Quantitative analysis of Six Sigma, Lean and Lean Six Sigma research publications in last two decades

The moderating role of Lean Six Sigma practices on quality management practices and quality performance in medical device manufacturing industry

Purpose

The purpose of this paper is to explore the moderating role of Lean Six Sigma (LSS) practices in explaining the relationship between quality management practices (QMPs) and quality performance.

Design/methodology/approach

Partial least square-based structural equation modeling (PLS-SEM) was used to empirically examine the moderating effect of LSS practices on QMPs and quality performance in Malaysian medical device manufacturing companies.

Findings

Findings revealed that both QMPs and LSS practices have a significant and positive effect on quality performance. Furthermore, LSS practices served as a substitute for moderating the positive relationship between QMPs and quality performance in such a way that the relationship becomes weaker as LSS practices increase.

Originality/value

LSS is acknowledged as the most well-known hybrid methodology; however, due to its relative newness, it has not been studied in great detail. Unlike previous studies, this paper argued that Lean and Six Sigma practices are distinct from its predecessor TQM practices; moreover, both Lean and Six Sigma practices do not need to substitute QM/TQM practices instead of complimenting the QMPs. In addition, this study adds to the growing body of QM literature by empirically examine the effect of LSS practices in moderating the relationship between QMPs and quality performance.

The Development of an Excellence Model Integrating the Shingo Model and Sustainability

Companies are continuously looking to improve their production systems using excellence models, with lean thinking, the Shingo model, six sigma and lean six sigma being the most comprehensive and applied. It is expected that the initial focus for the survival of companies is their economic profitability, but when economic needs are met, the next step is to achieve operational excellence. For this, in addition to economic objectives, it is necessary to include social and environmental objectives, i.e., the other two pillars of sustainability. This study aims to propose a conceptual model identifying the tools that can help achieve the desired results in the three pillars of sustainability aligned with operational excellence. The design of the conceptual model was based on a bibliometric analysis of the literature that relates the concepts of lean thinking, six sigma, lean six sigma and the Shingo model. The Web of Science was the platform selected for the collection of data, and the timeframe considered was 2010 to 2021. A total of 125 articles were analyzed using the VosViewer software, through which it was possible to analyze different topics of study related to the literature. The bibliometric analysis allowed for the identification of the temporal distribution of publications, the categorization of topics, different areas of application and the importance of the tools used in different practical cases. This study points out that companies have at their disposal several tools to achieve economic objectives. On the other hand, there is a set of more restricted tools that are used to meet the objectives of the social and environmental pillars. Future research should focus on identifying tools that meet social and environmental goals in order to strengthen these pillars that are essential for operational excellence and for the sustainability of companies.

Country-related future research agenda of Lean Manufacturing–A systematic literature review

Purpose

Many future research proposals of Lean Manufacturing (LM) are presented in the literature. The purpose of this paper is to determine these future research proposals of LM which are country-related and classify them.

Design/methodology/approach

A systematic literature review (SLR) of peer-reviewed journal articles in LM was conducted. A total of 145 articles published in 34 journals during 2010–2020 were collected from four major management science publishers namely, Emerald Online, Elsevier/Science Direct, Springer Link and Taylor and Francis. The country-related future research proposals of LM identified in the literature were classified according to, firstly, the continent of the country of reference, and secondly, some form of natural affinity of these proposals creating meaningful themes. The quality tool “affinity diagram” was applied to classify the country-related future research proposals of LM.

Findings

The country-related future research proposals of LM, which are increasing in the literature over time, refer mostly to studies to be conducted in several continents/countries and to multinational studies. Conducting studies specifically in Asia, Europe, South and North America, Africa and Australia–New Zealand is also suggested. The plethora of the country-related future research proposals of LM were classified, based on the affinity of their content, into 18 meaningful themes. These themes were also classified based on their affinity into two broad categories, namely “themes concerning the LM approach itself” and “themes concerning factors outside the LM approach”.

Research limitations/implications

The restricted number of the databases searched and the subjectivity of classifying the large number of the country-related future research proposals into themes are the main limitations of the present SLR. Based on these limitations, future literature review studies can be carried out.

Practical implications

Useful proposals are provided to researchers of several countries for conducting original and country-specific research studies which can enrich the knowledge of the implementation of LM under the specific circumstances of a country for the benefit of practitioners.

Originality/value

This study goes beyond previous literature review studies on LM by focusing exclusively on the LM future research agenda which is country related. The analytical presentation of the country-related future research proposals as well as the formulation of clusters of these proposals make the present SLR study substantially different from those carried out worldwide so far.

Exploring the emotional experience of lean

PURPOSE

This research aims to contribute to the literature on Lean implementation in healthcare by studying the emotional experiences of the relevant actors related to a Rapid Process Improvement Workshop (RPIW) in a UK healthcare context. The purpose of this study was to go beyond what people think about Lean and towards an exploration of their subjective, emotional and "feeling" experience and whether that emotional experience influenced Lean implementation.

DESIGN/METHODOLOGY/APPROACH

A phenomenological and symbolic interactionist qualitative case study was undertaken. Data related to participants' emotional experience were collected through non-participant observation and semi-structured interviews. Data were analysed using thematic network analysis.

FINDINGS

This paper provides novel insights into the emotional experience of Lean as experienced through an RPIW. The findings reveal that participation in an RPIW is much more than a technical process. It influences how people feel about themselves, is based on relationships with others, and requires mental, physical and emotional effort. All of these factors influence engagement with, initiation of and sustainability of the RPIW.

RESEARCH LIMITATIONS/IMPLICATIONS

A new conceptual framework for the planning and implementation of RPIWs has been developed. However, because of the chosen research approach, the results may lack generalisability. Therefore, researchers are encouraged to test the framework and proposed practice implications.

ORIGINALITY/VALUE

Despite emotions being an integral part of individual and social everyday life, emotional experience has not been studied in relation to Lean. This study is the first to explore emotions in relation to Lean, with implications for practice as to how RPIWs are managed with a new framework for implementation being proposed.

Simulation-based lean six sigma for Industry 4.0: an action research in the process industry

Purpose

The primary aim of this article is to ascertain the modalities of leveraging Lean Six Sigma (LSS) for Industry 4.0 (I4.0) with special reference to the process industries. Moreover, it intends to determine the applicability of simulation-based LSS in the automation of the mineral water industry, with special emphasis on the robust design of the control system to improve productivity and performance.

Design/methodology/approach

This study adopts the action research methodology, which is exploratory in nature along with the DMAIC (define-measure-analyze-improve-control) approach to systematically unearth the root causes and to develop robust solutions. The MATLAB simulation software and Minitab statistical software are effectively utilized to draw the inferences.

Findings

The root causes of critical to quality characteristic (CTQ) and variation in purity level of water are addressed through the simulation-based LSS approach. All the process parameters and noise parameters of the reverse osmosis (RO) process are optimized to reduce the errors and to improve the purity of the water. The project shows substantial improvement in the sigma rating from 1.14 to 3.88 due to data-based analysis and actions in the process. Eventually, this assists the management to realize an annual saving of 20% of its production and overhead costs. This study indicates that LSS can be applicable even in the advent of I4.0 by reinforcing the existing approach and embracing data analysis through simulation.

Research limitations/implications

The limitation of this research is that the inference is drawn based on a single case study confined to process industry automation. Having said that, the methodology deployed, scientific information related to optimization, and technical base established can be generalized.

Originality/value

This article is the first of its kind in establishing the integration of simulation, LSS, and I4.0 with special reference to automation in the process industry. It also delineates the case study in a phase-wise manner to explore the applicability and relevance of LSS with I4.0. The study is archetype in enabling LSS to a new era, and can act as a benchmark document for academicians, researchers, and practitioners for further research and development.

Evaluating the effect of critical failure factors associated with sustainable Lean Six Sigma framework implementation in healthcare organization

Purpose

The purpose of this study is to develop a structured hierarchical interrelationship-based model to evaluate the critical failure factors (CFFs) that affect the sustainable Lean Six Sigma (SLSS) framework implementation in a healthcare organization. Further, solution approaches have been provided that guide to eliminate them.

Design/methodology/approach

The CFFs has been identified through empirical study and clustered into six major categories for their better understanding. The interrelation among CFFs has been developed through total interpretive structural modeling (TISM) and classifies the nature using MICMAC technique. Further, prioritized the CFFs based on its driving and dependents power. The methodology enabled the decision-makers, practitioners to systematically analyze the CFFs and develop a structural model for implementing SLSS in the healthcare environment.

Findings

A total of 14 leading CFFs have been identified, and 7-level structured interrelationship-based model has been formed. The experts have provided the solution approach after careful analysis of the developed model. Based on the analysis, it was observed that the significant CFFs affect the deployment of the SLSS framework in healthcare organizations.

Research limitations/implications

The structured model and methodological approach have been tested in a healthcare organization. In the future, the approach can be applied in the different service sectors.

Practical implications

The present study has been conducted in a real-time industrial problem. The practitioners, decision-makers and academicians expressed the usefulness of methodology for understanding the CFFs interrelation and their effect on SLSS implementation. This study also guides decision-makers to systematically tackle related problems.

Originality/value

The development of a structured CFFs based model for SLSS framework implementation using the integrated TISM-MICMAC with a detailed solution approach is a unique effort in a healthcare environment.

Integrating the HACCP and SPC for hazard control and process improvement: a case of pharmaceutical industry

Purpose

The purpose of this study is to integrate two well-established frameworks with an aim to reduce the unwanted rejection rate recurring in the drug production process in pharmaceutical industries. The effectiveness of an integrated framework has been demonstrated by a real-time case study in a complex industrial environment, providing a platform for quality tools application in the pharmaceutical industry.

Design/methodology/approach

The hazard analysis and critical control points (HACCP) provided a basic framework for hazard analysis and its blending with statistical process control (SPC) aided in data-driven decision-making. The extensive brainstorming and Pareto analysis helped to identify potential critical-to-quality characteristics followed by SPC, x¯ and R charts, histograms and Cp and Cpk analysis to spot the critical control point. The fishbone diagram led to the extraction of the leading cause behind the identified problem. Then, based on recommended corrective actions, control limits were adjusted and the process was brought into control. Finally, a product-based cost analysis is also performed to illustrate the financial impact resulting from the proposed method’s successful implementation.

Findings

The integrated framework is applied to a drug production process which has a higher rejection rate (3%) because of the non-conformities. Based on Pareto analysis, potential failure causes were classified and prioritised as inappropriate composition (2.54%), packaging (0.35%), out-of-specification (0.069%), equipment failure (0.022%), input materials (0.018%) and miscellaneous (0.002%). It is found that 84% of the total rejection rate is contributed by inappropriate composition. After taking corrective actions, it is observed that the proposed method has helped to reduce the process rejection rate significantly (2.54-0.82%). In the monetary terms, 2.50% decline per unit costs is noted in this case study work. The proposed integrated framework’s success is further motivating other pharmaceutical industries to implement and expand it to other processes.

Originality/value

The case study is an attempt to contribute to the existing literature of quality management in pharmaceutical industries. In particular, it is a novel example to introduce the simple and user-friendly SPC tool into well-established HACCP framework to enhance its effectiveness in hazard identification. The case study results motivate managers to adopt quality techniques for achieving a higher quality standard and operational excellence.

Application of Six Sigma DMAIC methodology to reduce the defects in a telecommunication cabinet door manufacturing process

Purpose

The purpose of this paper is to apply the Six Sigma DMAIC methodology in order to reduce the rejections experienced in the manufacturing of the doors belonging to a telecommunication cabinet.

Design/methodology/approach

The process involved joining of sheet metal and hinge using welding operations with the help of a fixture. The methodology used is the structured DMAIC method in order to identify the root cause for the rejections and solve it.

Findings

The paper provides insights about the identification of the root cause for the defects and the solution to overcome it, and also the benefits that were obtained as a result of the application of the solution.

Research limitations/implications

This methodology has been applied to the variation observed in the dimensions of a particular component to be welded with a main part. This approach can be used to find such dimensional variations.

Practical implications

This study has been successfully carried out in a medium-scale industry which has total quality management in practice.

Originality/value

Six Sigma DMAIC was necessary for the identification and reduction of the defects which arose in the sheet metal and welding operations, and had to be resolved in order to increase the bottom-line.

Empirical analysis of Six Sigma project capability deficiency and its impact on project success

Purpose

The purpose of this paper is to understand the deficiencies in Six Sigma project capability and empirically validating its impact on project success.

Design/methodology/approach

Deficiencies are identified from literature focusing on Six Sigma challenges or barriers. The study used a survey approach by circulating questionnaires to 400 Six Sigma professionals from 40 multinational organisations. The conceptual model is composed of 16 items measuring five constructs for hypothesis testing. Furthermore, structural equation modelling was used to identify the relationship between Six Sigma project capability deficiency and project success.

Findings

The findings of the study suggest that inadequate top management support, inadequate resources and change management and inadequate quality maturity form Six Sigma project capability deficiency and affect project success.

Research limitations/implications

The study uses resource-based view to understand the deficiencies in Six Sigma project capability and their impact on project success. The study confirms that organisational capabilities in implementing Six Sigma affect the success of the projects.

Practical implications

The results of this study reveal that inadequate top management support, inadequate quality maturity of the organisation and inadequate resources and change management result into a deficiency in Six Sigma project capability. Quality managers in manufacturing and service organisations should attempt to improve these capabilities to achieve competitive advantage.

Originality/value

The study contributes to the literature by exploring the capability outlook of Six Sigma. The study attempts to fill the gap in Six Sigma literature by providing a structural model for understanding Six Sigma project capability deficiency and its impact on Six Sigma project success.

Lean Six Sigma for Intravenous Therapy Optimization: A Hospital Use of Lean Thinking to Improve Occlusion Management

Background: Continual improvement is a necessary part of hospital culture. This occurs by identifying opportunities for improvement that influence efficiency while saving money.

Methodology: An investigation of intravenous device-related practices was performed by the nurses of the intravenous access team, pharmacy, and hospital operations at Hartford Hospital using Lean Six Sigma methodology. Central venous access device occlusion and tissue plasminogen activator variability was identified. Using observation, measurement of performance, and root cause analysis, the hospital's practices, policies, and equipment were evaluated for the process of occlusion management. The team utilized a Six Sigma strategy employing the elements define, measure, analyze, improve, and control, which is a disciplined, data-driven methodology that focuses on eliminating defects (waste). Interventions initiated based on the assessment performed by the team using the define, measure, analyze, improve, and control approach included replacement of negative displacement needleless connectors with antireflux needleless connectors and specialty team assessment before tissue plasminogen activator use.

Results: Over the course of the 26-month study, Hartford Hospital experienced a 69% total reduction in tissue plasminogen activator use representing a total 26-month savings of $107,315. Other cost savings were reflected in areas of flushing, flushing disposables, and in a decrease in needleless connector consumption. Central line-associated bloodstream rates fell 36% following the intervention as an unexpected secondary gain, resulting in further savings related to treating this nonreimbursable hospital-acquired condition.

Conclusions: This study examined the influence of using Lean Thinking and Six Sigma methodology as a tool in saving hospital money, resulting in better patient outcomes.

Factorial structure for Six Sigma project barriers in Indian manufacturing and service industries

Purpose

The purpose of this paper is to identify the latent constructs of various barriers affecting Six Sigma implementation in Indian industries.

Design/methodology/approach

Literature review resulted in 15 frequently reported barriers in Six Sigma implementation. An empirical survey of 168 Six Sigma practitioners including green belts, black belts (BB), and master BB from 40 Indian companies was conducted with the help of a structured questionnaire. The responses were analyzed using exploratory factor analysis which resulted into five constructs.

Findings

The study proposes five constructs, namely “role of top management,” “cultural change,” “expected attitude,” “availability of resources,” and “level of quality maturity.” The focused approach by organizations to overcome barriers in Six Sigma can be oriented using these constructs.

Practical implications

Six Sigma implementation needs elimination of barriers in projects. Top management support in planning and resource allocation supplemented by favorable employee attitude in bringing cultural change can develop quality maturity to implement Six Sigma successfully.

Originality/value

This study fills the gap in the literature by studying critical success factors, critical failure factors, and barriers together. This study is one of its kinds in the Indian context which captures the views of Six Sigma certified professionals from the organizations which are implementing Six Sigma.