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1 – 10 of 347Jean‐Luc Maire, Maurice Pillet and Nathalie Baudet
The variability of the results of a visual control is often high. This paper aims to propose a new tool to give information about what improvement actions can be carried out to…
Abstract
Purpose
The variability of the results of a visual control is often high. This paper aims to propose a new tool to give information about what improvement actions can be carried out to reduce this variability.
Design/methodology/approach
The variability of a visual control can be measured by Kappa's Fleiss which measures the level of agreement between appraisers and experts. The R&R Gage is then classically used to give information about corrective actions which can be carried out in order to improve this level of agreement. The paper demonstrated that this information is not always sufficient.
Findings
By considering the two essential steps of a visual control (exploration and evaluation), the R2&E2 Gage proposed gives more precise information about the improvement actions to carry out to reduce the variability of a visual control. Repeatability and reproducibility, for detection and evaluation purposes, are considered separately.
Research limitations/implications
This R2&E2 gage is one result of a European research program called INTERREG. The aim of this program, which brings together two laboratories from the University of Savoy and EPFL, two institutional partners (CTDEC and CETEHOR) and some Swiss and French industrial companies, is to create methodological support and the tools needed to improve the visual control of high added‐value products.
Practical implications
This R2&E2 gage has been used in six industrial companies involved in the European program INTERREG. Significant improvement of the visual control has been observed over a short time.
Originality/value
The paper fulfils an identified need of industrial firms to have efficient tools improving the visual control of their products.
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Recently, gauge repeatability and reproducibility (GR&R) study has been highly regarded by the quality practitioners when QS9000 and D19000 become fashionable requirements for…
Abstract
Recently, gauge repeatability and reproducibility (GR&R) study has been highly regarded by the quality practitioners when QS9000 and D19000 become fashionable requirements for manufacturing industries. Measurement plays a significant role in helping organizations improve their product quality. Good quality of products is the key factor towards business success. Therefore, how to ensure the quality of measurement becomes an important task for quality practitioners. In performing the GR&R study, several parameters, such as the appropriate sample size of parts (n), number of inspectors (p) and replicate measurements (k) are frequently asked by quality personnel in industries. The adequacy of current way of (n, p, k) selection is very questionable. A statistical method using the shortest confidence interval and its associated computer programming algorithm are presented in this paper for evaluating the optimal allocation among sample size of parts (n), number of inspectors (p) and replicate measurements (k). Hopefully, it can provide a useful reference for quality practitioners in industries.
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Sven Berg, Ulf Jungmar, Jan Lundberg and Pekka Vähäoja
The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully…
Abstract
Purpose
The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully formulated hydraulic and gear oils taken from working systems.
Design/methodology/approach
In this investigation, two different spectrometric techniques, inductively coupled plasma‐optical emission spectrometers (ICP‐OES) and rotating disk electrode‐optical emission spectrometers (RDE‐OES), have been studied to determine the instruments' precision of measurement and ability to measure the absolute level of contamination. The study was based on a series of measurements using artificial contamination mixed with oil.
Findings
The ICP has better precision of measurement of the two instruments, but cannot predict the absolute values of contamination when oil samples are only treated by organic solvent dilution if the samples include large or dense particles. It is therefore not too good, with the sample pre‐treatment method used, at detecting wear processes that produce dense/large particles, such as pitting failure. For instance, microwave‐assisted acid digestion could be used for sample pre‐treating to obtain accurate results in that case. It should, however, be able to detect wear mechanisms that produce small particles such as abrasive wear in any case. The ICP has a repeatability value of r=3 percent and a reproducibility value of R=12 percent for contamination levels of between 50 and 400 ppm and r=0.6 and R=2 ppm, respectively, at values below 50 ppm. The RDE cannot predict the absolute value of contamination if this includes large or dense particles if proper sample pre‐treatment is not used. It is therefore not good at detecting wear mechanisms that produces dense/large particles (if the oil samples are not pre‐treated properly) such as pitting but should be able to detect abrasive wear and similar processes that produce small particles in any case. The RDE's precision of measurement is not as good as the ICP, with a reproducibility variation of R=r=25 percent for contamination levels between 20 and 500 ppm and R=r=6 ppm for contamination level below 20 ppm.
Research limitations/implications
Only the effects from lubricating oils are studied.
Practical implications
This study will significantly increase the industrial knowledge concerning measurement precision in particle contamination measurement systems.
Originality/value
No similar study is found.
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A new time‐domain reflectometry measurement method is described that provides accurate measurements of the average high‐frequency (0.1GHz ‐ 10GHz) dielectric constant of printed…
Abstract
A new time‐domain reflectometry measurement method is described that provides accurate measurements of the average high‐frequency (0.1GHz ‐ 10GHz) dielectric constant of printed wiring board materials and is suitable for “factory floor” use. A parallel‐plate transmission line is used for the sample geometry. Only simple numerical processes are required to extract the characteristic impedance and dielectric constant of the sample from the acquired data. The long‐term measurement reproducibility and short‐term measurement repeatability of the method are described.
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The effects that spinning technology and spinning parameters have on the color strength (K/S), strength, and breaking elongation of post dyed and mercerized yarns are investigated…
Abstract
The effects that spinning technology and spinning parameters have on the color strength (K/S), strength, and breaking elongation of post dyed and mercerized yarns are investigated in this study. The emphasis of the study is on the selection of long stable Egyptian cotton varieties, namely Giza 80, Giza 86, and extra long stable Giza 92. The cotton samples are spun by using compact, ring, and open end spinning technologies. For the purpose of this study, different yarn counts and twist multipliers are used. The mechanical properties, such as the tensile strength and breaking elongation of the produced yarn are investigated and compared before and after the mercerization treatment (slack and tension), followed by a reactive dyeing process. All of the samples are prepared for dyeing after mercerization. The dyeing performance in terms of the K/S is studied. When the results are examined, it is found that the samples that have undergone (bleaching + slack mercerization + reactive dyeing) generally have higher K/S values than samples that have undergone (bleaching + tension mercerization + reactive dyeing) and (bleaching + non-mercerization + reactive dyeing) respectively. Open-end spun yarns have a higher K/S compared to the compact and ring spun yarns with the lowest count yarn and twist level. The strength percentages are higher for compact, then ring and finally open-end spun yarns respectively with tension mercerization. There is no noticeable difference in the elongation% for all of the treatment processes. The authors have used quality engineering reproducibility and repeatability (R&R) tools to guarantee the repeatability and reproducibility of the results in this research paper.
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Hemant Krishnarao Wagh and Girish R. Desale
The helical spring lock washer (HSLW) is a part of nut bolt joint assembly used in different industries like automobile, aerospace, mechanical, chemical, electrical, electronics…
Abstract
Purpose
The helical spring lock washer (HSLW) is a part of nut bolt joint assembly used in different industries like automobile, aerospace, mechanical, chemical, electrical, electronics, etc. It works as a part of temporary joint and plays important role in loosening behavior of assembly under dynamic (vibrations) conditions. Thus, the purpose of this paper is to investigate the performance of HSLW under different controlled operating conditions in order to satisfy its functional requirement.
Design/methodology/approach
In the present investigation, a novel test rig is designed and developed to determine the load-deflection characteristics of HSLWs. The test rig facilitates the controlled linear displacement of the HSLW with predetermined angular rotation of the handle gives the corresponding reaction load on the display. Additionally, the repeatability and reproducibility of the test rig was carried out.
Findings
The newly designed and developed test rig is capable enough to differentiate the load-deflection characteristics during compressive loading and unloading of HSLWs. Additionally, the loss of strain energy can be determined from the load-deflection characteristics of HSLW.
Originality/value
The present test rig is designed and developed to investigate the load-deflection characteristics under compressive loading and unloading of HSLW. The test rig has least count of 0.4905 N for load measurement and 0.01389 mm for linear displacement.
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Sven Berg, Ulf Jungmar, Jan Lundberg and Pekka Vähäoja
The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully…
Abstract
Purpose
The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully formulated hydraulic and gear oils taken from working systems.
Design/methodology/approach
In this investigation two different spectrometric techniques, ICP‐OES and RDE‐OES, have been studied to determine the instruments' precision of measurement and ability to measure the absolute level of contamination.
Findings
The ICP has better precision of measurement of the two instruments, but cannot predict the absolute values of contamination when oil samples are only treated by organic solvent dilution if the samples include large or dense particles. It is therefore not too good, with the sample pre‐treatment method used, at detecting wear processes that produce dense/large particles, such as pitting failure. For instance, microwave‐assisted acid digestion could be used for sample pre‐treating to obtain accurate results in that case. It should, however, be able to detect wear mechanisms that produce small particles such as abrasive wear in any case: the ICP has a repeatability value of r=3 per cent and a reproducibility value of R=12 per cent for contamination levels of between 50‐400 PPM and r=0.6 PPM and R=2 PPM, respectively, at values below 50 PPM; the RDE cannot predict the absolute value of contamination if this includes large or dense particles if proper sample pre‐treatment is not used. It is therefore not good at detecting wear mechanisms that produce dense/large particles (if the oil samples are not pre‐treated properly) such as pitting but should be able to detect abrasive wear and similar processes that produce small particles in any case; the RDE's precision of measurement is not as good as the ICP, with a reproducibility variation of R=r=25 per cent for contamination levels between 20‐500 PPM and R=r=6 PPM for contamination level below 20 PPM.
Research limitations/implications
Measuring only on fully formulated oils from hydraulic and gear systems.
Practical implications
The study will be of significant support regarding industrial interpretation of measurement results from the most common oil particle measurement methods.
Originality/value
No other similar studies are known.
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Arjun Kumar, R.A. Rao, R.B. Gupta and S. Singhal
THIS paper describes a test method, developed on the Kirloskar AV‐1 (naturally aspirated) single‐cylinder diesel engine, for evaluating tendency towards detergency, ring sticking…
Abstract
THIS paper describes a test method, developed on the Kirloskar AV‐1 (naturally aspirated) single‐cylinder diesel engine, for evaluating tendency towards detergency, ring sticking and accumulation of deposits in heavy‐duty type lubricating oils. The repeatability, reproducibility and the discriminating ability of the method is found to be good when the engine is run under the prescribed test method for 120 hours. This method is likely to be included in Indian Standard Specification for IC Engine Lubricating Oils, IS : 496. To finalize this test method, a correlation programme was also run between five laboratories. The results obtained correlate with the Petter AV‐1 test procedure when using a fuel containing 0–4% sulphur.
Steven Cox, Virginia Elton, John A. Garside, Apostolos Kotsialos, João Victor Marmo, Lorena Cunha, Grant Lennon and Chris Gill
A process improvement sampling methodology, known as process variation diagnostic tool (PROVADT), was proposed by Cox et al. (2013). The method was designed to support the…
Abstract
Purpose
A process improvement sampling methodology, known as process variation diagnostic tool (PROVADT), was proposed by Cox et al. (2013). The method was designed to support the objectivity of Six Sigma projects performing the measure-analyse phases of the define-measure-analyse-improve-control cycle. An issue in PROVADT is that it is unable to distinguish between measurement and product variation in the presence of a poor Gage repeatability and reproducibility (R&R) result. The purpose of this paper is to improve and address PROVADT’s sampling structure by enabling a true Gage R&R as part of its design.
Design/methodology/approach
This paper derives an enhanced PROVADT method by examining the theoretical sampling constraints required to perform a Gage R&R study. The original PROVADT method is then extended to fulfil these requirements. To test this enhanced approach, it was applied first to a simulated manufacturing process and then in two industry case studies.
Findings
The results in this paper demonstrates that enhanced PROVADT was able to achieve a full Gage R&R result. This required 20 additional measurements when compared to the original method, but saved up to ten additional products and 20 additional measurements being taken in future experiments if the original method failed to obtain a valid Gage R&R. These benefits were highlighted in simulation and industry case studies.
Originality/value
The work into the PROVADT method aims to improve the objectivity of early Six Sigma analyses of quality issues, which has documented issues.
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Gijeong Seo, Md. RU Ahsan, Yousub Lee, Jong-Ho Shin, Hyungjun Park and Duck Bong Kim
Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which…
Abstract
Purpose
Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which must be addressed by time-consuming and cost-intensive tasks. This deteriorates the process repeatability, reliability and part reproducibility. So far, many AM efforts have been performed in an isolated and scattered way over several decades. In this paper, a systematically integrated holistic view is proposed to achieve QA for AM.
Design/methodology/approach
A systematically integrated view is presented to ensure the predefined part properties before/during/after the AM process. It consists of four stages, namely, QA plan, prospective validation, concurrent validation and retrospective validation. As a foundation for QA planning, a functional workflow and the required information flows are proposed by using functional design models: Icam DEFinition for Function Modeling.
Findings
The functional design model of the QA plan provides the systematically integrated view that can be the basis for inspection of AM processes for the repeatability and qualification of AM parts for reproducibility.
Research limitations/implications
A powder bed fusion process was used to validate the feasibility of this QA plan. Feasibility was demonstrated under many assumptions; real validation is not included in this study.
Social implications
This study provides an innovative and transformative methodology that can lead to greater productivity and improved quality of AM parts across industries. Furthermore, the QA guidelines and functional design models provide the foundation for the development of a QA architecture and management system.
Originality/value
This systematically integrated view and the corresponding QA plan can pose fundamental questions to the AM community and initiate new research efforts in the in-situ digital inspection of AM processes and parts.
Details