Preventive maintenance models – higher operational reliability

Abstract

Article citation info: Introduction and literature surveyMany maintenance strategies, policies and methods have been developed, which are aimed at making maintenance cheaper and more effective. Such programs have the minimization of costs, downtime and losses due to failure of critical objects of the equipment as their main objective. Cost minimization improves the effectiveness and profitability of the organization [1,2,9,12,13,20].For creation of the maintenance policies, well described data mining input is very important. [4].In recent years, useful models of preventive and predictive maintenance optimization with different complexity and applicability have been further developed.In the paper, [5] the authors proposed a quasi-periodic imperfect preventive maintenance policy. Finally, a real case study of preventive maintenance on Chinese diesel locomotives is examined to illustrate the proposed maintenance policy.The paper [6] proposes an approach in which preventive and failure replacement costs as well as inspection cost are taken into account to determine the optimal replacement policy and an age-based inspection scheme, such that the total average costs of replacements and inspections is minimized.Determination of the preventive effect of optimal replacement policies in the paper [8] is based on aging intensity and the cost ratio of failure and preventive replacements. One of its conclusions is that not every preventive maintenance is fully effective and a policy of, "run to failure" can be more effective (note: in some cases).The proposed model in the paper [10] takes into consideration the stochastic nature of equipment failures. The output from the model is a cost distribution against the time from which the minimum cost may be found for a particular period and this period is defined as the optimum lifespan of the machine part.The paper [11] considers periodic preventive maintenance policies for a deteriorating repairable system. On each failure, the system is repaired and, at the planned times, it is periodically maintained to improve its performance reliability. Most periodic preventive maintenance (PM) models for repairable systems have been studied assuming that the failure process between two PMs follows the nonhomogeneous Poisson process (NHPP), implying the minimal repair on each failure.The paper [14] regarding warranty policy considering three maintenance options for products with multiple failure modes also showed the broad usability of the Weibull distribution. This fact supports the decision of the authors to also use the Weibull function.The paper [15] presents a new mathematical function to model an improvement based on the ratio of maintenance and repair costs, and demonstrate how it outperforms fixed improvement factor models by analyzing the effectiveness in terms of cost and reliability of a system. Legát V, MošnA F, ALeš Z, JurčA V. Preventive maintenance models -higher operational reliability. eksploatacja i niezawodnosc - Maintenance and reliability 2017; 19 (1): 134-141, http://dx...

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“…These also offer an actual indication that predetermined preventive maintenance pushes up the working reliability of system. The decision lies with the maintenance specialists, whether or not they apply the designs and methods for improving the maintenance efficiency of industrial production equipment [16,22].…”

“…This distribution is applied to data modeling regardless of whether the failure intensity is rising, falling or constant. Weibull distribution is flexible and adaptable for data from a wide range [16][17][18]. One of the advantages of using Weibull distribution is that the failure rate can have a rising, falling or constant trend [19].…”

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“…After introducing the new maintenance system, it is rightfully expected to improve maintenance planning, cost-effectiveness, and other intangible benefits. According to various literary sources, time after implementation could possibly be reduced by up to 30% [20,23]; specific information from the pilot project was only from one workshop (mechanical machining workshop) from the company where the project was implanted and is 7%, as shown below.…”

“…In each subsequent iteration step, we determine new values of the coefficients A, B, C, and D, by adding corrections to the value from the previous iteration A k+1 = A k + A, etc. We terminate the iteration when the sum of the squares of deviations (R i ) 2 reaches the required accuracy, or when we perform a predetermined number of iterations [16,23,24], etc.…”

Optimal maintenance strategy on medical instruments used for haemodialysis process

“…The most common maintenance technique used is either preventive [5,17] or corrective [7] in nature. Both these techniques have time and again been deemed as ineffective because Corrective Maintenance (CM) [2] inculcates large and unpredictable downtimes while Preventive Maintenance (PM) [21,29] swings between extreme cases of 'more than necessary' and 'less than necessary' repairing frequency during infancy and aging periods respectively [34]. In particular, PM is carried out periodically on the basis of experience [41] or from the recommendation of the equipment manufacturers, and it does not account for unexpected failures because their failure mechanisms are time based [8].…”