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

2017 ◽  
Vol 34 (9) ◽  
pp. 1616-1638 ◽  
Author(s):  
Rajkumar Bhimgonda Patil ◽  
Basavraj S. Kothavale ◽  
Laxman Yadu Waghmode ◽  
Shridhar G. Joshi
Keyword(s):  
Reliability Analysis ◽  
Goodness Of Fit ◽  
Numerical Control ◽  
Maintenance Cost ◽  
Repairable Systems ◽  
Content Type ◽  
Cnc Turning ◽  
Warranty Period ◽  
Turning Center ◽  
Support Cost

Purpose The 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/approach This 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. Findings The 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/implications The 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 implications The 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/value The 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.

Life cycle cost analysis of a computerized numerical control machine tool: a case study from Indian manufacturing industry

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rajkumar Bhimgonda Patil ◽  
Basavraj S. Kothavale ◽  
Laxman Yadu Waghmode ◽  
Michael Pecht
Keyword(s):  
Life Cycle ◽  
Acquisition Cost ◽  
Life Cycle Cost ◽  
Motor System ◽  
Spindle Motor ◽  
Numerical Control ◽  
Repairable Systems ◽  
Content Type ◽  
Support Cost ◽  
Operation Cost

PurposeLife cycle cost (LCC) analysis is one of the key parameters in designing a sustainable product or system. The application of life cycle costing in the manufacturing industries is still limited due to several factors. Lack of understanding of LCC analysis methodologies is one of the key barriers. This paper presents a generalized framework for LCC analysis of repairable systems using reliability and maintainability principles.Design/methodology/approachThe developed LCC analysis framework and stochastic point processes are applied for the analysis of a typical computerized numerical control turning center (CNCTC) and governing equations for acquisition cost, operation cost, failure cost, support cost and net salvage value are developed. The LCC of the CNCTC is evaluated for the renewal process (RP) and minimal repair process (MRP) approach.FindingsThe LCC analysis of the CNCTC reveals that, the acquisition cost is only 7.59% of the LCC, whereas the operation, failure and support costs dominate and contribute nearly 93% of the LCC. The LCC per day for RP requires additional US$ 1.03 than that for MRP. The detailed LCC analysis of the CNCTC identifies the critical components of CNCTC and these components are: spindle motor, spindle motor cooling fan, spindle belt, drawbar, spindle bearing, oil seals, hydraulic hose, solenoid valve, tool holder, lubrication pump motor system, lubrication hose, coolant pump motor system, coolant hose, supply cables, drive battery.Originality/valueThe developed framework of LCC of a repairable system can be applied to any other repairable systems with the appropriate modifications. LCC analysis of CNCTC reveals that the procurement decision of a product or system should be based on LCC and not only on the acquisition cost. The optimum utilization of consumables such as cutting tools, coolant, oil and lubricant can save operation cost. Thus, use of high-efficiency electric motors and the usage of recommended consumables can prolong the life of several components of a system. Therefore, due consideration and attention to these parameters at product design stage itself will decrease failure and support cost and ultimately its LCC.

Integrated reliability and maintainability analysis of Computerized Numerical Control Turning Center considering the effects of human and organizational factors

2019 ◽  
Vol 26 (1) ◽  
pp. 87-103
Author(s):  
Rajkumar Bhimgonda Patil
Keyword(s):  
Organizational Factors ◽  
Numerical Control ◽  
Content Type ◽  
Failure Data ◽  
Turning Center ◽  
Maintainability Analysis ◽  
Human And Organizational Factors ◽  
Mean Time ◽  
Best Fit ◽  
Field Failure

Purpose Reliability, maintainability and availability of modern complex engineered systems are significantly affected by four basic systems or elements: hardware, software, organizational and human. Computerized Numerical Control Turning Center (CNCTC) is one of the complex machine tools used in manufacturing industries. Several research studies have shown that the reliability and maintainability is greatly influenced by human and organizational factors (HOFs). The purpose of this paper is to identify critical HOFs and their effects on the reliability and maintainability of the CNCTC. Design/methodology/approach In this paper, 12 human performance influencing factors (PIFs) and 10 organizational factors (OFs) which affect the reliability and maintainability of the CNCTC are identified and prioritized according to their criticality. The opinions of experts in the fields are used for prioritizing, whereas the field failure and repair data are used for reliability and maintainability modeling. Findings Experience, training, and behavior are the three most critical human PIFs, and safety culture, problem solving resources, corrective action program and training program are the four most critical OFs which significantly affect the reliability and maintainability of the CNCTC. The reliability and maintainability analysis reveals that the Weibull is the best-fit distribution for time-between-failure data, whereas log-normal is the best-fit distribution for Time-To-Repair data. The failure rate of the CNCTC is nearly constant. Nearly 66 percent of the total failures and repairs are typically due to the hardware system. The percentage of failures and repairs influenced by HOFs is nearly only 16 percent; however, the failure and repair impact of HOFs is significant. The HOFs can increase the mean-time-to-repair and mean-time-between-failure of the CNCTC by nearly 65 and 33 percent, respectively. Originality/value The paper uses the field failure data and expert opinions for the analysis. The critical sub-systems of the CNCTC are identified using the judgment of the experts, and the trend of the results is verified with published results.

Performance evaluation in CNC turning of AA6063-T6 alloy using WASPAS approach

2018 ◽  
Vol 15 (6) ◽  
pp. 700-709 ◽  
Author(s):  
Priyabrata Sahoo ◽  
Mantra Prasad Satpathy ◽  
Vishnu Kumar Singh ◽  
Asish Bandyopadhyay
Keyword(s):  
Surface Roughness ◽  
Goodness Of Fit ◽  
Optimization Technique ◽  
Cutting Parameters ◽  
Confirmatory Test ◽  
Depth Of Cut ◽  
Tool Vibration ◽  
Content Type ◽  
Cnc Turning ◽  
Multi Objective

PurposeSurface roughness and vibration during machining are inevitable which critically affect the product quality characteristics. This paper aims to suggest the implementation of a multi-objective optimization technique to obtain the favorable parametric conditions which lead to minimum tool vibration and surface roughness of 6063-T6 aluminum alloy in computer numerically controlled (CNC) turning.Design/methodology/approachThe case study has been accomplished according to response surface methodology RSM’s Box–Behnken design (BBD) matrix using Titanium Nitride-coated Tungsten Carbide insert in a dry environment. As the experimental results are quite nonlinear, a second-order regression model has been developed for the responses (surface roughness and tool vibration) in terms of input cutting parameters (spindle speed, feed rate and depth of cut). The goodness of fit of the models has also been verified with analysis of variance (ANOVA) results.FindingsThe significance efficacy of input parameters on surface roughness and tool vibrations has been illustrated through multi-objective overlaid 3D surface plots and contour plots. Finally, parametric optimization has been performed to get the desired response values under the umbrella of weighted aggregate sum product assessment (WASPAS) method and verified confidently with confirmatory test results.Originality/valueThe results of this study reveals that hybrid RSM with WASPAS method can be readily applicable to optimize multi-response problems in the manufacturing field with higher confidence.

Comparison of sustainability characteristics of conventional and CNC turning processes

2016 ◽  
Vol 14 (3) ◽  
pp. 422-445 ◽  
Author(s):  
K. Jayakrishna ◽  
R. Jeya Girubha ◽  
S. Vinodh
Keyword(s):  
Environmental Impact ◽  
Manufacturing Process ◽  
Cnc Machining ◽  
Numerical Control ◽  
Machining Parameters ◽  
Environmental Aspects ◽  
Content Type ◽  
Cnc Turning ◽  
Cnc Turning Process ◽  
Process Level

Purpose The purpose of this paper is to present the comparison of sustainability characteristics of conventional and computer numerical control (CNC) turning process. The sustainability performance measures of both the processes were also being evaluated. Design/methodology/approach The study discusses the achievement of sustainability characteristics at the manufacturing process level of widely used industrial process, mechanical machining. Sustainable development includes improvements in material, product design and manufacturing process orientations. The present study narrates the sustainability characteristics at the process level. Findings The results confirm that the overall sustainability characteristics of CNC machining are potentially high considering the economic and environmental aspects of the machining parameters. A detailed life cycle analysis for both conventional and CNC turning was performed to evaluate the environmental impact and benefits. Research limitations/implications The study contributed in the paper is limited to process dimension of sustainability. The economic and environmental aspects of machining were also being discussed. Practical implications The conduct of the study enabled the comparison of sustainability characteristics of conventional and CNC-turning processes. The approach could also be expanded for the comparison of sustainability characteristics of other manufacturing processes also. Originality/value The study is an attempt to explore the process sustainability by the comparison of environmental impact of making processes. Hence, the contributions are original.

Progressive maintenance policy for multiple repairable systems with imperfect maintenance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Garima Sharma ◽  
Rajiv Nandan Rai
Keyword(s):  
Power Plants ◽  
Maintenance Cost ◽  
Mean Residual Life ◽  
Time Interval ◽  
Imperfect Maintenance ◽  
Repairable Systems ◽  
Maintenance Policy ◽  
Data Set ◽  
Content Type ◽  
Maintenance Policies

PurposeDegradation of repairable components may not be similar after each maintenance activity; thus, the classic (traditional-time based) maintenance policies, which consider preventive maintenance (PM), age-based maintenance and overhauls to be done at fixed time interval, may fail to monitor the exact condition of the component. Thus, a progressive maintenance policy (PMP) may be more appropriate for the industries that deal with large, complex and critical repairable systems (RS) such as aerospace industries, nuclear power plants, etc.Design/methodology/approachA progressive maintenance policy is developed, in which hard life, PM scheduled time and overhaul period of the system are revised after each service activity by adjusting PM interval and mean residual life (MRL) such that the risk of failure is not increased.FindingsA comparative study is then carried out between the classic PM policy and developed PMP, and the improvement in availability, mean time between failures and reduction in maintenance cost is registered.Originality/valueThe proposed PMP takes care of the equipment degradation more efficiently than any other existing maintenance policies and is also flexible in its application as the policy can be continuously amended as per the failure profile of the equipment. Similar maintenance policies assuming lifetime distributions are available in the literature, but to ascertain that the proposed PMP is more suitable and applicable to the industries, this paper uses Kijima-based imperfect maintenance models. The proposed PMP is demonstrated through a real-time data set example.

A generalized model selection framework for multi-state failure data analysis

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rajkumar Bhimgonda Patil ◽  
Suyog Subhash Patil ◽  
Gajanand Gupta ◽  
Anand K. Bewoor
Keyword(s):  
Data Analysis ◽  
Reliability Analysis ◽  
State System ◽  
Numerical Control ◽  
Failure Behavior ◽  
Class Iii ◽  
Content Type ◽  
Failure Data ◽  
Binary State ◽  
Design Attribute

PurposeThe purpose of this paper is to carry out a reliability analysis of a mechanical system considering the degraded states to get a proper understanding of system behavior and its propagation towards complete failure.Design/methodology/approachThe reliability analysis of computerized numerical control machine tools (CNCMTs) using a multi-state system (MSS) approach that considers various degraded states rather than a binary approach is carried out. The failures of the CNCMT are classified into five states: one fully operational state, three degraded states and one failed state.FindingsThe analysis of failure data collected from the field and tests conducted in the laboratory provided detailed understandings about the quality of the material and its failure behavior used in designing and the capability of the manufacturing system. The present work identified that Class II (major failure) is critical from a maintainability perspective whereas Class III (moderate failure) and Class IV (minor failure) are critical from a reliability perspective.Research limitations/implicationsThis research applies to reliability data analysis of systems that consider various degraded states.Practical implicationsMSS reliability analysis approach will help to identify various degraded states of the system that affect the performance and productivity and also to improve system reliability, availability and performance.Social implicationsIndustrial system designers recognized that reliability and maintainability is a critical design attribute. Reliability studies using the binary state approach are insufficient and incorrect for the systems with degraded failures states, and such analysis can give incorrect results, and increase the cost. The proposed MSS approach is more suitable for complex systems such as CNCMT rather than the binary-state system approach.Originality/valueThis paper presents a generalized framework MSS's failure and repair data analysis has been developed and applied to a CNCMT.

An operating environment-based preventive maintenance decision model

2019 ◽  
Vol 26 (4) ◽  
pp. 592-610
Author(s):  
Aiping Jiang ◽  
Qingxia Li ◽  
Jinyi Yan ◽  
Leqing Huang ◽  
Haining Wu
Keyword(s):  
Reliability Analysis ◽  
Preventive Maintenance ◽  
Decision Model ◽  
Maintenance Cost ◽  
Redundant System ◽  
Content Type ◽  
Multiple Components ◽  
Safety And Reliability ◽  
Optimal Maintenance ◽  
The Cost

Purpose The purpose of this paper is to focus on finding the optimal maintenance interval and the minimum maintenance cost for redundant system, considering environment factors. Design/methodology/approach The authors propose a decision model with environment-based preventive maintenance for the repairable redundant system. Referring to the k-out-of-n model and Proportional Hazard Model, the reliability analysis is completed for the redundant system affected by internal and external issues. Meanwhile, the maintenance cost for the redundant system is divided into two categories: the fixed maintenance cost involving whole system replacement at the time of system failure, and the cost to replace failure components when the system still functions. Findings Upon the required reliability analysis, an optimal maintenance interval that minimizes the average maintenance cost per unit time is identified. The simulation results indicate that the optimal maintenance interval with consideration of environmental factors is significantly shorter than that without consideration of these factors, with the maintenance cost increase within 10 percent. Practical implications The redundant systems have widely been used in industries including the aero craft control system and warship power system. The model could be applied in the more real case considering the types of components and the operation environment, and help production managers better maintain machines by increasing the safety and reliability of the redundant model with the more frequent inspection. Originality/value Previous research of redundant system always focuses on internal degradation, while ignoring the reliability analysis for a redundant system with various multiple components under the influence of environment. However, this work could fill the theoretical gap, i.e. simultaneously consider both environmental and internal factors for a redundant system with non-homogeneous components. Meanwhile, the proposed superior model increases the reliability and safety of the k-out-of-n model with reasonable cost. Production managers could benefit a lot from this as well.

A three-level supply chain with warranty services, pricing and marketing decisions

2019 ◽  
Vol 14 (3) ◽  
pp. 686-716 ◽  
Author(s):  
Ata Allah Taleizadeh ◽  
Mahtab Sherafati
Keyword(s):  
Game Theory ◽  
Cooperative Games ◽  
Maintenance Cost ◽  
Theory Approach ◽  
Content Type ◽  
Agent Based ◽  
Warranty Period ◽  
Service Contracts ◽  
The Game Theory ◽  
Optimal Maintenance

Purpose This paper aims to present various three-level service contracts among the following three participants: a manufacturer, an agent and a customer. The interaction between the aforementioned participants will be modeled using the game theory approach. Under non-cooperative and cooperative games, the optimal sale price, warranty period and warranty price for the manufacturer and the optimal maintenance cost (repair cost) and marketing expenditure for the agent are obtained by maximizing their profits. The satisfaction of the customer is also maximized by being able to choose one of the suggested options from the manufacturer and the agent, based on the risk parameter. Design/methodology/approach Three-echelon supply chains with marketing and warranty services are studied. Game-theoretic approaches (non-cooperative and cooperative) are presented. The non-cooperative approaches are static (NE) and dynamic (Stakelberg) models. The cooperative approach is related to bargaining models (Nash bargaining games). The authors develop a sensitivity analysis of some parameters and their effect. Findings Based on the mentioned drawbacks (i.e. lack of a model containing warranty, marketing and pricing), despite their importance, a developed model is proposed in this research to cover one of the research gaps. In addition, main contributions of this paper that differentiate it from the existing papers are regarding inventory, lost sale and lost goodwill, which are significant in the comparison environment. Another advantage of this study is related to the solution approach, the game theory. Twofold of the games theoretical, i.e. cooperative (in three forms) and non-cooperative are considered, because of their importance. Three types of non-cooperative games are presented as follows: Nash equilibrium – each echelon decides respectively and simultaneously; manufacturer-Stackelberg – the manufacturer has more power than the agent and the agent has more power than the customer; and customer-Stackelberg – customer is leader of the agent and the agent is the leader of manufacturer. The involved cooperative game in this paper is the bargaining problem that the participants can determine how to share the additional profits. Originality/value In this paper, various three-level service contracts will be presented among the following three participants: a manufacturer, an agent and a customer. The interaction between the aforementioned participants will be modeled using the game theory approach. Under non-cooperative and cooperative games, the optimal sale price, warranty period and warranty price for the manufacturer and the optimal maintenance cost (repair cost) and marketing expenditure for the agent are obtained by maximizing their profits. The satisfaction of the customer is also maximized by being able to choose one of the suggested options from the manufacturer and the agent, based on the risk parameter. Several numerical examples are used to illustrate the models presented in this paper. Finally, the authors develop a sensitivity analysis of some parameters and their effects on the objective functions.

Expected maintenance waste reduction benefits after implementation of Just in Time (JIT) philosophy in maintenance (a statistical analysis)

2019 ◽  
Vol 25 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Sandeep Phogat ◽  
Anil Kumar Gupta
Keyword(s):  
Data Interpretation ◽  
General Information ◽  
Spare Parts ◽  
Waste Reduction ◽  
Maintenance Cost ◽  
Just In Time ◽  
Content Type ◽  
Great Saving ◽  
Research Findings ◽  
Structured Questionnaire

Purpose The maintenance department of today, like many other departments, is under sustained pressure to slash costs, show outcome and support the assignment of the organization, as it is a commonsensical prospect from the business perspective. The purpose of this paper is to examine expected maintenance waste reduction benefits in the maintenance of organizations after the implementation of just-in-time (JIT) managerial philosophy. For this, a structured questionnaire was designed and sent to the 421 industries in India. Design/methodology/approach The designed questionnaire was divided into two sections A and B to assist data interpretation. The aim of the section A was to build general information of participants, type of organization, number of employees, annual turnover of the organization, etc. Section B was also a structured questionnaire developed based on a five-point Likert scale. The identified critical elements of the JIT were included in the questionnaire to identify the maintenance waste reduction benefits in the maintenance of organizations. Findings On the basis of the 133 responses, hypothesis testing was done with the help of Z-test, and it was found out that in maintenance, we can reduce a large inventory of spare parts and also shorten the excessive maintenance activities due to the implementation of JIT philosophy. All the four wastes: waste of processing; waste of rejects/rework/scrap in case of poor maintenance; waste of the transport of spares, and waste of motion, have approximately equal weightage in their reduction. Waste of waiting for spares got the last rank, which showed that there are little bit chances in the reduction of waiting for spares after the implementation of JIT philosophy in maintenance. Practical implications The implication of the research findings for maintenance of organizations is that if maintenance practitioners implement elements of JIT philosophy in maintenance then there will be a great reduction in the maintenance wastes. Originality/value This paper will be abundantly useful for the maintenance professionals, researchers and others concerned with maintenance to understand the significance of JIT philosophy implementation to get the expected reduction benefits in maintenance wastes of organizations which will be helpful in the great saving of maintenance cost and time side by side great increment in the availability of machines.

Sign in / Sign up

Export Citation Format

Share Document