major results of four case studies are; (1) Preventive and breakdown maintenance are mainly used and actions are funded from different accounts. (2) The concept of cost-effectiveness is applied occasionally. (3) Lack of CBM-DSS for planning, follow up and evaluate maintenance profitability, and cost-effective improvements of company business and tenant living quality. (4) The profit generated by continuous heating of building thanks efficient maintenance is about 2.332 million SEK. The major conclusion; there is a reasonable opportunity to reduce buildings’ management and maintenance costs.

PurposeThe purpose of this paper is to develop the steps required for establishing and running cost‐effective condition‐based maintenance (CBM) exemplified for vibration‐based maintenance (VBM) and compared with real implementations in case companies.Design/methodology/approachThe study is based on published knowledge and experience within condition monitoring (CM) and CBM, and three case studies.FindingsThe study has shown that all three case companies are in a big need for systematic procedures for doing right things right, in the right time cost‐effectively (establishing and running a cost‐effective CBM).Research limitations/implicationsThe paper focuses on development of cost‐effective CBM exemplified for VBM. Also, the case companies belong to three branches: paper and pulp mills, energy producer and engineering manufacturing. The case companies have different levels in applying CBM/VBM, experience and knowledge in CM and CBM.Practical implicationsSystematic procedures for establishing CBM/VBM policy are developed, motivated and discussed in a way which enables the user to establish and run CBM/VBM policy cost‐effectively.Originality/valueThe steps of establishment of CBM/VBM provide a unique model for companies to establish and run cost‐effective maintenance its originality.

Using CM, we have past data for describing damage initiation & development and current data for describing the current condition of a component/machine. Data describing possible behaviour of t ...

Enhancement of company competitiveness and profitability demands continuous, high quality and trouble free production. Technical specifications and the condition of a wind turbine depend on the quality and condition of its significant components, which usually have the biggest impact on production continuity, - cost per KW and the environment. These necessitate intelligent technologies for maintaining the quality of significant components. Thus, it would be mandatory to select the most informative condition monitoring (CM) system and most cost-effective maintenance policy. In this paper, wind turbine problems are specified and described, available maintenance and CM techniques are discussed, and a maintenance solution with clearly specified objectives are suggested, discussed and the potential results are outlined in the end.

This paper presents a study, which examines the role of maintenance regarding improving product quality and company’s profitability. The empirical data for this study was drawn from a Slovenian com ...

Purpose – Maintenance management information technology (MMIT) systems have existed for some 40 years. The purpose of this paper is to investigate the advancement of these systems and compares the ...

Information technology (IT) could be an important tool for reaching efficiency and effectiveness within maintenance, provided that correct and relevant IT is applied. In this paper, a conceptual model for identifying maintenance management IT requirements is developed, with its practical application in a process for the IT requirements identification for maintenance management. The process is exemplified in two real-world cases. This paper suggests that the factors of goals, purpose and use should be considered on organisational and individual level in order to identify the IT demands. Correct level of IT applied, i.e. IT consisting of correct functionality required for planning, conducting and following up maintenance activities according to the state of maintenance and the strategy adapted, will contribute to successful maintenance management. Moreover, this paper promotes the use of a structured procedure for the identification of IT requirements for maintenance management.

Purpose – Spare parts needs are dependent on the characteristics of the product in question, e.g. its reliability and maintainability, and the characteristics of the environment in which the produc ...

Maintenance is usually considered as a cost-centre or necessary evil, because (according to this aspect) it costs the company unnecessarily big budget, while it should be treated as a profit-genera ...

Purpose – The purpose of this paper is to help build up a relevant database for mapping technical and financial effectiveness of production in order to make cost‐effective maintenance decisions. Design/methodology/approach – A theoretical model is developed based on past research and experience adopting a holistic systems approach on the production. A case study, which includes databases of two maintenance‐used software programs, verifies the potential of applying the model. Findings – The main result achieved is a model for identifying relevant data required for accurate problem tracing and localisation within maintenance and production processes using a top down approach. The main conclusions are integration of IT and data resources within the enterprise is needed for developing a holistic view of the production process and a well‐formulated and documented procedure of data identification will ensure that the data can be traced back to root sources and in this way we can support the work of continuous cost‐effective improvement by eliminating root causes of problems at an early stage. Research limitations/implications – Further model verification by industrial case studies would be of interest. Practical implications – The holistic approach and the model presented are applicable especially in capital intensive industries, where maintenance budget is not negligible and the amount of data to process is large. By structuring the data need and data identification process relevant performance measures will be monitored and advanced maintenance concepts can be applied. Originality/value – By applying the proposed model in industry, the data identification process itself and not the data contents is necessary to be standardised and structured. It shifts the focus of the quality aspect from just data level to both data and data collection level. The performance measures will therefore not be chosen depending on what the IT applications can provide in first hand, but upon what is needed for cost‐effective mapping, analysis, following up and assessment of maintenance performance.

In this paper a model is developed for identifying, monitoring and improving the economic impact of vibration-based maintenance (VBM). This model provides an additional possibility of identifying w ...

Today, world-class competitiveness is a must for companies. The undeniable global competition, characterised by both a technology push and a market pull, and the rapidly evolving technology and increased customer requirements put forward a lot of challenges for management. One of these challenges concerns the production equipment. High-speed technological innovation combined with severe competition shortens the equipment life cycle and puts equipment under higher stress. In order to deal with this problem, a company's strategic investments in production equipment should not only consider cost and capacity, but also technology trends, flexibility, etc. Another important aspect is maintenance. Proper maintenance helps to keep the life cycle cost down and ensures proper operations and smooth internal logistics. The decision on the required maintenance concept and a thorough and easily accessible technical knowledge are crucial here. More and more companies are searching for a customised maintenance concept. The framework described in this paper offers some guidelines to develop such a concept, and borrows some ideas from maintenance concepts described in literature. An important feature of the framework is that it allows to incorporate all information available in the company, ranging from experience of maintenance workers to data captured by modern Information and Communication Technology (ICT) means.

Profitable production demands continuously improved maintenance decision accuracy for reducing/avoiding failures and unplanned stoppages due to their consequences. More accurate decisions prolong life length of components, and consequently machines, and maintain the production running longer. When a condition-monitoring (CM) value exceeds a significant (warning) level, it demands a clear understanding of what happened and how it will develop in the next future to avoid failures. In addition to CM it demands reliable information concerning the probability of failure, residual lifetime, and when is the most profitable time of conducting maintenance. Companies strive to reduce production cost in order to increase the possibility of offering customers lower prices and generating additional competitive advantages. But applying new technologies for enhancing maintenance, production performances, and company competitiveness counters many problems in industry. In this paper, a new innovative e-maintenance decision support system (eMDSS) is introduced; the problems facing successful implementation of eMDSS based on a case study are introduced and discussed. Solutions to avoid the problems facing successful implementation of eMDSS are suggested and discussed. eMDSS offers a unique opportunity to achieve just in time dynamic and cost-effective maintenance by selecting the most profitable time for maintenance.

The problem addressed in this paper is how to utilise the concept of TQMain to develop an integrated vibration‐based maintenance (VBM) for detecting deviations in the machine condition and product quality (technical specifications) before the machine starts manufacturing defective items. Concepts of TQMain and integrated VBM are discussed. A technical analysis is conducted to identify quality problem cause roots when manufacturing crankshafts in Volvo Motor, Sko¨vde, Sweden. A factorial experiment is conducted to assess the effect and significance of the suspected causes. Vibration measurements from seven points are collected. The major conclusion of this study is: when using an effective, e.g. on the basis of TQMain concept, integrated VBM, deviations in product quality can be detected at an earlier stage than when using usual quality control diagrams. Manufacturing defective items can be reduced dramatically (or prevented), which will eliminate bad quality‐related losses.

Rolling element bearing failures in paper mill machines are considered in relation to their critical role in the machine function. The use of expensive, sophisticated and highly automated equipment and machines and the intention to achieve higher quality products, longer machine life, higher machinery effectiveness and safer operating processes were the main driving force motivating efforts to improve the maintenance concept during the last 50 years. In this paper, a conceptual model that integrates the available condition information, the deterministic models used in condition monitoring based upon mechanical theory and the probabilistic models used in the area of operational research is developed and its applicability is discussed. This model covers fault detection of a mechanical component such as a rolling element bearing, prediction of its vibration level in the near future, assessment of the probability of failure of a component over a finite period of time of interest.

Maintenance costs in advanced manufacturing companies, e.g. electronics manufacturing companies, have been steadily increasing as the companies upgrade their production facilities. Maintenance costs are normally a considerable portion of the product cost. To maintain a competitive place in the market, it is critical for an advanced manufacturing company to have a sound maintenance management system, which can control its maintenance costs at the lowest level and maintain its overall equipment effectiveness at the highest level. This paper reports on an integrated maintenance management system, which has been developed and implemented in an advanced electronics manufacturing company in Hong Kong. The methods and principles of the system are discussed in sections on maintenance performance auditing, cost recording and tracing, reliability centred maintenance planning and control, condition monitoring and on-line feedback control, and integrated maintenance planning and control.

Relevant and reliable data from the surroundings in addition to the vibration measurements are required to achieve effective diagnosis and prognosis when a vibration‐based maintenance (VBM) policy is used. The main conclusion is that the variation in the machine load and speeds influences the amplitudes of rolling element bearing defect frequencies. Therefore, changes in the machine speed and load should be considered when interpreting vibration spectra. This will improve the effectiveness and accuracy of fault diagnosis and prediction of the time to maintenance action. The paper classifies stoppage times and highlights the reasons behind them. Also, it discusses the consequential economic losses incurred by unplanned stoppages. During the period covered by this study (58 days), the total stoppage time was about 76.6 days and caused appreciable economic losses of about 2.3 million SEK.

Reviews overall models for maintenance management from the viewpoint of one who believes that improvements can be made by regarding maintenance as a “contributor to profits” rather than “a necessary evil”. The reasons why maintenance is such a “Cinderella function” are largely historical and can mostly be overcome by new information technology (IT) and its falling cost. Progress is now being held up by outdated notions of what is economically possible in data acquisition and analysis, and failure to revise basic maintenance and reliability concepts, some of which are now 30 years out‐of‐date. Integrated IT permits mathematical optimisation of supra‐departmental management decisions, e.g. co‐planning of production with maintenance, overhaul/renewal of machinery and improvement of product performance/quality. Life‐cycle profit (LCP) is a fair measure of overall effectiveness that emphasises the value rather than the cost of terotechnological activities.

In manufacturing systems intelligent techniques are being used to integrate and interpret data from multiple sensors to predict tool wear and tool life. Less attention is devoted to developments of integrated condition monitoring systems, which enable the user to evaluate a multi‐variant system based on the data collected from, e.g. maintenance, quality, production, etc. In this paper we discussed different approaches of how to keep availability, quality and productivity at high levels. Also, we proposed a new approach for an expert system concept, which is characterised by using a total quality maintenance (TQMain) concept; having a common database, and a continuously improved knowledge base with an intelligent inference engine. It can enhance data reliability, decision making certainty, remove the redundancy in monitoring systems, and allow the user to detect and eliminate reasons behind variations through effective diagnosis and prognosis. This will enhance the performance‐efficiency, availability and quality rate, i.e. overall equipment effectiveness of the manufacturing systems.

Many current vibration-based maintenance (VBM) policies for rolling element bearings do not use as much as possible of their useful lives. Evidence and indications to prolong the bearings' mean effective lives by using more accurate diagnosis and prognosis are confirmed when faulty bearing installation, faulty machinery design, harsh environmental condition and when a bearing is replaced as soon as its vibration level exceeds the normal. Analysis of data from roller bearings at two paper mills suggests that longer bearing lives can be safely achieved by increasing the accuracy of the vibration data. This paper relates bearing failure modes to the observed vibration spectra and their development patterns over the bearings' lives. A systematic approach, which describes the objectives and performance of studies in two Swedish paper mills, is presented. Explanations of the mechanisms behind some frequent modes of early failure and ways to avoid them are suggested. It is shown theoretically, and partly confirmed by the analysis of (unfortunately incomplete) data from two paper mills over many years, that accurate prediction of remaining bearing life requires: (a) enough vibration measurements, (b) numerate records of operating conditions, (c) better discrimination between frequencies in the spectrum and (d) correlation of (b) and (c). This is because life prediction depends on precise knowledge of primary, harmonic and side-band frequency amplitudes and their development over time. Further, the available data, which are collected from relevant plant activities, can be utilized to perform cyclic improvements in diagnosis, prognosis, experience and economy.

The reputation of an organisation is often built through hard work on improving quality, reliability, delivery time and price. In this paper a graphical method for the selection of a cost‐effective monitoring technique is suggested. This graphical method is also used to select the most cost‐effective replacement vibration level, when a vibration‐based maintenance is implemented, i.e. when the available data are mainly condition‐based replacement. This method is based on the concept of the total time on test, TTT‐plot. The use of this method is explained by three examples.

Assessment of disturbance data from production equipment provides valuable information for improving productivity. To implement total productive maintenance (TPM) it is necessary to assess the magnitude of different types of production losses, in order to direct activities and allocate resources in an optimal way. In many enterprises, the focus is directed towards major time losses due to break‐downs rather than minor losses in speed and time. A method for implementing data collection is to start gradually by a simple model and develop this to a combined model with computerised systems and manual recording. This gives both an exact assessment of the magnitude of the disturbance and a deeper understanding of the reason for losses. According to about 20 cases, the overall equipment effectiveness was only around 55 per cent. Further, it is quite clear that performance losses are the dominating ones. If the production process is new to the company it is hypothesised that overall equipment effectiveness will be lower than if the company is already familiar with production process.

Especially in the last two decades of an increasingly-competitive business environment, dwindling resources and an ever-increasing need to obtain value for money in all areas of corporate activity, it has become essential that all available resources be used optimally (Griffith, J. W. and Keely, B. J., Cost Engineering, 1978, September/Octobe r, 165-168). Physical assets form the basic infrastructure of all businesses and their effective management is essential to overall success. It has thus become essential to plan and monitor assets throughout their entire life cycle, from the development/proc urement stage through to eventual disposal. Life cycle costing* is concerned with optimising value for money in the ownership of physical assets by taking into consideration all the cost factors relating to the asset during its operational life. Optimising the trade-off between those cost factors will give the minimum life cycle cost of the asset. This process involves estimation of costs on a whole life basis before making a choice to purchase an asset from the various alternatives available. Life cycle cost of an asset can, very often, be many times the initial purchase or investment cost (Hart, J. M. S., Tetrotechnology Handbook, p. 22, HMSO, London, 1978; Hysom, J. L., Journal of Property Management, 1979, 44, 332-337). It is important that management should realise the source and magnitude of lifetime costs so that effective action can subsequently be taken to control them. This approach to decision making encourages a long-term outlook to the investment decision-making process rather than attempting to save money in the short term by buying assets simply with lower initial acquisition cost. It is suggested project managers should familiarise themselves with what the approach involves, to better appreciate how they might then contribute to the enhanced quality decision making which it makes possible. © 1997 Elsevier Science Ltd and IPMA

Maintenance management is a business function of which the considerable operational and tactical importance is still growing. As problems and opportunities are needed to be anticipated in time in order to make the necessary adjustments, sound performance reporting is indispensable. Presents a short overview of commonly used maintenance performance measurement systems based on literature study and industrial practice. Discusses experiences with the implementation of an in‐house developed performance measurement tool in Belgian industry. Presents recommendations concerning the introduction of a maintenance performance reporting system.

La demanda de mantenimiento correctivo en el entorno de los distintos hospitales existentes en un área sanitaria es una información importante para la optimización de recursos. Por ello en este trabajo se propone la utilización de un modelo que establezca, por un lado, la probabilidad de demanda de cada unidad asistencial y, por otro, la carga de trabajo que soporta cada tipo de instalación. Como caso de estudio se eligieron 33 unidades asistenciales del área de salud de Badajoz y se le asignaron las cargas de trabajo de mantenimiento correctivo por cada tipo de instalación, según la habían demandado en los últimos tres años. Se llevó a cabo un análisis de datos mediante el modelo de Rasch y se obtuvieron los índices de probabilidad de que una unidad asistencial concreta demande una determinada carga de trabajo respecto a un tipo de instalación, además de que una concreta carga de trabajo de una instalación sea demandada por una determinada unidad asistencial. Se comprobó como el modelo de Rasch se ajusta adecuadamente para la medida de las cargas de trabajo en el ámbito hospitalario y puede utilizarse como herramienta de ayuda a la toma de decisiones para la mejor optimización de los recursos., The demand for corrective maintenance in the hospitals in a health area is an essential information for planning the different tasks. Therefore, this work proposes the use of a stochastic model to establish, on the one hand, the probability of demand for each existing health care unit in a hospital and, on the other hand, the workload that supports each type of hospital facility. As a case study, 33 units were selected in the health area of Badajoz and the corrective maintenance workloads for each type of facility were assigned, according to the demand during the previous three years. A Rasch analysis was carried out to the data, obtaining the index of probability that a particular care unit demands a given workload for a type of installation, and that a particular workload of a facility is demanded by a particular unit. It was found that the Rasch model fits appropriately to the measurement of workload in an hospital and it can de used as a tool for decision making to optimize the resources.

Diplomsko delo prikazuje pravne, tehnološke in organizacijske elemente, potrebne za vzdrževanje dizel lokomotiv na slovenskih železnicah. S terotehnološkega vidika sta predlagani metodi za izračun življenjskega cikla stroškov. Le-ta je prikazan na primeru lokomotive 642. Opisane so tudi okoljske zahteve in postopki pri nabavi novih dizel lokomotiv. The diploma thesis presents legal, technological and organizational elements, that are needed for diesel locomotive maintenance on slovenian railways.From terotehnological aspect two metods are presented for calculating the life cycle cost. The calculation of LCC is shown for locomotive 642. Requirements and environmental procedures for acquisition of new disel locomotivesare also listed.