Lean Six Sigma Flashcards
What is CTQ?
Critical to Quality. These represent items that are directly related to customer satisfaction.
What are the key components to assessing defect performance?
DPMO = Defects per million opportunities.
Units (N) = Items produced Defects (D) = Event that doesn't meet a CTQ spec. Defect Opportunity (O) = CTQ's (same number) Defective - Units with one or more defects
DPMO = 1M x (D/(NxO)
Seven Key Principles of Lean Six Sigma
1 - Focus on the customer
2 - ID and understand how the work gets done
3 - Manage, improve, and smooth the process flow
4 - Remove non-value adding steps and waste
5 - Manage by fact & reduce variation
6 - Involve and equip people in the process
7 - Undertake improvement activity in a systematic way
What is DMAIC?
Define - Identify key causal factors. Use interrelations map and value stream maps.
Measure - How does process look to CTQ’s?
Analyze - Check possible causes using concrete data.
Improve -
- Generate ideas about possible solutions - Select most appropriate solution - Plan & test solution
Control - Actions and measurement to sustain the improvements.
What is an improvement charter and when is it used?
In advance of working in a Lean Six Sigma framework to solve a problem.
Contents; High level business case Problem statement Goal statement Project scope CTQ's Roles Milestones
When should reviews be undertaken during DMAIC?
End of Analyze - review how much you hope to achieve with project.
End of Improve phase - Did we get the results expected?
End of control phase - Were we able to sustain the results?
Kaizan Blitz Event
One week sprint to solve a problem
What is SIPOC? How do you create it?
Useful to focus on what needs to be measured in a system. Suppliers Inputs Process Outputs Customers
1 - List all different customers
2 - List all outputs sent to customers
3 - Set out steps in process. Construct high level picture of the process in 4-8 steps.
4 - List all the inputs you receive from suppliers
5 - Identify where the inputs came from
What is Kano?
Identifies the factors that go into customer satisfaction.
1 - Must Be’s - Obvious unspoken must have’s. If they aren’t met, significantly decrease satisfaction.
2 - One Dimensional - Features etc. The more the better (linear relationship with satisfaction).
3 - Delighters - Wow factors that surprise and delight customers.
What are different ways to segment customers?
Industry Size Spend Location End Use Product Characteristics Buying Characteristics Proce/cost sensitivity Age Gender Socioeconomics Frequency of purchase Impact/opinion leader Channel Loyalty Technology
What is a customer research plan? What are methods and outputs?
Used to as the “Why why why!” Fully understand and develop CTQ’s.
Methods - interviews/focus groups/surveys
Output - Customer wants and needs and competitor information
For interviews - (in this order)
Learn
Clarify points
Ask for suggestions
What should be kept in mind when developing CTQ’s?
Measureable
Target value and upper/lower bounds
Use paired comparison voting to prioritise
What are the steps to mapping out a process?
1 - Process stapling - following a customer order throughout the process
2 - Draw spaghetti diagram of entire process
3 - Deployment flowchart, using simple icons (circle = start/stop, diamond = decision, square = step or action) with time measured in each task
4 - Value stream map
What are the steps in creating a value stream map?
1 - ID the process you want to look at
2 - Set up small team for analysis
3 - Observe the work site and process in action
4 - Draw process map of material and product flow
5 - ID performance data you’d like to know
6 - Collect data needed for each step including time studies, error rates, units processed etc.
7 - Add arrows to show information flows
8 - Add overall timeline to show cycle time
What are the steps in collecting data?
1 - Agree on output measures that matter for CTQ’s
2 - Agree to ground rules with team on consistently and accurately collecting data
3 - Collect data
What are the ways and tools to identify and improve variation in a process?
Identify natural or special variation using control charts. If you have special variation, address this first. Work to improve natural variation through specific goals.
How do you create a control chart?
Use 20 datapoints from a process, calculate the Upper Control Limit (UCL) and LCL using 3 standard deviations from the mean. Monitor the process to determine if you have special variation or natural variation.
Control charts assist in managing BY FACT and data.
How do you determine if you have special variation in a control chart, and what do you do about it?
Special variation if; 1 - datapoints outside of contol limit (sometimes false alarm) 2 - If Seven consecutive points are; - Going up - Going down - Above the mean - Below the mean - Observed cyclicality
What is an X moving R chart and how do you construct?
X = datapoints R = rolling difference between two consecutive datapoints
UCL(X) = Mean of X + (A(2)*Mean of R) LCL(X) = Mean of X - ((A(2)*Mean of R) *A(2) = 2.666
UCL(R) = D(4)*R LCL(R) = D(3)*R *D(4) = 3.267 *D(3) = 0 (LCL = 0)
What are the different states in a control chart, what are the appropriate actions coming out of those states?
Ideal - Control limits within specs, data within both (Green Light!)
Threshold - Specs within control limits, data breaching specs but not control limits (Yellow Light, about to be chaos, run DMAIC)
On the Brink - Control limits within specs, data breaching control limits but not specs (Red light, about to be chaos. Run DMAIC)
Chaos = Control limits and spec limits breached by data. (Shit everywhere)
What are the two capability indices, why are they used and how are they measured?
C(p) = Determines if the specs are outside of the control limits, or the process can fit within the specs.
C(p) = (USL - LSL)/(UCL - LCL)
Minimum of 1 to be “capable”
C(pk) = If process is being managed within specifications
If mean is closer to USL, C(pk) = (USL - mean (x))/ 3 stdeviations
If mean is closer to LSL, C(pk) = (mean (x) - LSL)/3 stdeviations
What are the broad steps in the process of identifying cause and effect?
State problem
Brainstorm hypothesis
Create interrelationship diagram
Test and analyze to confirm or negate hypothesis
What are statistical tools to measure cause and effect in a system?
X = independent variable Y = dependent variable
State hypothesis in terms of X’s impact on Y, and chart the relationships between X’s and Y’s as strong and weak.
Measure statistical correlation between X’s and Y’s.
What is Takt time?
Required cadence. The production rate required to meet demand.
eg: Takt Time = Available capacity per shift# of orders per shift
= capacity in time per unit to process
What is OEE?
Overall equipment effectiveness.
A = Availability Rate = % of time equipment is up P = Performance Rate = % of time running at designed speeds Q = Quality rate = % of time product is built within spec
A x P x Q = OEE
What are the 7 wastes?
Overproduction Waiting Transportation Processing Inventory Motion
What are the “5 S’s” related to housekeeping?
Sort - Separate tools by frequency of use
Straighten - Put things frequenty used in easy access, remove and store others
Scrub - Keep tools and environment clean and tidy at all times
Systematize - Design operation so everything is sorted, straightened, and scrubed automatically.
Standardize - keep doing it through habit!
What is the Red Tag Exercise?
Tagging items with the last used date and placing within easy reach, storing, or discarding based on the frequency of use.
What is Jidoka?
Stopping an entire process when a defect occurs. This ensures the source of the defect is corrected, and no downstream defects occur as the result of one defect.
What is FMEA?
Failure Mode Effect Analysis
Assign risk weights, frequency, and probabilities of detection to each risk factor, prioritize accordingly and mitigate.
What are the 3 types of error proofing?
Contact - Prevent physical objects from passing through if not to spec. Ex: fixed diameter hole which product passes through to avoid larger than spec.
Fixed Value - Ensure quantities are accurate. Example, fixed size fry scoop at Mc D’s.
Motion Step - Make sure a step happens through motion detection or sensing pad.
What are the benefits of preventative maintenance?
System Reliability
Decreased Replacement Cost
Decreased System Downtime
Improved Spare Inventory Efficiency
What is Heijunka?
Standardized work. Avoid spikes or troughs in production.
