The intensity growth of manufacturing industry in India is increasing the demand of CNC turning centers. The producers of CNC turning centers are trying to fulfil this demand. The quality and reliability of such CNC turning centers is critical for manufacturers and users to meet the market demand. In this context, it is required to identify the potential failures and minimize their occurrence probability. Failure modes and effects analysis (FMEA) is a robust methodology used to study the risk and reliability of various systems. In this paper, FMEA methodology is used to analyze the risk involved in the operation of CNC turning centers. The objective of the analysis was to identify critical failure modes, components and sub-systems. The study uses field failure data from more than 50 CNC turning centers and more than five industrial experts. FMEA results are further compared to the failure rates obtained from the field failure data. The results of the FMEA analysis are useful for system reliability improvement and optimizing maintenance. Electrical and electronic components have higher failure rates compared to mechanical components. CNCS, MT, XZAS, HS, ChS and SS are found to be critical sub-systems.

Basavraj Shantaram Kothavale

School of Mechanical Engineering

Engineering and Technology

R. B. Patil

MIT-World Peace University (MIT-WPU) is a top educational institute located in Pune, India. It is recognized within&nbsp;UGC under Government of Maharashtra Act No. XXXV 2017.&nbsp;

It is part of the MIT group of institutions (established in 1983) which covers 10+ campuses across India and has more than 50,000+ students enrolled across various disciplines at a given point of time. The institute houses 15 schools ranging from Engineering &amp; Technology, Design, Pharmacy, Commerce, Governance among others. It offers undergraduate, postgraduate and PhD programs among different disciplines.&nbsp;

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MIT World Peace University

International Review of Mechanical Engineering

PurposeThe paper presents reliability, maintainability and life cycle cost (LCC) analysis of a computerized numerical control (CNC) turning center which is manufactured and used in India. The purpose of this paper is to identify the critical components/subsystems from reliability and LCC perspective. The paper further aims at improving reliability and LCC by implementing reliability-improvement methods.Design/methodology/approachThis paper uses a methodology for the reliability analysis based on the assessment of trends in maintenance data. The data required for reliability and LCC analysis are collected from the manufacturers and users of CNC turning center over a period of eight years. ReliaSoft’s Weibull++9 software has been used for verifying goodness of fit and estimating parameters of the distribution. The LCC of the system is estimated for five cost elements: acquisition cost, operation cost, failure cost, support cost and net salvage value.FindingsThe analysis shows that the spindle bearing, spindle belt, spindle drawbar, insert, tool holder, drive battery, hydraulic hose, lubricant hose, coolant hose and solenoid valve are the components with low reliability. With certain design changes and implementation of reliability-based maintenance policies, system reliability is improved, especially during warranty period. The reliability of the CNC turning center is improved by nearly 45 percent at the end of warranty period and system mean time between failure is increased from 15,000 to 17,000 hours. The LCC analysis reveals that the maintenance cost, operating cost and support costs dominate the LCC and contribute to the tune of 87 percent of the total LCC.Research limitations/implicationsThe proposed methodology provides an excellent tool that can be utilized in industries, where safety, reliability, maintainability and availability of the system play a vital role. The approach may be improved by collecting data from more number of users of the CNC turning centers.Practical implicationsThe approach presented in this paper is generic and can be applied to analyze the repairable systems. A real case study is presented to show the applicability of the approach.Originality/valueThe proposed methodology provides a practical approach for the analysis of time-to-failure and time-to-repair data based on the assessment of trends in the maintenance data. The methodology helps in selecting a proper approach of the analysis such as Bayesian method, parametric methods and nonparametric methods.

Fulltext

International Journal of Quality & Reliability Management

Reliability analysis of CNC turning center based on the assessment of trends in maintenance data

Reliability analysis and life cycle cost optimization: a case study from Indian industry

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Failure modes and effects analysis (FMEA) of computerized numerical control (CNC) turning center

Journal	International Review of Mechanical Engineering
Publisher	Praise Worthy Prize
Open Access	0