Criticality Of Spare Parts Research Articles

Spare parts inventory management: a new hybrid approach

PurposeThe purpose of this paper is to present a new hybrid approach based on criticality analysis and optimisation to deal with spare parts inventory management in the initial provisioning phase in the mining industry. Spare parts represent a significant part of mining companies' expenditures, so it is important to develop new approaches to reduce the total inventory value of these items.Design/methodology/approachThis hybrid approach combines qualitative and quantitative methods based on VED (vital, essential and desirable) analysis, analytical hierarchical process (AHP), and e-constraint optimisation method to obtain the spare parts to be stocked. The study was applied to a large mining company. The mineral sector was chosen due to the great importance to the emerging Brazilian economy and the lack of researches in this sector. In addition, the spare parts have a relevant weight on the total inventory cost.FindingsPresent a novel approach combining multi-objective optimisation and multi-criteria evaluation approaches to tackle the inventory decision in spare parts management. This work also defines and classifies relevant criteria for spare parts management in the mineral sector validated by specialists. The proposed approach achieves an average increase of 20.2% in the criticality and 16.6% in the number of items to be stocked compared to the historical data of the surveyed company.Research limitations/implicationsThis paper applies the proposed approach to a mining company in Brazil. Future research in other companies or regions should analyse the adequacy of the criticality criteria, hierarchy and weights adopted in this paper.Practical implicationsThe proposed approach is useful for mining industries that deal with a large variety of resource constraints as it helps in formulating appropriate spare part strategies to rationalise financial resources at both tactical and strategic levels.Originality/valueThe paper presents a new hybrid method combining the AHP a multi-criteria decision making (MCDM) approach coupled with e-constraint optimisation to deal with spare parts inventory management allowing for a better spare parts inventory analysis in the initial provisioning phase and providing managers with a systematic tool to analyse the trade-off between spare parts criticality and total inventory value.

Critical Evaluation and Optimal Allocation Model of Ship Spare Parts

In the case of limited funding, in order to avoid the serious consequences of the shortage of critical spare parts on equipment, priority must be given to ensuring that critical spare parts are not in shortage. The assumption of the traditional equipment support model is that the criticality of spare parts is the same, which will lead to the priority of lower-priced spare parts rather than the critical ones under the constraints of limited funds. In order to overcome this shortcoming, an optimal allocation model based on the criticality of spare parts is established in this paper. The genetic algorithm software were used to solve the model. The practical case shows that under the circumstance of limited guarantee funds, the key-based spare parts allocation model can be adjusted according to the criticality of the spare parts, the priority is given to the highly critical spare parts, and the critical general spare parts are also considered.

Metoda oceny krytyczności części zapasowych oparta o rozmyty proces hierarchii analitycznej AHP i funkcję strat Taguchi

Effective and efficient operation of a manufacturing system highly depends on the timely and correct implementation of maintenance operations. One of the most important factors affecting the successful implementation of maintenance operations is the determination of suitable inventory control policies for maintenance spare parts. Effective spare parts inventory management requires the criticality evaluation of spare parts. In this study, a novel spare parts criticality evaluation approach is proposed. First, the evaluation criteria are determined based on literature review and expert opinion and Fuzzy Analytical Hierarchy Process (AHP) is used to determine the criteria weights. Next, Taguchi loss functions and simulation modeling are employed for the calculation of loss values for the spare parts. Finally, a criticality ranking of the spare parts is obtained based on the weighted loss values which are calculated using criteria weights and loss values. The applicability of the proposed approach was tested by applying it to a spare part criticality evaluation problem faced by a manufacturing company.

A risk‐based approach to manage non‐repairable spare parts inventory

Purpose – The purpose of this paper is to propose a risk‐based approach for spare parts demand forecast and spare parts inventory management for effective allocation of limited resources. Design/methodology/approach – To meet the availability target and to reduce downtime, process facilities usually maintain inventory of spare parts. The maintaining of non‐optimized spare parts inventory claims more idle investment. Even if it is optimized, lack of attention towards the critical equipment spares could threaten the availability of the plant. This paper deals with the various facets of spare parts inventory management, mainly risk‐based spare parts criticality ranking, forecasting, and effective risk reduction through strategic procurement policy to ensure spare parts availability. A risk‐based approach is presented that helps managing spare parts requirement effectively considering the criticality of the components. It also helps ensuring the adequacy of spare parts inventory on the basis of equipment criticality and dormant failure without compromising the overall availability of the plant. Findings – The paper proposes a risk‐based approach that used conjugate distribution technique with the capability to incorporate historical failure rate as well as expert judgment to estimate the future spare demand through posterior demand distribution. The approach continuously updates the prior distribution with most recent observation to give posterior demand distribution. Hence the approach is unique in its kind. Practical implications – Appropriate spare parts unavailability could have great impact on process operation and result in costly downtime of the plant. Following proposed approach the availability target can be achieved in process industry having limited maintenance resources, by forecasting spare parts demand precisely and maintaining inventory in good condition. Originality/value – Adopting the approach proposed in the paper, risk level can be minimized and plant availability can be maximized within the financial constraint. The resources are allocated to the most critical components and thereby increased availability, and reduce risk.

Spare parts criticality evaluation using hybrid multiple criteria decision making technique

Criticality evaluation of spare parts is very important for controlling the spare parts inventory. The service levels that are specified consequent to the criticality evaluation serve as one of the inputs enabling smooth operation of production facilities. Systematic criticality evaluation of spare parts is the key to effective control of spare parts inventory systems. In order to deal with this problem, the criticality of the spare parts (SPs) must be confirmed. There are many factors to be considered as a part of the criticality of spare parts for maintenance activities. Consequently, evaluation procedures involve several objectives and it is often necessary to compromise among possibly conflicting tangible and intangible factors. For these reasons, MCDM has been found to be a useful approach to solve this kind of problem. In the present work, a three phase hybrid model is developed for the evaluation of criticality of the spare parts. The first stage involves identifying the criteria. The second stage is to prioritise the different criteria using fuzzy ANP, and then finally ranking of spare parts using fuzzy TOPSIS.

A hybrid decision support system for slow moving spare parts joint replenishment: a case study in a nuclear power plant

This paper presents a hybrid Decision Support System (DSS) for slow moving spare parts joint replenishment in a nuclear power plant. In this study, we integrate the fuzzy and grey theory-based spare parts criticality class evaluation model to confirm the target service level, and the web-based joint replenishment DSS to obtain reasonable purchase parameters that can be helpful for reducing total inventory holding costs. The proposed DSS was successful in decreasing inventories holding costs significantly by modifying the unreasonable purchase applications while maintaining the predefined target service level.

Spare parts criticality for unplanned maintenance of industrial systems

The paper presents a methodology and Decision Support System (DSS) for the establishment of spare parts criticality with a focus on industrial unplanned maintenance needs. The obtained criticality is used to rationalise the efficiency of the plant spare parts inventory. Through a top-down Failure Modes Effects and Criticality Analysis (FMECA) that is appropriately adapted to the unplanned maintenance requirements and through the introduction of the Component Dynamic Criticality concept, the components of an industrial production facility are ranked. For those with criticality lying above a calculated threshold, additional spares are suggested to be kept in the plant spare parts inventory. An application example demonstrates the method. [Received 14 May 2007; Revised 25 July 2007; Accepted 13 September 2007]

The Effectiveness of ``On-Board'' Maintenance

``On-board'' maintenance for offensive weapons systems and its relationship to the allocation of spare parts is discussed. A method for the selection of ``on-board'' spare parts is given and an expression for the increase in subsystem reliability through ``on-board'' repairs is derived. The concepts of effective reliability, combat effectiveness, and criticality of spare parts are examined. Curves obtained from a hypothetical but realistic maintenance situation show the given relationships between the criticality and the weight and volume of spare parts. These relationships provide a basis for decision on the allocation of spare parts for improving combat effectiveness through ``on-board'' maintenance.