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  • 1.
    Algabroun, Hatem
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Iftikhar, Muhammad Usman
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Weyns, Danny
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM). Computer Science Department, KU Leuven, Belgium..
    Maintenance 4.0 Framework Using Self-Adaptive Software Architecture2017In: Proceedings of 2nd International Conference on Maintenance Engineering, IncoME-II 2017.The University of Manchester, UK, The University of Manchester, UK , 2017, , p. 299-309Conference paper (Refereed)
    Abstract [en]

    With the recent advances of manufacturing technologies, referred to as Industry 4.0, maintenance approaches have to be developed to fulfill the new de-mands. The technological complexity associated to Industry 4.0 makes designing maintenance solutions particularly challenging. This paper proposes a novel maintenance framework leveraging principles from self-adaptation and software architecture. The framework was tested in an operational scenario where a bearing condition in an electrical motor needs to be managed, the results showed a proper operation. As a conclusion, the proposed framework could be used to develop maintenance systems for Industry 4.0.

  • 2.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A computerized model for assessing the return on investment in maintenance: following up maintenance contribution in company profit2009In: Engineering asset lifecycle management: Proceedings of the World congress on engineering asset management (WCEM 2009), 28-30 september 2009 / [ed] Dimitris Kiritsis, Christos Emmanouilidis, Andy Koronios, and Joseph Mathew, Springer, 2009Conference paper (Refereed)
    Abstract [en]

    In order to reduce as much as possible the economic losses that are generated due to lack or inefficient maintenance, it is necessary to map, analyse and judge maintenance performance and act on deviations before it is too late. It is always necessary for a company to act for increasing profit and consequently enhance its competitiveness. In this paper, a software model (MainSave) has been developed for mapping, monitoring, analysis, following up and assessing the cost-effectiveness of maintenance (and maintenance investments). MainSave can be used for assessing savings and profit/losses due to maintenance performance, identify problem areas and primarily plan for new beneficial investments in maintenance. The module has been tested at Fiat/CRF in Italy. The major conclusion is; applying MainSave it would be possible to identify, assess and follow up maintenance contribution in company business.

  • 3.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A Concept for Detecting Quality Deviation Earlier than when using Traditional Diagram in Automotive: A Case study2001In: International Journal of Quality & Reliability Management, ISSN 0265-671X, E-ISSN 1758-6682, Vol. 18, no 9, p. 917-940Article in journal (Refereed)
    Abstract [en]

    The problem addressed in this paper is how to utilise the concept of total quality maintenance (TQMain) to develop an integrated VBM (vibration-based maintenance) 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, Skövde, Sweden. A factorial experiment is conducted to assess the effect and significance of the suspected causes. Vibration measurements from 7 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 that when using usual quality control diagrams. Manufacturing defective items can be reduced dramatically (or prevented) which will eliminate bad quality- related losses.

  • 4.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    A graphical method to assess the probability of failure of a rolling element bearing and its residual life in paper mills when using a vibration monitoring system2000Conference paper (Refereed)
  • 5.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A Maintenance Model for Identification, Quantification and Elimination of Losses in Companies Profitability: Application Examples2009In: Proceedings of the 22nd international congress on condition monitoring and diagnostic engineering management / [ed] Aitor. Arnaiz; Ana. Aranzabe; B. K. N. Rao, Eibar: Fundación Tekniker , 2009, , p. 35Conference paper (Other academic)
    Abstract [en]

    A production process includes several sub-processes, which may also be called working areas or disciplines that are responsible for performing the different tasks required to accomplish the mission of the process. It is crucial that the tasks performed in these sub-processes are synchronised with each other without unnecessary and uncontrollable gaps and overlapping, which in turn may lead to losses in production time and manpower. It is important to avoid a shortage of resources, unplanned stoppages and idle times that may arise due to the gaps. In this paper gaps are generated due to missing the tasks or inputs that are required because of deficiencies in planning, the lack of responsibilities or of knowledge and experience concerning these inputs. On the other hand, effective synchronising of production-different disciplines will enhance production process effectiveness as well as company profitability and competitiveness.

    The problem addressed in this paper is: How should maintenance be considered in conjunction with plant activities, such as production, quality and personnel competence, in order to easily and effectively identify and quantify company losses in profitability and competitiveness and consequently to eliminate underlying causes? In this paper the gaps and overlapping between maintenance, production, competence and quality are defined, identified and described through a technical analysis of the production sub-processes and their respective sub-organisations. The major result achieved in this study is the development of a new model (Maintenance Function Deployment (MFD)), for an easy and effective identification and quantification of company losses in profitability and competitiveness for cost-effective elimination of the root-causes. MFD can be applied through identifying:

    1. the requirements that are necessary to achieve and maintain company strategic goals,

    2. tools to maintain the condition of these requirements,

    3. activities for the effective utilisation of the tools above, and

    4. the factors required to support the integration of maintenance with plant business for enhancing production process effectiveness as well as company profitability and competitiveness.

    The structure of the quality house has been used as a platform for developing MFD model for effectively integrating maintenance with production, competence and quality. Two examples are conducted to demonstrate the possibility of applying the model and its potential for enhancing production processes profitably. The main conclusion is: applying MFD gives an enormous opportunity to continuously maintain the quality of the working areas under consideration, which makes MFD one of the company’s objective-driven tools for enhancing its profitability and competitiveness. Also, it implies the application of the PDCA cycle, which in turn improves the integration of relevant working areas cost-effectively and continuously.

  • 6.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A Maintenance Model for Indentification, Quantification and Elimination of Losses in Companies Profitability: An Application Example2009In: COMADEM 2009: June 9-11 2009, San Sebastian, Spain, Miramar Palace / [ed] Aitor Arnaiz, Ana Aranzabe, and Raj BKN Rao, Eibar, Spain: Fundaci n Tekniker , 2009, p. 45-53Conference paper (Refereed)
    Abstract [en]

    A production process includes several sub-processes (working areas) that are responsible for performing the different tasks required to accomplish the mission of the process. Thus, it is important to avoid a shortage of resources, unplanned stoppages and idle times that may arise. The problem addressed in this paper is: How should maintenance be considered in conjunction with plant activities, such as production, quality and personnel competence for easily and effectively identifying and quantifying company losses in profitability and eliminating underlying causes? In this paper, the interactions between major working areas have been introduced and discussed. The major result achieved in this study is the development of a new model (Maintenance Function Deployment (MFD)), for an easy and effective identification and quantification of company losses in profitability. Four matrixes have been used for developing MFD model for effectively integrating maintenance with production, competence and quality. An application example is conducted to demonstrate the possibility of applying the model and its potential for enhancing production processes profitably. The main conclusion is: applying MFD gives an enormous opportunity to continuously maintain the quality of the working areas under consideration, which makes MFD one of the company’s objective-driven tools for enhancing its profitability and competitiveness.

  • 7.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    A method and an apparatus for predicting the condition of amachine or a component of the machine2016Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention relates to a methodand an apparatus for predicting the condition of a machine or a component of the machine based on measurements of a condition monitoring parameter. The apparatus comprising a data storage for storing a moving window including measurement values of the condition monitoring parameter, a monitoring module configured to determine whena measurement value exceeds a potential failure level at which damage of the machine or component is considered initiated, and to determine the point in time (tP) when the monitoring parameter exceeded the potential failure level, a data cleaning module configured to discarda new measurement value if it is smaller than the latest stored measurement value inthe moving window, to determine an expected value for the measurement based on a defined pattern for the condition monitoring parameter, which pattern reflects an expected behavior of the monitoring parameter after damage has been initiated, and the time elapsed since the point in time the monitoring parameter exceeded the potential failure level, and to discard the new measurement value if it deviates too much from the expected value, and to store not discarded measurement values in the moving window, and a prediction module configured to predict the level of the condition monitoring parameter at a future point in time based on the measurement

  • 8.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A model for the creation of industial competitiveness: the role of companies' internal effectiveness in the creation and improvment of their competitiveness: a model for integrating technology and finance2005In: Creation of Industrial Competitiveness: CIC 2001-2004 / [ed] Basim Al-Najjar ; Anders Pehrsson, Växjö: Växjö University Press , 2005, p. 29-38Chapter in book (Other academic)
  • 9.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A model that describes the impact of integrated vibration-based maintenance on company´s business2002Conference paper (Refereed)
  • 10.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    A model to diagnose the deviation in the maintenance performance measures2006In: Engineering Asset Management, 2006, p. 87-93Conference paper (Refereed)
    Abstract [en]

    In order to achieve the strategic goals, the company should utilise an efficient data gathering and analysis system for mapping the technical and economic situation, following up the development and detecting technical and economic deviations at an early stage to plan and perform necessary maintenance actions on time. In many cases, measuring and following up the development of relevant and well selected technical and economic performance measures can be more applicable for mapping the situation and making cost-effective decisions compared with monitoring big mount of data. But, in many cases it demands a reliable technique for interpretation of the behaviour of these performance measures especially if they are not linearly interrelated and if some of them reflect a combination of technical and financial impact. The problem addressed in this paper is; how is it possible to enhance the ability of detecting significant deviations in the maintenance performance measures at an early stage and tracing their root causes by using data- and knowledge base and inference engine? The major result achieved in this paper is a model developed for interpreting the changes in the maintenance performance measures and tracing their basic causes, which is verified in an example with typical data. The model consists of five modules; what performance measures to chose, how and why an eventual deviation on the performance measures occur, what to do to eliminate and prevent their reoccurrence and mapping of the current situation technically and financially. The main conclusion is that applying the model would enhance the ability of detecting changes in the maintenance performance through identifying the causes for elimination. In Al-Najjar et al (2004), a model for how to identify the measurable variables, which are needed to develop measures for monitoring maintenance performance behaviour systematically, is introduced and discussed. Also, five maintenance performance measures are propos

  • 11.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    A new vibration based approach for monitoring rolling element bearings1994Conference paper (Refereed)
  • 12.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    A universal coupling for transferring rotary movements between an inputshaft and an output shaft2016Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention relates to a universal coupling for transferring rotary movements between an input shaft and an output shaft (when the angel between the shafts can be about 90 degree), wherein each of the shafts are arranged to rotate about a longitudinal axis of the shaft, the coupling comprising: an input joint member and output joint member movably coupled to each, and the input joint member  is fixedly connected to the input shaft and the output joint member is fixedly connected to the output shaft.  Each of the input and output joint members comprises at least one annular part having a cross section and defining a central aperture, the annular part of the input joint member passes through the aperture of the annular part of the output joint member, and the annular part of the output joint member passes through the aperture of the annular part of the input joint member, and the area of each the central apertures is larger than the cross section area of each of the annular parts and two spaced apart contact points are formed between the annular parts of the input and output joint members.

  • 13.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Mathematics and Systems Engineering.
    Accuracy, effectiveness and improvement of Vibration-based Maintenance in Paper Mills: Case Studies2000In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 229, no 2, p. 389-410Article in journal (Refereed)
    Abstract [en]

    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 utilised to perform cyclic improvements in diagnosis, prognosis, experience and economy.

  • 14.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    An approach for continuous reduction in LCC when using integrated vibration-based maintenance: A case study1999In: Proceedings COMADEM '99, 1999, p. 159-168Conference paper (Refereed)
    Abstract [en]

    The biggest thread confronts achieving and maintaining high equipment effectiveness can be stated as; whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery. Also, it makes possible to follow damage development at an early stage to increase machine mean effective life and improve company's economy. The effect of TQMain on LCC of machinery and a company's economy is discussed. A case study to reveal savings in maintenance cost, when a vibration-based policy is involved, is presented. Using TQMain, company's economy can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes.

  • 15.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    An approach for selection of the most cost-effective vibration replacement level1998Conference paper (Refereed)
  • 16.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    An approach for the Selection of the most Cost- Effective Vibration Replacement Level1998Report (Other academic)
  • 17.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Assessment of the probability of failure of a rolling element bearing and its residual life in paper mills2000Report (Other academic)
  • 18.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    CBM Today and Tomorrow: A Model for Digitalised, Automated and Intelligent CBM Exemplified for VBM2017In: Proceedings of 2nd International Conference on Maintenance Engineering, IncoME-II 2017.The University of Manchester, UK, The University of Manchester, UK , 2017 / [ed] Jyoti K. Sinha, Manchester, UK: The University of Manchester, UK , 2017, p. 262-273, article id ME2017_1132Conference paper (Refereed)
    Abstract [en]

    Industry strives towards developing and implementing digitalised and automated production process, Industry 4.0. This states hard terms and conditions to develop new concept-based maintenance to meet the new production process demands. Intelligent and automated condition-based maintenance (CBM) exempli-fied in vibration-based maintenance (VBM) is one of the most suitable techniques for developing a maintenance concept fulfilling the demands stated by Industry 4.0. In this paper, we identified today´s VBM-process activities and their applica-tion, and introduced and discussed their status. In addition, we developed a model that describes future VBM, Cognitive VBM. Then, we compared cognitive VBM with the currently available VBM. The major conclusions are the potential benefit of applying Cognitive VBM is the continuous enhancement of company internal effectiveness in a cost-effective way.

  • 19.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Company´s business and competitiveness enhancement: A model of integrated vibration-based maintenance impact on company´s effectiveness2002In: Proceedings of COMADEM 2002: 15th International Congress on Condition Monitoring and Diagnostic Engineering Management, 2002, p. 238-248Conference paper (Refereed)
  • 20.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Computerised Maintenance Decision Support System (MDSS) for Simulating and Selecting the most Cost-effective Production and Maintenance Solution: Case Study in FIAT/CRF, Italy2010In: Computerised Maintenance Decision Support System (MDSS) for Simulating and Selecting the most Cost-effective Production and Maintenance Solution: Case Study in FIAT/CRF, Italy / [ed] Susumu Okumura, Tadao Kawai, Peng Chen and Raj B.K. N. Rao, Hikone, Japan: Sunrise Publishing Limited , 2010, p. 8-Conference paper (Refereed)
    Abstract [en]

    To survive the hard international competition, it is necessary for many companies to enhance their competition positions through, for example; reducing production cost, and maintaining and improving production process and product quality for increasing the profit margin. In order to achieve these strategic goals, a tool for making investments in maintenance more profitable is developed, introduced, tested and discussed. This tool/module is one of the modules included by an innovatively new Maintenance Decision Support System (MDSS). Theoretical backgrounds are introduced, and software prototype (AltSim) for making the application of any of the tool on the daily basis easier and more cost-effective are developed, discussed and their functionalities are tested in FIAT/CRF, Italy. It is designed to support maintenance and production engineers to achieve cost-effective maintenance decisions. The major result of this study is development and testing of innovatively new tool/software module for simulating and selecting the most cost-effective production and maintenance solution. The major conclusion that can be drawn is; applying AltSim it is possible to identify and select the most cost-effective solution when there are several technically application solutions for the same problem.

  • 21.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Condition based maintenance for mechanical systemsManuscript (preprint) (Other academic)
    Abstract [en]

    In this paper a sequential method for the selection of maintenance technique for mechanical systems is presented. It is based on technical knowledge concerning component failure mechanisms and failure causes. Classification of failures according to their consequences is stated. A modified version of failure modes, effects and criticality analysis is given and a way to identify significant components is discussed. Analysis of collected data is discussed and a method to identify a replacement level of a monitoring parameter is proposed. Criteria for the selection of a monitoring technique based on the intrinsic information of monitoring parameters are introduced. Finally, a decision rule for the selection of a suitable maintenance technique is suggested and a modified expression of the long run average cost per unit time is used as a distinguishing criterion between applicable strategies.

  • 22.
    Al-Najjar, Basim
    Lunds Universitet.
    Condition-based maintenance: Selection and improvement of a cost-effective vibration-based policy in rolling element bearings1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Modern machinery is expensive and therefore must run at high availability and effectiveness which cannot be achieved without an effective maintenance policy. Condition monitoring, (CM), techniques can be utilised to reduce or arrest the rate of deterioration of a component so increasing operating life. Successful implementation of condition-based maintenance, (CBM), results from a combined use of  knowledge of CM, failure analysis, design, data acquisition and analysis, and economic optimisation.

    The main result reported in this thesis is that the rolling element bearing’s mean effective life could be extended appreciably if an existing vibration-based maintenance policy is used effectively. This result is achieved by a combination of data analysis and logical development. A new maintenance approach was developed to overcome some of the limitations of total productive maintenance (TPM) and reliability-centered maintenance (RCM) and is based upon the Deming managerial feedback cycle (Plan-Do-Check-Act). This method is called Total Quality Maintenance, (TQMain). It is a methodology to sustain and improve continuously the technical and economic effectiveness of the essential manufacturing process elements. It is shown logically that by using vibration-based monitoring (VBM) program in the frame of a common database for a plant IT-system, a pre-requisite of TQMain, the causes behind quality deviations and failures can be identified and eliminated effectively at an early stage and the company’s economics would be improved. The CBM effectiveness and accuracy, i.e. reducing failures and making use of as much as possible of a component’s mean effective life, are usually related to the ability of the CM system to detect failure causes and follow defect development. Criteria to select the most cost-effective VBM system and the most cost-effective vibration-based maintenance policy are developed.

    But, in most real cases, CM systems are not utilised effectively and companies are satisfied with the partial savings achieved in maintenance cost. It is shown, by two case studies, that improvements in vibration-based maintenance can be achieved by effective feedback of the results of failures, renewal condition and VBM history analysis. Unfortunately the data coverage and quality in these studies were not sufficient, among other reasons due to the low number of failures and long bearing lives, so the conclusions, although supported by the work results, remain strong qualitative indications, rather than statistical proof. Criteria to measure the effect of improvements to confirm whether it is economically beneficial and to identify the basic reasons why it is not, are developed because it is important for never-ending improvement needed by the company to remain competitive.

    The contribution of this thesis is: The development of a sequential method for the selection and improvement of a cost-effective vibration-based maintenance policy. This methodology can be used to justify, on economic criteria, the use of VBM systems to indicate when rolling element bearings should be renewed. It is achieved through;

    Tools used in quality and maintenance technology and reliability analysis have either been modified or developed beyond their original concept such as; Maintenance cost equation, Total Time on Test-plots, Overall Equipment Effectiveness. Development of new tools to monitor maintenance effectiveness and accuracy, select the most informative CM parameter(s) and cost-effective vibration-based maintenance policy. A new maintenance approach, (TQMain), and a new envelope alarming method for VBM programs are also developed. Theoretical basis for improvements of the effectiveness of vibration-based maintenance of bearings in paper mill machines and two case studies which tend to confirm the theory are introduced.

  • 23.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Continuous reduction in LCC when using integrated vibration-based maintenance: a casestudy2000Report (Other academic)
  • 24.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Cost-eefective & continous improvement of production process and company's business when using Total Quality Maintenance (TQMain)2006In: Proceedings of the First International Conference on Maintenance Engineering, 2006, , p. 1-13p. 1-13Chapter in book (Refereed)
    Abstract [en]

    A new concept of condition-based maintenance (CBM), Total Quality Maintenance (TQMain) is presented. It aims to maintain not only machines but the quality of the essential elements involved in the production process, such as methods, operational conditions, personnel competence, raw material, quality and managerial systems. The major results achieved, which are based on several case studies, are: Evidence of prolonging the bearing's effective live by using more accurate diagnosis is confirmed when faulty bearing installation, faulty machinery design and harsh environmental condition are considered.

    Machine speed and load influence the information delivered by vibration signals. Applying vibration spectral analysis, it is possible to detect the deviations in the quality of a product during the processing time and before it is completed

    Maintenance profit of one paper machine was found to be at minimum about 3.58 MSEK yearly. The main conclusion is; identifying and eliminating causes behind deviations in quality and equipment condition at an early stage are vital to accomplish continuous improvements and to assure longer machine live and high quality products at competitive price

  • 25.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Cost-effective continuous improvement when using total quality maintenance (TQMain)2003In: ICOMS-2003 : International Conference of Maintenance Societies, 2003Conference paper (Refereed)
  • 26.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Criteria for the selection of a cost-effective maintenance policyManuscript (preprint) (Other academic)
  • 27.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Data coverage and quality, diagnosis and maintenance decision, and their economic impact on the company´s profits: case studies2002In: Proceedings of the 16th European Maintenance Congress : Euromaintenance 2002, 2002, p. 283-293Conference paper (Refereed)
  • 28.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Determination of potential failure initiation time using cumulative sum chart2016In: IFAC-PapersOnLine / [ed] Christos Emmanouilidis, Benoît Iung, Marco Macchi and François Pérès, Elsevier, 2016, Vol. 49:28, p. 43-48Conference paper (Refereed)
    Abstract [en]

    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 randomness in vibration measurements is introduced. Quality control tool Cumulative Sum (Cusum) Chart is adapted for monitoring variation in vibration level to determine the time of potential failure initiation. The result confirms the possibility of reducing false alarms arise due to randomness in vibration signals. The major conclusion; applying Cusum chart it is possible to determine the time of initiation of a potential failure for follow up its progression and accurate planning of maintenance.

  • 29.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dymanite: ett beslutsstödsystem för effektivare underhållsåtgärder, del III2010In: Bättre produktivitet, ISSN 1402-1145, no 6, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 30.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamic e-Maintenance: Applying eMaintenance Decision Support System (eMDSS) in Case Companies2011In: 7th IMA International Conference on Modelling in Industrial Maintenance and Reliability: Sidney Susses College, University of Cambrige, UK, UK: Institute of Mathematics & its applications , 2011Conference paper (Refereed)
    Abstract [en]

    In order to maintain and improve company profitability especially during financial crises and lower profit-margin, it is necessary to reduce economic losses. This can be achieved through maintaining and improving the quality of the elements involved in the production process. Therefore, the maintenance strategy applied should be dynamic to suit the changes occur in a production process cost-effectively. Therefore, it is essential for maintenance and production managers to have a system providing the data required to achieve dynamic and cost-effective maintenance decisions. In this paper, a new Maintenance Decision Support System (eMDSS) for achieving dynamic and cost-effective maintenance decisions is introduced, tested and discussed. It consists of three toolsets and five software modules for performing six services to; enhance accuracy of maintenance decisions, select the most cost-effective maintenance solutions, identify and prioritise problem areas, and assess losses in production time, and map, follow up and assess maintenance cost-effectiveness (maintenance savings and profit) to achieve continuous & cost effective improvement. The major result of this tsudy is verfication of a new innovative Mainteance Decision Support System (eMDSS). The system has been tested at Fiat (car manufacturer)/CRF in Italy and GORATU (CNC-machine manufacturer).  The main conclusion is; applying eMDSS it is possible to map production and maintenance processes, identify and prioritise problems, select the most cost-effective maintenance investment and follow up and control investments results.

  • 31.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamite: ett beslutsstödsystem för effektivare underhållsåtgärd, del II2010In: Bättre produktivitet, ISSN 1402-1145, no 3, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 32.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamite: ett beslutsstödsystem för effektivare underhållsåtgärder2009In: Bättre produktivitet, ISSN 1402-1145, no 7, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 33.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Economic criteria to select a cost-effective maintenance policy1999In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 5, no 3, p. 236-248Article in journal (Refereed)
    Abstract [en]

    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.

  • 34.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Economic importance of maintenance planning when using vibration-based maintenance policy2001Book (Other academic)
  • 35.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    eMaintenance Decision Support System: Case Studies for Securing Production Process & Following up Maintenance Contribution in Company Business2011In: COMADEM 2011 : proceedings of the 24th international congress on conditioning monitoring and diagnostics engineering management: advances in industial asset integrity management / [ed] Maneesh Singh, Raj B.K.N. Rao and J.P. Liyanage, India: PL, Kolkata , 2011, p. 395-406Conference paper (Refereed)
    Abstract [en]

    In general, all the elements involved in a production process, such as tools, machinery, methods, competence and working environment are exposed to dynamic changes. Thus, in order to maintain and improve company profitability and competitiveness especially during financial crises and lower profit-margin, it is necessary to reduce losses through maintaining and improving the quality of the elements involved in the production process. Therefore, the maintenance strategy applied should be dynamic to follow all these changes cost-effectively. The accuracy of maintenance decisions is essential for reducing economic losses generated due to unnecessary stoppages especially when stoppage time is very expensive. Therefore, it is necessary for maintenance and production managers to have a system providing the data required to achieve dynamic and cost-effective maintenance decisions. In this paper, the role of & importance of dynamic and cost effective maintenance in company business is discussed. Also, a scenario for applying a new eMaintenance Decision Support System (eMDSS) for achieving dynamic and cost-effective maintenance decisions is introduced, tested and discussed. eMDSS introduces four different strategies for continuously improving the cost-effectiveness of maintenance and production processes. It consists of three toolsets and five software modules for performing six services to;

    1. enhance accuracy of maintenance decisions

    2. select the most cost-effective maintenance solutions

    3. identify and prioritise problem areas, and assess losses in production time

    4. map, follow up and assess maintenance cost-effectiveness (maintenance savings and profit) for achieving continuous & cost effective improvement.

    The major result of this tsudy is a new innovative eMDSS. The system has been tested at Fiat (car manufacturer)/CRF inItalyand GORATU (CNC-machine manufacturer).  The main conclusion is; applying eMDSS it is possible to map production an maintenance processes, identify and prioritise investments results.

  • 36.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    En metod och en apparat för att prediktera tillståndet hos en maskin eller en komponent hos maskinen: PreVib algorithm2014Patent (Other (popular science, discussion, etc.))
    Abstract [sv]

    Ett ändamål med föreliggande uppfinning är att förbättra prediktionen av en tillstånds­övervaknings­parameter och därmed förbättra uppskattningen av den mest effektiva tidpunkten för att byta ut eller utföra underhåll på en maskin eller viktiga komponenter hos maskinen.

    Mätdata som används för predikteringen renas på ett sådant sätt att en optimal prediktering uppnås. Om någon del av maskinen är skadad borde mätningarna öka eftersom skadan i maskin­komponenten är irreversibel, d.v.s. den kan inte laga sig själv, vilket borde medföra att värdena på mätningarna inte kan minska över tiden. De utvalda värdena sparas i ett rörligt fönster anpassat att spara ett förutbestämt antal mätvärden.

    Predikteringen börjar när värdet av den uppmätta tillstånds­övervaknings­parametern har överstigit en potentiell skadenivå, d.v.s. skada har initierats, vid vilken det antas att en potentiell skada hos maskinen eller komponenten är initierad. Det förväntade värdet bestäms baserat på ett fördefinierat mönster som reflekterar ett förväntat beteende hos den övervakade parametern efter det att skada har initierats, och tiden som har förflutit mellan tidpunkten när mätningen utfördes och tidpunkten när övervakningsparametern översteg den potentiella skadenivån. Mätvärdena måste på så sätt uppfylla två olika villkor för att de ska tillåtas att sparas i det rörliga fönstret. 

    Predikteringen utförs baserat på mätvärden som sparas i det rörliga fönstret, dvs. som är renade från störningar. På så sätt förbättras predikteringen.

    På grund av det faktum att mätdata renas också under den första fasen är det möjligt att starta prediktionen baserat på mätvärdena som sparats i det rörliga fönstret så fort som värdet på övervakningsparametern har passerat den potentiella skadenivån. På så sätt baseras prediktionen på mätvärden sparade under den första fasen såväl som under den andra fasen.

    Tack vare reningen av mätvärdena minskas antalet nödvändiga mätningar för att åstadkomma en tillräckligt bra prediktering. Det är tillräckligt med tre mätvärden som har renats enligt uppfinningen för att få ett tillförlitligt resultat.

    Enligt en utföringsform av uppfinningen är det fördefinierade mönstret för tillstånds­övervaknings­parametern en kurva som börjar öka vid tidpunkten då övervaknings­parametern överstiger den potentiella skadenivån. Kurvan beskriver värdet hos övervaknings­parametern i förhållande till tiden som har förflutit sedan tidpunkten då övervakningsparametern översteg den potentiella skadenivån. Formen på mönstret och således på kurvan beror t.ex. på typen av parameter, typen av skada, t.ex. ett brott eller slitage, och typen av förslitningssprocess, maskinens last och hastighet, och typen och kvalitén hos maskinen eller komponenten. För många typer av fel är kurvan exponentiellt ökande. Kurvan bestäms t.ex. baserat på föregående värde för samma tillståndsövervakningsparameter för samma eller liknade typer av maskiner eller komponenter. Kurvan börjar vid samma tid som det har detekterats att en skada har initierats, d.v.s. vid den tidpunkten då övervakningsparametern överstiger den potentiella skadenivån, och kurvan ökar under hela den andra fasen. Det förväntade värdet av mätningen bestäms baserat på kurvan och tidpunkten för mätningen. På sätt är det lätt att bestämma det förväntade värdet på mätningen.

    Enligt en utföringsform av uppfinningen slängs det nya mätvärdet om mätvärdet avviker från det förväntade värdet med mer än ett gränsvärde, gränsvärdet kan vara förutbestämt eller beräknas dynamiskt under den andra fasen.

    Enligt en utföringsform av uppfinningen innehåller mätmetoden vidare: ett meddelande till användaren genereras för att kontrollera mätningen och tillhandahålla ett nytt mätvärde när man har upptäckt att mätvärdet avviker för mycket från det definierade mönstret, ett nytt mätvärde tas emot och det nya mätvärdet jämförs med det förväntade värdet som har bestämts i enlighet med det definierade mönstret för tillstånds­övervaknings­parametern, och en varning genereras om det nya mätvärdet också avviker för mycket från det förväntade värdet. I annat fall byts det äldsta av de sparade mätvärdena i det rörliga fönstret ut mot det nya mätvärdet. En ny mätning utförs om värdet på mätningen avviker för mycket från det förväntade värdet under den andra fasen. Alternativt tas ett nytt mätvärde automatiskt när det har detekterats att en mätning avviker för mycket från det förväntade värdet. I och med denna utföringsform kastas ett felaktigt mätvärde och ersätts med en ny förslitningsrelevant mätning. Om den nya mätningen också avviker för mycket från det förväntade värdet genereras en varning till användaren. Det kan antigen betyda att någonting är fel med mätutrustningen eller att skadan har utvecklats mycket fortare än förväntat och att en underhållsåtgärd brådskande behöver utföras.

    Enligt en utföringsform av uppfinningen innefattar metoden vidare: den predikterade nivån hos tillstånds­övervaknings­parametern jämförs med åtminstone ett gränsvärde för tillstånds­övervaknings­parametern, de föregående stegen upprepas åtminstone tills den predikterade nivån hos tillstånds­övervaknings­parametern överstiger gränsnivån och ett meddelande genereras avseende en underhållsåtgärd när den predikterade nivån hos tillstånds­övervaknings­parametern överstiger gränsnivån. Gränsnivån är t.ex. en varningsnivå som ligger nedanför utbytesnivån för komponenten eller maskinen. Det är också möjligt att ha flera gränsnivåer mellan den potentiella skadenivån och en utbytesnivå. Denna utföringsform gör det möjligt att föreslå en underhållsåtgärd med tillräcklig ledtid vid en kostnadseffektiv tidpunkt.

    Enligt en utföringsform av uppfinnen är maskinen en roterande maskin och mätvärdena någon av vibrationsmätningar, temperaturmätningar, ljudmätningar och chockpulsmätningar.

    Enligt en annan aspekt av uppfinningen uppnås detta ändamål av en datorprogramprodukt direkt nedladdningsbar i det interna minnet hos en dator, eller genom en fjärrstyrd dator, web-service, eller molntjänst innefattande mjukvara för att utföra stegen hos metoden när nämnda program körs på datorn.

    Enligt en annan aspekt av uppfinningen uppnås detta ändamål av ett dataläsbart medium som har ett program inspelat, där programmet får datorn att utföra stegen i metoden när programmet körs på datorn.

    Enligt en annan aspekt av uppfinningen uppnås detta ändamål av en apparat.

  • 37.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Establishing and running a condition-based maintenance policy: applied example of vibration-based maintenance2007In: Proceedings of WCEAM / CM2007, 2007, p. 106-115Conference paper (Refereed)
    Abstract [en]

    Maintenance is not only for solving technical problems as many may consider. It as a matter of fact is for solving production related problems, such as technical, environmental, etc. cost-effectively. This is why the technical part of maintenance, e.g. focusing on developing condition monitoring (CM) technology is not always sufficient alone to achieve a cost-effective maintenance policy. Without the maintenance management part responsible of identifying problem areas, data acquisition, management and analysis, decision-making procedures, planning and performing maintenance tasks at high quality and cost-effectively, the output of using any CM system cannot be guaranteed to be beneficial. In this paper, Condition monitoring and condition-based maintenance is introduced and discussed with respect to the differences between them. Also, the procedures required for establishing and running a condition/vibration-based maintenance is introduced, motivated and discussed.

  • 38.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ett beslutsstödsystem för kostnadseffektivare underhållsåtgärder2011Other (Other (popular science, discussion, etc.))
  • 39.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Ett nytt underhållskoncept för kvalitetssäkring och förbättring till minskadekostnader: Totalt kvalitetsunderhåll (TKU)1999Report (Other academic)
  • 40.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Hur vet man om det är bättre att utveckla produktionen än att flytta ut den?2005In: Bättre produktivitet, ISSN 1402-1145, no 8, p. 26-26Article in journal (Other (popular science, discussion, etc.))
  • 41.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Impact of integrated vibration-based maintenance on plant LCC: A case study2000In: Quality reliability and maintenance (QRM), 2000, p. 105-109Conference paper (Refereed)
    Abstract [en]

    The biggest thread confronts maintaining high equipment effectiveness is; whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, Total Quality Maintenance (TQMain), is introduced It aims at making intensive use of real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery at an early stage and to allow control of these deviations to improve technical and economic of process effectiveness continuously. The effect of TQMain on machine's LCC and a company's economy is discussed. A case study revealing savings in maintenance cost, when a vibration-based policy is involved is presented

  • 42.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Impact of real-time measurements of operating conditions on effectiveness and accuracy of vibration-based maintenance policy: A Case Study in Paper Mill2000In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 6, no 4, p. 275-287Article in journal (Refereed)
    Abstract [en]

    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 (fifty-eight days), the total stoppage time was about 76.6 days and caused appreciable economic losses of about 2,3 millions SEK.

  • 43.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Improved effectiveness of vibration monitoring of rolling bearings in paper mills1998In: Journal of engineering tribology, Vol. 212, no 2, p. 111-120Article in journal (Refereed)
    Abstract [en]

    Rolling element bearing failures in paper mill machines are considered in relation to their critical role in the machine function. The paper discusses these failures according to what becomes damaged and how, and relates them to the vibration spectra and their development over the bearings’ lives. Interpretation of some variations in the vibration signature, i.e. relating vibration amplitude changes and frequency shifts to the deterioration processes involved, are proposed and discussed. The literature was found mainly to confirm this analysis. A new approach to envelope alarming is presented and shown theoretically (logically) to offer later renewal with fewer failures, and therefore lower cost and higher productivity. Deficiencies in data coverage and quality, and the feedback of case study results, are discussed. A model to improve maintenance experience is proposed and discussed. Using vibration to monitor component condition, the accurate prediction of remaining 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 the amplitudes of (and) the frequencies generated by the component damage. Much money could be saved because some present policies utilise as little as half of the bearing useful life.

  • 44.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Improvement in effectiveness of vibration-based condition monitoring system in paper millsManuscript (preprint) (Other academic)
  • 45.
    Al-Najjar, Basim
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Improvement in effectiveness of vibration-based monitoring systems1997Report (Other academic)
  • 46.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Integrated vibration-based maintenance1999Conference paper (Refereed)
  • 47.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Integrated vibration-based maintenance detecting quality deviations earlier than when using traditional diagram in the automative industry: a case study2000In: Advanced manufacturing: modular manufacturing, supplier integration, production planning, 2000, p. 157-165Conference paper (Refereed)
  • 48.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Just in Time Dynamic & Cost-effective Maintenance (JiT dMaint) for more Reliable Production: A Case Study2012In: Journal of Applied Engineering Science, ISSN 2247-3769, Vol. 10, no 2, p. 107-115Article in journal (Refereed)
    Abstract [en]

    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 the condition in the close future are usually lack in the available commercial systems although it is important for planning production/maintenance actions, reducing failures/accidents, & consequently reducing losses & production cost. In general, accurate maintenance decisions prolong life length of components/machines and maintain production continuity which adds competitive advantages. When CM parameter exceeds a significant (warning) level, it demands a clear understanding of what happened to avoid failures. Also, reliable answers concerning; what is the probability of failure of a component, its residual life and when is the most profitable time of conducting maintenance are necessary. In this paper, a new innovative eMDSS consists of three strategies for cost-effective maintenance & production processes is introduced and discussed. The major focus is given on one strategy (Accurate Maintenance Decisions). This strategy offers opportunity to achieve Just on Time Dynamic & Cost-effective Maintenance by selecting the most profitable time for maintenance is developed, tested in case companies and discussed. It offers unique solutions to increase maintenance profitability by enhancing maintenance decision accuracy via;

    1. Predicting the value of CM parameter, e.g. vibration, level, PreVib.
    2. Estimating the probability of failure at the close future and component residual life, ProLife.
    3. Using this new information, it will easily estimate the most profitable time for maintenance action.

    Accurate Maintenance Decisions provides data about future situation in addition to the current & past data, which is necessary for production and maintenance successful planning. This toolset; predicts the vibration level (PreVib), assesses the probability of failure of equipment and its residual life (ProLife), and consequently it becomes possible to determine the best time of maintenance action. It has been tested in several Swedish and European companies within the branches of car manufacturing, production machine manufacturer and process industry.  This study was partly funded by EU-IP DYNAMITE (Dynamic Decisions in Maintenance ) 2005-2009 and partly by E-maintenance Sweden AB. The major conclusions are; applying this toolset it is possible to reduce failures appreciably, prolongs the life length of components/equipment, and perform profitable maintenance.

  • 49.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Just in Time Dynamic & Cost-effective Maintenance (JiT dMaint) for more Reliable Production: A Case Study2012In: 21st European Congress on Maintenance and Asset Management, Belgrade, 2012, p. 277-286Conference paper (Refereed)
    Abstract [en]

    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 the condition in the close future are usually lack in the available commercial systems although it is important for planning production/maintenance actions, reducing failures/accidents, & consequently reducing losses & production cost. In general, accurate maintenance decisions prolong life length of components/machines and maintain production continuity which adds competitive advantages. When CM parameter exceeds a significant (warning) level, it demands a clear understanding of what happened to avoid failures. Also, reliable answers concerning; what is the probability of failure of a component, its residual life and when is the most profitable time of conducting maintenance are necessary. In this paper, a new innovative eMDSS consists of three strategies for cost-effective maintenance & production processes is introduced and discussed. The major focus is given on one strategy (Accurate Maintenance Decisions). This strategy offers opportunity to achieve Just on Time Dynamic & Cost-effective Maintenance by selecting the most profitable time for maintenance is developed, tested in case companies and discussed. It offers unique solutions to increase maintenance profitability by enhancing maintenance decision accuracy via;

    1. Predicting the value of CM parameter, e.g. vibration, level, PreVib.
    2. Estimating the probability of failure at the close future and component residual life, ProLife.
    3. Using this new information, it will easily estimate the most profitable time for maintenance action.

    Accurate Maintenance Decisions provides data about future situation in addition to the current & past data, which is necessary for production and maintenance successful planning. This toolset; predicts the vibration level (PreVib), assesses the probability of failure of equipment and its residual life (ProLife), and consequently it becomes possible to determine the best time of maintenance action. It has been tested in several Swedish and European companies within the branches of car manufacturing, production machine manufacturer and process industry.  This study was partly funded by EU-IP DYNAMITE (Dynamic Decisions in Maintenance ) 2005-2009 and partly by E-maintenance Sweden AB. The major conclusions are; applying this toolset it is possible to reduce failures appreciably, prolongs the life length of components/equipment, and perform profitable maintenance.

  • 50.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Just-in time and dynamic maintenance (JIT-Maint) for turbine, generator, gearbox and sawmills: case stories2015In: 28º COMADEM + X CORENDE 2015 / [ed] Marta Clelia Ruch, Asociación Argentina de Ensayos no Destructivos y Estructurales, AAENDE , 2015Conference paper (Refereed)
    Abstract [en]

    Profitable production demands continuously improved maintenance decision accuracy to reduce unplanned stoppages, prolong components/machines  life length and maintain production continuity. When CM, e.g. vibration level or oil temperature, value exceeds a warning level, it demands a clear understanding of what happened and how it will develop to avoid failures. It demands also reliable information, e.g. probability of failure, residual  life and when is the most profitable time for maintenance. Companies strive to reduce production cost through reducing non-value adding times, e.g. failures, for offering customers lower prices and generating additional competitive advantages. In this paper, a new tool (Prediction of Vibration and oil temperature, PreVib) for predicting the condition of a turbine, generator and gearbox is introduced,  discussed and tested. The solution offers a unique opportunity to achieve just in time dynamic and cost-effective maintenance by selecting the most profitable time for maintenance. PreVib is tested in a power plant. The major results: Failures can appreciably be reduced thanks the high precision of prediction ( + 90%), i.e. a negligible difference from the real measurement: PreVib does not demand extensive or additional data, and not replace available maintenance systems. The major conclusion is that applying PreVib, it is possible to reduce failures appreciably, prolong life length of components/equipment and perform profitable maintenance

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