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Procedía Technology 9 (2013) 812 - 818
CENTERIS 2013 - Conference on ENTERprise Information Systems / PRojMAN 2013 -International Conference on Project MANagement / HCIST 2013 - International Conference on Health and Social Care Information Systems and Technologies
Establishing the maintenance and repair body of knowledge: comprehensive approach to ensuring equipment maintenance and repair organization efficiency
A.V. Kizim*
Volgograd State Technical University, Lenin avenue 28, Volgograd, Russia, 400005
Abstract
This paper describes a comprehensive approach to ensuring equipment maintenance and repair organization (MRO) efficiency in solving tasks with supporting tools and a systematic approach. Types of support for MRO, classification of MRO methodologies, basic organization aspects of the program, information and methodical support for MRO, which makes maintenance and repair body of knowledge (M&R BOK) are presented. The ways of improving MRO by using the system approach, correlated goals and key performance indicators, and also some methods of improving the MRO organization efficiency are proposed. The MRO process formalization with functional and business models and incorporating them into a common information MRO support model is proposed. The MRO KPI was described as a model. The application of intellectual agents and multi-agent system for performance monitoring, data collection and decision making are described. The life cycle cost of the equipment formula is proposed. The tasks of optimization in MRO support and knowledge accumulation, application and reasoning by ontologies are commonly described.
© 2013 The AuthorsPublishedbyElsevierLtd.
Selection and/orpeer-reviewunder responsibility of SCIKA - Association for Promotion and Dissemination of Scientific Knowledge
Keywords: maintenance; repair; MRO; efficiency; CMMS; automation; performance;KPI; program and information support; methodical support; use of knowledge; maintenance strategies; intelligent agents; life cycle cost; ontology.
* Corresponding author. Tel.: +7-919-980-0256; fax: +7-8442-24-81-00 E-mail address: kizim@mail.ru.
2212-0173 © 2013 The Authors Published by Elsevier Ltd. Selection and/or peer-review under responsibility of SCIKA doi:10.1016/j.protcy.2013.12.090
- Association for Promotion and Dissemination of Scientific Knowledge
1. Introduction
Enterprise performance depends on equipment efficiency. Mechanical departments of a company or service organizations (contractors) perform the function of facilitating smooth running of the equipment. Availability of the equipment is provided by high-quality, timely and safe maintenance and repair (MRO) in a case of rational use of resources.
Methodical [11], mathematical [14, 16], programming, informational, organizational, technological and other supporting tools can be used for more effective management of MRO processes [12, 13, 15]. Specialized software and information systems can be used to automate maintenance and repair. Depending on the scale of the problem there may be the following program system classes: ERP (Enterprise Resource Planning), EAM (Enterprise Asset Management) and CMMS (Computerized Maintenance Management System). The current competitive environment has variability. The enterprise should constantly look for ways to reduce costs and improve productivity to be competitive. One such tool is the rational organization of the MRO.
This paper shows the basic organization of effective enterprise equipment maintenance and repair based on a systematic approach, obtained on the basis of years of combining experience in the development and implementation of supporting maintenance and repair of software systems. The MRO Body of Knowledge (M&R BOK) is made due to combining joint research, teaching and team of MRO software developers' supervision activities which allowed obtaining the following proposal of the application software, informational and methodological MRO support organization [11, 12].
2. Improving maintenance and repair efficiency with application of a systematic approach to the problem of maintenance and repair support
The systematic approach strongly affects efficiency more than private solutions in any field of research.. The following set of tools for organizations of full equipment operation maintenance and repair support is offered from the standpoint of systems analysis is offered.
The following main problems of the effective MRO carrying out can be considered in the area of scientific MRO work support organization: the rational maintenance and repair strategies using; production losses and maintenance costs minimizing throughout the equipment life cycle; maintenance and repair resources optimization, effective management of MRO services (as well as stand-alone contract repair and service company), their profitability and key performance indicators increasing (there are stand-alone company or subdivision task management, work ordering and organization, the effectiveness of maintenance and repair services evaluating and improving, works controlling, the production program making), the preventive actions definition to prevent the emergence of failures and increase the equipment reliability (MRO form and order selection: decision support and planning; the best time of MRO execution determination: equipment condition monitoring and its failure forecasting). Many of the identified problems have solutions applied for maintenance and repair services support, but not all of them are settled in full. To enhance the competitiveness of an enterprise special attention should paid to them.
According to Lawson [17], such effects as reducing the number of equipment failures, downtime, maintenance costs, and increasing lifetime, reliability and performance can be achieved by application of science-based MRO organizations.
Selecting agents that affect efficiency of equipment maintenance and repair carried out. After that they are interviewed to identify issues of concern and to better understand the existing state of affairs. A correct understanding of the client's needs are always gives a much more significant result than the absence of feedback.
To understand the current state of affairs it is necessary realize a study of the complex used in the enterprise organizational, technical, technological, social, and other maintenance and repair mechanisms. The MRO process formalization can be performed with functional and business models, such as IDEF "as-is" [10], BPML etc. The MRO process elements and links formalization, functional units' decomposition, input and output information, power and material flows identification, affecting agents" structure and methodological and organizational rules determination affecting the process are performed. The obtained results are incorporated into a common information MRO support model.
Furthermore, an analysis of the received model of the process in order to identify weaknesses and prospects for increasing the efficiency of maintenance and repair has been performed. Improvement-problem statement is made. One part of which is time-limited by the terms, and the other is constant. The problem should be fixed. One way to describe the problem statement is using a goal mechanism.
Further, the proper tools to achieve formulated goals and also monitoring, measuring and performance evaluating of their achievement are defined.
The following instruments of achieving formulated goals can be applied: the local algorithms and methods for solving problems such as indicators optimization, management decision-making support (to improve the adequacy of the decision-making), increasing the reliability of detail or construction unit. Also the complex methods and approaches of MRO organizing support can be applied.
3. Goals and indicators using to improve maintenance and repair efficiency
3.1. The using of key performance indicators to improve MRO efficiency
The new MRO technique is just one of the effective production management conditions. For the MRO systematic approach it is required to formulate a hierarchy of goals, which are necessary to achieve the global goal (the enterprise competitiveness improving). You must have the MRO effectiveness monitor and analyze ability by using of performance indicators.
The special metrics, such as key performance indicators, which are combined with a balanced scorecard, is necessary to use to understand the current maintenance and repair performance level, the goals achievements" degree as well as directions of their further development and improvement. Thus, the system of key performance indicators (KPI) based on the goals hierarchy and reflecting the current situation and the level of defined objectives achievement is constructed, according to [9].
The understanding of equipment maintenance and repair performance level is the data source for KPI building, which requires work performance evaluations analysis. Assessment of the operations effectiveness (OE) expressed in quantitative (eg, operation or up-time hours) and in qualitative terms (eg, % of the plan implementation). If the company practices maintenance and repair, then it is essential to determine not only the MRO works OE, but also their optimization methods, which are expressed in relative indicators (for example, repair work time relative decreasing and up-time increased etc.). Then OE is expressed by key performance indicators.
KPIs can be described using a set-theoretic model: P = <N, A, Tp, U, P, B, GV, Tr, F, G>, where N is name of indicator, A - using area (object, agent or all MRO process); Tp - type of indicator (Tp={quantitative, qualitative}), U - indicators unit of measurement value, P - indicators measurement (monitoring) values frequency (P={noting; day; week; month; quarter; half year; year}), B - bordering value, GV - indicators goal value; Tr - trend of indicator value; F - calculating formula for indicator; G - goals associated with indicator.
KPI calculation requires data of events related to the MRO process characteristics and the equipment state. It is required for the application of automated data collection and storage organization (such data as
equipment performance parameters and maintenance services performance). The collection of information is needed to organize each stage of the MRO work.
The multi-agent technology using intelligent software agents can be applied during the monitoring, data collection, decision making and so on. For example, with the logic of "belief-desire-intention" (BDI), f.e. [2, 21, 23] and etc. intellectual agents works together in multi-agent system.
Agent's model formalizing with this approach involves using of Kripke structures adapted to intellectual agent behavior prediction task, [18]: M = (W, д, Г, B, D, I), where: Wis a set of possible worlds of beliefs WB, desire WD and intentions W, i.e. W = WB и WD и W, W: ({Sw: w e W},{Rw: w e W }); л - purpose function that assigns a set of statements (equation of state) of many Ф which are true in a given state to each state i of the world w, т.е. ^(w, s) ^ Ф', w e W, se Sw, Ф'сФ; д - assignment function, assigning some action to each reachable relation r, described in world w, i.e. д^, r) ^ w e W, re Rw, ^eS; Г- agent's system of goals presented as a set of objective functions Y(s)er defining priorities to achieve agents set conditions; B, D, I - relation on the set of worlds and states. In border of the agent's beliefs is obtaining the result B с WBxSxWB.
Organization of a joint service agents network interaction is described by [7, 20].
A number of techniques which are the part of an overall approach to data processing and data mining been used to process and organize collected data. There are primary data preprocessing, detection of abnormal data; using association rules; classification; cluster analysis; decision trees; factor analysis; regression analysis; analysis of the structural data; analysis of sequences.
Continuous MRO effectiveness evaluating process and adaptive change insertion in the MRO process are necessary to organize when using the systematic approach to solve the problem of maintenance and repair efficiency. The result obtained is the repair service efficiency Ем optimum value.
According to Levitt [19], the repair services efficiency criterion can derived as Ем = См + Lp, where См is costs necessary to perform repair and maintenance actions; Lp - manufacturing losses. Such contradiction, that the low maintenance costs leads to a significant loss of production and a significant total spent has been known. On the other hand, high costs lead to decreasing margins. In [14] it was argued that the optimum corresponds to the case where the amount of surplus value loss and the cost of repairs have minimal value.
3.2. Main stages of the iterative MRO organization system based on KPIs
The main stages of the iterative system MRO organization based on KPIs have been offered: 1) KPIs system development or enhancement. 2) Equipment maintenance and repair works carrying out. 3) KPIs data collection and calculation. 4) Equipment MRO system optimization carrying out.
In this case, if the equipment failure event occurs, it is necessary to carry out the following algorithm of actions to prevent failures in the future: 1) The problems leading to a fault identification. 2) Problem analysis to identify its causes, failure modes, arising from failures effects, frequency, severity and type of failures. 3) Suitable system solutions (known methods choice and adaptation or new ones developing). 4) New solutions application with measurement of their effectiveness and comparison with the old methods. Such methods can be applied to prevent failures: failures root cause analysis (RCA), FMECA, etc.
4. Comprehensive MRO process efficiency
4.1. Improving the efficiency of MRO execution performance
The efficiency of MRO performance organization improvement is possible by using modern and advanced MRO methodologies and their combinations. In the process of improving equipment maintenance and repair
approaches historically, a transfer from reactive repairs (i.e. emergency repairs after failures occasion) to preventive maintenance (PM) was realized. This can be divided into the following types: scheduled maintenance (or Planned maintenance, PlM), Condition-based maintenance (CBM); and preventive maintenance based on forecast data (Predictive maintenance, PdM). Each of these approaches has some advantages and disadvantages, and should be applied according to its terms of use. The approach to reducing or extending the PlM time, was not approved during the search for methods to minimizing the maintenance and repair cost. For better maintenance and repair management it is necessary to apply different MRO organizational approaches to different equipment groups. For example there are critical equipment (for uninterrupted work), repairs cost, maintenance and repair time, etc. Risk matrixes can also be used for solving similar problems.
4.2. Improving the equipment efficiency
Indicators of efficiency: Overall equipment effectiveness (OEE) and total effective equipment performance (TEEP) are commonly used in industries [6]. OEE and TEEP are two closely related KPI measurements that report the overall utilization of facilities, time and material for manufacturing operations. These top view metrics directly indicate the gap between actual and ideal performance. Overall equipment effectiveness quantifies how well a manufacturing unit performs relative to its designed capacity, during the periods when it is scheduled to run. TEEP measures OEE against calendar hours, i.e.: 24 hours per day, 365 days per year. A good achievement for the enterprise level in equipment effectiveness is about 80-90%.
Due to the fact that the equipment availability depends on work reliability, it is first necessary to solve the issues of complex systems reliability, which results in a large area of scientific work. We are interested in the organizational and methodological aspects of the problem, inherent in MRO technology named "Reliability centered maintenance" (RCM) [22]. This method is based on a combination of risk management and equipment operating parameters monitoring and control. The possibility of its use in MRO support tools is determined due to the use of knowledge organization and learning methods, as well as the procedures for their use (i.e. inference). Case based reasoning (CBR) on ontology can be applied as an inference machine.
4.3. Management of equipment life cycle total cost
Equipment costs includes not only the cost of purchase and maintenance but also the life cycle cost of the equipment LCC = Cic + Cin + Ce + Co + Cm + Cs + Cenv + Cd, where Cic is initial buying cost, Cin - the cost of installation, training and commissioning, Ce - energy costs, Co - cost of normal operation, Cm -maintenance and repair cost, Cs - cost of downtime (not full production output), Cenv - cost of consumables required for the proper functioning of equipment, Cd - cost of decommissioning and disposal of equipment and materials. Accordingly, the change of any equipment life cycle phase value or life cycle component cost structure involves a change in the total cost LLC. To improve the equipment efficiency, it is sufficient to reduce the cost of any LCC components. A stronger solution is a comprehensive approach to the simultaneous reduction of various groups of costs, affecting the value of LCC. For its implementation a complex application of the methodological, software and informational support in conjunction with the mathematical methods and algorithms is necessary. We have selected a generic composition of maintenance and repair support tasks and related methods to ensure effective equipment operation [10, 11]. It"s description is beyond the scope of this paper. The parameter "Return on Investment" (ROI) is also an important parameter of the MRO asset life cycle cost efficiency.
4.4. Optimization tasks in MRO support
The minimizing MRO cost Cm (which consist of repair costs RC and maintenance cost MC) with production losses minimization PL due to poor equipment technical condition are the maintenance and repair costs effectiveness criterions. Ensuring timely delivery of required resources is essential.
According to [10], solving task commonly can be described as a model <S, K, E, P>, where S is a set of possible solutions; K- criteria; E - a set of evaluations, P - a set of decision maker's preferences. In this case, a set of criteria K = <RC, MC, PL>, and the objective function can be written in common as: {min{f(RC + MC)}, min {f(PL)}.
Typical tasks also are problems of determining work ordering and scheduling. MRO model can be represented by models of queuing systems: Markov chains methods, Petri nets and multi-agent systems. The MRO models prototype for defining characteristics and simulation prospects, which allows determining the effectiveness of various MRO strategies, was constructed.
Maintenance and production strategies, which are subcontractor and contractor constraints, have been treated in [4]. Investigation of some rational production unit operating strategy carried out by [3].
5. Application of knowledge accumulation and using technologies to improve MRO
Particular attention in the MRO research and rationalization is given to the study of service and repair rules and strategies applied in the organization. They can be formalized in different degrees using corporate standards and methodological support.
An important issue of support organization is knowledge collection and organization in a united informational repository (the knowledge base). Knowledge organization for maintenance and repair support can be done in various ways, each of which has certain advantages and disadvantages. For maintenance and repair tasks, in addition to information about the serviced assets facilities, territorial and divisional organization, maintenance and repair agents, there are a variety of information classifications, rules governing the maintenance and repair in a point of view of time, resource attributes and limitations, depending on the maintenance or repair type.
Knowledge representation (in addition to the classical relational data models) can be represented in the form of knowledge maps, frames, prototypes and precedents. Ontology mechanism is more structured and adapted for using in maintenance and repair process and its components knowledge representation, [1]. A result of inference has been gotten by using the mechanism of case based reasoning (CBR). Information systems flexible adjustment on applied MRO methodologies is important for practical application. For example, the PlM using for maintenance of equipment that is under warranty and regulated by state oversight.
6. Conclusion
The work describes brief results obtained during the maintenance and repair program-informational and methodological support organization. They form a maintenance and repair body of knowledge (M&R BOK) which can be used for MRO organization along with MRO automation and support. Some provisions of the M&R BOK are realized in ASTOR software and information system which implements maintenance and repair services of industrial enterprises and specialized outsourcing contracting repair organizations. Author appreciated to RBBR for supporting (project №13-01-0079813).
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