Papers by Keyword: Maintenance Strategy

Abstract: This paper analyzes preventive maintenance scheduling of bottleneck equipment in a line concept of a wafer manufacturing line that has buffer in between equipment. After the start-up of the manufacturing, it has implemented time based maintenance and counter based maintenance without any fix sequence. The maintenance team will select in advance the date and time of the actual preventive maintenance to be perform and making sure all resources are planned. Then maintenance team implemented a Preventive Maintenance sequence which gives the lowest impact in production loss without sacrificing equipment’s quality and safety. This Preventive Maintenance Scheduling sequence is the best suitable method for manufacturing equipment that has buffer in between equipment which is arranged in a line concept. It has also been tested and proven in a wafer manufacturing industry.

Abstract: Every manufacturer requires plant maintenance. Knowing that an effective maintenance system increases sales and decreases maintenance cost of the production facility, maintenance is deemed to be substantial contributions to improved plant profit changing from a necessary evil to a profit centre. Unfortunately, this sometime is a far cry from reality. This paper offers a concept of incorporating risk into maintenance and development of a Decision Support System (DSS) for decision makers in the maintenance department. It helps prioritise critical equipment and select its associated maintenance strategy for optimum results. The results of validating the devised AHP-based software package in a case study company in Indonesia are promising since the company successfully gains 3.65% in Net Line Efficiency and 3.13% in Gross Line Efficiency as well as enjoys an advantage over 4.56 points decrease in Operation Performance Loss.

Abstract: This work provides a detection method for failure in rotating machines based on a change of vibration pattern and offers the diagnosis about the operation conditions using Fuzzy Logic. A mechanic structure (as an experimental prototype where faults can be inserted) called Rotating System has been used. The vibration standard of the Rotating System, called "The Spectral Signature", has been obtained. The changes in the vibration standard have been analyzed and used as parameters for detecting incipient failures, as well as their condition evolution, allowing predictive monitoring and planning of maintenance. The faults analyzed in this work are caused due to insertion of asymmetric masses for unbalancing in the axle wheel. The system for diagnosing Fuzzy System was calibrated to detect and diagnose the conditions: normal, incipient failure, maintenance, and danger, using linguistic variables. The frequency of rotation and the amplitudes of vibration of the axle wheel are considered in each situation as parameters for analysis, diagnostic, for the decision by the Expert System based on Fuzzy rules. The results confirm that the proposed method is useful for detecting incipient failures, monitoring the evolution of severity and offering grants for planning and decision making about maintenance or prevention of rotating machines.

Abstract: The design quality of the nuclear power plants (NPPs) has a direct impact on the operation and maintenance, which involves the safety and reliability of NPPs. Planning and development of the maintenance requirements of system and equipment in initial design stage of NPPs, and determination of reliability maintenance strategy compilation methods enable to fulfill good connection between design and operation of important value. After investigation and analysis, with a combination of reliability analysis method, experience feedback and common analysis approach, the methodology of reliability maintenance strategy compilation in design stage of NPPs has been initially established. And such methodology not only meets the maintenance requirements of system and equipment in design stage, but also enables to check the rationality and operability of process design from the maintenance implementation level, at the same time, it has great value in application regarding improving operational reliability of NPPs and avoiding non-essential major modification during operation of NPPs.

Abstract: Taking on the features of agility, intelligence, Internet and socialization in the wake of rapid expansion of global manufacture and cutthroat competition, to establish an e-intelligence maintenance system is crucial for manufacturing enterprise to reduce costs and increase profits in the global market. Based on the analysis of requirement for e-intelligence maintenance in manufacturing industry of our country, this paper puts forward the remote coordination mechanism, the risk control mechanism and the security mechanism. Then explores the eMS strategy formation and optimization which based on Case-based reasoning, intelligent evaluation model of eMS and an effective integration schemes of realizing an enterprise web e-manufacturing and an e-business tool.

Abstract: The reliability analysis of the coal mining vehicle is expounded by the application of Reliability Centered Maintenance (RCM). According to RCM, maintenance mode and service period of the equipment are determined after a logical judgment and effective analysis of equipment reliability and malfunction results. Corresponding maintenance strategies are established. It is estimated that the strategy may be further applied in equipment maintenance strategy.

Abstract: t is hard to acquire the failure data of ship unloader and the mean time to failure is not independent identically distributed, and there are many defects existed in the maintenance method such as high cost and bad effect. In this work, we propose a method based on Weibull Distribution model to deal with the failure data of a large-scale grab ship unloader, build up the model of MTBF (Mean Time Between Failure) and preventive maintenance time, and show the example with failure data, which provides references to maintenance of the ship unloader. Finally, we present the decision process of the reliability-centered maintenance strategy, maintenance type of the grab ship unloader and the maintenance of the key parts, which provides scientific decision support for the maintenance of the ship unloader equipments.

Abstract: The optimized maintenance strategy of multi-stage production line is influenced by device processing ways, parts process plan and equipment deterioration process and other factors. Moreover, the production processes of parts exist constraint relationship. Based machining process plan of complex parts, the order relations of its operation processes is analyzed; the optimized multi-stage production line maintenance model is constructed with multiple objectives including production time, maintenance time, production cost and maintenance cost; the genetic algorithm is used to solve the model, and the Monte Carlo method is applied to carry out the simulation computation for fitness function of chromosome of genetic algorithm; the results give the maintenance threshold of each equipment of the line, their configurations and allocation of the various operation processes of parts at the same time. Finally, an example is presented to prove the effectiveness.

Abstract: The unavailability equations of several aging scenarios of standby safety component are derived and the risk of standby safety system is quantified. The different maintenance strategies are adopted for no aging scenario and several aging scenarios respectively. The two kind of test and maintenance (T&M) policies are adopted for no aging scenario and several aging scenarios. A numerical example is introduced for the illustration. The system unavailabilities under different configurations of parallel safety system and T&M policies are computed and compared. It can be derived that the combination of different T&M policies and configurations is significant effect on the risk of standby safety system and optimal STI and T&M interval.

Abstract: In China a large number of bridges built in 1960s and 1970s are still in operation. They went through several decades of intense heat and cold winter, water scouring, and accelerated load-increasing, which will lead to the deterioration of the structure. They are in the need of maintenance, reinforcement and transformation. The bridge assessment, maintenance, reinforcement and strengthening for the safety and reliability of existing bridges had attracted the attention of researchers. It’s essential to reinforce the old bridges with appropriate designs and construction technologies to improve its load-carrying capacity and extend the service life to meet the requirements of the current transportation. This paper first introduced China’s current situation and existing problems of the bridges. Then the strengthening methods and techniques for the existing damaged bridges are presented. The conclusions and future prospects are finally given.