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Six sigma Slides Best and Simple

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6 Sigma Green Belt Lecture

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Six sigma Slides Best and Simple

  1. 1. www.linecraftdesigns.com Six Sigma Green Belt
  2. 2. www.linecraftdesigns.com 1 An Introduction to Six Sigma
  3. 3. www.linecraftdesigns.com 2 Before Getting to Know “Six Sigma” It is Important to Understand, What is Quality?
  4. 4. www.linecraftdesigns.com Define Qualilty Compliance to customer requirements / specifications In different industries the concept of quality may differ  Banking Industries – Time bound and accurate delivery of services  Manufacturing Industries – Production of product with in the specified specifications  BPO Services – Time Bound Response but consequences of compromised quality are same “Loss in Revenue, Damage to Brand Image” 3
  5. 5. www.linecraftdesigns.com Total Quality Management (TQM) Total Quality Management may be defined as “ managing the entire organization so that it excels on all dimensions of products and services that are important to the customer” It has two fundament operational goals  Careful design of the product or service  Ensuring that the organization’s system can consistently produce the design Maintaining the quality of the product or service is the prime responsibility of Top Management Top management is responsible, if an organization is not delivering quality product or service to its customers 4
  6. 6. www.linecraftdesigns.com Developing Quality Specifications… Design Quality – It refers to inherent value of the product in the marketplace and is thus a strategic decision for the firm.  The dimensions of quality are:- • Performance – Primary product or service characteristics • Features- Added touches, bells and whistles, secondary characteristics • Reliability / durability – Consistency or Performance over time, Probability of failing, useful life 5
  7. 7. www.linecraftdesigns.com Developing Quality Specifications… • Serviceability – Ease of repair • Aesthetics – Sensory Characteristics (sound, feel, look and so on) • Perceived Quality – Part performance and reputation 6
  8. 8. www.linecraftdesigns.com Example of Dimensions of Quality 7 Measures Product Example Service Example DIMENSION LASER Printer Checking Account at a Bank Performance Pages per minute Print Density Time to process customer requests Features Multiple paper trays Color Capability Automatic bill Paying Reliability/ Durability Mean time between failures Variability of time to process request Serviceability Availability of authorized repairs centers, Modular design Online Reports, Ease of getting updated information Aesthetics Controls buttons layout, Case style, Courtesy of dealer Appearance of bank lobby, Courtesy of teller Perceived quality Brand name recognition, Rating in customer reports Endorsed by community leaders
  9. 9. www.linecraftdesigns.com Developing Quality Specifications… • Conformance Quality – It refers to the degree to which the product or service design specifications are met. It is evident that a product or service can have high design quality but low conformance quality, and vice versa (e.g. Six Sigma process) • Quality at source- It can also be understood as conformance of quality, while producing the product or delivering a service i.e. production of products should be done such a way that the chance of bad quality is zero. With efficient POKA YOKE, a quality product can be ensure at the source. Both quality of design and quality of conformance should provide products that meet the customer’s objective for those products. This is often termed the product’s fitness for use, and it entails identifying the dimensions of the product or service that the customer wants ( that is the voice of the customer) and developing a quality and control program to ensure that these dimensions are met. 8
  10. 10. www.linecraftdesigns.com PDCA in TQM • When to Use Plan–Do–Check–Act -As a model for continuous improvement. -When starting a new improvement project. -When developing a new or improved design of a process, product or service. -When defining a repetitive work process. -When planning data collection and analysis in order to verify and prioritize problems or root causes. -When implementing any change. 9 The plan–do–check–act cycle (Figure) is a four–step model for carrying out change. Just as a circle has no end, the PDCA cycle should be repeated again and again for continuous improvement.
  11. 11. www.linecraftdesigns.com Plan–Do–Check–Act Procedure • Plan- Recognize an opportunity and plan a change. • Do- Test the change. Carry out a small-scale study. • Check- Review the test, analyze the results and identify what you’ve learned. • Act- Take action based on what you learned in the study step: If the change did not work, go through the cycle again with a different plan. If you were successful, incorporate what you learned from the test into wider changes. Use what you learned to plan new improvements, beginning the cycle again. 10
  12. 12. www.linecraftdesigns.com Cost Of Quality • It refers to all the cost attributable to the production of quality that is not 100% perfect. • It is been observed that bad quality of product may cost as large as 15%-20% of sales value. • The cost of quality are generally classified into four types:- 1. Appraisal Cost- Cost of Inspection, testing and other task to ensure that the product or process is acceptable. 2. Prevention Costs- The sum of all the cost to prevent defects, such as the costs to indentify the cause of the defect, to implement corrective action to eliminate the cause, to train personnel, to redesign the product or system, and to purchase new equipment or make modifications. 3. Internal Failure Costs- Costs for defects incurred within the system: scrap, rework, repair. 4. External Failure Costs- Cost for defects that pass through the system: customer warranty replacements, loss of customer goodwill, handling complaints and product repair. 11
  13. 13. www.linecraftdesigns.com Appraisal Costs Costs incurred in measuring and controlling current production to assure conformance to requirements, such as A. Purchasing appraisal costs 1. Receiving or incoming inspections and tests 2. Measurement equipment 3. Qualification of supplier product 4. Source inspection and control programs 12
  14. 14. www.linecraftdesigns.com Appraisal Costs B. Operations (manufacturing or service) appraisal costs 1. Planned operations inspections, tests, audits a. Checking labor b. Product or service quality audits c. Inspection and test materials 1. Set-up inspections and tests 2. Special tests (manufacturing) 3. Process control measurements 4. Laboratory support 1. Measurement equipment 1. Depreciation allowances 2. Measurement equipment expenses 3. Maintenance and calibration labor 5. Outside endorsements and certifications 13
  15. 15. www.linecraftdesigns.com Appraisal Costs C. External appraisal costs 1. Field performance evaluation 2. Special product evaluations 3. Evaluation of field stock and spare parts D. Review of tests and inspection data E. Miscellaneous quality evaluations 14
  16. 16. www.linecraftdesigns.com Prevention Costs Costs incurred to prevent the occurrence of non-conformances in the future, such as A. Marketing/customer/user 1. Marketing research 2. Customer/user perception surveys/clinics 3. Contract/document review B. Product/service/design development 1. Design quality progress reviews 2. Design support activities 3. Product design qualification test 4. Service design qualification 5. Field tests 15
  17. 17. www.linecraftdesigns.com Prevention Costs C. Purchasing 1. Supplier reviews 2. Supplier rating 3. Purchase order tech data reviews 4. Supplier quality planning D. Operations (manufacturing or service) 1. Operations process validation 1. Operations quality planning 2. a. Design and development of quality measurement and control equipment 2. Operations support quality planning 3. Operator quality education 4. Operator SPC/process control 16
  18. 18. www.linecraftdesigns.com Prevention Costs E. Quality administration 1. Administrative salaries 2. Administrative expenses 3. Quality program planning 4. Quality performance reporting 5. Quality education 6. Quality improvement 7. Quality audits 8. Other prevention costs 17
  19. 19. www.linecraftdesigns.com Internal failure cost Costs generated before a product is shipped as a result of non-conformance to requirements, such as A. Product/service design failure costs (internal) 1. Design corrective action 2. Rework due to design changes 3. Scrap due to design changes B. Purchasing failure costs 1. Purchased material reject disposition costs 2. Purchased material replacement costs 3. Supplier corrective action 4. Rework of supplier rejects 5. Uncontrolled material losses 18
  20. 20. www.linecraftdesigns.com Internal failure cost C. Operations (product or service) failure costs 1. Material review and corrective action costs a. Disposition costs b. Troubleshooting or failure analysis costs (operations) c. Investigation support costs d. Operations corrective action 2. Operations rework and repair costs a. Rework b. Repair 3. Re-inspection / retest costs 19
  21. 21. www.linecraftdesigns.com Internal failure cost 4. Extra operations 5. Scrap costs (operations) 6. Downgraded end product or service 7. Internal failure labor losses D. Other internal failure costs 20
  22. 22. www.linecraftdesigns.com External Failure Costs Costs generated after a product is shipped as a result of non-conformance to requirements, such as A. Complaint investigation/customer or user service B. Returned goods C. Retrofit costs D. Recall costs E. Warranty claims F. Liability costs G. Penalties H. Customer/user goodwill I. Lost sales J. Other external failure costs 21
  23. 23. www.linecraftdesigns.com 22 Introduction to Six-Sigma Theory
  24. 24. www.linecraftdesigns.com The Theory of Six Sigma • Six Sigma reflects the goal of having customer specification limits of the item produced by a process be twice the natural variation (±3σ) of the process output • In another way, the process variation should be half of the specification limits • Where σ is the standard deviation of the process • Theory of Six Sigma assumes that the process is “Normally Distributed” 23
  25. 25. www.linecraftdesigns.com 3σ Process • A 3σ process defines 99.73% outcomes are within the specification limits • That means 0.27% of outcomes are out of the specification limits or 2700 defects out of one million 24
  26. 26. www.linecraftdesigns.com 6σ Process • To make the process compliance to 6σ, the standard deviation of the process has to be reduced to half of 3σ process • A 6σ process defines 99.99966% outcomes are within the specification limits, that means 0.00034% outcomes are outside the specification limits i.e. 2 parts per billion 25
  27. 27. www.linecraftdesigns.com 26 Six-Sigma Quality
  28. 28. www.linecraftdesigns.com Six Sigma Quality One of the benefits of Six Sigma thinking is that is allows managers to readily describe the performance of a process in terms of its variability and to compare different process using a common metric. This metric is defects per million opportunities (DPMO). This calculation requires three pieces of data : 1. Unit : The items produced or being seviced 2. Defect : Any item or event that does not meet the customer’s requirements. 3. Opportunity : A chance for a defect to occur DPMO= 27
  29. 29. www.linecraftdesigns.com Six Sigma Quality Example- The customer of a mortgage bank expect to have their mortgage application processed with in 10 days of filing. This would be called a Critical Customer Requirement, or CCR, in Six Sigma terms. Suppose all defects are counted (loan in a monthly sample taking more than 10 days to process), and it is determined that there are 150 loans in the 1000 application processed last month that don’t meet this customer requirement. Thus the DPMO= 150/1000X1,000,000 , or 150000 loans out of every million processed that fail to meet a CCR. Put differently, it means that only 850,000 loans out of a million are approved with in time expectations. Statistically, 15% of the loans are defective and 85% are correct. 28
  30. 30. www.linecraftdesigns.com DPMO and σ level (Process Capability) • There are two ways by which we can know the sigma level the process is performing in : 1. Direct Method: This involves directly comparing the DPMO value with the chart to find the sigma level the process is performing in. From the previous example, the DPMO was found out to be 150,000 From the table the sigma level can be found out to be around 2.53 2. From Excel A more accurate sigma level can be found out from using excel,. Use the formulae =NORMSINV (1-(No of defect/Number of opportunities))+ 1.5 For the above example, the sigma level was found that the process has a capability of operating at 2.53σ 29 Sigma DPMO 1 697672 1.3 581815 1.6 461140 1.9 344915 2 308770 2.3 211928 2.6 135687 2.9 80762 3 66811 3.3 35931 3.6 17865 3.9 8198 4 6210 4.3 2555 5 233 6 3.4
  31. 31. www.linecraftdesigns.com 30 Six-Sigma Methodology
  32. 32. www.linecraftdesigns.com Six-Sigma Methodology • Six Sigma's methods include many of the statistical tools that were employed in other quality movement. • Six Sigma method is employed in a project orented fashion through- • Define, Measure, Analyze, Improve, Control (DMAIC) cycle. • The DMAIC cycle is more detailed version of Deming PDCA cycle which consist of four steps Plan, Do, Check and Act – that underly Continuous Improvement • Continuous Improvement- Also know as “Kaizen” seeks continuous improvement of Machinery, Material, labor utilization, and production methods through application of suggestions and ideas of company team. • Six Sigma also emphasizes the scientific methods, particularly hypothesis testing about the relationships between process inputs (X’s) and outputs (Y’s) using design of experiments (DOE) methods 31
  33. 33. www.linecraftdesigns.com Six-Sigma Methodology The Standard approach to Six Sigma project is DMAIC methodology developed by General Electric, as describe below 1. Define (D) • Identify customer and their priorities • Identify a project suitable for Six Sigma efforts based on business objectives as well as customer needs and feedback • Identify CTQs (Critical-To-Quality characteristics) that the customer consider to have the most impact on quality 2. Measure (M) • Determine how to measure the process and how it is performing • Identify the key internal processes that influence CTQs and measure the defects currently generated relative to those processes. 3. Analyze (A) • Determine the most likely cause defects • Understand why defects are generated by identifying the key variables that are most likely to create process variation 4. Improve (I) • Identify means to remove the cause the defects • Confirm the key variable and qualify their effects on the CTQs • Identify the maximum acceptance range of the key variables and a system for measuring deviations of the variables • Modify the process to stay in the acceptable range 5. Control (C) • Determine how to maintain the improvements • Put tools in place to ensure that the key variables remain within the maximum acceptable range under modified process. 32
  34. 34. www.linecraftdesigns.com As a Management system • It has been observed that although most organizations can show solid successes at the project level, a collection of projects typically doesn’t add up to the breakthrough performance and sustainable improvement that Six Sigma has a reputation for delivery. • What’s missing from such project-oriented implementations is an infrastructure that links leadership behavior and management systems to project selection, coaching and oversight. • Organizations are looking for the statistical leaders who can launch an implementation and teach the methodology to project teams. Most of these recruitment efforts occur through resume screening and conversations at the project level. In other words MBBs (Master Black Belts) are hired mainly, and often only, based on the technical requirements of a statistical leader . • In fact only about one third of an MBB’s role is technical, rest is about leading, yet nobody’s testing for leadership 33
  35. 35. www.linecraftdesigns.com As a Management system Five leadership behaviors that are crucial to support an infrastructure of breakthrough improvement:  Passion for creating customer value  Leading through fact-based decision making  Driving execution  Moving through performance metrics  Advocacy for breakthrough improvement When hiring Six Sigma leaders, organization should look for evidence of these behaviors in addition to technical abilities. Existing MBBs, as well as champions and other Six Sigma leaders for that matter, should also consciously develop these behaviors to improve the effectiveness of their implementations 34
  36. 36. www.linecraftdesigns.com A Management System that Drives Six Sigma • Breakthrough Six Sigma performance can only occur when Six Sigma is aligned with an organization’s overall business strategy. • The more closely an individual project is tied to organizational goals, the better its chances for producing far reaching and lasting results. • The more fluidly the work of Black Belts, Green belts, and improvement teams fits into the large stream of daily operations, the more essential that work will appear to the rest of the organization • A management system should integrate the following strategic business methods and approaches to guide Six Sigma project selection and reward Six Sigma staff: • Scorecards to prioritize business objectives • Dashboards to track operational metrics • Performance management system to rewards Six Sigma staff in way that is consistent with recognition for non Six Sigma staff 35
  37. 37. www.linecraftdesigns.com 36 Elements of Six Sigma
  38. 38. www.linecraftdesigns.com Elements of Six Sigma There are three key elements of quality:  Customer  Process  Employee. Everything a organization should do to remain a world-class quality company focuses on these three essential elements. 37
  39. 39. www.linecraftdesigns.com Customers Delighting Customers • Customers should be the center of a business strategy • Customers define quality of product and services • They expect performance, reliability, competitive prices, on-time delivery, service, clear and correct transaction processing and more. • In every attribute that influences customer perception. • Just being good is not enough. Delighting our customers is a necessity. Because if you don't do it, someone else will! 38
  40. 40. www.linecraftdesigns.com Process Outside-In Thinking (GE View) • Product Quality requires us to look at business from the customer's perspective • Look at processes from the outside-in view • Understanding the transaction lifecycle from the customer's needs and processes, to discover what customers are seeing and feeling • This knowledge will identify areas where significant values or improvements may be added from customers perspective. 39
  41. 41. www.linecraftdesigns.com Employee Leadership Commitment • People create results. Involving all employees is essential to a quality approach. Organization should be committed to providing opportunities and incentives for employees to focus their talents and energies on satisfying customers. • All employees should be trained in the strategy, statistical tools and techniques of Six Sigma quality. • Quality Overview Seminars: basic Six Sigma awareness. • Team Training: basic tool introduction to equip employees to participate on Six Sigma teams. • Master Black Belt, Black Belt and Green Belt Training: In-depth quality training that includes high-level statistical tools, basic quality control tools, Change Acceleration Process and Flow technology tools. • Quality is the responsibility of every employee. Every employee must be involved, motivated and knowledgeable for a successful organization 40
  42. 42. www.linecraftdesigns.com 41 Analytical Tools for Six Sigma and Continuous Improvement
  43. 43. www.linecraftdesigns.com Analytical Tools for Six Sigma The analytical tools of Six Sigma have been used for many years in traditional quality improvement programs. What makes their application to six sigma unique is the integration of these tools in a corporate management system. 1. Quality Function Deployment (QFD) 2. Cause and effect matrix 3. Failure mode and effect analysis (FMEA) 4. Control Chart 5. T- Test 6. Design of Experiment (DOE) 42
  44. 44. www.linecraftdesigns.com Quality Function Deployment (QFD) In Six Sigma DMAIC, Quality Function Deployment (QFD) is a methodology and tool used in the Define stage. QFD is used to: • Collect customer’s requirements/desires as specified by the customers in their own words • Prioritize these desires • Translate them into engineering/process requirements • Establish targets to meet the requirements. • QFD is also termed as: • Voice of the Customer • House of Quality • Customer-Driven Engineering • Matrix Product Planning QFD is a customer driven product or service planning process. It is a methodology for translating customer requirements into company requirements at each stage from Concept Definition (R&D) to Process Engineering and Production and into the marketplace. The QFD matrix is a tool to translate CCRs (Critical Customer Requirements ) into CTQs (Critical to Quality). 43
  45. 45. www.linecraftdesigns.com Quality Function Deployment (QFD) QFD collects the voice of the customer (VOC) in their own lingo and incorporates this VOC into the companies cross-functional team’s project management of the integrated development process. The QFD process establishes customer objectives and measures and records them on a series of matrices 44 QFD matrix QFD matrix translates the CCRs into CTQs. The final score helps prioritize the CTQs and helps you decide which CTQs to tackle first.
  46. 46. www.linecraftdesigns.com The QFD Methodology 45 Identify both internal and external customers. Create a list of customer requirements/desires (Whats) by  Asking the customer, questions such as “What are the important features of The Product”  Capturing the customer’s own words or “Voice of the Customer” or VOC  Categorizing the Whats into groups/buckets if needed. Prioritize the above collected Whats on a scale of 1-5, with 5 being the most important. This ranking is based on the VOC (Voice of Customer) data. The CCRs (Whats) are listed vertically in the first column and all related CTQs (Hows) are listed horizontally across the top . In the second column, assign 1 to 5 based on the importance of the CCRs, where 5 is the most critical to the customer. Score each CTQ (Hows) on how strongly it correlates to each CCR. Remember we are looking at the absolution value of the correlation. It could be either positively correlated or negatively correlated. Use 5 for a strong correlation and 1 is a weak one. Leave it blank if there is no correlation. Some CCRs will have few CTQs that relate and rest unrelated. Compile list of CTQs (Hows) necessary to achieve the CCRs (Whats.) Translate the CCRs from VOC (Whats) into CTQs (Hows)
  47. 47. www.linecraftdesigns.com The QFD Methodology.. 46  Arrows show direction for improvement (up for increasing, down for decreasing, etc.) For each What, find out the correlation with each How. If the correlation is strong use 5. If its week use 1. If its in between, use a number 2,3,4 based on how strong the correlation is. Next multiply the importance rating for the CCR by the correlation score for each CTQ. Add up the scores vertically for each CTQ and place that value in the bottom score row. Once the score is computed for all CTQs, the ones with the highest scores are the highest priority Six Sigma project objectives to work on.
  48. 48. www.linecraftdesigns.com Cause and Effect Matrix Cause and effect diagram is a very simple and very effective method for root cause analysis of quality problems Causes are usually grouped into major categories to identify these sources of variation. The categories typically include: • People: Anyone involved with the process • Methods: How the process is performed and the specific requirements for doing it, such as policies, procedures, rules, regulations and laws • Machines: Any equipment, computers, tools, etc. required to accomplish the job • Materials: Raw materials, parts, pens, paper, etc. used to produce the final product • Measurements: Data generated from the process that are used to evaluate its quality • Environment: The conditions, such as location, time, temperature, and culture in which the process operates 47
  49. 49. www.linecraftdesigns.com FMEA (Failure Mode Effect Analysis) Failure Modes and Effects Analysis (FMEA) is a systematic, proactive method for evaluating a process to identify where and how it might fail and to assess the relative impact of different failures, in order to identify the parts of the process that are most in need of change. FMEA includes review of the following: • Steps in the process • Failure modes (What could go wrong?) • Failure causes (Why would the failure happen?) • Failure effects (What would be the consequences of each failure?) • Based on severity of the failure mode of the process a severity number “S” is given (range 1-10) • Based on occurrence of the failure an occurrence number “O” is given (range 1-10) • Based on detection techniques available in the process to detect the failure in the process a detection number “D” is given (range 1-10) • The effectiveness of process is calculated by Risk Priority Number (RPN) that is RPN=S X O X D range (1-1000) • RPN number indication of risk of failure in the process, threshold value of RPN is decided by the team involved in the FMEA (Industry standard is RPN=90~100) • Any process with RPN more than threshold, must have recommended actions to reduce the RPN number 48
  50. 50. www.linecraftdesigns.com FMEA…. 49 Note:- RPN number is an indicator of risk, but improvement actions are required for any process with severity more than 9 For example:- RPN for item A is 90, but for item B RPN is 112, therefore as per RPN threshold theory recommended actions are required for Item B. But As severity of Item A is high “9”, therefore recommended action for item A is also required.
  51. 51. www.linecraftdesigns.com Control Chart 50 There are three main elements of a control chart as shown in Figure A control chart begins with a time series graph. A central line (X) is added as a visual reference for detecting shifts or trends – this is also referred to as the process location. Upper and lower control limits (UCL and LCL) are computed from available data and placed equidistant from the central line. This is also referred to as process dispersion.
  52. 52. www.linecraftdesigns.com Control Chart.. Control limits (CLs) ensure time is not wasted looking for unnecessary trouble – the goal of any process improvement practitioner should be to only take action when warranted. Control limits are calculated by: • Estimating the standard deviation, σ, of the sample data • Multiplying that number by three • Adding (3 x σ to the average) for the UCL and subtracting (3 x σ from the average) for the LCL Mathematically, the calculation of control limits looks like: (Note: The hat over the sigma symbol indicates that this is an estimate of standard deviation, not the true population standard deviation.) Because control limits are calculated from process data, they are independent of customer expectations or specification limits. 51
  53. 53. www.linecraftdesigns.com Control Chart Controlled Variation Controlled variation is characterized by a stable and consistent pattern of variation over time, and is associated with common causes. A process operating with controlled variation has an outcome that is predictable within the bounds of the control limits. 52
  54. 54. www.linecraftdesigns.com Control Chart Uncontrolled Variation Uncontrolled variation is characterized by variation that changes over time and is associated with special causes. The outcomes of this process are unpredictable; a customer may be satisfied or unsatisfied given this unpredictability. 53
  55. 55. www.linecraftdesigns.com Control Chart Please note: process control and process capability are two different things. A process should be stable and in control before process capability is assessed. 54
  56. 56. www.linecraftdesigns.com Control Chart The X BAR CHART is used to evaluate consistency of process averages by plotting the average of each subgroup. It is efficient at detecting relatively large shifts (typically plus or minus 1.5 σ or larger) in the process average. The R chart, on the other hand, plot the ranges of each subgroup. The R chart is used to evaluate the consistency of process variation. Look at the R chart first; if the R chart is out of control, then the control limits on the X bar chart are meaningless. 55
  57. 57. www.linecraftdesigns.com Control Chart Process Capability “The range over which the natural variation of a process occurs as determined by the system of common causes. It is measured by the proportion of output that can be produced within design specifications” Three situations are possible: Case I: When the process capability is less than the tolerance (6σ<USL-LSL) USL – Upper specification limit LSL – Lower specification limit 56
  58. 58. www.linecraftdesigns.com Control Chart Case II: When the process capability is equal to the tolerance (6σ=USL-LSL) 57
  59. 59. www.linecraftdesigns.com Control Chart Case III: When the process capability is less than the tolerance 6σ>USL-LSL 58
  60. 60. www.linecraftdesigns.com 59 Control Chart Process Capability Index
  61. 61. www.linecraftdesigns.com 60 Control Chart Capability Index
  62. 62. www.linecraftdesigns.com 61 Introduction to Minitab- A tool for Statistics Minitab Analyze your data and improve your products and services with the leading statistical software used for quality improvement worldwide Minitab can – • Exploring data with graphs • Conducting statistical analyses and procedures • Assessing quality • Designing an experiment There will be detiled content on Minitab in upcoming classes To have a little flavour of Minitab, lets hypothesis testing with Minitab
  63. 63. www.linecraftdesigns.com 62 Performing an ANOVA • One of the most commonly used methods in statistical decisions is hypothesis testing. Minitab offers many hypothesis testing options, including t-tests and analysis of variance. Generally, a hypothesis test assumes an initial claim to be true, then tests this claim using sample data. • Hypothesis tests include two hypotheses: the null hypothesis (denoted by H0) and the alternative hypothesis (denoted by H1). The null hypothesis is the initial claim and is often specified using previous research or common knowledge. The alternative hypothesis is what you may believe to be true. Perform an ANOVA 1 Choose Stat ➤ ANOVA ➤ One-Way. 2 In Response, enter Days. In Factor, enter Center. In many dialog boxes for statistical commands, you can choose frequently used or required options. Use the sub dialog box buttons to choose other options.
  64. 64. www.linecraftdesigns.com 63 Perform an ANOVA 3 Click Comparisons. 4 Check Tukey’s, family error rate, then click OK. 5 Click Graphs. For many statistical commands, Minitab includes built-in graphs that help you interpret the results and assess the validity of statistical assumptions. 6 Check Individual value plot and Boxplots of data. 7 Under Residual Plots, choose Four in one. 8 Click OK in each dialog box.
  65. 65. www.linecraftdesigns.com 64 t-Test in Six Sigma • The 1-Sample T test evaluates whether some chosen number is likely to be the true mean of a population, based on information from a sample. • The 2-Sample T Test evaluates whether two samples were likely drawn from different populations. • The Paired T Test is similar to the 2-Sample test, but is for data that occur in natural pairs.
  66. 66. www.linecraftdesigns.com 65 One Sample test The data show reductions in Blood Pressure in a sample of 17 people after a certain treatment. We wish to test whether the average reduction in BP was at least 13%, a benchmark set by some other treatment that we wish to match or better BP Reduction% 10 12 9 8 7 12 14 13 15 16 18 12 18 19 20 17 15 BP Reduction Percent 302520151050 99 95 90 80 70 60 50 40 30 20 10 5 1 Mean 13.82 StDev 3.925 N 17 AD 0.204 P-Value 0.850 Probability Plot of BP Reduction Normal - 95% CI
  67. 67. www.linecraftdesigns.com 66 One Sample t-test – Minitab results The p-value of 0.20 indicates that the reduction in BP could not be proven to be greater than 13%. There is a 0.20 probability that it is not greater than 13%.
  68. 68. www.linecraftdesigns.com 67 Two Sample t-test You realize that though the overall reduction is not proven to be more than 13%, there seems to be a difference between how men and women react to the treatment. You separate the 17 observations by gender, and wish to test whether there is in fact a significant difference between genders. Gender 95% Bonferroni Confidence Intervals for StDevs M F 654321 Gender BP Reduction M F 20181614121086 Test Statistic 0.96 P-Value 0.941 Test Statistic 0.14 P-Value 0.716 F-Test Levene's Test Test for Equal Variances for BP ReductionM F 10 15 12 16 9 18 8 12 7 18 12 19 14 20 13 17 15
  69. 69. www.linecraftdesigns.com 68 Two Sample t-test The test for equal variances shows that they are not different for the 2 samples. Thus a 2-sample t test may be conducted. The results are shown below. The p-value indicates there is a significant difference between the genders in their reaction to the treatment.
  70. 70. www.linecraftdesigns.com 69 Design of Experiment (DOE) Design of Experiments (DOE) techniques enables designers to determine simultaneously the individual and interactive effects of many factors that could affect the output results in any design. DOE also provides a full insight of interaction between design elements; therefore, it helps turn any standard design into a robust one. Simply put, DOE helps to pin point the sensitive parts and sensitive areas in designs that cause problems in Yield. Designers are then able to fix these problems and produce robust and higher yield designs prior going into production. DOE Example: Let us assume that we have designed an amplifier and we need to design an experiment to investigate the sensitivity of this amplifier to process variation. In other words, we would like to find out if there are any elements in the design that largely affect the output response due to their high sensitivities to the output measure.
  71. 71. www.linecraftdesigns.com 70 DOE.. In this example, let us chose three elements where we want to see their effects on the Gain of the amplifier. These elements are: W (the width of the microstrip lines), a resistor (R), and a Capacitor (C). Since we chose three elements, we must construct 8 experiments (2^3) for a Full factorial experiment. We assign a -1 and +1 values to each of the elements. For example the nominal value of the Resistor is described with a “0”. A “-1” represents a -5% variation from its nominal value and a “+1” represents a +5% variation from its nominal value. Therefore if our resistor’s nominal value is 20 ohms, a “-1” represents a 19 ohms value, and a “+1” represents a 21 ohms value. Step 1 Start by choosing variables that affect the response Example: For W -1 corresponds to 9.5 µm +1 corresponds to 10.5 µm 0 corresponds to nominal value, 10µm
  72. 72. www.linecraftdesigns.com 71 DOE.. Step 2 Next, we run the simulation eight times to get the gain (our output measure) for all the combination of +1’s and -1’s of the three elements and this is what we get:
  73. 73. www.linecraftdesigns.com 72 DOE.. Step 3 From the results above, let us extract the main effects of Capacitor, C on the Gain. We calculate the average Gain when C is “-1” and when C is “+1” and determine the total gain variation due to the Capacitor. The table below shows that this gain variation (due to C) is .044 dB. Main Effect of Capacitors, C on Gain
  74. 74. www.linecraftdesigns.com 73 DOE.. Next we do the same thing for the Resistor. Notice that the gain variation due to the Resistor is .85 dB, which is much higher than that of the Capacitor. (See table below). This already tells us that the resistor is a trouble component and causes higher variation in the gain.
  75. 75. www.linecraftdesigns.com 74 DOE.. The main effects can be plotted for easier view of the components’ sensitivities to Gain. Below is the main effects plot of the Capacitor and the resistor (calculated above) on the Gain variation.
  76. 76. www.linecraftdesigns.com 75 DOE.. Step 4 DOE is also very useful in getting information on the interactions between the elements in a design and how these interactions affect the variation in the output measure (Gain, in our example) The table below calculates the interaction effect between W and R. The interaction is very small and negligible (.0088 dB).
  77. 77. www.linecraftdesigns.com 76 DOE..
  78. 78. www.linecraftdesigns.com 77 DOE.. Step 5 Doing the same procedure for all elements and their interactions, we obtain the following results. Obtaining the Rest of the Coefficients Construct a linear equation to represent the experiment results: Gain=13.8 + .09W + .85R + .044C + .0088WR + …. Etc.
  79. 79. www.linecraftdesigns.com 78 DOE.. Step 6 Pareto Charts are very useful in DOE. The results can be plotted on a Pareto type chart in order to make it much easier to visualize the main and interaction effects of all components to the Gain variation. It is very clear from the results above that the Resistor R has the most contribution to the Gain variability and sensitivity. The designer will then focus his / her efforts in reducing that variation due to the resistor. One way to do that in Board or MIC designs is to buy a screened part that has +/- 1% tolerance instead of a +/- 5% tolerance. In MMIC design, the designer would want to either use a different resistive layer of lower sensitivity, or make the resistor as wide as possible since this would reduce its sensitivity.
  80. 80. www.linecraftdesigns.com 79 Failures
  81. 81. www.linecraftdesigns.com Why six sigma fails • No concept of Customer expectations • No vision related to Customer expectations • No follow-up on the annual operating plan • Lack of alignment (horizontal or vertical) • No visible leadership at the executive level • Business executives do not show up for report-outs (conveys a lack of priority) • Deploying Six Sigma without a goal (reason for deployment) • Deploying Six Sigma with a goal but no plan on how to get there • Abdicating the deployment plan to a consulting company • Trying to change the organization without a detailed change process • Not having metrics in place for management participation • No metrics for Champions • Champions do not show up for report-outs • Having metrics in place but no feedback (or limited feedback annually, semi-annually, quarterly) • Not having multiple projects queued up for each MBB, BB or GB (so when they complete a project the next one has already been selected) • Not communicating deployment plans effectively through the organization • No rewards or recognition program • A rewards or recognition program that does not recognize teams • No retention program for trained personnel 80
  82. 82. www.linecraftdesigns.com 81 Customers
  83. 83. www.linecraftdesigns.com Voice of Customer (VOC) “The “voice of the customer” is a process used to capture the requirements/feedback from the customer (internal or external) to provide the customers with the best in class service/product quality. This process is all about being proactive and constantly innovative to capture the changing requirements of the customers with time” The “voice of the customer” is the term used to describe the stated and unstated needs or requirements of the customer. The voice of the customer can be captured in a variety of ways: Direct discussion or interviews, surveys, focus groups, customer specifications, observation, warranty data, field reports, complaint logs, etc. This data is used to identify the quality attributes needed for a supplied component or material to incorporate in the process or product. 82
  84. 84. www.linecraftdesigns.com 83 Six Sigma COPIS/ SIPOC Model The Voice of the Customer (VOC) is aggressively evaluated and used to determine needed outputs and hence the optimal process configuration needed to yield those outputs and their necessary inputs for which the best suppliers are identified and allied with. Customers Suppliers Outputs InputsProcess Steps
  85. 85. www.linecraftdesigns.com 84 Six Sigma COPIS/ SIPOC Model The SIPOC is often presented at the outset of process improvement efforts such as Kaizen events or during the "define" phase of the DMAIC process. It has three typical uses depending on the audience: • To give people who are unfamiliar with a process a high-level overview • To reacquaint people whose familiarity with a process has faded or become out-of-date due to process changes • To help people in defining a new process Several aspects of the SIPOC that may not be readily apparent are: • Suppliers and customers may be internal or external to the organization that performs the process. • Inputs and outputs may be materials, services, or information. • The focus is on capturing the set of inputs and outputs rather than the individual steps in the process
  86. 86. www.linecraftdesigns.com 85 Example SIPOC: Automobile Repair Supplier Input Process Output Customer Vehicle owner Customer service representative Facility manager Parts window Repair inquiry Vehicle for repair Permission to proceed with individual recommendations Open bay Parts for approved repairs Observations Schedule visit Diagnose problem Prepare work order Source parts Perform repairs Notify that service is complete Appointment date and time Repair recommendations and cost estimates Work order Parts for approved repairs Telephone/e- mail/text message notification Repaired vehicle Vehicle owner Mechanic Customer service representative
  87. 87. www.linecraftdesigns.com 86 Complementary Tool
  88. 88. www.linecraftdesigns.com Lean Management “A systematic approach to identifying and eliminating waste(non-value-added activities) through continuous improvement by flowing the product at the pull of the customer in pursuit of perfection” Types of waste (MUDA) • Storage • Transportation • Waiting • Motion • Process • Defects • Over-production 87
  89. 89. www.linecraftdesigns.com Theory Of Constraints • Maximum speed of the process is the speed of the slowest operation • Any improvements will be wasted unless the bottleneck is relieved “Bottlenecks must be identified and improved if the process is to be improved” Identification of constraints allows management to take action to alleviate the constraint in the future • Reduce cycle time : Time from receipt of customer order to shipment • Improve manufacturing cycle efficiency (MCE) : Processing time / total cycle time 88
  90. 90. www.linecraftdesigns.com Theory of constraints Based on the concepts of drum, buffer and ropes Drum Output of the constraint is the drumbeat • Sets the tempo for other operations • Tells upstream operations what to produce • Tells downstream operations what to expect Buffer Stockpile of work in process in front of constraint • Precaution to keep constraint running if upstream operations are interrupted Rope Sequence of processes prior to and including the constraint • Want to “pull” the rope at the maximum speed • Speed of the constraint 89
  91. 91. www.linecraftdesigns.com Quick response manufacturing QRM Includes all Activities in the Customer Chain, Including: • Material Planning • Shop Floor Control (POLCA) • Supply Chain • Customers & Sales Function • Up-Front, Office Operations • Mindset and Performance Measures 90
  92. 92. www.linecraftdesigns.com Factory Physics – An Overview Toyota Production System • JIT(Just in time) • Autonomation ( Automation with a human touch) Practices Setup reduction (SMED) Motivation: Small lot sequences not feasible with large setups. • Internal vs. External Setups: – External – performed while machine is still running – Internal – performed while machine is down Approach: • Separate the internal setup from the external setup • Convert as much as possible of the internal setup to the external setup • Eliminate the adjustment process • Abolish the setup itself (e.g., uniform product design, combined production, parallel machines) 91
  93. 93. www.linecraftdesigns.com Factory Physics- Continued… Worker training Cross-Trained Workers: •float where needed •appreciate line-wide perspective •provide more heads per problem area Shared Tasks: •can be done by adjacent stations •reduces variability in tasks, and hence line stoppages/quality problems Vendor Quality control Fool proofing (poka-yoke) 92
  94. 94. www.linecraftdesigns.com Factory Physics- Continued… Kanban A “kanban” is a sign-board or card in Japanese and is the name of the flow control system developed by Toyota. Role Kanban is a tool for realizing just-in-time. For this tool to work fairly well, the production process must be managed to flow as much as possible. This is really the basic condition. Other important conditions are leveling production as much as possible and always working in accordance with standard work methods. Push vs. Pull: Kanban is a “pull system” – Push systems schedule releases – Pull systems authorize releases 93
  95. 95. www.linecraftdesigns.com Factory Physics- Continued… Integrality to JIT: •JIT requires high quality to work •JIT promotes high quality •identification of problems •facilitates rapid detection of problems •pressure to improve quality •Techniques: • Process Control (SPC) • Easy-to-See Quality • Insistence on Compliance (quality first, output second) • Line Stop • Correcting One's Own Errors (no rework loops) • 100 Percent Check (not statistical sampling) • Continual Improvement • Housekeeping • Small Lots • Vendor Certification • Total Preventive Maintenance 94
  96. 96. www.linecraftdesigns.com 95 Ways of Six Sigma
  97. 97. www.linecraftdesigns.com Six Sigma Way of Transformation 96 Six Sigma Way Six Sigma Way is:  Mindset/Way of thinking  A way of doing manufacturing/service business  Methodology/Tools for continual improvement
  98. 98. www.linecraftdesigns.com 97 Practice Problems
  99. 99. www.linecraftdesigns.com Practice Problems 1. A manager states that his process is really working well, out of 1500 parts, 1477 were produced free of a particular defect and passed inspection. Based upon Six-Sigma theory, how would you rate this performance, other things being equal. 2. Professor Chase is frustrated by his inability to make a good cup of coffee in the morning. Show how you would use a fishbone diagram to analyze the process he uses to make a cup of his evil brew. 3. Use the benchmarking process and as many DMAIC analytical tools as you can to show how you can improve your performance in your weakest course in school. 4. Consider a simple repair performance job that you performed that did not turn out particularly well. Analyze the mistakes 5. Prepare a SIPOC flowchart of the major steps in the process of boarding a commercial flight. Start the process with the passenger arriving curbside at your local airport. 6. Prepare an opportunity flow diagram for the same process of boarding a commercial flight. 98
  100. 100. www.linecraftdesigns.com Practice Problems 7. A shoe manufacturing firm learned through a Lean Six Sigma project their boot soles could be made of a different material requiring two less steps in the process. Removal of these two steps yielded a monthly cost savings of $7,500. Therefore the reported financial savings for this LSS project were _____________. a. $45,000 b. $75,000 c. $90,000 d. $120,000 99
  101. 101. www.linecraftdesigns.com Practice Problems 8. A Belt utilized a diamond symbol in a Process Map she created for the process that was subject to her LSS project. By use of the diamond symbol she was showing a(n) _______________ point in the process. a. Ending b. Beginning c. Decision d. Repair station 100
  102. 102. www.linecraftdesigns.com Practice Problems 9. When in the process of trying to identify the Critical X’s for a LSS project a Belt creates a(n) _____________ because frequently it is 20% of the inputs that have an 80% impact on the output. a. Pareto Chart b. FMEA c. Np Chart d. X-Y Diagram 101
  103. 103. www.linecraftdesigns.com info@linecraftdesigns.com www.linecraftdesigns.com Thank You!