Lean six sigma

Lean six sigma

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  Lean Six Sigma:A pristine tool for quality in pharmaceuticals S.S. Manikiran, N.L. Prasanthi. Department of Pharmaceutics, Chalapathi lnstitute of Pharmaceutical Sciences, Lam, Guntur Abstract ln present day, due to increased global competition the organizations sharpen their functionality and process to.gain competitive advantage. For this purpose, many firms use management systems like total quality management, ISO certiflcation, agile and lean manufacturing etc., but these systems are neither time effieient nor profitable in terms of qualfty. Therefore, the implementation of lean six sigma methodologl is required to help the companies in continuous improvement (Cl) with strong business competition and organizational effectiveness. Lean focuses mainly on the waste elimination and six sigma on the control and process variability using statistical tools. They can exist separately, but.ff they are used together, tremendous advantages are obtained. This review focuses mainly on the concepts of lean and six sigma methods. lt also lists out the technolory used for the methodology. Key words: Lean, six sigma, pareto charts, DMAIC, certification. lntroductlon: Nowadays, the pharmaceu many ' challenges in the market due to in ng the cost of raw materials, opposition f faults within the manufacturing process. This llasled to declining the profits in the industry. As Benjamin Franklin said, 'A penny saved is a penny earned'. The pennies are found in decreasingthe rework and waste, creating the smooth production flow and improvement in process. The process improvement is observed by continuous quality improvement (CQl), process improvement (Pl), quality assurance (QA), quality management (QM) and reengineering 11'21. ln the 19th century, the term 'six sigma'was coined by Bill Smith, a Motorola Engineer, to describe a new quality control process that merged from total quality management. The design of six sigma methods began with the development of the normal distribution curve by Carl Freedrich Gauss in the 19th century, which has been depicted in Figure 1. ln the 20th century, Shewhart (father of control charts) coined the term 'quality' which is closely related to three sigma level. Sigma measures how far a given process deviates from perfection. Six sigma means six times the distance of standard deviation. To achieve it, the process cannot produce more than 3.4 defects per million opportunities or 99.9997% perfection. Defect mea ns a nyth ing outside the customer specification. At the same time, Edward Deming framed the PDCA cycle which means 'plan-do-check-act' cycle. This is a continuous Figure t Model slx sigma normal distribution curve -eycJeand a never ending process; thereare always improvements to be made t3'41. This is the core for the six sigma concept. The six sigma methodology though considered an entirely new and innovative strateg/, does not involve any new technologies, theories or techniques. The ideas and the concepts of Deming became Toyota production system or lean six sigma. Eiji Toyoda and Taiichi Ohno introduced the concept of 'Just-in-Time' and Jidoka (stopping the process immediately after identifying the errors) which are the main pillars of the Toyota production system t5t. The principles of the Toyota's system are- . Defining customer value . ldentifyingthe value stream for customer.needs and debires . ldentifying waste in the prooess . Creation of a continuous process flow . Continually working to reduce the number of steps and time it takes to reach the customer satisfaction Lean process was founded by Taiichi Ohno in 1950s, which is sub part ofToyota production system wjth the key aspects including perfection, elimination of waste and recognition & importance of employee contribution. ln 1999, Spear and Bowen observed four rules for the lean manufacturing process t6r. They are; . Standard work - Allthe work procedures must be communicated simply and easily in chart form. The work should be specified to content, sequence, timing and outcomes. . Clear relationships and communication - Every customer- supplier connection is direct, with unambiguous ways to communicate. The product and information flows from one department to another and the barriers between the departments are reduced. Consistent cycle time is the indication of good internal supplier-customer relationship. . Simple flow - The pathway for every product and.service must be simple and direct without any loops, forks and fast paths. . Scientific method - lt is the driving force for the quality management in the lean process. lt should be done under the guidance of a teacher and at.the lowest possible level in the organization. The tools used for the lean concept are represented as 5S. They keep the working space in ordertTl. They are; iii'jriii :itii ltl.:i.t i i rL I *E-mail: prasanthi_pharma@yahoo-com Pharma Times - Vol. 51 - No. 05 - May ZO1S I tS h I
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  Kaizen - ltis a process expedited by subordinates focused on making small improvements in the organization. Gemba (go and see) - This is the real time observation of the process aimed at pinpointingthe process defects. Value stream mapping (VSM) - This is the tool used to identify the process waste and the causes ofthe waste. Jikoda/Automation - lt stops production in case a defect occurs. . Kanban - lt manages inventory levels and brings into attention excessive or low inventory. Lean management mainly focusses on the elimination of non- value added activities or wastes t8l. Generally, I types of wastes are observed in a manufacturing process, which are depicted in Figure 2. Accbrding to Marcel Proust "The real voyage of discovery consists not in seeking new lands but seeing with new eyes". Flgwe 2: Wastes ldentlfled ln lean process Six sigma is a methodology of a management program developed by Motorola to win in the international market competition created bythe Japanese companies. Six sigma working is forthe high level of quality with low level of variability by detecting and removing defect causes. This is the best method for improving the performances that focuses on reducingthe number of defects in products, processes and services. The comparison of six sigma with traditional process is given in Table 1. The key elements in the six sigma process improvement are customers, process and employees. The customers define the quality; which means what the customers need to gain customer delight. Observing the process gives a chance to identify weak areas with in a process to improve them te'1o1. The conlpany has to involve all its employees in the six sigma prograh. All-ttie'inti'mUire should have lood role with measurable objectives. The employees should showtheirtalent and ability to satisfy the customers. The six sigma members should have specific responsibilities or role areas such as leadership, sponsor, implementation leader, coach, team leader, team member and process owner. The members should be certified, the six sigma training a great benefit as it gives opportunities for any company to become more efficient and competitive. The six sigma certification proves that the individual have practica I applications and knowledge of six sigma. Some companies offer in-house oertification. Most people getting through online registration process t1l fl. Six sigma certification is differentiated by their belt levels. They are; Pharma Times - Vol. 51 - No. 05 - Uay zOtS I t+ Table t Comparlson of tradltlona! approach wlth six sl(ma White belt - This is the basic skill in the six sigma methodologl. These members are not the regular members of process improvementteam. The training helpsthe employees to review the project process, to understand the information presented in the meetings and to participate bitterly in project selection process. This traininggives only basic introduction of six sigma, so all the six sigma professionals not recognize it as a true six sigma certificate. Yellow belt - This certificate is above the white belt. lt is also considered as an introduction to the concepts of six sigma. But they learn about the DMAIC cycle often used to improve process. The concepts in the yellow belt arer six sigma roles, team development and management, basic quality tools such as pareto charts, run charts, scatter diagrams and histograms, common six sigma metrics, data collection, measurement system analysis, root cause analysis and introduction to hypothesis testing. Their everyday work reflects the quality Vs profit relationship. Green belt - The green belt certified candidates can work within six sigma team under the supervision of black belt or master black belt. Sometimes they can handle smaller projects on their own. Generally, they have intermediate statistical analysis properties and are referred as worker bees because they do majority of the work during the projects. They can be act as middle managers, business analysts or project managers. They are considered as worker bees of the six sigma methodology. The concepts they learn are all the information in the yellow belt, failure mode and effects analysis, project and team management, probability and central limit theorem, statistical distribution, descriptive statistics, basic hypothesis testing, waste elimination and basic control charts. Black belt - The certified person can act as project leader or incharge of the six sigma projects on process improvement projects. The minimum requirements for black belt certification include everything in the yellow and green belt and also advanced project and t€am management skills, knowledge of the six sigma brainstorming and project tools, advanced statistics, an idea of quality programs including lean and total quality management, ability to design a proce$s, capability for diagramming processes including flow chafts and stream approach Parameter Tradltional approach Slx slgma approach Deciding Trail and error Resistant design Analysis Experience Data Focus Product Process Time Reactive Proactive Planning Short term Long term Control External control Self control Psychological agreement lntegration Loyalty Structures and systems Bureaucratic Organic Employee relations Low confidence, personnel fianagement Hith confidence, human resource management
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  ' maps anduse ofsoftware to conduct analysis such as excel or Minitab. By implementing the six sigma concept by black belt persons save the company at least $ 1,00,000. . Master black belt - This is the highest certification level in the six sigma methodolory. ln a company these candidates manage the black belt and green belt members, offer advice and educate about challenging statistical concepts and train other six sigma methodolo$r. the certified candidates act as in charge of six sigma project at the organization level. The process to achieve six sigma level is highly complex and very difficult. The proper utilization of these certified members is necessary. The proper handling in the difficult situations and disciplined improvement efforts is important t141. The six sigma concept is applied by using different methodologies such as; . DMADV - lt refersto a data-driven qualitystrateryfordesigning products and processes. This methodolory is used to create new product designs or process designs in such a way that it results in a more predictable, mature and defect free performanie. This methodology having 5 steps; Define-Measure-Analyze- Design-Verifl. Define means define the problem and project goal that needs to be addressed. Measure means measure and determine the customer needs and specifications. Anlayze means analyse the process to meet the customer needs. Design means design a process that will meet customer needs t151. Verify means verifying the design performance and ability to meet customer needs. . DFSS methodology - lt is a separate and emerging discipline related to six siglma quality process. This methodology utilizes tools, training and measurements to design products and processes that meet customer expectations. lt having 5 steps; Defi nel dentify-Design-Optim ize-Y erify. I n th is method defi ne means define what the customer want or what they do not want; identify means identify the customer and the project; design means design a process that meets customer needs; optimize means determine the process capability and optimize the design and verify means test, verify and validate the design. . DMAIC methodology - lt is a data-driven quality strategy for improving processes. This methodology is used to improve an existing business process. lt having 5 steps; Define-Measure- Analyzelmpove-Control. ln this method definemeans define the problem or project goal that needs to be addressed; measure means measure the problem and process from which it was produced; analyse means analyse the data and process to determine root cause of defects and opportunities; improve means improve the process by finding solution to fix, diminish and prevent future problems and control means implement, control and sustain the improvement solutions to keep the Process on the new course t16' 181. Out of the above given m'eth;dobgtes the DMATC:nd DMADV methodologies are widely using in six sigma concepts. The description of the terms in those methods is given below. . Define phase - ln this phase, four majortasks are undertaken. They are project team formation, document customer core business process, develop a project charter and to develop the SIPOC process map. The use of define phase is to clarify the issues, to know who will be involved in the project, the scope ,of process being improved, to know the impacted and level of efforts needed to generate engagement and to clarify what the customers of the process expects requires. The project charter is a contract between the organizations leadership and the projectteam created atthe outset ofthe project. It is a document that names the project, summarizes th6 project by explaining the business case in a brief statement and lists the pOect scope and goals. The well-written project charter describes the problem and intended scope ofthe project, confirms the terms plan matches to the expectations of the senior management, identifies the team members percentage of time allotted to the project work, establishes timeline for the project as a vehicle to establish common understanding of the project. The components in the project charter are: i. Business case - The business case is the reason why it is importantto project. The business reasons for doingthe project. It includes financial impact, customer impact and risk of not taking action. : ii. Problem statement - lt is a short description of the issue to be addressed. lt not only contains the solution, but also the root cause and the department or individual at fault. lt gives the data related to what is the problem and what is the measure to ccirrect it. iii. Goat statement - lt deflnes the expected improvements the team is seeking to achieve in clear, concise and measurable terms. lt is the measurement of goal. Usually smart goals are establishing such as specific, measurable, attainable, relevant and time bound. iv. Scope - lt defines the magnitude of the project. The time, money and resources given by the team. v. Team members - These are the people who will participate in the project. Core team members meet regularly and resource team members meet if need is there. Percent of time allocation should be'listed for all core team members. lt is the good practice to identify the percent of weekly time each member m€mber needs to commit work on the project. vi. Preliminary plan - The timeline and actions to be taken by week/rnonth. The voice of the customer (VOC) is the customei needs and their perceptions of the product or services. Customers means the recipients of products or services from a specific process. The types of customers are based upon the specific process. They are a) common internalcustomers - such as human resource (HR) and information technology (lT) employees and b) externalcustomers - people outside the organization that receive products and services. Generally, the customer voice includes friendly, fast, convenient, easyto use, accurate, flexible, responsive, affordable, good quality and accessible. Stake holder is anyone who has a vested interest in process performance and they do not receive process or service from the process. They may be managers, owners, shareholders or external suppliers. SIPOC is a high level map of a process, it have a series of steps and activities thattake input, add value and produce an output. lts process map is Su ppl ier-l nputProcess-Output-Customer. lt shows how the process is going on currently and how these processes can be modified and improved in the remaining phases of DMAIC. At the end of design phase, it is possible to know the customer or end user and their resistance issues and requirements; goal and scope of the project i.e. budget, time constraints and deadlines. The main purpose of the define phase is to verify. lt starts with identifying the problem and ends with understanding the issue by the management supervision. There are number of ways to identify d a^ Pharma Times - Vot. 51 - No. 05 - May 2O1S | 1S
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  a project forimprovement, first they focus on the external factors after that focus on internal-cost problems t1el. The useful tool to narrow the problem is pareto diagram. . Measure phase - ln this phase, overall performance of the core business process is measured. This phase has three important parts such as, a) Data collection and data collection plan, which is prepared to collect the data to identify the areas where the current process needs to be improved. The data should be collected from three sources such as input, process and output. b) Data evaluation, the collected data is evaluated, and sigma is calculated during this process. This process gives the defect data of the sigma. This is calculated by using the formula; Number of defects DPMO= x 10,00,000 Number of units x Number of opportunities DPMO means defects per million of opportunities, based on this value sigma value is decided from the Yield t0 Sigma conversion table, as given in T6ble 2. c) Failure mode and effects analysis (FMEA), this is the final stage of measure phase, it refers to preventing the defects before they o'ccur t2o1. lt indicates the places of possible risk. The main subject of measuie phase is to collect and analyse the data which is needed in the control phase to show the differences and assess the progress. . Analyse phase - This phase is aimed to define the causes of defects, measure those defects and analyse the defects. ln this phase, identification of main reasons for problems, identification of difference between current and target performance, estimation of resources required to achieve the goals and identification of possible obstacles. This phase has number of sub sections such as, a) Source analysis also called as root cause analysis, which is used to identify the defects that are derived from the sources of information or work generation. After finding the cause, attempts are made to resolve the problem. lt is performed in a three step process i) Open step - ln this phase the project members brainstorm all the possible expla nations for current siplma performance, ii) Narrirw step - ln this phase team narrows the list of possible explanations for current sigma performance, iii) Close step - Here team members validate the narrowed list of explanations which explain sigma ierformance. b) Process analysis - lt has a more detailed process map and analysingthe map wherethe greatest inefficiencies exist. Process means precise movement of information, materials, data from one place to other. c) Data analysis - Analyze the data which is already collected or new data in the analyse phase, to find out defects and resolve the problem. d) Resource analpis - Analpingthe employees having proper skills or not, observing the raw materials required for manufacture, process and deliver are moving in the correct time or not. lf the team identified any delay in any process i.e. considered asa resource problem. e) Communication analysis - ldentifyingthe problem by interactingwith the inside customers and external customers. Poor communication may lead to high defects. ' ln sigma program, analysis phase can be performed by using various tools such as Box Plot, Cause and Effect Diagram, Progressive Analysis, Ranking, Pareto Analysis, Prioritisation Matrix, Value Analysis etc., . lmprove phase - ln this phase, implementing the changes which eliminates the imperfections by preparing the structure of work division, developing and testing possible solutions and designing the implementation plan. The aim of this phase is to take necessary information to create and develop an action plan in orderto improve the functioning of the organization, financial aspects and customer relationship issues. The possible solution for the plan should be presented and performed. . Control phase - This is the last phase of DMAIC methodology, in this phase controlling the improved process, monitoring the results in a continuous way by documentation of the plan of standardisation and process monitoring improvement, confirrnation of the improved procedures and transferring the ownership of the relevant teams after the completion of the project. The team focuses on the fourspecifig aspects ofcontrol such as quality control, standardization, control methods and responding when defects occur. The projectteam checks how to control the newly improved process and create a response plan to ensure the new process t21' 22). The lean and sixsigma methodologies can be used independently ortogether. These concepts can be applied in any industrysuch as pharmaceutical, automobile, electronic and medical device industry to resolve the issues of unnecessary costs. The combination of these two concepts are useful for the improvement of business concepts observed in Motorola and General Electric 1241. The lean six sigma proJect framework is depicted in Figure 3. The lean six Table 2: YIeld to slgma conversion table Yield (%) DPMO Cost of infedorlty (%) Slgma 30.9 6,90,000 80 1.0 62.9 3,08,000 50 2.O 93.3 66,800 30 3.0 99.4 6.270 L7 4.0 99.98 320 7 5.0 99.9997 3.4 <5 6.0 Figule 3: The lean slx sigma project management process flow chart Pharma Times - Vol. 51 - No 05 - May zoto i tO
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  r/ ., I I I sigma concept workingon the concept of five principles such as; a) specify value - lt is necessary to specify what adds value from the end customer perspective, so that non value activities can be identified and removed; b,) ldentify the value stream - ldentify all the activities that don't aggregate any value to the final product; c) Create flow - Promote continuous flow in the process by eliminating wastes; d) Customer pull - Respond to the customer demand, produce what customers want at the tirne; e) Pursue perfection - Continually remove wastes, striving for a perfect process. ln the pharmaceutical industry from the past 15 years there has been a little change and the industry is in the 2 to 3 sigma quality levels i.e. 308,537 defects per million opportunities. While the quality of new drugs has improved, shortages and recalls continue to be seen, particularly of legacy products, for many companies manufacturing is far less important than clinical goals, evidenced by the number of complete response letters, 483s and warning letters that FDA presents manufacturers each year t25). At present, the industry is moving from management to performance based regulation and toward specifications that are based on clinically relevant goals. The six sigma concept is useful for the pharmaceutical companies to develop a process that results predetermined quality at the end of the manufacturing process. The implementation of six sigma helps in preventing the rejects, reducing the product cycle time, facilitating continuous process improvement and automation t261. The implementation of six sigma concept is big task and some steps are required for the organization. They are, . Plan your own route - Selection of best path to six sigma which is suitable for your organization. . Define your objective - What the organization want to achieve and priorities . Stick to what is feasible - Set up the plans which matches to the organizations resources and scope. . Preparing leaders - To launch and guide the six sigma efforts. Creatingsix sigma organization - Preparing black belt members and assigning the roles for their responsibilities. Training the organization - lt is required to train the employees for the six sigma concepts in the organization. Piloting six sigma effort - lt can be applied to any aspect of six sigma including solutions derived from process improvement or design or redesign projects. The selection of most appropriate problem to attack is the difficult task in the six sigma concept. Generally, two methods are using to generate the projects. They are; a) Top-down approach - This is used for business strategy aligned with customer needs. Theyare broad in scope and requires moretime i.e,3-6 months; b) Bottom-up approach - ln this case black belts choose the projects that are suited for their team. This approach is not suitable tg tie directlyto strategic concerns of the managementl2Tl. This approach receiving little recognition from the top. Technlcal tools used ln slx slgme concepts: The six sigma team members should be masters in these concepts to implement in the organization t281. They are; a) Critical to qualitytree (CTQ)- lt is used in the design phase of DMAIC, to validate and brainstorm the needs and requirements of the customer of the process for improvement. To draw thb CTQ tree have to identify the customers of the process, needs of the customer, first level need and detailed level of needs required. b) Process map - This map is using in the design phase by the team members. lt is a picture of the current steps in the process . targeted for the lmprovement. lt having five categories such as identification of the supplier, inputs supplier provide, the name ofthe process, output and the customers ofthe process. These steps are in the SIPOC. The map is shown in Figure 4. Histogram - lt is used in the analysis stage of DMAIC for the data collected in the measure stage. The data is organised as charts or graphs. lf the data is continuous histograms a re widely using. Pareto chart - lf the data is discrete then it is represented as pareto charts by the team members. Discrete data means go/ no go, yes/no, defect/no defect type data. The team members have to create reason codes for the defect occurs and count and categorize the data to construct as pareto charts. Sample pareto chart was depicted in Figure 5. Causeeffect diagrams - These are importantto assisttheproject team in determining root causation in the cause effect diagram. It captures all the ideas ofthe projectteam related to whatthey feel. lt lists the five'M' and 'E'; materials, methods, machinery, measurement, manpower and environment. The sample representation of cause effect diagram is shown in Figure 6. Scatter diagram - lt takes an idea about the root causation and tracks corresponding data, in response the team is trying to d) e) I I Flgure 4: Process map representatlon 7 I Customer complaints and warranty data Pharma Times - Vol. 51 - No. 05 - May zofi | n
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  m 18 't6 14 72 10 I 6 4 2 o 1m.y, 1{m9l 80% 6{n6 40% 2Wo g% Ardity Ady CsliFcde CartfE{e Em}Es:{ng frdeEffPtrt Fg List Etr tifrwg oss Ats6ty FlEure 5: Sample Pareto dlagram Cat !o Flguro 6: Root causo analysls representatlon wlth flshbone dlagram improve. The team can validate the data by basic data collection, designed experiment or by scatter diagram. The sample sgatter diagram was shown in Figure 7. g) Affinity diagram - This diagram is used to sort or categorise a large number of ideas into major themes or categories. This is useful if theteam is readyto brainstorm solutions in the improve stage of DMAIC. For this, each team mernber has to write one idea on wall, the ideas have to sorted into similar groups and finally have to create a header card for each general category of ideas. The sample affinity diagram is shown in fiigure 8. a Figure 7: Sample scatter dlagram Pharma Times - Vol. 51 - No 05 - May zots | 18 Flgure 8: Sample afinlty dlagram :' h) Run chart - Run charts are nothing but camcorders, which record some process element overtime. The sample run chart is shown in Figure 9. 012145678910 , Flgure 9: Sample run chart showlilE upward tlend Control chart - The control charts are similar to run charts and uses the data from a run chart to determine the upper and lower control limits. Control limits are variations above or below the average of the data, which can be calculated mathematically and indicated by dotted lines. The sample run chart is shown in Figure 10. Mean chart 601 , m2 r- ml i 6ml 598 : 507 i o 10, 6t 4l 2: or c oooioooioioooooooor 2A6At012r{151a20 Flgure 10: Sample control charts a 5 .! o 1 f-
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  - t' I The organizations whichare usingthe six sigma concept are in wide variety of sectors such as healthcare, manufacturing, banking and finance, logistics management, construction and project rnanagement, and marketing and distribution. Approximately, more Oan 15O organisations implementing the six sigma concepts, the success information of the some of the organisations was summarized belowt2el; . Motorola - 30.2 billion savings in eleven years . General electronic - 2 billion savings in one year . Duponts Yerkes plant - mqre than 2 million dollars . Bechtel corporation - 200 million dollars . Arcelik-LG - 6 trillion dollars . Cigna health care - 19 billion dollars . Seagate technology - 9.8 billion dollars . Dow chemicals - 57 billion dollars ' . Transplace lnc. - 66 million dollars . ln the pharmaceutical industry, there is a great need of productivity and efficiency. The purpose behind the money consumption in the industry is due to liability and cost in revalidation process. With the help of this concept number of defects in the process can be minimized by removing the waste and improving the process. Concluslon: Lean six sigma utilizes the synergized power of both lean and six sigma concepts. lt ensures the continuous process wh-ich leads the production cheaper with satisfled product to the customers increased profitability of the organization. The use of LSS in industry ensures the elimination of waste and defects in the development of drugs and design of dosage forms. lt decreases the production cost and has been proven as one of the most effective tools to use in industry. The lean thinking with the application of DMAIC, one of the method for quality improvement used in six sigma concept can increase the effectiveness of the problem. Reduced complications, waste elimination and cost-saving provide value to the industry. The lean sigma methodology gives effective solution for the process improvement needs but it is not the actual solution to the problem. References: 1. Katarina Pavlovic, Vojislav Bozanici. Lean and Six Sigma Concepts - Appiication in Pharmaceutical lndustry. 4th lnternational Qriality Conference, May 19th 2010, Center for Quality, Faculty of Mechanical Engineering, University of l(ragujevac. 2. Reger RK, LT Gust?fson,EM Demarie, JvMullane. RBframing the organization: Why implem6ntingiofafqiatity is easier said than done. The Academy of Management Review 1994;,19(3):565-584. 3. George M, Rowlands D, Price M, Maxey J. The Lean Six Sigma Pocket Toolbook: A Quick Reference Guide to 100 Tools for lmproving Quality and Speed. New York: McGraw-Hill, 2005. 4. Sokovic M, Pavletic D, Pipan KK. Quality improvement methodologies - PDCA cycle, RADAR matrix, DMAIC anc, DFSS. Journal of Achievements in Materials and Manufacturing Engineering 2O10;43(1): 476-443. 5. 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SAlbliwi, J Antony. lmplementation of a lean six sigma approach in the manufacturing Sector: a systematic literature review, in: Proceedings of the 11th lnternational Conference on Manufacturing Research (ICMR) 2013. 27. P Hasle, A Bojesen, PL Jensen, P Bramming. Lean and the working environment: a review of the literature. lnternational Joui'nal of 0perations & Production Management20t2; 72(7): 829-849. 28. Pfeifer T, WReissiger, C Canales. lntegrating Six Sigma with quality ma nagement s)6tems. The TQM Magazi ne20o4; t6(4):24!-249. 29. Kaynak H. The relationship between total quality management practices and their effects on firm performance. Journal of Operations Ma nagement 2OO3: 27:405-435. I li I Pharma Times - Vol. 51 - No. 05 - May eOtS I tS