Lean Six Sigma Flashcards
Define, Measure, Analyze, Improve, Control
What does DMAIC stand for?
Overproduction, Queuing, Transport, Over Processing, Inventory, Unnecessary Motion, Defects & Errors
Additionally: waste of Human potential, Energy & Space
What are the Seven Deadly Wastes in Lean?
Defining Value, Constructing Value Stream Map, Creating Flow Processes, Add Pull as connector when flow not practical, Continually improve to achieve True Lean State
What are the five steps to implementing Lean?
Customer wants you to do it, The material / info being processed or transform to final product, done right the first time
What are the Three Criteria for Value Adding?
Determine the most common type of defect
Find the projects with the greatest return.
To prioritize
What are the two main uses of the Pareto Chart?
Monitor stability of the process, determine if process is stable and ready for improvement and demonstrate improved process performance.
What are the three uses of an I-MR Chart?
Probability that the process will produce zero defects
What is the concept of rolled throughput yield?
The best performance one can reasonably expect to get from a process.
What is the definition of Entitlement?
All value added / non-value added, process inputs, process outputs and data collection points.
What will a process map identify?
Supplier, Inputs, Process, Outputs, Customers and Requirements.
What does SIPOCR stand for?
"A systematic approach to identifying and eliminating waste (non-value adding activities) through continuous improvement by flowing the product at the pull of the customer in pursuit of perfection" The MEP Lean Network
What is the concept of Lean?
Sort - out what's not needed Store - what is needed Shine - the area Standardize - the layout Sustain - the effort
What are the 5 S?
Single Minute Exchange of Die
What is SMED?
no more than 3.4 defects per million opportunities for defects
Six Sigma ?
What is the problem? Where does the problem occur? When was the defect first observed? How extensive is the problem? How do you know the problem is a problem?
LSS Problem Statement
Improve Quality - ability of products & services to conform to the customer’s wants and needs (requirements)
Eliminate Waste - make waste visible so you can eliminate any activity that takes up time, resources, or space, but does not add value
Reduce Lead Time - improve the velocity of the process by reducing the total time it takes to complete a series of tasks within a process
Reduce Total Costs -eliminating waste and reducing lead times will reduce both direct and indirect costs associated with the production of a product or service
Goals of Lean
- ) Specify Customer Value
- ) Map the Value Stream
- ) Establish Flow
- ) Implement Pull
- ) Pursue Perfection
5 Lean Principles
Can be traced back to at least 1850 and the concept of interchangeable parts which was perfected by Eli Whitney
Early 1900’s - Frederick Taylor and Frank Gilbreth introduced the concepts of standardized work, time study, work standards, process charts and motion study standardization (the idea of eliminating waste was originated here)
1910’s – Henry Ford took all the elements of production and arranged them in a continuous system (considered to be the first practitioner of JIT and Lean Manufacturing)
1940’s – Deming, Juran and Ishikawa introduced SPC and TQM
1940’s to 1970’s – Toyoda and Ohno developed the Toyota Production System (TPS), JIT, stockless production (considered to be the first formal Lean manufacturing system
History of Lean
1850
1910
1940’s
1940’s - 70’s
- Develop process measures
(KPIs, Operational definitions) - Collect process data
(data collection plans)
3.Check data quality
(MSA, Resolution)
4.Understand process behaviour
(distribution, process stability, short vs. long term variations)
5.Baseline process capability & potential
Steps of the Measure phase
- Analyse the process
2.Develop theories
(potential root causes)
- Analyse the data
(what does the data say?) - Verify root causes & understand cause & effect
Steps of the Analyse phase
- Law of the Market
(customer is King)
2. Law of Flexibility (speed & flexibility are linked: flexible process allows fast product change) 3. Law of Focus (focus on key time traps)
- Law of velocity (Little’s law)
(Work In Progress slows down processes costs money & hide quality problems) - Law of Complexity & Cost
5 laws of Lean
Failure Mode & Effect Analysis
=> when you have to prevent an event form ever happening
=> little opportunity to learn from past faillures (faillure rate too low)
What is FMEA?
Severity * Occurence * Detection = RPN
RPN = Risk Priority Number
What is rated in a FMEA?
25 minimum
Recommended minimum sample size for histograms?
20 minimum
Recommended minimum data points for Run charts?
Deciding if process is stable
Investigating Clustering, Mixtures, Trends & Oscillations in the process
Why use Run charts?
80% of failures are generally caused by 20% of the root causes
80/20 principle?
25 minimum
use Individual Value Plots if subgroups contain less than 25 data points
Recommended minimum subgroup size for Box Plots?
Box Plots (if more than 25 data per subgroup)
Individual Value Plots (if less than 25 data per subgroup)
100% Stacked Bar Charts (to compare proportions of attribute oer categorical data)
Graphical tools for analysing & comparing subgroups?
Whiskers represent the data range (minimum to maximum)
BUT whiskers can be maximum 1.5 times the length of the box (points beyond that are considered “outliers”)
What represent the Box Plot whiskers?
Increased sample size is a major contributor to gaining statistical confidence
How to increase statistical confidence?
Measure the strength of a correlation
varies from -1 to +1
Correlation can be statistically significant (p0.05)
What is the use of the Pearson coefficient?
Analysis of Variance test
to compare average of 3 or more samples
What is ANOVA?
In GR&R
to identify relative variations due to the gauge and the appraisers
In Regression
to identify relative variations due to the different process inputs
In DOEs
to assess the relative variations due to input factors & their interactions
Where is ANOVA used?
All factors are significant (p
Criteria for judging the quality of a regression model ?
The regression model should not be used beyond the bounds of the data used to create it
What are the limitations of a regression model?
ID the process output variable(s) ID the process inputs that might affect the output Design the experiment Run the experiment Analyse the result run further experiments if necessary
DOE roadmap ?
Screening of main influencing factors
Modelisation of inputs variations on the process output
Optimisation of process parameters
Objectives of a DOE?
All factors are significant (p
Criteria for judging the quality of a multifactorial model ?
Generate potential solutions
Select best solutions
Assess the the risks
Pilot & Implement
Steps of tthe Improve phase?
An idea generation technique
Stands for Substitute Combine Adapt Modify Put to another use Eliminate Reverse
What is SCAMPER?
