International Journal of Recent Research Research and Review, Vol. VI, Issue 3, December December 2013 ISSN 2277 – 8322
LEAN SIX SIGMA SIGMA – PROCESS IMPROVEM IMPROVEMENT ENT TECHNIQUES TECHNIQUES 1
2
Udita Saini , Sujata 1 2
M.Tech (SE), ITM University, University, Gurgaon Gurgaon (Haryana), (Haryana), India
Assistant Professor Professor (CSE/IT Dept.), ITM ITM University, Gurgaon Gurgaon (Haryana), (Haryana), India Email:
[email protected],
[email protected] (TPS) which which is based on the the concept concept of elimination elimination of waste in processes which had resulted in productivity gain and improvement improvement of speed and flow in the value stream. Six Sigma when coupled with Lean Principles is called Lean Lean Six Sigma Sigma which which prof profess esses es elimin eliminatin ating g waste waste in in process steps by using Lean tools which enhances value in Six Sigma implementation one one step further by increasing speed by identifying and removing non-value adding steps in a process. process. Execution Execution of Lean Lean Six Six Sigma projec projectt uses a structured structured method method of of approach approaching ing problem problem solving solving normally described described by acronym acronym DMAIC which stands for Define, Define, Measure, Measure, Analyze, Analyze, Improve Improve and Control. Control. Many organizations have achieved phenomenal success by implementing Lean Six Sigma. This paper focuses and highlights overview and details of some of the important aspects of Lean, Six Sigma and Lean Si x Sigma.
Abstract - Six Sigma was a c oncept developed in 1985 by Bill Smith of Motorola. Six Sigma is a business transformation methodology that maximizes profits and delivers value to customers by f ocusing on the reduction of variation and elimination of defects by using various statistical, data-based tools and techniques. Whereas, Lean is a business transformation methodology which was derived from the Toyota Production System (TPS) which focuses on increasing customer value by reducing the cycle time of product or service delivery through the elimination of all forms of waste and unevenness in the workflow. The concept of Lean Six Sigma is a combination of both the Lean and Six Sigma. The aim of this paper is to define the meaning and basic principles of Process Improvement Techniques. For this purpose, Process Improvement Techniques focused on Lean, Six Sigma and blended approach as Lean Six Sigma. These techniques have been used in private sector, sector, manufactur manufacturing ing and service service organisation organisationss for several years.
II. LEAN DEVELOP DEVELOPMENT MENT Lean Thinking is specifying value by specific products, identifying the value value stream for each product, make make value flow without interruptions, let the customer pull value from the producer, and pursue perfection [1]. Lean Thinking has its roots in the Toyota Production System and has been developme deve lopment nt over time, time, with Womac Womack k and Jones Jones regar regarded ded as the originators originators of the term and its associated principles. Lean is considered to be a radical alternative to the traditiona tradi tionall method method of mass mass producti production on and and batc batching hing principles for optimal efficiency, quality, speed and cost [2].. Th [2] Thee five five cor coree princ principl iples es of of Lea Lean, n, base based d on an underlying assumption that organisations are made up of processes are [1]: i) Spe Specify cify the val value ue des desire ired d by the cus custome tomer. r. It It is is also also useful to identify who the real customer is and better understand their requirements, which can be complex. ii) Ident Identify ify the value stream for each prod product uct prov providing iding that value and challenge all of the wasted ste ps. iii) Make the product product flow continuo continuously usly.. Standardising Standardising processes around best practice allows them to run more
Keywords - Process improvement Techniques, Lean thinking, Six Sigma, Lean Six Sigma
I.
INTRODUCTION
Due to increased globalization and constant technological advances and other competitive pressures, the organizations have to accelerate the pace of change to adapt to new situations situations.. Six Sigma is is the most popula popularr quality and and process improvement methodology which strives for elimination of defects in the processes whose origin is traced back to the pioneering and innovation work done at Motorola and its adoption by many companies including GE, Ford, General Motors, Xerox etc. The primary objective of Six Sigma is to reduce variations, in products and processes, to achieve quality levels of less than 3.4 defects defects per million opportuni opportunities ties (DPMO). Lean was an another quality and productivity improvement methodology methodology introduced introduced in Toyota Toyota Production Production Systems Systems
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smoothl hly y, freeing up time for cre ativity and innovation. iv) Introduce pull between all step epss where con tinuous flow is imp impos ossib sible le.. This This foc focus uses es upo upon n the the dem dem nd fro from m the customer custo mer and triggers triggers events events backwards backwards through the value chain. In this way inventory and hu man act activi ivity ty is linked to customer needs. v) Manag agee to toward rdss pe perfectio ion n so that no non- alue adding acti ac tivi vity ty wi will ll be re remov moved ed fr from om th thee val value ue c hain and the number numb er of steps steps and the amount amount o time and information infor mation needed needed to serve the custome custome continually falls.
Review Revi ewin ing g cus custo tome merr com compl plai ai ts, and assigning team memb me mber erss task taskss to det deter ermin minee their internal and external customers custo mers values values and what what the the y consider consider waste waste in this process. ii)) Ru ii Runn nnin ing g Ka Kaiz izen en Bl Blit itzz or ra rap p id improvement events involving employees from with and/or across departmen entts, wh which sco scop pe ou out i ssues to be resolved and implement the required change s. iii) ii i) Ca Carr rry yin ing g out out pr proc oces esss map mappi ping and value stream: Mapping Mappi ng out out the proce process ss and assigning cycle and value-added time to each step, looking for bottlenecks, and lis listing ting any tea team m conc concer er ns or or ques questio tions ns to be addressed at a later time. Also root cause analysis and brainstorming can be used to anal analyse yse the bottlene bottlenecks, cks, find fin d solut solution ions, s, and str stream eamline line t e process. iv)) 5S act iv ctiv ivit ity y as part of of,, or sep epaa ate to, the Kaizen Blitz and proces processs mapping. mapping. 5S 5S i a rig rigoro orous us for form m of housekeeping which supports the pursuit of waste elimination. It consists of: a) Se Seir irii (Si (Sift ftin ing) g):: Com Compr pris ises es of the removal of all unnecessary items. b) Seiton (Si mplifying): This is hen work site items are arranged arrang ed in the the most most effectiv effectiv e way whi which ch could could be influenced by frequency of se, work sequence or weight/size weight /size.. The location location fo each item is clearly visible and labelled – so if so ething is missing or in the wrong wrong place it can be clearl clearl y seen. c) Se Seis iso o (Swee (Sw eepin ping) g):: The traditional view of The housekeeping about keeping everything clean, even spotless. d) Shitsuke (S tandardise): Re gularly auditing the workplace workp lace to ensure ensure standard standard are being maintained and improved. e) Sei Seiket ketsu su (Se (Self lf Dis Discip ciplin line): e): To o with general working enviro env ironmen nment, t, prov provisio ision n of of work wear and and sust sustain aining ing the housekeeping. v) Imp Implem lement ent cro crossss-func functio tional nal teams involving all rele va vant em employees th that wo work direct irectly ly on the process process at all levels within and outside of the department. vi) Th Thee imp imple leme ment ntaati tio on of of sta stan nd ard work, which is a meth me thod od of de defi fini ning ng,, or orga gani niss ing and agreeing the activity activ ity in a process process to ensure the most effective and efficie eff icient nt use of reso resourc urces, es, peo peop p le, tools and equipment. vii)) Usi vii Using ng Visu Visual al Manag Manageme ement nt a s a means to display standards stand ards or targets in in a proces proces s area, together with the current performance achieved. The purpose of this is to make problems visible to the whole team quick quickly, ly, so that they can be tackled promp ly. It is impo importa rtant nt to to note note tha thatt Le n is argued to be a philosophy suggesting that what o ganisations need or are
Fig. 1: Lean Development C cle Within Lean it is stated that all other activitie that do not provide value are a waste and should be eli mi minat nated ed [3 [3]. ]. Ther Th eref efo ore re,, a cr cruc ucia iall ele eleme ment nt of Le Leaan is th thee re re oval of non added value or waste, varia iab bility and infle xibility [4]. These als also o ha have Ja Japanes esee te term rmss of of mu muda ( aste), mura (unevenness) and muri muri (overburden) (overburden) [3]. Bhatiaa and Drew Bhati Drew [4] ident identify ify those those which which are of particular relevance relev ance to the any busin business ess are: i) Was Waste; te; scr scrap ap and rewo rework, rk, wai waitin ting, g, inventory, unnecessary motion, unnecessary tra sp spo ort, over production and over processing. ii)) Var ii aria iab bil ilit ity y; exa examp mple less of of wh whic ich h in in pu pu lic services include the variation is gathering evidence for a trial. iii) ii i) In Infl flex exib ibil ilit ity y es espe peci ciaall lly y wi with th re rega gard rd to st ffing levels being inflexible and the same every day on the assu as sump mpti tion on th that at a st stan anda dard rd se serv rvic icee nec neces essarily offers econom eco nomies ies of scale scale,, whereas whereas cust custom om r segments require different levels and types of servic . Many tools for Lean implementation have als also o been sugges sug gested ted and are are capab capable le of being being uti utilis lised ed within any business [5], [6]: i) Und Unders erstan tandin ding g custo customer mer valu valuee and and wha whatt he customer considers waste. Focusing on not only the ultimate cust cu stom omer er but but int inter erna nall and and exte extern rnal al cus custo to ers as well.
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creating is a Lean lifestyle [3],[6]. Also the implementation of Lean is described as a journey with the various stages of the implementation being landmarks of the total journey [6].
in the project. Without measurement there is no control. Measurements are essential to collect data. iii) Analy Analyse: se: Using the right right approac approach, h, analytical analytical tools tools or methods will help to find a clearly defined solution. Data is analysed into information to create a knowledge base and make decisions for actions. iv) Impro Improve: ve: Select Select and impleme implement nt the best best solution solution to remove the cause of a problem will bring the desired result. Improvements are corrective and preventive actions. v) Contro Control: l: After After the the implem implementat entation ion of of improveme improvement nt activities, monitoring becomes essential to control the processes. There is a clear team structure within a Six Sigma project with members moving from a Green Belt to a Master Black Belt depending on their training and level of involvements within projects. In summary, team members members on Six Sigma projects have the following roles [8]: i) Exe Execut cutive ive who who commi commits ts resou resources rces and and spons sponsors ors the the projects. ii) Maste Masterr Black Belt who who provide providess training training and and coachin coaching. g. iii) Black Belt Belt who leads leads the improvemen improvementt project. project. iv) Green Belt who suppo supports rts and runs projec projects. ts. v) Champ Champion ion who who is involv involved ed in in support supporting ing the the project project.. Champions lead projects and ensure that all improvements become cemented. Green Belts participate in projects and are usually can engineers, supervisors and quality control experts. They receive mentoring from the Black Belts [11]. The tools used in Six Sigma deployments vary from the developme deve lopment nt and analysis analysis of visual charts charts to the use of similar tools used in Lean Implementations Implementations [9]. The use of of pareto charts, scatter diagrams, histograms, regression analysis and statistical process control, combine the rigor and objectivity objectivity of statistica statisticall analy analysis sis with the ability to visually interpret quantitative information, thereby reveal rev ealing ing more more proces processs inf inform ormati ation. on. These These allo allow w differentiation between common variations and special variations varia tions to be highlight highlighted. ed. Statis Statistical tical Process Process Control Control (SPC) charts show variation in process through data points over time relative to a central line with upper and and lower control limits. They highlight whether a process is in control or or whether corrective action action is needed. Effective change and sustained improvement can only be claimed if the process is known to be in control control [12].
III. III. SIX SIGMA SIGMA METHOD METHODOLO OLOGY GY The basic goal of a Six Sigma strategy is to reduce variation within the tolerance or specification specification limits of a service performance characteristic. In order to improve the quality of a typical service, it is imperative imperative to measure or quantify variation variation and then then develop potential potential strategies to reduce red uce vari variatio ation n [7]. [7]. Six Sigma Sigma aims aims to to reduce reduce organisational costs and enhancing customer satisfaction through throu gh the reductio reduction n of defects defects or service service failure. failure. It concentrates on measuring product/service quality, reducing reduc ing variation variation,, driving driving proc process ess improveme improvements nts and reducing cost, using a set of statistical and management tools to make make improveme improvement nt leaps [8]. Six Sigma Sigma projects projects aim to reduce the defect rate to a maximum of 3.44 errors per million exposures (i.e. 0.00000344%) [9] as shown in Table I [10]. [10]. Altho Although ugh Antony [7] remin reminds ds us us that that the the focus of of Six Sigma is not not on counting counting the the defects defects in processes, but the number of opportunities within a process that could result result in defects. TABLE I Sigma level 1
DPMO 691,462
Percent defective 69%
Percentage yield 31%
2
308,538
31%
69%
3
66,807
6.7%
93.3%
4
6,210
0.62%
99.38%
5
233
0.023%
99.977%
6
3.4
0.00034%
7
0.019
0.0000019%
99.99966% 99.9999981%
A key focus of the Six Sigma approach is the implementation of projects using a defined methodology called DMAIC (Define, Measure, Analyse, Improve and Control). Six Sigma implementations use a DMAIC methodology [8]: i) Def Define ine:: A clear clear and expli explicit cit defin definiti ition on of the the proble problem m is vital vital in projec projectt selection selection and prioriti prioritisation sation.. A well defined problem sets ground rules for improvement. ii) Meas Measure: ure: Measu Measuremen rementt points, points, source sources, s, tools tools and equipment, and precision precision and accuracy play a vital role
IV. A COMBINED COMBINED APPRO APPROACH ACH - LEAN SIX SIGMA The concept concept of Lean Six Sigma is a combination of both the Lean and Six Sigma. Anderson et al. [13] suggest that Lean manufact manufacturing uring addresses addresses proc process ess flow and and waste
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wherea wher eass Six Six Si Sigm gmaa add addre ress sses es va vari riat atio ion n and and d sign. Smith [11] [1 1] hi high ghli ligh ghts ts th that at re remo movi ving ng th thee lo low w han hangi gi g fruit with Lean Le an al allo lows ws ch chal alle leng nges es to be id iden enti tifi fied ed th that at r equire a Six Sigm Si gmaa app appro roaach usi sin ng sta stati tist stic ical al to tool olss to to unc uncover unseen roots and problems. Fina Fi nall lly, y, De Dedh dhia ia [8 [8]] su sugg gges ests ts th that at en enha hanc nced ed sa ings can be achieved through combining the approaches stating that Lean Six Sigma Sigma can can be used in all sectors. sectors. Lean can reduce waste and impro improve ve proce process ss efficien efficiency cy and Si Sigma can redu re duce ce var varia iati tion on an and d imp impro rove ve per perfo form rman ance ce.. Sa vings can be double dou bled d when when Lean Lean and Six Sigm Sigmaa are used in a coordinat coor dinated ed manner. manner. Both can be use use d in non manufact uring envir onments. This is su pported by O’Rouk O’R oukee [14] [14] the inte intende nded d outcom outcomee of Lea Lea Six Sigma projects is that the combination of both the disc ipline of Six Sigma and the speed of Lean implementations will produce business and operational excellence. Every organization strives to optimize its operations, furt furthe herr bas baseed on on the the typ type of of pro prob blems lems,, co com bining Lean and/or Six Sigma tools with traditional project management tech techni niqu ques es can can be be a powe powerf rful ul comb combin inat atio ion n as as s hown below in Figu Figure re 2 [15]: [15]:
departments. Lean is inclusive and involves the whole of the organisation. iii) ii i) Six Si Sigm gmaa focu focuses ses on co cost st an an d quality. Lean focuses on business strateg y, y, or organis tional design/structure, cult cu ltu ure an and d pro procces esse sess of of the the w ole value stream. iv) Six Sigm Sigmaa focuse focusess on spec specifi ifi c goals and objectives, identifies route causes, tests h ypot ypothese heses, s, validates validates the analysis and suggests ecommendations. On comp co mple letio tion n of of pro proje ject ctss Six Six Sig Sig a teams disband. v) Lean is about continuous im rovement as there will always be waste in the process.. Lean is ongoing and in the new learning organis tion, employees are continually conti nually build building ing their skil s and improving. Lean becomes part of their daily wor king lives. Proud Pro udlo love ve et et al. al. [17] [17] ex expl plai ai that in practice Lean appe ap pear arss to be a mor moree par parti tici cipa patt ve, bottom-up approach than Six Sigma. One One reason fo this might be that Lean is char charact acteris erised ed as as relyi relying ng mo mo e on intuition and deep inssight fo in for ex exam amp ple when pr producing future state value stream strea m maps. Proudlove Proudlove et al. [ 17] poin pointt out that: that: a) Six Si Sigm gmaa is is a ge gene neric ric,, r ot-cause and solution unknown problem-sol ving ap roach. Precisely what componen comp onents ts of the process process t o change and what to chan ch ange ge th them em to sh shou ould ld em emee ge from the rigorous, anal ytical, da data-driven me meth dology with potential over-emphasis on being da ta-driven, rather than problem-driven. b) Lean, in contrast, brings princi ples for improving flow and some tried-and-tested so lut lution ions. s. These These may be used us ed at an ea early rly st stag agee to con const strr ct a vision of the future conf co nfig igur urat atio ion n of of the the val value ue st stre re m, which which may be be used to guide and co-ordinate impro ements. Arh rhn nei eite terr an and d Ma Male ley yef efff [1 [18] 8] su sug g est that Lean and Six Sigma can can be integrat integrated ed together together i n order order to comp complement lement implem emeentatio ion ns. Th They [18] said hat Lean organisations should make more use of data in d ecision making and use methodolog meth odologies ies that that promote promote a mor e scientific approach to qualit y. In turn, Six Sigma orga isations can gain from traini ng ng in Le Lean management m thods to eliminate all forms of waste. waste. Dedhia supports the use of Lean Six Sigma in order to achieve positive financial impacts. Lean can reduc reducee waste and improve improve proce process ss efficiency efficiency an Six Sigma can reduce vari va riat atio ion n and and im impr prov ovee per perfo form rmaa nc nce. e. Sa Savi ving ngss can can be doubled when Lean and Six igma are used in a coordinat coor dinated ed manner. manner. Both ca be used in non man anuf ufaact ctu uri ring ng envi viro ronm nmen ents ts but both require management’s active support. Both Both six six sigma sigma and lean lean have have at at he he art the business process and the proces s impr ovement a proaches. An holistic
Fig. 2: Lean Six Sigma Process, Tools and and Business Results This section briefl y discussed the simi larities and differenc diffe rences es betwee between n the the appro approaches, aches, Lean an Six Sigma, before stating their combined approach. Ferguson Fergu son [16] states that reco recognisi gnising ng the the differences between Lean or Six Sigma means that ret urns can be maximised by knowing when to use which in the right contex con textt and envir environm onment ent.. Ferguso Ferguson n [16] ou outli tlin n s that: i) Lea Lean n is a philo philosop sophy, hy, whil whilee Six Six Sigma Sigma is a programme. ii) Six Sigm Sigmaa projec projectt teams teams exclude exclude thos thosee ot involved and the benef benefits its occurred occurred from projec projects ts a e speci specific fic to
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model model and methodology methodology should should thus retain retain thi s at its heart (Fig (Figur uree 3). 3). The The rout routee thro throug ugh h thei theirr appr appro oa ches should depend primarily upon the issues that the or anisation is faci facing ng and and its its natu nature re,, as as wel welll as as bei being ng infl influe uenced by the organisation’s and individual’s aspirations and perceptions [19].
[3]
[4]
[5]
[6]
[7]
[8] Fig. 3: A holistic m odel for business process i provement [9]
V. CONC CONCLU LUSI SION ON Lean Lean Six Sigma Sigma is a disc discipli iplined ned meth methodo odolo lo y which is rigorous, rigorous, data driven, driven, result-orien result-oriented ted approac approac to process improvement. It combines two industry recognized methodologi methodologies es evolved evolved at at Motorola Motorola,, GE, oyota, and Xerox to name a few. By integrating tools and processes of Lean and Six Six Sigma, Sigma, we’re creating creating a powerf powerf l engine for impro improvi ving ng qua quali lity ty,, effi efficie ciency ncy,, and spe speed ed in in ev ry aspect of business. Lean and Six Sigma are initiatives th at were born from the pursuit of operational excelle nce within manufacturing companies. While Lean serves to eliminate waste, waste, Six Sigma reduces reduces process process variabil variability ity i striving for perfection. When combined, the result is a ethodology that serves to improve processes, eliminate product or process defects and to reduce cycle times a d accelerate processes. Lean and and Six Sigma are concep conceptually tually soun soun technically fool proof proof methodolog methodologies ies and is here to stay and deliver break through results for a long time to come.
[10] [1 0] [11]
[12]
[13 [1 3]
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