A Production Scheduling Model with Maintenance

2014 ◽  
Vol 1036 ◽  
pp. 885-890 ◽  
Author(s):  
Iwona Paprocka ◽  
Wojciech M. Kempa ◽  
Krzysztof Kalinowski ◽  
Cezary Grabowik
Keyword(s):  
Failure Mode ◽  
Failure Rate ◽  
Production Scheduling ◽  
Production Model ◽  
Time To Failure ◽  
Detection Capability ◽  
Scheduling Model ◽  
Mean Time ◽  
Predictive Scheduling ◽  
Prediction Capability

In the paper, a production model with maintenance is presented. Successive failure-free times of a bottleneck are supposed to have predefined distributions and are followed by distributed times of repair. Having values of parameters: Mean Time To Failure and Mean Time of Repair, a predictive schedule is generated. To assess wastes due to unplanned events of the bottleneck, such as unplanned downtime the Overall Equipment Effectiveness indicator is applied. To assess failure rate of the bottleneck the Parts Per Million Opportunities indicator is applied. Prediction capability, detection capability of a failure and effects of the failure occurrence are evaluated and registered in the Exploitation Failure Mode and Effects Analysis form. The objective of the presented predictive scheduling model is to achieve: zero machines failures, zero defects, zero accidents at work.

Robust Scheduling, a Production Scheduling Model of Failures

2013 ◽  
Vol 307 ◽  
pp. 443-446 ◽  
Author(s):  
Iwona Paprocka ◽  
Bożena Skołud
Keyword(s):  
Production Scheduling ◽  
Regression Method ◽  
Production Model ◽  
Unknown Parameters ◽  
Minimal Impact ◽  
Normal Distributions ◽  
Robust Scheduling ◽  
Scheduling Model ◽  
Mean Time ◽  
Classical Regression

In the paper a production model with failures is presented where successive failure-free times are supposed to have normal distributions and are followed by normally distributed times of repairs. Unknown parameters of the distribution are estimated using e.g. empirical moments approach. Predictions of unknown parameters are done using classical regression method. Having Mean Time To First Failure, and Mean Time of Repair a disturbance robust predictive schedule is generated using an immune algorithm and rule Minimal Impact of Disturbed Operation on the Schedule.

scholarly journals Effect of Grid Instability on Power Generation System's Reliability

2020 ◽  
pp. 27-37
Author(s):  
Joseph Benedict Bassey ◽  
Isaac F. Odesola
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Failure Rate ◽  
System Reliability ◽  
Power Distribution ◽  
Power Plants ◽  
Time To Failure ◽  
Generation System ◽  
Reliability Indices ◽  
Mean Time

Aims: Reliability assessment of power generation system may be performed with the concept of system adequacy, security or both. Grid being a major component in the power distribution chain is seen to have some influence on the state of the generation system reliability because of the perturbation that may arise from it. In this study, the generation system reliability is evaluated using both the system adequacy and security concept. Study Design: To capture the system security problems attributed to grid disturbance, the generation system is structured into two component systems (1 - generation component and 2 - transmission component) with a series arrangement. Methodology: The reliability indices such as, mean time to failure, mean time to repair, failure rate and repair rate are assessed on component bases and with respect to the entire generation system. Results: The effect of failure rate of the transmission component on the entire generation system failure rate was evaluated as 66.25%, 55.55%, 33.33%, 55.00% and 35.72% in year 2013, 2014, 2017 2018 and 2019 respectively for FIPL Power Plant and 52.94%, 82.35%, 61.38% and 100% effect was evaluated in the year 2016, 2017, 2018 and 2019 respectively for GT5 of Omoku Power Plant. Conclusion: These results showed that there is a significant influence of grid disturbances on the reliability state of the two gas turbine power plants in Nigeria. Measures on possible reliability state improvement of the power generation systems were suggested to include training and retraining of technical personnel on the management of major equipment in the generation and transmission stations. 

Research on Spurious Trip of 1oo2 Safety Instruments of Petrochemical Installation with Repair Considered

2010 ◽  
Vol 118-120 ◽  
pp. 596-600
Author(s):  
Jian Xin Zhu ◽  
Xue Dong Chen ◽  
Shi Yi Bao
Keyword(s):  
Failure Rate ◽  
System Reliability ◽  
Repairable System ◽  
Time To Failure ◽  
Redundant System ◽  
Common Cause ◽  
System A ◽  
Definition Of ◽  
Mean Time ◽  
Complex Influence

An innovative nuisance trip calculation method based on Markov model was proposed in this paper which was used to evaluate the effect of repairment on system reliability. By analysis of the availabilities of classic 1 out of 2 (1oo2) repairable system, a new definition of spurious trip was put forwarded where online repair was considered. Compared with the benefits obtained by online repairment, the repair-caused-nuisance-trip was analyzed in this paper. Numerical calculation revealed that the online repair is helpful for anti-spurious trip in 1oo2 redundant system. Dangerous failures, if not repaired or cannot be online fixed, have complex influence on system reliability. The dangerous failure is sometimes benefit for anti-spurious performance if it is not repaired. But Mean Time To Failure Spurious (MTTFs) reduces with the increase of dangerous failure provided that dangerous failure rate is bigger than safe failure rate. Meanwhile, the finding that common cause can reduce the chance of nuisance trip was also proposed in this paper, though the influence is too small to be neglected.

scholarly journals Survival and failure trends of cerebrospinal fluid shunts with distal slit valves: comparative study and literature review

2020 ◽  
Vol 25 (3) ◽  
pp. 209-216
Author(s):  
Jeremy S. Wetzel ◽  
Alex D. Waldman ◽  
Pavlos Texakalidis ◽  
Bryan Buster ◽  
Sheila R. Eshraghi ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Failure Rate ◽  
Csf Shunt ◽  
Time To Failure ◽  
Survival Curves ◽  
Mean Time To Failure ◽  
Distal Catheter ◽  
Catheter Obstruction ◽  
Shunt Survival ◽  
Mean Time

OBJECTIVEThe malfunction rates of and trends in various cerebrospinal fluid (CSF) shunt designs have been widely studied, but one area that has received little attention is the comparison of the peritoneal distal slit valve (DSV) shunt to other conventional valve (CV) type shunts. The literature that does exist comes from older case series that provide only indirect comparisons, and the conclusions are mixed. Here, the authors provide a direct comparison of the overall survival and failure trends of DSV shunts to those of other valve type shunts.METHODSThree hundred seventy-two new CSF shunts were placed in pediatric patients at the authors’ institution between January 2011 and December 2015. Only ventriculoperitoneal (VP) shunts were eligible for study inclusion. Ventriculoatrial, lumboperitoneal, cystoperitoneal, subdural-peritoneal, and spinal shunts were all excluded. Rates and patterns of shunt malfunction were compared, and survival curves were generated. Patterns of failure were categorized as proximal failure, distal failure, simultaneous proximal and distal (proximal+distal) failure, removal for infection, externalization for abdominal pseudocyst, and addition of a ventricular catheter for loculated hydrocephalus.RESULTSA total of 232 VP shunts were included in the final analysis, 115 DSV shunts and 117 CV shunts. There was no difference in the overall failure rate or time to failure between the two groups, and the follow-up period was statistically similar between the groups. The DSV group had a failure rate of 54% and a mean time to failure of 17.8 months. The CV group had a failure rate of 50% (p = 0.50) and a mean time to failure of 18.5 months (p = 0.56). The overall shunt survival curves for these two groups were similar; however, the location of failure was significantly different between the two groups. Shunts with DSVs had proportionately more distal failures than the CV group (34% vs 14%, respectively, p = 0.009). DSV shunts were also found to have proximal+distal catheter occlusions more frequently than CV shunts (23% vs 5%, respectively, p = 0.005). CV shunts were found to have significantly more proximal failures than the DSV shunts (53% vs 27%, p = 0.028). However, the only failure type that carried a statistically significant adjusted hazard ratio in a multivariate analysis was proximal+distal catheter obstruction (CV vs DSV shunt: HR 0.21, 95% CI 0.05–0.81).CONCLUSIONSThere appears to be a difference in the location of catheter obstruction leading to the malfunction of shunts with DSVs compared to shunts with CVs; however, overall shunt survival is similar between the two. These failure types are also affected by other factors such etiology of hydrocephalus and endoscope use. The implications of these findings are unclear, and this topic warrants further investigation.

scholarly journals Perencanaan Perawatan Mesin Welding Mig Pada Produksi Sub Frame Di PT. XYZ Dengan Metode Reliability Centered Maintenance (RCM)

2021 ◽  
Vol 6 (1) ◽  
pp. 26-38
Author(s):  
Zulkani Sinaga ◽  
Solihin Solihin ◽  
Mochamad Ardan
Keyword(s):  
Failure Mode ◽  
Time To Failure ◽  
Risk Priority Number ◽  
Mean Time To Failure ◽  
Effect Analysis ◽  
Mean Time Between Failure ◽  
Reliability Centered Maintenance ◽  
Mean Time To Repair ◽  
Mean Time

Pemeliharaan merupakan suatu proses yang dilakukan untuk menjaga keandalan, ketersediaan dan sifat mampu merawat komponen atau mesin. Program pemeliharaan yang efektif dan efisien akan mendukung peningkatan produktifitas sistem produksi. PT. XYZ merupakan perusahaan nasional bergerak dibidang karoseri truck mengalami penurunan produktivitas disebabkan belum adanya strategi perawatan khususnya mesin welding jenis MIG sehingga sering terjadi downtime mesin mengakibatkan proses produksi menjadi terhambat. Berdasarkan alasan tersebut dibutuhkan program pemeliharaan yang efektif dan efisien dengan menerapkan analisis menggunakan metode  Reliability Centered Maintenance (RCM) guna menciptakan metode pemeliharaan yang akurat, fokus, dan optimal dengan tujuan mencapai keandalan yang optimal. Penelitian dilakukan dengan mengikuti langkah-langkah perhitungan berdasarkan Failure Mode and Effect Analysis (FMEA) dan penetapan strategi pemeliharaan dengan dibantu menggunakan software minitab 18. Hasil penelitian diperoleh Risk Priority Number (RPN) untuk komponen wire feeder sebesar 611, dengan pola distribusi waktu normal, nilai parameter median 61,9391 dan standar deviasinya 48,6053, nilai Mean Time To Failure (MTTF) sebesar 61,9391 jam dan selang interval waktu penggantian komponen sebesar 10,1349. Berdasarkan hasil perhitungan performance maintenanace diketahui nilai Mean Time Between Failure (MTBF) antara 31,92 ~ 72,09 jam, Mean Time To Repair (MTTR) anatara 1,19 ~ 1,78 jam dan availability antara 94,67% ~ 98,24%, setelah dilakukan tindakan perawatan pencegahan selama periode tersebut dihasilkan nilai availability sebesar 98,01% artinya kerusakan pada komponen wire feeder dapat teratasi.

scholarly journals Perencanaan Perawatan Mesin Pump 107 Dengan Metode Reability Centered Maintenance (RCM) di PT. Petrokimia Gresik

2018 ◽  
Vol 1 (02) ◽  
pp. 33-38
Author(s):  
Rezza Wira Utomo
Keyword(s):  
Service Life ◽  
Failure Mode ◽  
Failure Rate ◽  
Failure Modes ◽  
Treatment Method ◽  
Maintenance Scheduling ◽  
Effect Analysis ◽  
Mean Time ◽  
Working Efficiency ◽  
Causes Of Failure

PT. Petrokimia Gresik is one of the largest fertilizer companies in Indonesia, locatedin Gresik, East Java. The pump 107 engine on the Ammonia unit is often damaged due to itslargest size compared to other types of pumps, as well as the result of carrying thick orconcentrated fluid (bluish black) so that it is heavy for the drainage process. The purpose ofthis study is to plan and recommend the proposed treatment method on the pump enginebased on the method used to improve the working efficiency of the pumping machine 107and determine the failure mode and diagnosis of the effects of failure modes that occur in thecomponent. The method used is the Reability Centered Maintenance (RCM) method whichis expected to be able to produce maintenance or maintenance scheduling that is increasinglydirected so that it can improve the performance and efficiency of the engine, reduce repaircosts, and extend the service life of the machine itself. From this study, the results are in theform of Faliure Model And Effect Analysis (FMEA), FMEA table preparation is carried outbased on component function data and maintenance reports which can then be determined byvarious failures resulting in malfunction. From the compilation of FMEA, it can be seenwhat the causes of failure are and what impacts they have caused. Next, the value of MeanTime Between Failure (MTBF) pump 107-JA is 15,829 hours, pump 107-JB is 43,764 hoursand pump 107-JCM is 19,578 hours. Maintainability M (t) or Mean Time to Repair (MTTR)value on pump 107-JA is 2,914 hours, pump 107-JB is 3,411 hours, and pump 107-JCM is3,1 hours, Availability A (t) value is pump 107-JA at 84.44%, pump 107-JB at 92.76% andpump 107-JCM at 86.31%. The last one is found that the failure rate of pump 107-JA is0.063172, pump 107-JB is 0.02284 and pump 107-JCM is 0.051.

Reliability Assessment of an Electronic System: A Case Study of Nokia N1650 Mobile Phone Charger in Zaria, Nigeria

2013 ◽  
Vol 824 ◽  
pp. 170-177
Author(s):  
Olaitan Akinsanmi ◽  
K.R. Ekundayo ◽  
Patrick U. Okorie
Keyword(s):  
Mobile Phone ◽  
Failure Rate ◽  
Electronic System ◽  
Time To Failure ◽  
Reliability Level ◽  
System A ◽  
System Data ◽  
Mean Time

This paper assesses the reliability of a Nokia N1650 mobile phone charger used in Zaria, Nigeria. The Part Stress Method was employed to assess the reliability of the system. Data on the failure rate of the system components were used, with special considerations given to factors like environment of use, quality of power supply and service personnel. A comparative assessment was made on the system, when operated within the Zaria environment and when operated within the country for which it was designed for (China).The result shows that a lower reliability level is associated with the use of the system in Zaria, Nigeria as compared with the reliability level when in use in the country for which it was designed for. The Mean-Time to Failure of the system which is the time it is expected to function without failure (MTTF) in Nigeria is 1 years as against 10 years in China. The ratio is 10:1 in favour of the designed country. The ratio of the failure rate of the system is also 10:1 in favour of the designed country, meaning it fails ten times faster in Zaria environment as compared to the country for which the system was designed for. These are accounted for by higher variation in the environmental factors such as temperature, poor power quality, and poor maintenance culture in the applied environment.

Method of Improving Production Scheduling Based on the Genetic Algorithm

2011 ◽  
Vol 411 ◽  
pp. 415-418
Author(s):  
Yong Gao ◽  
Ming Yu Li ◽  
Jian Ping Wang
Keyword(s):  
Genetic Algorithm ◽  
Production Scheduling ◽  
Model Simulation ◽  
Optimization Method ◽  
Production Model ◽  
Forward Simulation ◽  
Production Schedule ◽  
Scheduling Optimization ◽  
Simulation Data ◽  
Scheduling Model

In order to improve the inventory control efficiency and quality in manufacturing company, one production scheduling optimization method is put forward. Simulation of production model is firstly constructed, such as description of the production model, simulation data, machine processes and scheduling model. Moreover, Genetic Algorithm is applied to generate a production schedule for efficient running of machine. The simulation result is analyzed to verify the method by comparing product simulation with actual production.

scholarly journals Systematic Routine for Setting Confidence Levels for Mean Time to Failure (MTTF)

2014 ◽  
Vol 2 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Jimin Lee ◽  
Robert Yearout ◽  
Donna Parsons
Keyword(s):  
Density Function ◽  
Exponential Distribution ◽  
Failure Rate ◽  
Survival Data ◽  
Reliability Function ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Arrival Times ◽  
Negative Exponential ◽  
Mean Time

There are circumstances where an item is intentionally tested to destruction.  The purpose of this technique is to determine the failure rate (λ) of a tested item.  For these items, the quality attribute is defined as how long the item will last until failure.  Once the failure rate is determined from the number of survivors and total time of all items tested the mean time to failure (MTTF) which is a typical statistic for survival data analysis issues.  MTTF is calculated by dividing one by failure rate (λ).  From this one obtains the reliability function R(t) = e-λt where t is time.  This allows the cumulative density function F(t) = 1- e-λt  to be determined.  This density function, f(t) = λe-λt is a negative exponential with a standard deviation (σ) = 1/λ.  Thus setting a warranty policy for the tested item is difficult for the practitioner.  An important property of the exponential distribution is that it is memory less.  This means its conditional probability follows P(T > s + t |T > s)=P(T > t) for all s, t ≥0.  The exponential distribution can be used to describe the interval lengths between any two consecutive arrival times in a homogeneous Poisson process.  The purpose of this research paper is to present a simple technique to determine a realistic confidence level. Using the same technique the warranty level for the tested item can be predicted.

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