Six Sigma Lean
What is a value stream map?
Value stream mapping is used to identify major sources of non value-added time in a value stream, envision a less wasteful future state, and develop an implementation plan for future activities.
What are the common tools for process analysis?
Value stream maps, process maps, flowcharts, procedures, work instructions, spaghetti diagrams, circle diagrams, etc.
What is Normal distribution?
Normal distribution is a continuous distribution where any two data values may have an interval in between. The bell shaped normal curve has probabilities that are found as the area between any two z values. Normal distribution has 5 characteristics: -The mean, mode, and median are equal. -Most values concentrate near the mean and decrease in frequency further from the mean. -Symmetrical about the central value. -The curve has only one mode. -All data points fall within the curve either 50% to the left or 50% to the right.
What is CTQ?
Critical to Quality, created based on customer feedback
What is DPMO
Defects per Million Opportunities, a standardized measure of the error rate of a process
What are the tools used in Define stage?
Some of the main tools you can use in the Define phase are: -The Project Charter Template -Brainstorming -Graphs -Stakeholder Analysis -Historical Data -The Voice of the Customer
What is an under-coverage bias?
Under-coverage bias occurs when some members of the population are inadequately represented in the sample.
What components do Lean controls include?
- Leadership and top management commitment - All leaders and top management should be trained as Six Sigma Champions, asking the right questions and understanding their roles and functions - Include Lean Six Sigma planning within the business operating plan - Ensure the return on investment for training has at least a 20 fold return on the investment - Develop a Six Sigma mentoring process - Ensure projects are financially validated and management's sign-off on the project's actual savings
What is the The Principle of Determinism?
This principle explains that every outcome is the result of a process being applied to it or determined by the application of a function. The Principle of Determinism is a core belief running through Six Sigma. All outcomes are determined by the way inputs are transformed.
Deming's Theories: Theory of Variation
In the theory of variation, his philosophy focuses on improving the product and service variability in design and manufacturing processes.
What is CTC metric?
The Critical to Cost metric refers to consideration of: -The costs of inventory kept on hand -The amount of labor put into production -The cost of raw materials -All sorts of overhead, such as employees and delivery costs
What are the 7 elements of waste?
The 7 classic wastes include overproduction, inventory, defects, over-processing (unneeded steps), waiting, motion (unnecessary travel around a factory) and transportation (material movement back and forth from storage). An 8th element of waste is emerging called "knowledge and latent skill." This is where organizations fail to take advantage of skills or talent or are not effective at transferring learning between employees.
What are the methods to select a Six Sigma project?
- Matrix diagrams are a planning tool for displaying the relationships among various data sets. - Process decision program charts (PDPC) identify what may go wrong in a plan under development. Once possible issues are identified, prevention controls and countermeasures can be developed to prevent the problems. - Project viability matrix
When implementing Six Sigma, what factors are important to understand?
-Understand who your customers are and what is important to them -Understand customer feedback through the Voice of the Customer and determine the requirements for your product -Prioritize issues related to your product -Determine internal processes and what causes variation -Determine the causes of defects -Develop ways to address defects -Develop metrics to standardize and measure the changes made in the process
What is value stream analysis?
Analyze the factors that contribute to the value of a product or service from the view point of the customer. a. What creates value for the customer b. What doesn't create value but is a necessary requirement or dependency throughout the overall process c. What adds no value and it's not needed by any part of the process -> should be eliminated ○ One important consideration: What is the complexity of the activity during the cycle time? ○ Reducing, restricting, or even removing non-value added items is a clear and easy way to reduce overall cycle time ○ Do not overlook the "setting up period" for any activity
What is Binomial distribution?
Binomial distribution is different from a normal distribution, although the shape of the curve will be similar. The binomial distribution is a discrete probability distribution. It shows the probability of getting "X" successes in a sample of "N" from an 'infinite' population, where the probability of a success is "Y."
What is a CTA flow-down?
CTQ flow-down is used to convert the voice of the customer to specific needs using a tree map, where the tree map is the voice of the customer and the branches lead to the specific features.
Deming's Theories: Theory of Knowledge
In the theory of knowledge, Deming emphasized that knowledge is not possible without theory, and experience does not establish a theory by itself. He says copying a best practice without understanding the theory behind it could be devastating for an organization.
What is Pareto Priority Index (PPI)?
It is a method to evaluate projects: PPI = Savings ($) x Probability of Success / Cost x Completion Time The PPI increases as the probability of success or savings value increases, but decreases as the cost to implement or the completion time becomes greater. Cons: Consideration of business reputations, customer or stakeholder weight, supplier timing, or even staffing impact are not taken into account here.
What is Pareto Analysis?
It is the 80:20 rule. The Pareto principle states that 20% of inputs result in 80% of outputs. Pareto charts are graphical tools used for ranking causes from most significant to least significant. Once these issues are revealed, improvement efforts can have a greater impact and be more cost effective.
What is Kanban?
Kanban uses a system of signal cards that is simple and shows someone that something in a process needs attention.
How does a Lean organization look like?
Lean enterprise eliminates waste and non value-added activities. Lean focuses on delivering more value to the customer and addressing the voice of the customer. It creates efficiency based on optimizing flow in a process and empowers employees to improve their work. Lean always asks, "how can we get better?" Lean does not eliminate people or employees, is not a shortcut, and does not micromanage. Lean focuses on removing the non value-added delay, waste, and rework from your processes. Lean can be used in any industry or business to improve speed, quality, and cost. When implemented properly, Lean Six Sigma focuses on results, not training.
What is a Spaghetti diagram?
Spaghetti diagrams identify potential improvements to a physical layout to remove unnecessary movement or bottlenecks. Spaghetti diagrams are primarily used for Lean manufacturing in production facilities.
What is the difference between Black Belts and Green Belts?
The core differences would be their spheres or influence within the business, as generally the Green Belts will be at a lower level than the Black Belt. Green Belts may not be required to have a great deal of managerial or leadership skills and may not be as statistically capable as a Black Belt.
What are the considerations for Cost metrics?
The cost of errors in a process may be unreported or not obvious but can include production costs on reworking: -Running the machines again -Holding on to stock or raw material unnecessarily -Even the cost of accommodating such items Another cost to consider are staffing costs to produce quick movement or even staffing cost waste when downtimes and slack periods occur. A quality issue can create a cost issue.
What are the characteristics of CTQ
The most common forms of CTQ are: -CTC Critical to Cost -CTS Critical to Safety -CTP Critical to Process -CTD Critical to Delivery
What are the two basic principles Lead is based on?
The removal of irregularity and the removal of irrelevance That is, attempting to get uniformity within production and removing wasteful processes. Get the most streamlined process within a production environment to create the most consistently "good product" in the most efficient way.
Deliverables in Measure Phase
The second stage is where the starting point metrics are recorded to baseline the current performance level and constraints of the process to be worked upon. 1. Key process metrics (KPOVs) 2. Data collection plan 3. A baseline for performance 4. Documentation of variation 5. Communications to team members and stakeholders
What are the steps in a Deming Cycle?
The steps in the Deming PDCA or PDSA Cycle are: 1.Plan a change or test it (P). 2.Do it (D) by carrying out the change or test on a small scale. 3.Check it (C) by observing the effects of the change or test. 4.Study it (S) by reviewing what you have done or changed. 5.Act on what you have learned (A). 6.Repeat and continuously evaluate the process.
What is a voluntary response bias?
Voluntary response bias occurs when sample members are self-selected volunteers; the resulting sample tends to over-represent individuals who have strong opinions.
What are the considerations for Quality metrics?
- How does rework impact CTQ?
How to reduce poor quality?
1. Understanding who your customers are and what is important to them 2. Understanding customer feedback, called the Voice of the Customer, and determining the necessary requirements for your product 3. Prioritizing issues related to your product Determining internal processes and what causes variation 4. Determining what causes defects 5. Developing ways to address the defects 6. Developing metrics to standardize and measure the changes made in the process
What are the 4 types of process measurements in Six Sigma?
Cost, quality, safety, or time
Estimating the Baseline
No matter what information you come up with, it is key to the success of the Six Sigma project that this baseline is agreed upon with the process owner, champion, and key stakeholders as the starting point from which improvement is to be developed.
What is RTY?
Rolled Throughput Yield (RTY) is the probability that a product will pass through the entire production or service process without rework and defects.
What is CTS metric?
The Critical to Schedule metric relates to the time it takes to pass through one or more stages of a process, such as delivery timing, time on hand of goods stocked, and arrival times for materials.
What is Variance?
Variance is a calculation across a range of data that shows how spaced out the information is.
What is a DMADV process?
When we need to create a new process that is in alignment with Six Sigma methodology, we use this. DMADV is an acronym for Define, Measure, Analyze, Design and Verify. The last 2 stages of the DMAIC process are replaced with Design and Verify to indicate that you design the best process and verify that it is the best process. A lot of companies will not use this acronym and prefer to keep DMAIC clearly stated.
What are work instructions?
Work instructions specify the steps that need to occur for tasks in a process.
What is the problem solving strategy formula?
y=f(x), or more accurately, y=f(x)+ Ɛ -'y' represents the desired outcome, result, or goal you want to achieve. -'x' represents the input, factors, variables, or elements required to create the outcome. -'f' represents the function or process applied to the variables, by which they are modified, changed, or altered - the transformation processor. -'Ɛ' represents some level of error or the amount of difference due to uncertainty or predictability when the process is applied and how near or far it is from the desired outcome.
What is a process?
A process is a series of tasks that is repeated time and again. It has a set order to it.
What is Analysis of Variance (ANOVA)?
Analysis of Variance (ANOVA) is a statistical technique for analyzing experimental data. It subdivides the total variation of a data set into meaningful component parts associated with specific sources of variation in order to test a hypothesis on the parameters of the model or to estimate variance components. ANOVA is used to test whether the means of many samples differ, but it does so using variation instead of mean. It compares the amount of variation within the samples to the amount of variation between the means of samples. ANOVA is effective to separate inherent variance and special cause variance, and it also provides a methodology to evaluate the robustness of a process to various levels of a factor.
What does benchmarking your process mean?
Benchmarking is a comparison and cross-referenced review of similar processes within associated businesses.
What is bias?
Bias is a measure of the distance between the actual value and the average value of a part. It occurs when the survey sample does not accurately represent the population. Selection bias: The bias that results from an unrepresentative sample
What is Chi square?
Chi square is used to test whether a sample is drawn from a population that conforms to a specified distribution. Chi square is also called goodness of fit. Chi square is calculated by summing the Chi square contributions from each category in the hypothesis. The hypothesis is: -H0 the sample conforms to the specified distribution. -H1 the sample does not conform to the distribution.
What are the causes of variation?
Common cause variation is the statistical variation in the measurement of a process that comes from understood and predictable sources. Special cause variation isn't what you expect to see in the context of your processes. It is something unusual has happened that's influencing the results.
What is the "Voice of the Customer"?
Customers define requirements, needs, or wants. They have a vested interest in a project. They also pay for the project, support resource needs, and evaluate and use the results of the project. They provide the "Voice of the Project" and are considered the "Voice of the Customer." Defining the Voice of the Customer (VOC) includes what the customers' requirements are for products and services and what their expectations are: both positive and negative, including likes, dislikes, problems, and suggestions. The VOC asks what each customer desires, specifically what is important to them and what do they perceive is a defect in a quality or service. To determine VOC, you can use surveys, focus groups, interviews, or observation.
Deming's Theories: Theory of Psychology
In the theory of psychology, he helped explain how to understand people, interactions between people, and interactions between leaders and employees in a system of management.
What are the benefits of Six Sigma Lean?
Increased profit, less overhead, improved delivery, lower operating costs, increased customer satisfaction, higher sales, less inventory, etc.
What is a flowchart?
It shows the steps in a process from start to finish.
What is a Matrix Diagram?
It uses a prioritization matrix to rank competing priorities.
How does Six Sigma different from some other quality management methodologies?
It verifies improvement in terms of numbers. The use of measurement and statistics is a fundamental requirement of the process methodology.
What are the different types of variation?
Natural process limits measure variation in a process. The natural process limits are positioned at plus and minus three standard deviations from the target. Thus, if the process is stable, about 99.7% of the process output will be within the natural process limits. Specification limits are limits required by the customer that the supplier must ensure the process can produce to the required process capability value or specification. Cyclical variations are time based with a repeated pattern. Temporal variation is variation with time.
What is a non-response bias?
Nonresponse bias occurs when individuals chosen for the sample are unwilling or unable to participate in the survey.
What is Poisson distribution?
Poisson distribution is a discrete probability distribution. It is used when the sample size is not restricted and it is not possible to specify the number of occurrences but you do know the average number of occurrences.
What is Poka Yoke?
Poka-yoke error-proofing is also known as Poka Yoke. Poka Yoke is a concept in quality that means mistake proofing. The process to apply Poka Yoke is: -Identify the operation or process based on a Pareto Chart. -Analyze the 5 whys and understand the ways a process can fail. -Decide the right Poka Yoke approach, such as using a shut out type or an attention type that an error has been made.
What are the considerations for Scheduling metrics?
Quality can impact scheduling. Another consideration of scheduling impact is the measure of cycle times and the time between elements of a process. You may have the most efficient stages, but if you have products sitting around for days between stages, there are storage costs and time impacts. Reducing these delays and wait times can flow through to the overall timing.
What is a Six Sigma Green Belt?
Someone who is qualified to a Six Sigma Green Belt standard has all the knowledge and capability to organize and run a Six Sigma project. They should have a good and solid understanding of the DMAIC process, a number of Six Sigma tools within their toolkit, and an understanding of how process changes can be implemented.
What are the basic steps in Define stage?
The basic steps in the Define Stage are to: •Develop Project name and Purpose •Complete the Project Charter •Develop a High Level Process Map •Identify the Process Owner, Champion, and Team •Identify Customers and Requirements critical to quality •Define Align Goals with Business Initiatives •Determine the Projected Return On Investment
What do we use standardization of metrics for?
Standardization of metrics helps to collaboratively measure, control, and manage processes. It establishes benchmarking for performance comparison and uncovers best practices for gaining a competitive advantage.
In order to maintain the new and improved practice and prevent personnel slipping back into previous ways, what do we need to do in Control phase?
Standardize the practice by providing: - Training - SOPs - Plans to monitor and control deviation from the process
What is the cause and effect philosophy of Six Sigma?
The cause and effect philosophy of Six Sigma means that you look at a 'process' and see how the process allows for variation. The inputs, process function, and errors within that process all affect the outcome. They cause the outcome to be a particular way - the cause and effect of Six Sigma.
Deliverables in Improve Phase
The fourth stage uses the information found in your analysis and develops possible solutions. Once the best solutions are developed, they are deployed as an improvement. 1. Solutions 2. Implementation plan
What is a fishbone diagram?
It's also called cause and effect diagram. It looks at all the potential causes of underlying process factors or they generate potential failures to be addressed later on. -> brainstorm all potential relationships -> State the outcomes in terms of problems or issues. -> Choose significant branches to form the main bones of examination -> Follow the path along the bone to agree or dismiss potential causes (not known until validated)
What are the most common tools for Lean?
Kaizen, Poka yoke, Takt time, 5 Whys, 5S, Spaghetti diagram, Touch time, Work times Kanban, Theory of Constraints, Value Stream
What is Process decision program charts (PDPC)?
Process decision program charts (PDPC) identify what may go wrong in a plan under development. Once possible issues are identified, prevention controls and countermeasures can be developed to prevent the problems. The steps used to develop the PDPC chart include developing a tree diagram of the proposed plan, reviewing each task, brainstorming what could go wrong, reviewing all the potential problems and brainstorming possible countermeasures for each potential problem, and then determining which to implement.
What is Cost of Poor Quality (COPQ)?
The Cost of Poor Quality is the sum of internal and external failures. It is measured differently depending on the industry. Six Sigma reduces costs and waste by determining the COPQ through the processes of: -Understanding who your customers are and what is important to them. -Understanding customer feedback through the Voice of the Customer and determining the requirements for your product. -Prioritizing issues related to your product. -Determining internal processes and what causes variation. -Determining the causes of defects. -Developing ways to address the defects. -Developing metrics to standardize and measure the changes made in the process.
What is CTQ metric?
The Critical to Quality metric refers to the accuracy or expected look of a product
What is Deming Cycle?
The Deming Cycle is also known as the Plan-Do-Check-Act (PDCA) Cycle or Plan-Do-Study-Act (PDSA) Cycle. It was invented by Walter Shewhart, but popularized by and significantly enhanced by Deming. PDCA and PDSA are cyclic processes for planning and testing improvement activities prior to full-scale implementation.
What is a Funnel Report?
Helps you work through many either trivial or significant factors that can impact the outcome Begin by using all the variables you wish to consider Using set criteria, reduce the number by taking out the most trivial and whittling down to the core elements to be considered. (sometimes referred to as "spiraling" or "spiral analysis".
What is a 5S tool?
The 5S tool is a Lean tool that allows examination of a process to identify non value-added elements: Sort, Straighten, Shine, Standardize, and Sustain. 1.Sort: Remove what is not needed. 2.Straighten: Organize what remains. 3.Shine: "Clean" the work area. 4.Standardize: Make sure a regular cleaning and maintenance schedule is in place. 5.Sustain: Embed 5S as part of the culture. The 5 S method improves safety and communication, improves process flow, increases compliance, reduces space requirements, boosts morale, removes non value-added steps, and reduces time wasted looking for items.
Deliverables in Define Phase
This first stage sets the context within which the Six Sigma project is to be performed. 1. Fully trained project team 2. Customer expectations or Voice of the Customer (VOC): Requirements, Critical characteristics (Critical to Quality elements (CTQs), key business drivers of internal and external customer satisfaction. What is important to them? What do they perceive as a defect in a quality or service? 3. Project charter 4. Known business process mapping
What is Taguchi Method (Design of Experiments)?
This method is to reduce and greatly improve engineering quality and productivity by reducing environmental variation. Design of experiments deals with planning, conducting, analyzing, and interpreting controlled tests to evaluate the factors that control the value of a parameter.
What is Six Sigma?
A "sigma" is a term used to denote variance from the mean average of an event. Six Sigma originally referred to the ability of manufacturing processes to produce a very high proportion of output within specification. Six Sigma is an improvement methodology which uses the following phases to make changes to any process: Defining, Measuring, Analyzing, Improving, and Controlling. Six Sigma measures the capability of a process to perform defect-free work with a failure rate of 3.4 parts per million or 99.9997%. The goal of Six Sigma is improved process performance and increased customer satisfaction through variation and defect reduction, resulting in consistently producing high quality services, products, or processes.
What is DPU?
Defects per unit (DPU) is a product's or service's nonfulfillment of an intended requirement or reasonable expectation for use.
Who Is Dr. Deming?
Dr. W. Edwards Deming (1900-1993) is best known for reminding management that most problems are systemic and that it is their (management's) responsibility to improve the systems so that workers can do their jobs more effectively. When developing better interactions between employees and managers, he noticed that workers were responsible for 10 to 20 percent of the quality problems in a factory, and that the remaining 80 to 90 percent was under management's control. It was their responsibility to manage the programs accordingly.
What is FTY?
First Time Yield (FTY) is the number of defect-free units produced divided by the number of total units going into the process. The FTY is calculated by the total number of processes multiplied by the number of defect-free products/the total number of products. First Time Yield Or First "Pass" Yield is a tool for measuring the amount of rework in a given process. It is a good example of a cost of quality metric.
Deming's Theories: Theory of Optimization
In the theory of optimization, the objective of an organization is the optimization of the total system and not the optimization of individual subsystems.
What is an X-Y Diagram?
It charts the equation y = f (x), explaning the input/output relationship.
What is a SIPOC diagram?
It is the most common tool to help define a process. The SIPOC helps team members determine process activities, stakeholders, and boundaries. It shows the Suppliers, Inputs, Process, Outputs, and Customers of a process. Suppliers: The process provide the inputs, and every input should have a supplier. Inputs: The activities that trigger the process, such as a customer order. Processes: The activities that are carried out to convert the inputs into outputs. Outputs: The tangible product or service that the process produces. Customers: The people who receive the Outputs. Every Output should have a Customer.
What are procedures?
Procedures are documents (instructions) that specify how a process is to be carried out. They may also indicate standard operating procedures.
What is Failure Modes & Effects Analysis (FMEA)?
Process FMEA is a structured analytical tool used to identify and evaluate the potential failures of a process for existing products or services. The failures are any errors or defects in the product or service which affect the customer. FMEA provides information in quantifying weighted priorities, risks, and contributing characteristics of a problem.
what is QFD?
Quality Function Deployment, a VOC analysis tool. It translates customer requirements into performance measures.
What is difference between Six Sigma and Lean?
Six Sigma - Reduce error rate and process variability Lean - Reduce waste and non-value added activities
What are the steps to reduce variation?
Standardization, be consistent, and control. -Standardize materials and sources of them. -Standardize work to reduce in-process variation. -Standardize gauging. -Be consistent and make sure you have control of new materials or tools or methods prior to implementation.
What is Six Sigma team composition?
Team formation: Stakeholders, executives, champions, and team members (yellow belts) who are led by a green belt or black belt. 1. Executives: Provide the strategic alignment within the organization for initiatives and Six Sigma projects 2. Champions: Guide the team through organizational support and resources, removing roadblocks. They will be responsible for 'resourcing' the project in terms of people and funds. 3. Master Black Belts: Manage the strategic direction of the Six Sigma program; train black and green belt 4. Black Belts: Lead problem-solving Six Sigma team 5. Green Belts: Assist with data collection and analysis for black belt projects 6. Yellow Belts: Review overall activities and participant as contributing project team members. A Yellow Belt will usually be a general member of the workforce, utilized for their skills, knowledge, or experience within the process that is being reviewed by the Six Sigma project. Usually their role will be temporary and only be relevant to each project. 7. Project Team: Execute the actual work
What are the 4 states of variation?
The Ideal State:Processes are in statistical control and meet the customer's requirements. The Threshold State: Processes are in statistical control but do NOT meet the customer's requirements. The "On the Brink" State:Meet the customer's requirements or needs but NOT in statistical control. (i.e. unpredictable) The "Red Light" State: Processes are neither in statistical control or do they meet the customer's requirements.
What is Multi-Vari Analysis
The Multi-Vari analysis is used to analyze processes which have several different inputs and outputs. There are several types of Multi-Vari, also called Multivariate analysis. This includes: -MANOVA analysis, which is the acronym for Multiple Analysis of Variance. -Factor and Principal Component analysis, which reduces a large number of inputs into a smaller number of defined inputs. -There is also Discriminant analysis, where there are several inputs but only one category of output.
What is central limit theorem?
The central limit theorem explains why many distributions tend to be close to the normal distribution. The central limit theorem describes the characteristics of the population of the means created from the means of an infinite number of random population samples of size. The central limit theorem predicts that: -The distribution of means will increasingly approximate a normal distribution as the size N of samples increases. -The standard deviation of the population of means is always equal to the standard deviation of the parent population divided by the square root of the sample size (N). -The mean of the population of means is always equal to the mean of the parent population from which the population samples were drawn.
Deliverables in Control Phase
The fifth stage focuses on developing control plans and activities to monitor and sustain your improvement. 1. Process standardization 2. Procedure documentation 3. Monitoring plan 4. Transition of project ownership
What are the 3 types of averages most commonly used in statistics?
The mode, median, and mean average The mode or modal point is a range that occurs most frequently. The median average is the center point of a range of values. The mean average is worked out by adding together all of the values and dividing by the number of total values.
What is the purpose of Define stage?
The purpose of the Define Stage is to define the problem, agree on the goals, and listen to the voice of the customer.
Deliverables in Analysis Phase
The third stage reviews the metrics, and using a variety of tools, gains an understanding of the cause and effects interactivity within the system being looked at. 1. Root cause analysis 2. Gap analysis 3. Top-to-bottom data and process analysis
What is the ultimate goal of Lean Six Sigma?
The ultimate goal is continued improvement and sustained quality.
What are process drivers?
They are factors that have the greatest impact on the outcome and where you want to move the process stages.
