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5-1 Collect & Interpret Data Use SPC to Maintain Current Process Collect & Interpret Data Select Measures Define Process Is Process Capable ? Improve Process Capability Is Process Stable ? Investigate & Fix Special Causes No Yes No Yes Collect & Interpret Data: Diagnosing Variability Purpose:Begin to understand why there is variability in data collected The Quality Improvement Model
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5-2 Collect & Interpret Data What size shoe do you wear? 1 2 3 4 5 6 7 8 9 10 11 12 Size 11 Shoes Why aren’t size 11’s all the same size?
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5-3 Collect & Interpret Data GC CHDM Test Method Example Why don’t we get the same %Water value?
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5-4 Collect & Interpret Data Cause & Effects Matrix Cause & Effect Matrix – A Tool to Identify and Quantify Sources of Variation
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5-5 Collect & Interpret Data l Relates the key inputs to the key outputs (customer requirements) using the process map as the primary information source l Key outputs are scored as to importance to the customer l Key inputs are scored as to relationship to key outputs l Pareto of key inputs to evaluate in the FMEA and control plans l Input into the initial evaluation of the Process Control Plan Cause and Effects Matrix
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5-6 Collect & Interpret Data l Identify key customer requirements (outputs) from process map or other sources l Rank order and assign priority factor to each Output (usually on a 1 to 10 scale) l Identify all process steps and materials (inputs) from the Process Map l Evaluate correlation of each input to each output low score low score : changes in the input variable (amount, quality, etc.) have small effect on output variable high score high score : changes in the input variable can greatly affect the output variable l Cross multiply correlation values with priority factors and sum for each input Cause & Effect Matrix Steps
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5-7 Collect & Interpret Data Examples Note: Only a partial list
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5-8 Collect & Interpret Data Bottle Production Example Note: Only a partial Map
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5-9 Collect & Interpret Data Excel Template C&E Matrix.XLS 1. List Key Outputs Cause & Effect Matrix Form
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5-10 Collect & Interpret Data 1. List Key Outputs The Outputs are defined in Step 1 of Process Mapping Bottle Production Example
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5-11 Collect & Interpret Data 2. Rank Outputs as to Customer importance Cause & Effect Matrix Form
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5-12 Collect & Interpret Data 2. Rank Outputs as to Customer importance Bottle Production Example
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5-13 Collect & Interpret Data 3. List Key Inputs by Process Step Cause & Effect Matrix Form Note: Information obtained from process map
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5-14 Collect & Interpret Data This step uses the Process Map inputs directly. Notice the Process Inputs follow the Process map step-by-step. 3. List Key Inputs by Process Step Bottle Production Example Note: Only a partial list of inputs
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5-15 Collect & Interpret Data 4. Relate Inputs to Outputs Cause & Effect Matrix Form
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5-16 Collect & Interpret Data l You are ready to relate the customer requirements to the process input variables l Correlational scores l Correlational scores : No more than 4 levels 0, 1, 3 and 9 l Assignment of the scoring takes the most time l To avoid this, spell out the criteria for each score: 0 0 = No correlation 1 1 = The process input only remotely affects the customer requirement 3 3 = The process input has a moderate effect on the customer requirement 9 9 = The process input has a direct and strong effect on the customer requirement Relating Inputs to Customer Requirements
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5-17 Collect & Interpret Data 4. Relate Inputs to Outputs This is a subjective estimate of how influential the key inputs are on the key outputs Bottle Production Example Note: Only a partial list of inputs
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5-18 Collect & Interpret Data Sum of (Rating x Correlation Score) values for all Requirements 5. Cross- multiply and prioritize Cause & Effect Matrix Form
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5-19 Collect & Interpret Data 5. Cross- multiply and prioritize We now start getting a feel for which variables are most important to explaining variation in the outputs Bottle Production Example Note: Only a partial list of inputs
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5-20 Collect & Interpret Data We have sorted on the cross- multiplied numbers and find that the input variables in the box above are the most important We can now evaluate the control plans for these input variables Bottle Production Example Note: Only a partial list of inputs
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5-21 Collect & Interpret Data Minitab: Creating Pareto Plots Stat > Quality Tools > Pareto Chart Choose Chart defects table Enter the information as shown below Open the Minitab Worksheet C and E in the Minitab Datasets folder. Follow the commands on pages 5-21 and 5-22 to create a Pareto Chart.
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5-22 Collect & Interpret Data Minitab: Creating Pareto Plots Choose Options Select Do not chart cumulative percent Hit OK twice
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5-23 Collect & Interpret Data l Place the outputs across the top of the matrix and rank Place inputs down the side of the matrix starting with the first process step and moving to the last This approach is okay for small process with relatively few steps l Should only be used for processes with a relatively small number of steps and inputs General Approach
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5-24 Collect & Interpret Data l Phase I Place the outputs across the top of the matrix and rank Place the process steps down the side of the matrix Correlate process step to outputs Pareto the process steps l Phase II Start a new C&E Matrix with the inputs from the top three or four process steps Recommended when first starting a project oFocuses the efforts and gives the team a feeling that they’re working on the important process steps first oGives you a running start at the FMEA and preliminary Control Plan Analysis Focused Approach
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5-25 Collect & Interpret Data l Standard Operating Procedures Do they exist? Are they understood? Are they being followed? Are they current? Is operator certification performed? Is there a process audit schedule? Control Plan Evaluation
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5-26 Collect & Interpret Data l Controllable Input Variables l Controllable Input Variables: How are they monitored? How often are they verified? Are optimum target values and specifications known? How much variation is there around the target value? How consistent are they? l Other Questions l Other Questions: How often is the input variable out of control? Which input variables should have control charts? Control Plan Evaluation
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5-27 Collect & Interpret Data Exercises 1.)Your Catapult Team should complete page 8 of the blue “Catapult Process” handout. 2)Copy/Paste your results into PowerPoint 3)Be ready to present your results Limit yourselves to 30 minutes for this exercise.
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