A REVIEW OF SIX SIGMA APPROACH: METHODOLOGY, OBSTACLES AND .

G.J. E.D.T.,Vol.3(4):1-5(September-October, 2014)ISSN: 2319 – 7293A REVIEW OF SIX SIGMA APPROACH: METHODOLOGY, OBSTACLES ANDBENEFITSKumar Dhiraj1& Kaushish Deepak2Department of Mechanical Engineering, Geeta Institute of Management and Technology, Haryana, IndiaAbstractSix Sigma is an approach that improves quality by analyzing data with statistics. In recent years there has been asignificant increase in the use and development of the Six Sigma methodology in manufacturing industry and others. TheSix Sigma approach has been increasingly adopted worldwide in the manufacturing sector in order to enhance productivityand quality performance and to make the process robust to quality variations. Understanding Methodology, key features,obstacles of the six sigma method allows organizations to better support their strategic directions, and increasing needs forcoaching, mentoring, and training. It also provides opportunities to better implement six sigma projects. This paperreviews Methodology, obstacles and Benefits of six sigma practices and identifies the key factors influencing successfulsix sigma project implementations. Effective six sigma principles and practices will succeed by refining the organizationalculture continuously. Cultural changes require time and commitment before they are strongly implanted into theorganization.Key words: Six sigma, DMAIC, Methodology, Benefits, Obstacles.1. IntroductionSix sigma method is a project-driven managementapproach to improve the organization’s products,services, and processes by continually reducing defectsin the organization. It is a business strategy that focuseson improving customer requirement understanding,business systems,productivity,and financialperformance. Dating back to the mid-1980s, applicationsof the six sigma methods allowed many organizations tosustain their competitive advantage by integrating theirknowledge of the process with statistics, engineering,and project management (Anbari, 2002). Numerousbooks and articles provide the basic concepts andbenefits of the six sigma method (Harry and Schroeder,2000) (Hoerl, 1998, 2001). The challenges and realitiesin implementing the six sigma method successfully areimmense. However, the benefits of applying the sixsigma method to technology-driven, project-drivenorganisation are equally great. The objective of thispaper is to review and examine the evolution, benefits,and challenges of six sigma practices and identify thekey factors influencing successful six sigma projectimplementation. The paper also integrates the lessonslearned from successful six sigma projects and theirpotential applications in managing traditional projects,and considers further improvements to themethodologies used for managing six sigma projects.Wider applications of six sigma principles to theorganization will succeed through senior managementinvolvement, organizational commitment, culturalchange, and effective project management.What is Six Sigma?Six Sigma can be defined as a business improvementstrategy used to improve business profitability, drive outwaste, reduce costs of poor quality and to improve theeffectiveness and efficiency of all operations so as tomeet or even exceed customers’ needs and expectations(Antony J. and Banuelas R., 2004).‘Six Sigma’ is a management innovation methodology toproduce virtually all products or services that are defectfree based on the process data by improving businessprocesses and thereby satisfying customer and employeeand reducing costs. In short ‘Six Sigma’ is several thingsA statistical basis of measurement: 3.4 DPMOA philosophy and a goal: as perfect as practicallypossible, (Greg Brue, 2002).2. Methodology of Six SigmaSix Sigma has been defined as the statistical unit ofmeasurement, a Sigma that measures the capability ofthe process to achieve a defect free performance. SixSigma has the ability to produce products with only 3.4defects per million, which is a world-class performance.Six Sigma has also been described as a high performancedata driven approach in analyzing the root causes ofbusiness problems and solving them.2.1 Basic ConceptSix Sigma is considered to be a new initiative introducedby Motorola in the late 1980s, hence several papers fromthe early 1990's concentrate on explaining thedevelopment of Six Sigma using the Motorola case(Tennant G., 2001). These authors discuss the newMotorola quality improvement program, namely SixSigma, which has led to improvements in their qualityperformance and consequently propose Six Sigma as anew opportunity for any organization that wants toimprove quality. Other authors attempt to investigate andexplain the Six Sigma methodology in a descriptivemanner without empirical evidence or any relatedbusiness. These papers are valuable to researchers newto Six Sigma in providing background information, andgiving evidence of the emerging importance of themethodology. Two key conceptual papers also considerthe overall concept, attempting to analyse thedevelopment of Six Sigma and explain its statisticalfoundation. Bothe presents a statistically based reasonfor adding a 1.5 Sigma shift before estimating processcapability, proposing a new capability index, calleddynamic Cpk (Bothe D., 2001). He also suggests future1

G.J. E.D.T.,Vol.3(4):1-57293(September-October, 2014)study on the impact and behavior of the shift in variouscircumstances. Antony studies the strengths and theweaknesses of Six Sigma in detail and links Six Sigmato statistical thinking (Antony J. and Banuelas R., 2004).He suggests that Six Sigma has a strong statisticalfoundation and consequently is likely to continue to beof importance in the future.2.3 DMAIC ProcessDMAIC is a closed-loop process that eliminatesunproductive steps, often focuses on new measurements,and applies technology for continuous improvement.Some papers focus on explaining the DMAIC contents,with some authors discussing each phase of DMAIC indetail (Snee R. D., 2004). For example, Rasis et al.present self-learning training material for DMAIC, usinga fictitious application (Rasis D., 2003). This paper helpsthe readers to learn how to carry out a small-scale SixSigma project, including guidance on the application oftools. It indicates a perceived need for training materialand suggests that an avenue for further research is todevelop training material to cover wider range ofapplications and larger scale projects. Other papersconcentrate on specific aspects of DMAIC, such as theproject selection process in the Define phase or processcontrol in the Control phase, explaining some keymeasures in Six Sigma, such as project metrics and RollThroughput Yield (RTY).For example, Snee emphasizes the importance of theproject selection process in the Define phase for thesuccessful implementation while Mason suggests usingmultivariate statistical process control in the Controlphase. These papers tend to explain the features ofDMAIC rather than critically appraising or enhancing it.Future research should investigate whether aspects ofDMAIC need to be modified to increase its scope, forexample for the service sector or non-profitorganizations. If so, research to enhance themethodology may then be needed. Table 2 presents thekey steps of Six Sigma using DMAIC process.Table 2. Key Steps of DMAIC Process (Young HoonKwak, et.al, 2006)StepKey processesDefineDefine the requirements & expectationsof the customer.Define the project boundaries.Define the process by mapping thebusiness flow.MeasureMeasure the process to satisfycustomer’s needsDevelop a data collection planCollect and compare data to determineissues and shortfallsAnalyzeAnalyze the causes of defects andsources of variationDetermine the variations in the processPrioritize opportunities for futureimprovementImproveImprove the process to eliminatevariationsDevelop creative alternatives andimplement enhanced planControlControl process variations to meetcustomer requirementsDevelop a strategy to monitor andcontrol the improved processImplement the improvements of systemsand structures2.2 Two perspectives of six sigma processesA.) Business viewpointIn the business world, six sigma is defined as a ‘businessstrategy used to improve business profitability, toimprove the effectiveness and efficiency of alloperations to meet or exceed customer’s needs andexpectations (Antony and Banuelas, 2001). The sixsigma approach was first applied in manufacturingoperations and rapidly expanded to different functionalareas such as marketing, engineering, purchasing,servicing, and administrative support, once organizationsrealized the benefits. Particularly, the widespreadapplications of six sigma were possible due to the factthat organizations were able to articulate the benefits ofsix sigma presented in financial returns by linkingprocess improvement with cost savings. Table 1summarizes Six Sigma business strategies, tools,techniques, and principles.B.) Statistical viewpointSix sigma method has two major perspectives. Theorigin of six sigma comes from statistics andstatisticians. Hahn et al. (1999), Hoerl and Snee (2002),and Montgomery (2001) discuss the six sigma methodfrom a statistical, probabilistic, and quantitative point ofview. From the statistical point of view, the term sixsigma is defined as having less than 3.4 defects permillion opportunities or a success rate of 99.9997%where sigma is a term used to represent the variationabout the process average (Antony and Banuelas, 2002).If an organization is operating at three sigma level forquality control, this is interpreted as achieving a successrate of 93% or 66,800 defects per million opportunities.Therefore, the six sigma method is a very rigorousquality control concept where many organizations stillperforms at three sigma level (McClusky, 2000).Table 1. Strategies, Tools, Techniques and Principles(Young Hoon Kwak, et.al, 2006)Strategies & Principles Tools & TechniquesProject management Statistical process controlData-based decision Process capability analysismakingKnowledge discovery Measurement system analysisProcess control planning Design of experimentsData collection tools &Robust designTechniquesVariability reduction Quality function deploymentBelt systemDMAIC processChange managementtoolsISSN: 2319 –Failure mode & effectsanalysisRegression analysisAnalysis of means &variancesHypothesis testingRoot cause analysisProcess mapping2.4 DFSS ProcessDesign for Six Sigma (DFSS) is a systematicmethodology utilizing tools, training and measurementsto enable the organization to design products andprocesses that meet customer expectations and can be2